Presentation type:

Session 1 – Innovative geophysical sensing methods in hydrological and critical zone research

GC8-Hydro-7 | Orals | Session 1

TEMBO Africa: New sensors and geo-services for water management and agriculture  

Nick van de Giesen, Hessel Winsemius, Frank Annor, Tomáš Fico, Eugenio Realini, Remko Uilenhoet, and Salvador Peña-Haro

TEMBO Africa is a project funded by the European Commission that seeks to fill some of the many geo-data gaps in Africa. Specifically, TEMBO Africa will produce operational data products for rainfall, river flow, soil moisture, bathymetry, and open water. With these products, new services will be developed for reservoir management, germination insurance, and flood early warnings. The products will be the result of the combination of innovative in situ sensors, satellite observations, and environmental models. There will be at least seven innovative in situ sensing methods involved, namely X-band rainfall radars, neutron counting for soil moisture based on natural boron, commercial microwave links, camera-based velocimetry, bathymetry with fish finders, raindrop intervalometers, and GNSS level sensors. TEMBO Africa is transformative in that it aims to reduce the total costs of ownership of the geo-services to less than 10% of present costs. We do not only look at the capital costs of the sensors but also at reduction of maintenance cost and the availability and development of human resources. For this reason, co-development is essential to ensure that context specific challenges are addressed. In this presentation, we highlight the general design approach and early results.

The work leading to these results has received funding from the European Horizon Europe Programme (2021-2027) under grant agreement n° 101086209. The opinions expressed in the document are of the authors only and no way reflect the European Commission’s opinions. The European Union is not liable for any use that may be made of the information.

    TEMBO Africa 


How to cite: van de Giesen, N., Winsemius, H., Annor, F., Fico, T., Realini, E., Uilenhoet, R., and Peña-Haro, S.: TEMBO Africa: New sensors and geo-services for water management and agriculture , A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-7,, 2023.

There is a large discrepancy between the spatial extent of a catchment and the volume or area covered by a single sensor, particularly for sensors operating below the soil surface. Especially in the unsaturated zone, spatial heterogeneity combined with the very small soil volume represented by a data point (often 1 cubic decimeter or less), this contrast necessitates vast sensor networks that are costly to maintain and generate large quantities of data that require extensive processing to provide information useful at scales relevant for land and water management.

Over the past years, we developed a technology to measure the concentration of selected gases in soils by burying gas-permeable, flexible tubes of up to tens of meters of length in the soil at desired depths and flushing them with a gas of known composition (e.g., dry air). Pressure changes observed during short intervals during which the gas flow is stopped can be used to derive the difference in partial pressures of a target gas inside the tube and in the soil surrounding the tube. After processing, this gives the average concentration of the target gas in the soil surrounding the entire length of the tube. The technology is operational for CO2, and will be employed in a forest ecosystem to measure soil respiration in real time.

By specific choices of the tube material, the composition of the flushing gas, and the reference system, the measurement system can be adapted to other gases. If the target gas is water vapor, the relative humidity (RH) of soil air can be measured. According to first laboratory results this results in a measure of the area-averaged soil water content assuming local phase equilibrium between water vapor and liquid soil water. In very dry soil, e.g., in arid and hyper-arid regions, the RH of the soil air drops measurably. In this case the averaged matric potential of the soil water can be monitored in situ in a range far beyond that of water-filled tensiometers.

The presentation will explain the set-up of the system, showcase completed trials and elaborate on on-going plans for CO2-concentration measurements in a forest soil. 

How to cite: Lazik, D., de Rooij, G., and Hashar, M.: An innovative membrane-based sensor technology for large-scale measurements of gas concentrations in the subsurface, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-31,, 2023.

GC8-Hydro-33 | Orals | Session 1

Monitoring wet stream dynamics in ephemeral streams: stage-cam system experimental evidence 

Simone Noto, Andrea Petroselli, Flavia Tauro, Ciro Apollonio, and Salvatore Grimaldi

Scientific interest in ephemeral streams increased in the last decades, but monitoring their dynamics remains a major challenge in hydrology. Motivated by the last advancements in computer vision techniques, we propose an optical-based and non-invasive low-cost approach to provide a continuous estimation of the water level fluctuations. The system comprises a consumer grade wildlife camera with near infrared (NIR) night vision capabilities and a target pole set in the thalweg. The water level estimated through a simple white pole is compared to estimations obtained through different types of targets, such as broader coloured bars, with the aim to identify the optimal stage-cam setup. The feasibility of the approach is demonstrated through a set of benchmark experiments performed in natural settings with different illumination conditions and during rainfall events. Our findings show that broader bars enhance the visibility of the target but also increase the reflection effect of the water. Therefore, using the stage-cam configuration comprising the narrow target and optimizing the parameters involved in the image analysis procedure may be sufficient to monitor water level dynamics.

How to cite: Noto, S., Petroselli, A., Tauro, F., Apollonio, C., and Grimaldi, S.: Monitoring wet stream dynamics in ephemeral streams: stage-cam system experimental evidence, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-33,, 2023.

To understand and predict soil moisture dynamics it is essential to take the role of the vegetation into account. For example, hydrological processes in agricultural soils are strongly affected by seasonal vegetation dynamics in terms of rooting depth and root distribution. Here we present a new approach to monitor and model root dynamics and its influence on soil moisture in the critical zone using mini-rhizotrons combined with phenological observations.

The setup in the field observatory consists of a portable root scanner connected to a tablet computer and a number of acrylic glass tubes with a diameter of two inches that are inserted into the soil at the start of the growing season of selected crops. 360-degrees-scans of soil and roots are taken regularly at different depths in the tubes. Root parameters such as length, diameter, surface and density are identified automatically from the data for each soil layer. Complementary observations of aboveground plant phenology, obtained either by visual inspection in-situ or by remote sensing techniques, are related to the root parameters.

Results from mini-rhizotron data collected at two observatories in Germany show that vertical root distribution and maximum rooting depth in agricultural soils, which varies with plant species and phenology, weather patterns, soil type and management, irrigation etc., are crucial parameters to explain the observed temporal variability and vertical gradients in soil moisture satisfactorily. Deriving these parameters from above-ground phenology and incorporating them into a soil water model led to a significant improvement when compared to a model version based on reference rooting depths from the literature. Thus, we argue that mini-rhizotrons constitute a useful supplement to hydrological observatories and can help understand and predict soil moisture dynamics in the critical zone.

How to cite: Herbst, M., Böske, L., and Falge, E.: Observing spatio-temporal variations in rooting depth and density as a control factor for soil moisture dynamics, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-46,, 2023.

GC8-Hydro-56 | Orals | Session 1

Improved extraction of hydrologic information from geophysical data during an artificial hillslope infiltration

Benjamin Mary, Konstantinos Kaffas, Matteo Censini, Francesca Sofia Manca di Villahermosa, Andrea Dani, Matteo Verdone, Federico Preti, Paolo Trucchi, Daniele Penna, and Giorgio Cassiani

GC8-Hydro-91 | Orals | Session 1

First multi-year cosmic-ray neutron sensing cluster: insights from three years of soil water storage observations across depths and scales at an agricultural research site  in North-East Germany 

Lena Scheiffele, Katya Dimitrova-Petrova, Maik Heistermann, Till Francke, Daniel Altdorff, and Sascha Oswald

Cosmic ray neutron sensing (CRNS) allows for the estimation of root-zone soil water storage at the hectare scale. Therefore, CRNS can be valuable assets of long-term hydrological observatories aimed at unravelling key hydrological processes beyond the point scale. One such observatory is the cluster established within the Cosmic Sense project, situated within the ATB research site in Marquardt, NE Germany, and probably the best-equipped CRNS field laboratory so far. Here we present an overview of datasets which uniquely combined three years of observations (2019-2022) from a dense CRNS cluster with a wealth and variety of supplementary measurements. The long-term operating CRNS cluster (8 permanently installed sensors) was complemented with (i) short-term measurements of additional stationary CRNS, expanding the cluster footprint, (ii) rover CRNS campaigns as well as (iii) a dedicated irrigation experiment which was monitored by a cross-scale combination of sensors, including UAV and CRNS roving. Alongside the CRNS, insights on soil water storage states and fluxes were gained by long-term measurements of profile soil moisture (at 27 locations, up to 105 cm depth), soil water tension (up to 200 cm depth), groundwater and surface water levels (3 locations along the hillslope) and GNSS-R (Global Navigation Satellite Systems reflectometry). Snapshot information of near-surface water storage dynamics were obtained by UAV-based remote sensing. Furthermore, Electrical Resistivity Tomography profiles along the hillslope supplied a 3D view of water storage distribution in depth. Ground truthing campaigns, ancillary measurements of biomass and soil properties helped  capture the spatial distribution of these properties  and made the interpretation of the soil water content data more robust. Overall, the Marquardt cluster is unique in its combination of a dense CRNS cluster along with the long ongoing operational period of more than three years and the wealth of additional hydrometerological data. Additionally, the 3-year data-set captures a wide range of wetness conditions, from prolonged dry spells to heavy rainfall events and snow episodes. Therefore, such a comprehensive dataset, combining innovative techniques with traditional hydrometeorological measurements gives the opportunity to investigate a range of research questions. Those could be related, but not limited to, the study of dominant flow paths and hydrological connectivity during heavy rainfall; the suitability of sensor combinations to best study water storage dynamics in a heterogeneous landscape and the retrieval of spatial soil water storage patterns using a CRNS cluster and ancillary data.

Cosmic Sense Official University of Potsdam Webpage

How to cite: Scheiffele, L., Dimitrova-Petrova, K., Heistermann, M., Francke, T., Altdorff, D., and Oswald, S.: First multi-year cosmic-ray neutron sensing cluster: insights from three years of soil water storage observations across depths and scales at an agricultural research site  in North-East Germany, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-91,, 2023.

GC8-Hydro-73 | Orals | Session 1

A novel combined approach for bridging scales in spatiotemporal soil moisture monitoring applying metrological principles 

Sascha E. Oswald, Sebastian Rothermel, Gabriele Baroni, Anna Balenzano, Henrik Kjeldsen, Martin Schrön, and Miroslav Zboril

One of the key environmental variables and essential climate variable is soil moisture, with its high relevance for applications such as agriculture, forestry, water management including hydrometeorological extreme events or hydrological modelling. Yet accurate measurement of soil moisture is limited by its high natural spatiotemporal variability, given spatially (vertically and horizontally) variable hydraulic properties of soil, and events that are highly variable themselves (in time, extension and intensity).

One geophysical method to close the gap between point-scale measurements and satellite-based remote sensing is Cosmic Ray Neutron Sensing (CRNS). Its integration area of about 0.1 km² is above the coverage of wireless sensor networks and at least when combined to CRNS clusters can cover several pixels of high resolution satellite remote sensing, e.g. by the ESA Sentinel-1 Earth Observation mission. We combine these three methods to bridge the scales in monitoring of soil moisture, and this within a novel metrological framework on validation and standardization.

The basis for that is an EU-wide collaboration project of 18 institutions called SoMMet[1]. Its approach is to thoroughly establish CRNS as a bridging method at intermediate scale by linking it to point-scale soil moisture sensors with certification according to newly established metrological standards while testing a range of CRNS detector designs in facilities for neutron metrology. The aim is to achieve an improved comparability and reliable estimates of uncertainty and provide recommendations on network design and validation practices, which shall result in a more widespread transfer into remote sensing applications and hydrological modelling.

A central component is to conduct field comparison and testing campaigns covering the different scales at three high-level field sites across Europe. One of the candidate sites is located close to Potsdam, Northern Germany. Having evolved from temporary soil moisture field campaigns it hosts the sole long-term CRNS cluster (currently 15 CRNS probes) that covers a conjoined area. This is somewhat similar to wireless in-situ sensor networks, but working non-invasively, with partially overlapping footprints and last not least on larger scale, here about 0.6 km² altogether. We will present examples of SoMMet field test sites, and especially first results of this CRNS cluster from 2023 in its recently extended coverage set-up that now brings it further up to satellite remote sensing resolution.

[1] Acknowledgment: The project 21GRD08 SoMMet has received funding from the European Partnership on Metrology, co-financed from the European Union’s Horizon Europe Research and Innovation Programme and by the Participating States.

How to cite: Oswald, S. E., Rothermel, S., Baroni, G., Balenzano, A., Kjeldsen, H., Schrön, M., and Zboril, M.: A novel combined approach for bridging scales in spatiotemporal soil moisture monitoring applying metrological principles, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-73,, 2023.

GC8-Hydro-90 | Orals | Session 1

CRNS-based monitoring technologies as solutions for climate-resilient agriculture 

Markus Köhli, Patrick Stowell, Jannis Weimar, Patrizia Ney, Felix Nieberding, Ulrich Schmidt, Heye Bogena, and Klaus Görgen

Accurate soil moisture (SM) measurements are key in hydrological observations and subsequent applications as it can greatly improve our understanding of soil processes. Recently, Cosmic-Ray Neutron Sensors (CRNS) have been recognized as a promising tool in SM monitoring due to its large footprint of several hectares and half a meter in depth. The key characteristic feature of the method is the exceptionally high moderation strength of hydrogen, which makes it nearly independent of the soil chemistry. CRNS has a great potential for irrigation and monitoring applications as to the non-invasive nature of the method and the low-maintenance, independently operating sensors. From the initial focus on hydrological research. CRNS are increasingly used in agriculture, e.g. irrigation management and soil moisture mapping, and have been integrated LoRa or NB-IoT networks for fast data transmission. Two projects are discussed which advance CRNS technologies into monitoring networks.

COSMIC-SWAMP aims to provide an open-source water monitoring platform that integrates cosmic ray sensing data with FiWare Smart Application compliant analysis routines. Extending the existing Smart Water Management Platform (, COSMIC-SWAMP supports dynamic processing of multiple co-located cosmic ray sensor streams to support automated and continuous growth forecasting using Wageningen/WOFOST crop models.

ADAPTER involves the development and provision of innovative simulation-based information products. Addressing weather- and climate-resilient agriculture, daily and comprehensive long-term weather and soil information are made available to the agricultural community and all interested parties as easy-to-use analyses, data products, and information interfaces ( The hydrological model ParFlow coupled to its Common Land Model (CLM) module provides a nationwide water balance prediction with 600 m spatial resolution. The data assimilation within the product platform is supported by an independent network of CRNS stations (12 agricultural locations in North Rhine-Westphalia).

This contribution provides an overview about the current state of the art in CRNS methodological integration, neutron detection technology and development of IoT interfaces with measurements and forecasts focusing on the water balance, including groundwater.

How to cite: Köhli, M., Stowell, P., Weimar, J., Ney, P., Nieberding, F., Schmidt, U., Bogena, H., and Görgen, K.: CRNS-based monitoring technologies as solutions for climate-resilient agriculture, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-90,, 2023.

The OZCAR (Critical Zone Observatories network) Research Infrastructure (RI) brings together several observatories documenting the critical zone, the thin pellicle on the Earth's surface between the non-weathered rocks and the lower atmosphere, which is the living environment of living beings. These long-term observatories were historically created in France to answer specific scientific questions such as the impact of rainfall acidification on forests, the genesis of extreme floods or the understanding of nitrate pollution. They monitor different compartments of the critical zone (atmosphere, soil, surface water, groundwater, cryosphere, wetlands, biosphere, etc.) through the measurement of a large number of meteorological, hydrological, hydrogeological, geochemical, surface fluxes and vegetation dynamics variables.

The aims of OZCAR RI are:

  • i) To foster data sharing with the scientific community through the development of a common data portal;
  • ii) To promote the use of the collected data in models;
  • ii) To allow the development and deployment of new measurement techniques, taking advantages of large projects funded by the French government such as the CRITEX project (Innovative equipment for the critical zone, 2011-2022) and the TERRA FORMA project (Designing and testing a smart observatory of socioecological systems in the Anthropocene, 2021-2029), that aim at deploying innovative measurements to document the critical zone and design new observatories in the Anthropocene;
  • iv) To favor interdisciplinary researches through dedicated calls.

The observatories, and their counterparts at the European scale gathered in eLTER RI, are highly instrumented sites where new measurement techniques can be tested and deployed, where hydrological functioning hypotheses can be assessed through the exploitation of data and models. These observatories are also good places to addressing some of the 23 unsolved problems in hydrology. The presentation will illustrate the value of a network of critical zone and hydrological observatories through examples of researches conducted in the OZCAR RI network.

How to cite: Braud, I. and Gaillardet, J.: The OZCAR Critical Zone Observatory Network: an opportunity to enhance hydrological research through sites, data and model sharing, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-26,, 2023.

GC8-Hydro-28 | Poster | Session 1

Measuring Soil Properties and Processes with Thermo-Time Domain Reflectometry Sensors 

Robert Horton, Tusheng Ren, Joshua Heitman, Yili Lu, and Yongwei Fu

Recent advancements in fine-scale thermo-TDR measurements of soil thermal and electrical properties provide opportunities to measure state variables in soil (temperature, water content, ice content, and air-filled porosity), soil properties (bulk density, thermal diffusivity, volumetric heat capacity, thermal conductivity, and bulk electrical conductivity) and energy and mass fluxes in soil (sensible heat, latent heat for evaporation or freezing, infiltrating liquid water, and upward moving liquid water).  It is also possible to estimate soil hydraulic properties from thermo-TDR thermal property and electrical property measurements. This presentation will include laboratory and field investigations that demonstrate the usefulness of thermo-TDR measurements to characterize heat and mass transfer properties and fluxes in soil.

How to cite: Horton, R., Ren, T., Heitman, J., Lu, Y., and Fu, Y.: Measuring Soil Properties and Processes with Thermo-Time Domain Reflectometry Sensors, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-28,, 2023.

GC8-Hydro-36 | Poster | Session 1

Upgrading standard weather station with cosmic ray neutron sensors in Italy: challenges, results, and opportunities. 

Gabriele Baroni, Stefano Gianessi, Riccardo Mazzoleni, Cinzia Alessandrini, Claudio Gandolfi, Orietta Cazzuli, Francesca Ragazzi, Stefano Ferraris, Davide Canone, Christian Ronchi, Roberto Cremonini, and Secondo Barbero

Over the last decades, several new observation systems have been developed, tested, and implemented in dedicated experimental sites by research groups in many countries all around the World. The data collected at these high-level test sites have boosted research and collaborations providing the basis for new hypothesis testing, better process understanding and model improvements. In contrast, national and more operational ground monitoring networks are still largely based on traditional instruments. Moreover, the different networks and the data are not always well integrated, even at the regional level. For these reasons, the capability to monitor the main components of the hydrological cycle over large areas is still limited and the observation systems to support the management of the water resources and for environmental protections can be improved. By using soil moisture and snow water equivalent monitoring as examples, in this contribution we present and discuss challenges, results and opportunities in upgrading national weather stations and improving the service provided by the public environmental agencies. Specifically, the difficulties of implementing ground monitoring networks are first discussed. The opportunities provided by the development of new non invasive sensors based on cosmic-ray neutrons detection are then presented. The activities and the results conducted during the last years to move this technology further from research to operation are shown. The current uptake from a number of Italian environmental agencies is reported. The key components and current challenges for a successful implementation are finally discussed.

How to cite: Baroni, G., Gianessi, S., Mazzoleni, R., Alessandrini, C., Gandolfi, C., Cazzuli, O., Ragazzi, F., Ferraris, S., Canone, D., Ronchi, C., Cremonini, R., and Barbero, S.: Upgrading standard weather station with cosmic ray neutron sensors in Italy: challenges, results, and opportunities., A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-36,, 2023.

GC8-Hydro-47 | Poster | Session 1

When does near-surface flow occur in a pre-Alpine headwater catchment? 

Victor Gauthier, Anna Leuteritz, and Ilja van Meerveld

Overland and subsurface flow are major runoff processes but remain poorly understood for pre-Alpine catchments with low permeability soils. The connectivity of these near-surface flow pathways leads to quick changes in streamflow during events. However, their occurrence is highly variable in both space and time, and depends on the geomorphological setting and event characteristics. Therefore, the aim of the TopFlow project is to investigate the generation and connectivity of overland flow and shallow subsurface flow in a Swiss pre-Alpine catchment.

We installed runoff plots at 14 locations inside a 20-ha catchment to measure overland flow and shallow (up to ~40 cm) subsurface flow during two summers: 2021 and 2022. In addition, we used homemade electrical resistance sensors to detect near-surface flow and saturation and we measured groundwater levels and soil moisture. The plots are located at different topographic locations and under different vegetation. In this presentation, we will present our first results on the occurrence of the overland flow and shallow subsurface flow and relate them to the topographic position and rainfall- and antecedent wetness conditions.

How to cite: Gauthier, V., Leuteritz, A., and van Meerveld, I.: When does near-surface flow occur in a pre-Alpine headwater catchment?, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-47,, 2023.

GC8-Hydro-51 | Poster | Session 1

Potential and limitations of cosmic-ray neutron sensors for irrigation management in small fields 

Cosimo Brogi, Heye Reemt Bogena, Vassilios Pisinaras, Markus Köhli, Olga Dombrowski, Harrie-Jan Hendricks Franssen, Andreas Panagopoulos, Johan Alexander Huisman, Konstantinos Babakos, and Anna Chatzi

Given the expected increase of droughts related to climate change, soil moisture (SM) monitoring will likely become essential for farmers as it helps to reduce water consumption while mitigating crop losses. Cosmic-Ray Neutron Sensing (CRNS) is a promising SM monitoring method that is based on the negative correlation between fast neutrons originating from cosmic radiation and SM content. As CRNS integrates SM over a large radius of ~130-210 m with a penetration depth of ~15-85 cm, it has advantages over point-scale and remote-sensing methods. However, it is yet unclear how well CRNS can monitor areas with complex SM heterogeneity, such as small irrigated fields. In this study, two CRNS equipped with a novel gadolinium oxide thermal shielding were installed in two small (~1.2 ha) irrigated apple orchards located in the Pinios Hydrologic Observatory (Greece). Each CRNS was supported by an Atmos41 all-in-one climate station, by water meters measuring irrigation timing and amounts, and by a network of 12 wireless SM measurement nodes (SoilNet) that monitored SM at 5, 20 and 50 cm depth. The results showed that the CRNS was sensitive to the weekly irrigation events, but that it showed a general underestimation of the magnitude of SM fluctuations caused by the irrigation, which resulted in a RMSE of 0.058 cm3 cm-3. To better understand these results, we used the URANOS model to simulate neutron transport for a CRNS placed in the centre of a square irrigated field of varying dimensions (0.5 to 8 ha). The simulation results showed that CRNS can be used to monitor irrigation in fields as small as 0.5 ha in certain SM conditions and that a gadolinium-based thermal shielding provides the best monitoring results due to the much-reduced detection of thermal neutrons. Nonetheless, a considerable number of detected neutrons (above 60%) can originate outside the target field if the irrigated field is small, and in such cases a CRNS may not be able to clearly distinguish irrigation from SM variations in the surroundings. In an attempt to correct for such SM variations not related to irrigation, an additional SoilNet node was installed outside one of the two irrigated apple orchards in September 2021. By combining the results of neutron transport simulations with the information provided by this additional SoilNet node, a correction of CRNS-derived SM was developed that better captures both timing and magnitude of SM changes (RMSE reduced to 0.031 cm3 cm-3). These results show that the combination of real-world studies with neutron transport simulations can help to establish CRNS as a reliable tool in irrigation management.

How to cite: Brogi, C., Bogena, H. R., Pisinaras, V., Köhli, M., Dombrowski, O., Hendricks Franssen, H.-J., Panagopoulos, A., Huisman, J. A., Babakos, K., and Chatzi, A.: Potential and limitations of cosmic-ray neutron sensors for irrigation management in small fields, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-51,, 2023.

Upscaling of soil water content (SWC) information towards the large-scale (>10 km) is highly desired to address the increasing demand on SWC products at various sectors. Random forest (RF) regression has been suggested as suitable method to generate large SWC maps from a limited amount of observations. RF deals with multiple prediction variables (predictors) to derive the missing values of a desired variable (e.g. SWC) based on their internal relationship. Cosmic ray neutron sensing (CRNS) is an alternative method for passive SWC mapping and monitoring, either by stationary CRNS sensors or by mobile CRNS roving. CRNS has a certain advantage over most classical hydrogeophysical approaches because of its footprint at the hectares-scale and beyond, particularly true for roving data, which qualifies CRNS data as suitable input for RF regressions. However, commonly CRNS roving data contain a high amount of noise and outlier values, related to the statistical distribution of neutron counting, which hinders the signal interpretation and could lower the quality of the RF regression performance. There are so far two ways to overcome the noise problem and to achieve a higher data stability; i) increasing of the aggregation time, which decreases the signal uncertainty but also reduces the spatial resolution and ii) applying smoothing algorithms, e.g. interpolation or moving averages, which results in more stable values, but it does not solve the outlier problem.

We used SWC data from CRNS roving along the Selketal catchment at the Harz mountain, Germany, to test the performance of a score criteria for an adaptive removal of potential outliers. The score criteria are internal test parameters, providing an indication about the probability of values that might be an outlier or not. Therefore, each observation was subject to a group of queries, asking its conformity to the surrounding values by selected statistical parameters. Based on the total score of the queries, the potentially unreliable observations were removed using various thresholds and used as input for the RF regression. RF regression was performed using static (e.g. topographical indices, soil properties) and dynamic (precipitation) predictors generating SWC maps from an area of ~2700 km². SWC input data were split into training (~2/3) and validation sets (~1/3).

Preliminary results showed that the application of the score criteria resulted in more stable spatial pattern and improved the R² from 0.099 to 0.196, 0.266 and 0.308 for score 6, 4 and 3, respectably. Achieved root mean squared error also decreased with stronger filtering, ranging from 0.14 for the original datasets to 0.078 for score 3. However, by using the score 3 threshold, 22.4% of the data were omitted. Hence, an optimization between the amount of excluded data and the resulting improvement of prediction needs to be developed and tested. The implementation of the spatial relationship in-between the observations and a weighting of the score values according to their importance should further increase the performance. Due to its easy application and its adjustable criteria selection, the proposed filtering approach has the potential to become more popular in CRNS roving studies.

How to cite: Altdorff, D., Dega, S., Paasche, H., and Schrön, M.: Improvement of soil moisture regionalization based on random forest regression by applying score criteria for mobile cosmic-ray neutron sensing data, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-67,, 2023.

GC8-Hydro-85 | Poster | Session 1

A Vision for Transformative Hydrological Monitoring – Planning for the UK Floods and Droughts Research Infrastructure (FDRI) 

Jonathan Evans, John Bloomfield, Gemma Coxon, Simon Teagle, Wouter Buytaert, Matt Fry, Lucy Ball, Ali Rudd, James Sorensen, Nick Chappell, Thorsten Wagener, and Gareth Old

Here we present the UK vision for new world-leading hydrological observation networks and sensor innovation test beds that will provide the long-term datasets needed to enable the mitigation of the impacts of hydrological extremes. Plans are underway for a Floods and Droughts Research Infrastructure (FDRI). This represents a major capital investment expected to be funded by the UK Research and Innovation Infrastructure Fund and delivered through the Natural Environment Research Council (NERC) at an estimated cost of £38m. FDRI is urgently needed to make the UK more adaptable and resilient to floods and droughts. It will include major new hydrological catchment instrumentation, with innovative technology to provide observations of key components of the terrestrial water cycle, and in-field facilities for trialling and developing new sensing technologies. Extensive community consultation and reviews have identified key science questions that are being used to inform infrastructure design. Successful impact will be enabled through strong investment in digital infrastructure to achieve a hydrological data commons. Integrated near real-time datasets will be publicly accessible, consolidated and inter-operable, ready for application specific analysis and modelling. As FDRI planning develops, there are opportunities to design-in the latest thinking on catchment monitoring strategies with innovative sensing, and to ensure that long-term hydrological datasets will be able to answer a wide variety of future research questions.

How to cite: Evans, J., Bloomfield, J., Coxon, G., Teagle, S., Buytaert, W., Fry, M., Ball, L., Rudd, A., Sorensen, J., Chappell, N., Wagener, T., and Old, G.: A Vision for Transformative Hydrological Monitoring – Planning for the UK Floods and Droughts Research Infrastructure (FDRI), A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-85,, 2023.

GC8-Hydro-89 | Poster | Session 1

Temperature-corrected calibration of GS3 dielectric sensors 

Paolo Nasta, Heye Bogena, Alexander Huisman, Benedetto Sica, Carolina Allocca, Ugo Lazzaro, Caterina Mazzitelli, Harry Vereecken, and Nunzio Romano

In the Upper Alento River Catchment (UARC; southern Italy), two test sites, having different physiographic and soil features, were instrumented with SoilNet wireless sensor networks controlling GS3 (METER Group, Inc. USA) capacitance sensors deployed at soil depths of 15 and 30 cm at twenty locations to monitor soil permittivity, soil temperature, and apparent electrical conductivity. The conversion of soil permittivity into soil water content is challenging given the high clay content of the soil. Therefore, the both factory and Topp’s calibration functions are compromising soil water content dynamics with underestimated dynamics during dry periods and overestimations in the wet season. In addition, the soil moisture measurements is influenced by the very strong soil temperature variations. In this study we combined a laboratory calibration with in-situ intensive validation campaigns. The laboratory calibration of GS3 electromagnetic sensors was carried out on repacked soil samples by simultaneously measuring soil permittivity and soil water content at prescribed temperature steps within the range observed in the field (from 4.5 °C and 31.9 °C). A new empirical regression-based calibration law was developed for the two study areas to relax the impact of soil temperature on the measurement of soil permittivity. The temperature-corrected approach was validated in the field by taking thermo-gravimetric measurements of soil water content using a stainless steel soil core sampler over five field campaigns at soil depths of 15 and 30 cm. Our results demonstrated that the proposed site-specific calibrations properly reflect the seasonal dynamics of observed soil water content and outperform both factory and Topp’s calibration functions.

How to cite: Nasta, P., Bogena, H., Huisman, A., Sica, B., Allocca, C., Lazzaro, U., Mazzitelli, C., Vereecken, H., and Romano, N.: Temperature-corrected calibration of GS3 dielectric sensors, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-89,, 2023.

Dielectric sensors have been used for decades to monitor soil water content. While such measurements are straightforward for insulations, they may be challenging for electrically conductive materials. As a result, the performance of soil moisture sensors based on capacitance technology rapidly decreases with soil salinity. In alternative, dielectric permittivity and electrical conductivity may be estimated at once and very accurately by measuring the complex impedance of the sample. We present a new method for measuring the complex impedance, which can be implemented with very inexpensive circuitry. The resulting dielectric measurements are shown to be accurate for conductivity up to 20 dS/m. We will present preliminary results in soilless material and discuss the benefits of accurate dielectric measurements in greenhouse applications. 

How to cite: Castiglione, P. and Campbell, G.: Complex dielectric measurements permit accurate estimate of soil water content in saline environments., A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-99,, 2023.

GC8-Hydro-105 | Poster | Session 1

Improving the prediction of extreme events with new-generation CRNS probes 

Enrico Gazzola, Luca Stevanato, Luca Morselli, and Paul Arnaud

It is of the utmost importance to know the water content in a soil, or soil moisture, for its role in triggering destructive events. In recent years, soil moisture has been recognized as a key information to improve wildfire predictions, proving more reliable than predictions based on weather data. Accumulation of water in slopes can reduce cohesion and friction thus triggering landslides and mudslides, while indeed the water quantity in the form of snow (SWE – Snow Water Equivalent) is responsible for avalanches.

Cosmic Ray Neutron Sensing (CRNS) technology provides unique capabilities to determine water content in soil, snow, and biomass by filling the gap left by current methods in term of scale and depth. A single, autonomous probe placed over the ground, requiring little maintenance, is able to provide real-time data on a large scale (hectares), in deep (tens of cm in soil, meters in snow).

The new generation of CRNS probes allows the contextual detection of muons, which provides detailed information about variations of the local flux of incoming cosmic rays. Previous probes rely on a public network of reference stations to monitor flux variations, with the closest station possibly being hundreds of km away from the site and the data availability being reliant on an external entity. On situ monitoring of the incoming flux is therefore a key improvement of the method reliability.

In 2022 ANAS, the Italian company responsible for road infrastructures, funded a Proof-of-concept project called MY-LAND, with the aim of verifying on field the capability of CRNS probes to support risk assessment. In the framework of this project, FINAPP installed two CRNS probes for large-scale soil moisture measurement along the Longarone - Belluno Smart Road, obtaining data that were used together with hydrological models of the area to assess the risk of landslides or flash floods. The first probe was installed in Acquabona (Cortina d’Ampezzo), where a high risk of debris flows is expected, and the second in Perarolo di Cadore, where a landslide is considered a threat to the town.

Two significant landslide events were observed in the sites during the experiment. Results show how CRNS technology, when supported by the knowledge of specific hydrological models of the land and weather forecast, is able to provide a valuable contribution to risk assessments and decisional processes.

How to cite: Gazzola, E., Stevanato, L., Morselli, L., and Arnaud, P.: Improving the prediction of extreme events with new-generation CRNS probes, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-105,, 2023.

GC8-Hydro-108 | Poster | Session 1

On the Key Eco-hydrodyanmic Features of Vegetated Rivers: a Case Study in southern Italy 

Giuseppe Francesco Cesare Lama and Mariano Crimaldi

The proper analysis and prediction of the hydrodynamic interaction between water flow and vegetation covering natural and manmade vegetated rivers are among the main objectives of Ecohydraulics. Riverine and riparian plants have a paramount impact on flow resistance and water quality associated with vegetated water bodies. Also, the presence of vegetation considerably affects the mean and turbulent flow fields with important implications on oxygen production and nutrient transport within vegetated open channels. In this perspective, the use of advanced field and remote sensing techniques to measure the most relevant features of plants constitutes a stimulating open research window. The interplay between riparian vegetation and water flow in vegetated water bodies has a key role in the dynamic evolution of aquatic and terrestrial ecosystems in wetlands and lowlands. The present study analyzes the effects of the spatial distribution of reed (Phragmites australis (Cav.) Trin. ex Steud.) beds, an invasive riparian species extremely widespread in wetland and lowlands worldwide, on the main hydraulic and hydrodynamic properties of an abandoned vegetated reclamation channel located in southern Italy. A field campaign was carried out to obtain Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI) of reed beds through both ground-based and Unmanned Aerial Vehicle (UAV) methodologies, and to correlate them to the channel’s flow dynamic and water quality main features. Hydrodynamic simulations of the vegetated reclamation channel were performed and validated based on the experimental measurements of the hydraulic and vegetational parameters acquired in the field to build up a robust model to be employed also in future Ecohydraulic research. The evidence of this study constitutes useful insights into the quantitative analysis of the correlation between the spatial distribution of riparian vegetation stands in natural and manmade vegetated water bodies and their hydrodynamic and water quality main features. The outcomes of the present work can be seen as stimulating new viewpoints to be taken into account for the proper management of biomass belonging to riparian and riverine vegetation developing within vegetated water streams.


How to cite: Lama, G. F. C. and Crimaldi, M.: On the Key Eco-hydrodyanmic Features of Vegetated Rivers: a Case Study in southern Italy, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-108,, 2023.

GC8-Hydro-120 | Poster | Session 1

Mapping spatiotemporal soil moisture in highly heterogeneous agricultural landscapes using mobile dual-spectra cosmic-ray neutron probes 

Majken Looms, Søren Julsgaard Kragh, Rena Meyer, Karsten Høgh Jensen, and Mie Andreasen

The cosmic-ray neutron (CRN) probe has successfully been used to estimate soil moisture time series at various soil and land cover types across several climatic zones. Previous studies also demonstrate the value of mobile CRN campaigns (i.e. roving) for soil moisture mapping. However, the published study locations have mainly been homogeneous in terms of land cover and soil type. At such conditions, simple on-site calibration using small-scale soil samples can be sufficient. Nonetheless, soil sampling is typically time-consuming, is not always possible and/or is not necessarily representable of the true conditions. Furthermore, measured neutron intensities are dependent on all the hydrogen pools within the footprint, primarily soil moisture, but also litter layer and biomass. Thus, calibration using 100+ soil samples for each point along the survey route is necessary in highly heterogeneous agricultural landscapes. The requirement of such spatiotemporal calibration has hindered a full embracement of the CRN roving method. Neutron sensors with multiple energy sensitivities, here named dual-spectra CRN, can instead be combined to separate the influence of various hydrogen pools.

In this work, we used a dual-spectra CRN rover to collect data along a 34.5 Km NE-SW line in Denmark (approximately 176 line Km) at an average speed of 29 Km/h. The data was collected biweekly from December 2018 to May 2019 resulting in 12 campaigns in total. The dual-spectra averages of each campaign correlate to the SMAP soil moisture product, with a higher correlation for purer signals of thermal and epithermal neutron counts. Furthermore, the epithermal neutron intensity and thermal-to-epithermal ratio maps are dependent on the land cover type enabling the use of a simple and robust methodology to obtain spatiotemporal soil moisture maps using these multiple signals. The estimated spatiotemporal soil moisture values are within expected ranges and are not as the neutron signal dependent on land cover. Instead, the average soil moisture appears to be dependent on the estimated hydraulic conductivity map for the area.

How to cite: Looms, M., Kragh, S. J., Meyer, R., Jensen, K. H., and Andreasen, M.: Mapping spatiotemporal soil moisture in highly heterogeneous agricultural landscapes using mobile dual-spectra cosmic-ray neutron probes, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-120,, 2023.

GC8-Hydro-130 | Poster | Session 1

Improving Soil Moisture Monitoring from Cosmic Ray Neutron Sensors under Various Climate Conditions 

Roland Baatz, Patrick Davies, Heye Bogena, Emmanuel Quansah, and Leonard K. Amekudzi

Soil moisture is a critical hydrological variable affecting rainfall-runoff processes, regulating net ecosystem exchange, and an essential agricultural variable that constrains food production. Soil water deficiency results in water stress to plants, causing a reduction in biomass and yield production. Thus, assessing soil moisture conditions and estimating the effects of drought or water excess are relevant and important information associated with a decline in agricultural yield. This study analyses time series data of the Cosmic Ray Neutron Sensor (CRNS) to estimate soil moisture in three different climatic zones with distinct seasonal dynamics. The CRNS allows non-invasive and continuous monitoring of soil moisture by detecting the neutrons generated by cosmic rays that mainly interact with the hydrogen atoms in soil water. This study demonstrates an improved CRNS signal processing to enhance the temporal accuracy and overall signal-to-noise ratio by observing sub-daily soil moisture changes. In particular, this study investigates the effectiveness of the Moving Average (MA), Median filter (MF), Savitzky-Golay (SG) filter, and Kalman filter (KF) to minimize errors in soil moisture estimates at distinct points in time. We anticipate the improved signal-to-noise ratio to benefit CRNS applications such as the detection of rain events at the sub-daily resolution, provision of SM at the exact time of a satellite overpass, and irrigation applications.

How to cite: Baatz, R., Davies, P., Bogena, H., Quansah, E., and Amekudzi, L. K.: Improving Soil Moisture Monitoring from Cosmic Ray Neutron Sensors under Various Climate Conditions, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-130,, 2023.

Session 2 – Environmental monitoring and modeling with the support of UAS and satellites

Water resources and the ecosystems depending on them are under growing pressure due climate change and human activities. Managers and governments need to take effective mitigation and adaptation measures, but decisions are often based on incomplete information as in situ observations are declining, and impacts on ecosystem functioning are not entirely clear. Earth Observation data can help by improving our understanding on the joint regulation of water and carbon fluxes and the links among terrestrial, aquatic and atmospheric processes across whole watersheds and even precipitation-sheds.  

Currently, there is a wide range of satellite data streams that can be used in synergy to estimate ecohydrological variables, but this requires a redesign of methods. Additionally, remote sensing in the optical domain is mostly used to estimate structural characteristics of vegetation such as biomass, greenness or leaf area index, while estimation of rapidly changing ecophysiological variables, such as stomatal conductance, transpiration or photosynthesis, the distinction between metabolic pathways (C3 or C4) or water use strategies (iso/anisohydric) is still a challenge.  

Drones or UAS can provide information complementary to satellites by acquiring in (quasi) real time environmental variables under clouds. They can bridge the scale mismatch with in situ datasets, augment them, and allow monitoring of small farms or narrow headwater streams among others. An emerging technology are hyperspectral miniaturized sensors on drones but the data quality is affected by lower signal to noise ratios compared to airborne sensors, flying under intermittent clouds and turbulences, and in several cases a lack of thorough radiometric and spectral calibrations.

At the conference, I will present some examples of research that jointly exploit hyper/multispectral and thermal data with proximal, drones, or satellite sensors to estimate ecohydrological variables and evaluate interventions using data-driven or process based models. For example, how biochar affects water use efficiency of rice, understanding better leave thermoregulation under heatwaves or drought or develop indicators of the ecological state of freshwater systems. In addition, some of the current limitations and future perspectives of this technology will be discussed.

How to cite: Garcia, M.: Environmental monitoring and modeling with the support of UAS and satellites, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-59,, 2023.

GC8-Hydro-58 | Orals | Session 2

Estimating evapotranspiration by using canopy conductance models with Sentinel-2 data in irrigated crops in California and Australia 

Oscar Rosario Belfiore, William P. Kustas, Guido D'Urso, Kyle Knipper, Nicolas Bambach-Ortiz, Andrew J. McElrone, Dongryeol Ryu, Sebastian Castro, John H. Prueger, Nishan Bhattarai, Joseph G. Alfieri, Lawrence E. Hipps, Maria M. Alsina, Carlo De Michele, Francesco Vuolo, and Qotada Alali

Deriving evapotranspiration is crucial for determining the water requirements of crops and for efficiently allocating water resources for irrigation. Various experiments and methods have proven that earth observation (EO) is a useful tool for estimating evapotranspiration and supporting irrigation and water resource management at different scales.

This study presents a framework based on the Penman-Monteith big leaf model and Shuttleworth-Wallace sparse canopy model for estimating the evapotranspiration in irrigated crops with partial and full-canopy conditions.

The approach fully utilizes the high-resolution and multi-spectral capabilities of the Sentinel-2 (S2) sensors for the derivation of surface parameters such as hemispherical shortwave albedo(α), Leaf Area Index (LAI), and the water status of the soil-canopy ensemble by using the OPTRAM model. Proposed by Sadeghi [1], the OPTRAM model uses the pixel distribution in the Shortwave Infrared Transformed Reflectance (STR)-NDVI space, where the water content of the soil-canopy system is linearly correlated to the STR index.

In detail, the proposed approach estimates the contributions of soil and canopy to the total evapotranspiration by incorporating the OPRAM model to assess the water status of the surface and adjust the resistance terms in the combination equation [2]

The results are validated by using Eddy Covariance data collected during the GRAPEX (Grape Remote Sensing Atmospheric Profile Evapotranspiration eXperiment) project [3], T-REX (Tree crop Remote sensing of Evapotranspiration eXperiment) project, and COALA (COpernicus Applications and services for Low impact agriculture in Australia) project [4]. These projects are conducted respectively in irrigated vineyards and almond orchards in California, and in irrigated maize and alfalfa in Australia.

[1] Sadeghi, Morteza, Scott B. Jones, and William D. Philpot.: A linear physically-based model for remote sensing of soil moisture using short wave infrared bands. Remote Sensing of Environment 164, 66-76 (2015).

[2] D’Urso, G., Bolognesi, S. F., Kustas, W. P., Knipper, K. R., Anderson, M. C., Alsina, M. M., ... & Belfiore, O. R.: Determining evapotranspiration by using combination equation models with sentinel-2 data and comparison with thermal-based energy balance in a California irrigated Vineyard. Remote Sensing, 13(18), 3720 (2021).

[3] Kustas, W.P., Anderson, M.C., Alfieri, J.G., Knipper, K., Torres-Rua, A., Parry, C.K., Nieto, H., Agam, N., White, W.A., Gao, F. The grape remote sensing atmospheric profile and evapotranspiration experiment. Bulletin of the American Meteorological Society 2018, 99, 1791-1812.

[4] COALA project.

How to cite: Belfiore, O. R., Kustas, W. P., D'Urso, G., Knipper, K., Bambach-Ortiz, N., McElrone, A. J., Ryu, D., Castro, S., Prueger, J. H., Bhattarai, N., Alfieri, J. G., Hipps, L. E., Alsina, M. M., De Michele, C., Vuolo, F., and Alali, Q.: Estimating evapotranspiration by using canopy conductance models with Sentinel-2 data in irrigated crops in California and Australia, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-58,, 2023.

GC8-Hydro-72 | Orals | Session 2

Remote sensing of Land Surface Temperature for precision irrigation modelling: experience for different case studies. 

Marco Mancini, Nicola Paciolla, Chiara Corbari, Carmelo Cammalleri, Giovanni Ravazzani, and Alessandro Ceppi

Agriculture will progressively require more and more attention due to changing climatic conditions and increasing population, consequently threatening food security worldwide. Improving irrigation efficiency and its control on large agricultural areas has become a must for the present and next future.

Satellite data coupled with pixel-wise energy and water balance plays a relevant role in the soil moisture assessment and relative irrigation water needs for different crop and soil types.

In this framework, data from remote sensing is a potential source of information and in particular land surface temperature is nowadays extensively used in agricultural monitoring as input of energy balance models (residuals) that provide evapotranspiration estimates and so irrigation water needs.

Two main issues hinder the quality of the results from these models: (a) sub-pixel heterogeneity, in particular related to mixed crops (e.g. row and tree crops), which can be captured only partially by the available LST spatial resolution and (b) temporal frequency of the information, which for most freely-available products is usually in contrast with spatial resolution (e.g., 1 km data from MODIS is available daily, whereas 90 m data from Landsat only once every 7-8 days).

This work discusses the use of land surface temperature for calibration and validation of a pixel-wise soil-energy-water balance model and its impact on irrigation volumes for different case studies.

The discussion is carried out on several case studies characterized by different land use heterogeneity due to arboreal or crop cover and comparing satellite and ground data. LST data at different grid resolutions (10^0 to 10^2 m) are available and have been used with a corresponding spatial scheme to model the pixel soil, energy and water balances.

How to cite: Mancini, M., Paciolla, N., Corbari, C., Cammalleri, C., Ravazzani, G., and Ceppi, A.: Remote sensing of Land Surface Temperature for precision irrigation modelling: experience for different case studies., A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-72,, 2023.

Evapotranspiration (ET) is the largest loss term in the terrestrial water balance and plays a key role in the energy and carbon cycles. Accurate and timely measurements of ET are critical for understanding the ecosystem responses to climate change and managing water resources. Traditional methods for measuring ET are either highly individualistic leaf- or stem-scale approaches or large-scale tools that aggregate across entire landscapes. Unmanned aerial vehicles (UAVs) constitute a new frontier in measurement of ET that bridges the gap between in situ measurements and remotely sensed observations of water and energy fluxes. With advances in sensor technology and data processing algorithms, UAV-based remote sensing of ET provides both an avenue to refine satellite-based algorithms for retrieving water use and an improved understanding of the fundamental exchange processes between vegetation and the atmosphere.

We present an approach for estimating ET at leaf to landscape scales using thermal imagery, structural data, and a suite of environmental sensors mounted on a UAV platform. Our approach derives ET solely from UAV-acquired data using a combined atmospheric profiling and surface energy balance algorithm. Centimeter-scale leaf position and orientation information derived from Structure-from-Motion (SfM) are integrated with the functional data to constrain available energy, allowing for multi-scale estimation of plant water use within and across canopies.

Using thermal imagery and a suite of environmental sensors mounted on a UAV platform, we calculated ET of a Mediterranean grassland in Southern California at <1-m spatial resolution for 16 flights across the 2021 and 2022 growing seasons. We compare UAV-derived fluxes using four different formulations of aerodynamic resistance to measurements from an eddy covariance tower at the site. We then discuss the relative importance of surface temperature, aerodynamic terms, and meteorological variables for calculating ET from surface energy balance, highlighting the limitations of current approaches and the potential opportunities for future studies.

How to cite: Morgan, B. and Caylor, K.: A novel surface energy balance algorithm for estimating evapotranspiration from UAV-acquired data, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-95,, 2023.

Soil moisture is a key variable to our understanding of heat and water fluxes at the land-atmosphere interface. Satellite-based remote sensing instruments offer soil moisture data sets with global coverage that help advancing climate modeling and weather forecast models. However, the development of algorithms to estimate soil moisture from these satellite missions is complex and depends on several other parameters such as vegetation cover and surface roughness.

This demands for comprehensive reference data sets to validate and calibrate satellite products against but faces a challenge in spatial resolution: Traditional in situ methods measure on a representative horizontal scale of few meters while satellite instrumentation offers a much coarser resolution of hundreds of meters to tens of kilometers. Cosmic-ray neutron sensing (CRNS) fills this measurement gap by averaging over the moisture content of the upper soil layers within a footprint of approximately ten hectares. Mobile applications of CRNS extend the method’s coverage to up to a square kilometer. In the recent years the interest was set to understanding neutron transport by Monte-Carlo simulations for complex environmental topographies. As a conclusion, its remarkable performance in signal interpretation allows for a promising prospect of more comprehensive data quality.

With snapshot measurements of soil moisture with a spatial resolution of 50 m and a coverage of up to 1 km2 using mobile CRNS, high-quality data sets can be obtained as ground truthing for remote sensing products. These on demand campaigns can cover different land types and may be combined with existing sensor networks in order to improve soil moisture retrieval algorithms for satellite-based instruments.

How to cite: Weimar, J. and Köhli, M.: Validation potential for Remote Sensing soil moisture products using Cosmic-Ray Neutron Sensing, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-49,, 2023.

GC8-Hydro-79 | Orals | Session 2

Prediction of soil properties by lab and airborne spectral data 

Bar Efrati and Eyal Ben Dor

Over the preceding 50 years, issues of soil degradation, food insecurity, water scarcity, and loss of ecosystem services are at the center of environmental studies and global concern. These environmental and social issues have intensified the need for sustainable land management and higher-quality global-scale information on soil. The use of soil spectroscopy and hyperspectral remote sensing (HRS) has advanced the soil science discipline by providing an accurate, rapid, and inexpensive estimation of the Earth’s soil composition. In this study, we created field and lab soil spectral libraries (SSL) and predicted elementary soil properties such as water infiltration rate (WIR), soil texture content, and organic carbon (OC), essential for agricultural management. These models were applied in a case study of Campania,  Italy,  to the high-end HRS AVIRIS NG NASA sensor with a ground resolution of 3 meters, and 224 spectral bands along the VNIR-SWIR range (400-2500 nm). In addition, we discuss the differences between field, lab, airborne, and satellite spectra and emphasize the need for separating the models.

How to cite: Efrati, B. and Ben Dor, E.: Prediction of soil properties by lab and airborne spectral data, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-79,, 2023.

GC8-Hydro-63 | Orals | Session 2

Integrating soil structure in hydrologic models of the unsaturated zone 

Efthymios Chrysanthopoulos, Christos Pouliaris, Kostas Markantonis, Ioannis Tsirogiannis, and Andreas Kallioras

Most hydrologic models of the unsaturated zone predict soil hydraulic parameters using empirical equations (Pedotransfer functions - PTFs) driven by a limited set of soil characteristics, predominantly soil texture. Despite the increasing capabilities of PTFs, due to the advancement of machine learning algorithms and neural networks over the course of the years, several researchers have pointed out that PTFs integrate limited or any information for soil structure (Novick et al., 2022).  Soil structure, which is not correlated with soil texture, is affected by several factors, such as climate variations, biophysical activity, clay minerals, and the growth of roots, which determines the process of water movement in the unsaturated zone.

In this study, two laboratory methods were implemented (centrifuge and salt solution method) in order to define the water–retention curve of 1 m. undisturbed soil sample from an experimental kiwi field, located in the Epirus region (NW Greece). The water–retention curve correlates volumetric soil water content (θ) with matric potential, which becomes more negative when soils dry and is recognized as the fundamental driver of water flow in the unsaturated zone. Furthermore, a new permeability cell was constructed to conduct the falling head permeability method on undisturbed soil samples to determine saturated hydraulic conductivity (Ksat). The combination of all these methods led to a complete characterization of the undisturbed samples' hydraulic properties.

Subsequently, Hydrus-1D model was chosen to simulate the water movement in the soil–crop system within the experimental kiwi field, both by integrating predicted soil hydraulic properties from soil texture data and by embedding those measured from laboratory methods.  The results generated by the different approaches were compared and an inverse modeling process was followed to improve the efficiency of the model’s predictions based on observations.


This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call SUPPORT OF REGIONAL EXCELLENCE (project code MIS: 5047059).

Novick, K. A., Ficklin, D. L., Baldocchi, D., Davis, K. J., Ghezzehei, T. A., Konings, A. G., MacBean, N., Raoult, N., Scott, R. L., Shi, Y., Sulman, B. N., & Wood, J. D. (2022). Confronting the water potential information gap. Nature Geoscience, 15(3), Article 3.

How to cite: Chrysanthopoulos, E., Pouliaris, C., Markantonis, K., Tsirogiannis, I., and Kallioras, A.: Integrating soil structure in hydrologic models of the unsaturated zone, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-63,, 2023.

GC8-Hydro-27 | Orals | Session 2

Combining UAS LiDAR, sonar and radar altimetry for river hydraulic characterization 

Monica Coppo Frias, Alexander Rietz Vesterhauge, Daniel Haugård Olesen, Filippo Bandini, Henrik Grosen, Sune Nielsen, and Peter Bauer-Gottwein

Hydraulic characterization of river reaches is fundamental for flood risk assessment and flood forecasting. Hydraulic models can translate discharge into water levels, with measurements of river topography, water level and hydraulic roughness. Traditionally, these measurements are taken with in-situ surveys that are normally costly and time consuming when large or spatially distributed datasets are required, and difficult to retrieve in some locations. Remote sensing solutions have been widely used in the last years to measure inland water topography and water levels, reducing the time and cost of traditional surveys. Satellite earth observations can measure inland water bodies with high temporal and spatial frequency, but they only work in large rivers, can have limited accuracy and cannot measure the submerged portion of the river. UAS techniques offer high-resolution measurements of river topography, including river bathymetry and water level in medium-sized streams that are too big to wade through, offering a good opportunity to recover a full river hydraulic characterization.

UAS techniques have been widely used in hydrologic surveys, especially in smaller streams where satellite-based solutions are unfeasible due to the measurement sparsity. In addition, these techniques are very versatile, offering different types of measurements depending on the payload attached to the airborne system. River bathymetry can be retrieved using sonar or water penetrating radar (WPR), which provides depth measurements that, combined with water level measurements, can be used to calculate bathymetry. Moreover, land elevation can be measured with a LiDAR payload, providing topographic information on the river edges and adjacent floodplains. Radar altimeters can also provide water level measurements at a very high spatial resolution and accuracy. These data-sets can be used together to calibrate hydraulic roughness, which cannot be observed at the scale needed.

In this study, we propose a new UAS data acquisition technique for full hydraulic characterization of a river reach combining sonar bathymetry, LiDAR elevation of the land adjacent to the river and radar water level measurements to calibrate a hydraulic model. The method is demonstrated in a reach of Ryå stream in Jammerbugt, Denmark. This stream has a river width of around 10 meters and is characterized by dense vegetation in the surroundings, with deep areas where it is not possible to wade through. The bathymetry is observed using a sonar payload that measures depth in contact with water and water level measurements from RTK. The sonar depth is acquired in 1 day with a quasi-continuous UAS flight that measured 54 cross-sections separated by 100 meters. The land elevation is measured using a LiDAR in scanning mode, which gives measurements for 8 km of the river reach in less than half a day. The water level measurements were taken with a radar altimeter payload for 8 km of the river reach. The topographic and water level measurements are used in a hydraulic model to calibrate hydraulic roughness by estimating water levels that are compared with observed water level from radar altimetry.

How to cite: Coppo Frias, M., Vesterhauge, A. R., Olesen, D. H., Bandini, F., Grosen, H., Nielsen, S., and Bauer-Gottwein, P.: Combining UAS LiDAR, sonar and radar altimetry for river hydraulic characterization, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-27,, 2023.

GC8-Hydro-48 | Orals | Session 2

Mapping and quantification of groundwater–surface water exchange along a headwater stream using Distributed Temperature Sensing: First findings from the Wüstebach Catchment, Germany 

Jochen Wenninger, Konstantina Katsanou, Alessandro Cattapan, Raymond Venneker, Heye Bogena, and Roland Bol

Groundwater-Dependent Ecosystems (GDEs) are valuable as they support ecosystem services at local and regional scales. Although they are closely related, surface- and groundwater bodies have traditionally been studied and managed separately. Since local hydrogeology and climate conditions affect GDEs, detailed spatial and temporal studies on their chemical and quantitative interactions are required.

A multi-disciplinary approach was used to investigate the interactions between surface- and groundwater in the Wüstebach test site, a 38.5 ha headwater catchment located in the Eifel National Park, Germany. This catchment is operated by the Forschungszentrum Jülich and is part of the TERENO Eifel Lower Rhine Valley Observatory. Along the streambed, a Fibre Optic Distributed Temperature Sensing (FO-DTS) experiment was set up in October 2022 to monitor the temperature changes of surface water along a 293 m long transect. The FO cable was connected to a Silixa XT-DTS instrument and temperature measurements were collected at 25 cm and 15 min sampling intervals. Moreover, a series of conservative tracer measurements were carried out using slug and continuous injection tests along the stream to quantify the amounts of groundwater exfiltration. In addition, spatially detailed electrical conductivity readings along the stream together with groundwater level measurements were carried out and water samples were collected for chemical determinations. Results of the salt dilution injections revealed that the headwater stream receives a significant contribution from groundwater along the transect, while the initial DTS recordings pinpointed several distinct locations where groundwater inputs occur along the stream; which were also identified on the field. An improved understanding of the catchment's quantitative and qualitative water flows is anticipated as a result of the mapping and subsequent quantification of the groundwater input.

How to cite: Wenninger, J., Katsanou, K., Cattapan, A., Venneker, R., Bogena, H., and Bol, R.: Mapping and quantification of groundwater–surface water exchange along a headwater stream using Distributed Temperature Sensing: First findings from the Wüstebach Catchment, Germany, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-48,, 2023.

GC8-Hydro-37 | Poster | Session 2

Bridging structural and functional hydrological connectivity in dryland ecosystems 

Octavia Crompton, Gabriel Katul, Sally Thompson, and Dana Lapides

On dryland hillslopes, vegetation water availability is often subsidized by the redistribution of rainfall runoff from bare soil (sources) to vegetation patches (sinks). In regions where rainfall volumes are too low to support spatially continuous plant growth, such functional connectivity between bare soil and vegetated areas enables the establishment and persistence of dryland ecosystems.  Increasing the connectivity within bare soil areas can intensify runoff and increase water losses from hillslopes, disrupting this redistribution and reducing the water available to sustain ecosystem function.  Inferring functional connectivity (from bare to vegetated, or within bare areas) from structural landscape features is an attractive approach to enable rapid, scalable characterization of dryland ecosystem function from remote observations. Such inference, however, would rely on metrics of structural connectivity, which describe the contiguity of bare soil areas.  Several studies have observed non-stationarity in the relations between functional and structural connectivity metrics as rainfall conditions vary. Consequently, the suitability of using structural connectivity to provide a reliable proxy for functional connectivity remains uncertain and motivates the work here. 

Rainfall-runoff simulations across a wide range of dryland hillslopes, under varying soil and rainfall conditions, are used to establish relations between structural and functional connectivity metrics.  The model results identify that the relations vary between two hydrologic limits -- a `local' limit, in which functional connectivity is related to structural connectivity, and a ‘global’ limit, in which functional connectivity is most related to the hillslope vegetation fraction regardless of the structural connectivity of bare soil areas. The transition between these limits within the simulations depends on rainfall intensity and duration, and soil permeability. While the local limit may strengthen positive feedbacks between vegetation and water availability, the implications of these limits for dryland functioning need further exploration, particularly considering the timescale separation between storm runoff production and vegetation growth.

How to cite: Crompton, O., Katul, G., Thompson, S., and Lapides, D.: Bridging structural and functional hydrological connectivity in dryland ecosystems, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-37,, 2023.

GC8-Hydro-38 | Poster | Session 2

Influence of soil hydrological conditions on the accumulation of heavy metals in tree species in the post-mining landscape of Freiberg, Germany (Saxony) 

Viktoriia Lovynska, Oliver Wiche, Carsten Montzka, Svitlana Syntyk, Visakh Sivaprasad, Alla Samarska, and David Mengen

The post-mining landscape of Freiberg, Saxony, Germany is characterized by soils with elevated concentrations of non-essential elements, particularly arsenic (As), cadmium (Cd) and lead (Pb). While literature on soil mineralization and factors influencing the soil-plant transfer in managed agroecosystems is extensive, information on the accumulation in native woody plant species, including soil-associated factors influencing their accumulation, is still lacking. In this study, we evaluated the concentrations of 24 elements, including As, Cd and Pb in leaves and branches of three taxa of tree species (Betula pendula, Populus tremula and Salix spec.) throughout the study area and compared the results with data on potentially plant available element concentrations in soil (sequential extraction), total element concentrations as well as with remote sensing data on surface soil moisture and water availability in the root-zone. Populus tremula and Salix spec. were identified as plant species that are suitable for bioindication of soil pollution. Leaf concentrations were substantially higher compared to branches. The concentrations in leaves largely reflected the availability of elements in soil. Concomitantly, higher soil-plant-transfer of elements correlated with remote sensing data, onsurface water accumulation and water content in the root-zone. This suggests that higher soil water contents increase the availability of the toxic elements to plants and/or impacts the translocation of elements to aboveground plant parts. The contribution of soil-associated factors and plant-associated factors to the hyperaccumulation observed remains a field for further research. Nevertheless, we could demonstrate that coupling leaf analysis with remote sensing data on soil moisture could be a promising approach in environmental assessments as well as in phytoremediation and phytomining approaches.  

How to cite: Lovynska, V., Wiche, O., Montzka, C., Syntyk, S., Sivaprasad, V., Samarska, A., and Mengen, D.: Influence of soil hydrological conditions on the accumulation of heavy metals in tree species in the post-mining landscape of Freiberg, Germany (Saxony), A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-38,, 2023.

GC8-Hydro-16 | Poster | Session 2

morphometric analysis of the Soummam basin using remote sensing and GIS technologies

khemmal hichem yakoub, Hani Azzedine, and Benmarce Kaddour

GC8-Hydro-32 | Poster | Session 2

Improving water resource management through the development of a flux tower network and remote sensing modeling of evapotranspiration and water stress of woody perennial crops in California 

William Kustas, Nicholas Bambach, Andrew McElrone, Kyle Knipper, Alfonso Torres-Rua, Matthew Roby, Maria Mar Alsina, John Prueger, Joseph Alfieri, Sebastian Castro, Lawrence Hipps, Lynn McKee, Oscar Belfiore, and Guido D'Urso

Improving water resource management in the western United States is critically needed to achieve sustainability between the competing demands of water supplies for cities and towns, for agriculture, particularly irrigated regions, by industries principally for generating electricity, and for the environment (i.e., providing adequate ecosystem services). The last decade marked by historically severe droughts revealed the need for new water management policies and environmental regulations. Moreover, the impact of climate change not only has exacerbated droughts but also may be causing episodic extreme wet periods requiring a new paradigm on water management strategies for surface water reservoirs and groundwater aquifers. The Sustainable Groundwater Management Act (SGMA) is an example of developing a water management policy for sustainability of water resources in California. California produces 80% of the world’s almonds, is the 4th largest wine producer worldwide while also providing three-quarters of the fruits and nuts in the U.S. Much of the production requires reliable water sources for irrigation.  This has motivated research into designing networks of evapotranspiration (ET) flux tower measurements in grape and tree crop systems in conjunction with developing new remote sensing tools for mapping crop water use, ET, to efficiently use and conserve water resources across the over 1.5 million acres of woody perennial crop production fields.  This acreage is largely irrigated and uses approximately 70% of freshwater resources in the region.  The two projects, GRAPEX (Grape Remote sensing Atmospheric Profile and Evapotranspiration eXperiment) and T-REX (Tree-crop Remote sensing of Evapotranspiration eXperiment) have the overall goal to identify management opportunities to maximize water use efficiency in vineyard, almond and other woody perennial crops.  This presentation will describe the measurement network used for understanding the water and energy flux exchange of these complex cropping systems and in validating and refining remote sensing modeling tools from UAS and satellite platforms for estimating ET and crop water stress from plant and sub field to regional scales required for improving water management strategies of these agricultural systems.

How to cite: Kustas, W., Bambach, N., McElrone, A., Knipper, K., Torres-Rua, A., Roby, M., Alsina, M. M., Prueger, J., Alfieri, J., Castro, S., Hipps, L., McKee, L., Belfiore, O., and D'Urso, G.: Improving water resource management through the development of a flux tower network and remote sensing modeling of evapotranspiration and water stress of woody perennial crops in California, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-32,, 2023.

GC8-Hydro-54 | Poster | Session 2

Monitoring Environmental Variables to Promote Precision Agriculture 

Viviana Maggioni, Christian Massari, Janani Kandasamy, Yuan Xue, Sara Modanesi, Domenico De Santis, Francesca Sofia Manca di Villahermosa, Daniele Penna, Paolo Benettin, and Marco Dionigi

Precision agriculture is a modern approach based on farm and irrigation management to improve the efficiency in the use of water resources. Precision agriculture, therefore, maximizes crop productivity and yield through technologies that identify, analyze, and monitor variability within a field and optimize profitability, sustainability, and land protection. This study proposes a combination of approaches to monitor a suite of environmental variables with the goal of improving agricultural management. We selected the experimental vineyard of Grignanello (Tuscany, Italy), located on a mild slope at 350 m.a.s.l in the famous Chianti wine region, where extensive ecohydrological data are available. In combination with this set of ground-based observations, the Environmental Policy Integrated Climate Model (EPIC) is adopted to model key variables for crop production, including soil temperature and soil water content. Using the EPIC model, we generate three sets of simulations based on three different parameterizations (i.e., original cosine, enhanced cosine, and pseudo heat transfer). By comparing model output against ground-based measurements and UAV-based soil temperature, we assess what model set-up is more accurate and for which environmental variable of interest. Furthermore, a new set of soil temperature and soil moisture estimates is obtained by taking the mean of the three EPIC simulations. Thus, we assess the possibility to improve the performance of the single models, as shown in previous studies across the Central Valley in California. Outcomes from this work will provide a solid basis towards developing a decision guidance system for precision agriculture management. 

How to cite: Maggioni, V., Massari, C., Kandasamy, J., Xue, Y., Modanesi, S., De Santis, D., Manca di Villahermosa, F. S., Penna, D., Benettin, P., and Dionigi, M.: Monitoring Environmental Variables to Promote Precision Agriculture, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-54,, 2023.

GC8-Hydro-18 | Poster | Session 2

Hydrological regime of Sahelian small water bodies from combined Sentinel-2 MSI and Sentinel-3 SRAL data 

Mathilde de FLEURY, Laurent Kergoat, and Manuela Grippa

Sahelian small water bodies are critical resources that people use for multiple purposes: irrigation, fishing, bathing, drinking water, livestock watering. Better understanding their hydrological regimes and quantify water inflows and outflows is necessary to achieve better management of these water bodies. Thanks to satellite technological advances allowing regular monitoring in space and time, remote sensing techniques provide a major tool to do this. In this work we develop a remote sensing based method to quantify water fluxes in Sahelian small water bodies.

Water heights from Sentinel-3 SAR Radar Altimeter (SRAL) are combined with water areas estimated through MNDWI thresholding on Sentinel-2 Multispectral Instrument (MSI) images (using Google Earth Engine) to create a height-area curve for each studied lake. Dense water height time series are then obtained by pooling water height from both altimetry and optical data. Water height variations are compared to evaporative losses, estimated by the Penman–Monteith method with data from ECMWF ERA5, to analyse water fluxes during the dry season, when precipitation is null.

This method is applied on 37 lakes in the Central Sahel (Mali, Burkina Faso and Niger), whose areas range from 0.04 km2 to 37.91 km2, over the five year period 2016-2020. The five-year averaged dry-season difference between water height decrease and evaporation varies from –12.45 mm.d-1 to 9.71 mm.d-1. Lakes display three different regimes: a net water loss (i.e. water height decrease greater than evaporation), a net water supply, and a balanced behaviour (i.e. water losses correspond to evaporation).

Water supply is mainly observed in lakes in the the Inner Niger Delta and it is likely due to connections to the Niger River hydrographic network. The main flood in the Inner Niger Delta occurs indeed after the end of the rainy season. Water loss is mainly found in the centre of Burkina Faso and correspond to water withdrawal for small-scale irrigation. Interannual variability is related to changes in rainfall, in the length of the dry season, and in anthropogenic actions. Only 6 out of 37 lakes show a change in regime from positive to negative or vice versa within the study period. One of these lakes is a reservoir whose infrastructure was damaged by attacks during conflicts which caused leaks.

The remote sensing method developed allows to better understand the regime of small Sahelian water bodies and assessing water fluxes and anthropogenic water withdrawals. Oncoming SWOT data will allow to apply this approach to a much larger number of water bodies in this region and more generally in semi-arid areas.

How to cite: de FLEURY, M., Kergoat, L., and Grippa, M.: Hydrological regime of Sahelian small water bodies from combined Sentinel-2 MSI and Sentinel-3 SRAL data, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-18,, 2023.

GC8-Hydro-60 | Poster | Session 2

Earth Observation data for the monitoring of irrigation water use in Italy: The case study of the INCIPIT project. 

Guido D'Urso, Oscar Rosario Belfiore, Antonio Coppola, Alessandro Comegna, Attilio Toscano, Gabriele Baroni, Simona Consoli, Daniela Vanella, Giuseppe Longo Minnolo, Matteo Ippolito, Dario De Caro, Alessandro Castagna, and Claudio Gandolfi

Agriculture is the main source of pressure on water resources, so accurate estimates of irrigation demands play a key role in sustainable water management. The INCIPIT (INtegrated Computer modeling and monitoring for Irrigation Planning in Italy) project (funded by Italian Min. Univ. and Research) aims to address the gaps between research and practical application in monitoring irrigation water use in six Italian regions [1].

It is designed to meet the requirements of sustainable water policies, such as the Water Framework Directive and the MIPAAF Ministry Decree, by providing accurate measurements and estimations of irrigated areas and water volumes. The project uses the ESA Sentinel-2 (S2) satellites as a valuable source of information to map irrigated areas and estimate distributed irrigation water requirements.

This study presents the results of the IRRISAT methodology, the first Italian satellite-based irrigation advisory service [2], which was applied in the Campania region. The methodology uses a one-step approach, based on the Penman-Monteith equation, and is adjusted with canopy parameters from S2 data, to quantify irrigation water abstraction. Effective irrigated areas were assessed by using pre-existing maps, unsupervised clustering, and supervised machine learning algorithms applied to vegetation index data [3].

The results of the methodology for the irrigation seasons of 2019 and 2020 will be presented for seven Irrigation and Land Reclamation Consortiums, which vary in size, irrigation scheme, farm delivery, irrigation methods, and crop types.

[1] INCIPIT Project,

[2] Vuolo F., D’Urso G., De Michele C., Bianchi B., Cutting M.: Satellite-based irrigation advisory services: a common tool for different experiences from Europe to Australia”. Agricultural Water Management, Elsevier, vol. 147: 82-95; (2015).

[3] Falanga Bolognesi S., Pasolli E., Belfiore O. R., De Michele C., D’Urso G.: Harmonized Landsat 8 and Sentinel-2 Time Series Data to Detect Irrigated Areas: An Application in Southern Italy". Remote Sensing, MDPI, vol.12, no. 8: 1275; (2020).

How to cite: D'Urso, G., Belfiore, O. R., Coppola, A., Comegna, A., Toscano, A., Baroni, G., Consoli, S., Vanella, D., Longo Minnolo, G., Ippolito, M., De Caro, D., Castagna, A., and Gandolfi, C.: Earth Observation data for the monitoring of irrigation water use in Italy: The case study of the INCIPIT project., A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-60,, 2023.

Groundwater resources are biodiversity hotspots, and provide crucial ecosystems services. Yet, groundwater dependent ecosystems (GDEs) are exposed to several anthropogenic threats, including climate and land use change. Tackling these threats requires improving the on-the-ground identification of GDEs at the global scale and especially in vulnerable areas such as the Mediterranean biome where water is scarce.

In order to identify the location of groundwater dependent vegetation (GDV) in the landscape and create a harmonized global map of GDV a novel multi-instrument and multi-scale approach was developed. The approach combines a geodata-based potential GDV zones-index (pGDVZ) together with high-resolution vegetative, hydrogeological and topographic remote sensing parameters.

The pGDVZ integrates global and openly available datasets to combine groundwater vegetation interaction, land use, soil characteristics and landscape wetness potential. The index is currently tested for the whole Mediterranean. Results can help to pinpoint areas of high GDVZ potential where regional high-resolution identification of GDV is necessary.

The regional GDV-mapping concept implements different criteria aiming at: 1) high vitality and wetness during dry periods (e.g., Enhanced Vegetation Index, Normalized Difference Vegetation Index, Normalized Difference Water Index), 2) low seasonal changes in vitality, 3) low interannual changes in vitality, 4) high topographic potential of water accumulation and low water table depth and 5) general topography (elevation, slope). Processing of different remote sensing data (e.g., Sentinel 1;2, Digital Elevation Models, MODIS) is performed using the Google Earth Engine. Botanical mapping as well as integration of several geodata is used for validation and calibration of derived GDV-likelihoods. Furthermore, the integration of vegetation plots extracted from sPlot, the global vegetation database introduces a novel methodology to train machine learning algorithm for classification and modelling of GDV.

After successfully testing the mapping approach at local scale in the ‘Cilento, Vallo di Diano and Alburni National Park’ in Campania (Italy), a two-step upscaling methodology is currently designed to implement the concept on regional (county) and global (biome) scale.

How to cite: El-Hokayem, L., De Vita, P., and Conrad, C.: Mapping of potential groundwater dependent vegetation zones in the Mediterranean using a simple index based on global-available geodata and high-resolution remote sensing, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-61,, 2023.

GC8-Hydro-97 | Poster | Session 2

Downscaling and validation of 1km ESA Soil Water Index for soil moisture monitoring on agricultural land in temperate climate conditions 

Christopher Conrad, Johannes Schmelzer, Julian Schlaak, and Johannes Löw

Near-surface soil moisture is an important parameter for estimating the water balance of ecosystems, especially for the exchange of water between atmosphere and soil. In the past decades, global and continental products, e.g. the Soil Water Index (SWI) of ESA, have been developed for large-scale monitoring from passive and active microwave data. ESA SWI was developed for Europe based on the surface soil moisture product derived from Sentinel-1 C-band SAR data (1km resolution) and Metop ASCAT surface soil moisture (12.5km). However, for practical, small-scale applications on the local level, there is currently little data available. This contribution elaborates on the validation of the SWI for temperate agricultural regions at the example of the agrometeorological network of the JECAM test site DEMMIN in Northeast Germany. For this purpose, two resampling methods, a bilinear interpolation and a statistical downscaling approach using Random Forest were tested on SWI data from 2019. The statistical downscaling approach integrates Sentinel satellite data and the Topographical Wetness Index based on a 10m resolved elevation model. Both resampling methods showed similar results. Over time, the SWI significantly overestimates the in situ data before and after the crop growing season. A higher agreement is observed in the summer months. For 19 of the 29 investigated agrometeorological stations a statistically positive correlation with R>0.5 was found. The remaining stations showed little to no correlation, most likely due influences of various crops types on the remote sensing data. The results suggest a temporally limited applicability of the SWI 1km data for local assessments of soil moisture.

How to cite: Conrad, C., Schmelzer, J., Schlaak, J., and Löw, J.: Downscaling and validation of 1km ESA Soil Water Index for soil moisture monitoring on agricultural land in temperate climate conditions, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-97,, 2023.

Hydrology relies on the measurement of various variables, among which snow water equivalent (SWE) plays a crucial role in predicting runoff, particularly for catchments with high levels of snow accumulation. However, SWE measurements are rare and limited to point scales, making it difficult to obtain accurate spatialized estimates. While current satellite missions do not directly measure SWE, they offer valuable proxy information that can be used to reconstruct SWE. We propose using optical and radar sensors from MODIS, Sentinel-2, and Landsat missions to extract data on snow persistence on the ground and merge this multi-scale information to obtain accurate estimates of SWE. The technique involves observing snow patterns at high spatial resolutions from Landsat and Sentinel-2 missions and using this information to reconstruct a low-resolution image from MODIS. Additionally, information on the duration of melting can be obtained using Synthetic Aperture Radar (SAR) from Sentinel-1. In-situ air temperature data is used to estimate potential melting, and snow depth observations are used to determine if accumulation is occurring. The final output is daily high-resolution SWE maps. This approach has the advantage of not relying on precipitation observations, which are often uncertain in high-elevation catchments. We investigate the effectiveness of this approach in estimating peak snowmelt discharge for two monitored catchments in South Tyrol (Italy), comparing the results to those obtained using state-of-the-art hydrological models such as GEOtop and New Age. These results have the potential to significantly improve snowmelt estimation in poorly monitored basins.

How to cite: Bertoldi, G., Premier, V., Bozzoli, M., and Marin, C.: A comparison of a new remote sensing-based SWE estimation method  with physical models for improving snow melt estimation in alpine catchments, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-100,, 2023.

GC8-Hydro-69 | Poster | Session 2

Identifying controls on throughfall variability at the hillslope scale through satellite data and UAV-assisted techniques 

Matteo Verdone, Pilar Llorens, Christian Massari, Ilja van Meerveld, and Daniele Penna

Spatio-temporal variability of throughfall (TF) in forested catchments depends on climatic forcing, forest stand parameters, and rainfall characteristics. Identifying and quantifying these controls is fundamental for a correct analysis and modelling of interception and catchment hydrological response. Despite many studies carried out at the stand and hillslope scale focused on the analysis of controls on TF variability, very little is known about the role of hillslope topography and the associated tree population characteristics in shaping throughfall spatio-temporal variability. In addition to ground-based measurements, satellite and unmanned aerial vehicle (UAV)-data can be explored to obtain a more robust assessment of the main drivers of TF variability. Therefore, this work aimed at i) identifying the dominant factors on throughfall variability in a European beech stand along a steep hillslope; and ii) quantifying forest interception at the hillslope scale and upscaling it at the small catchment scale using ground-level measurements and UAV-derived and satellite observations.

The experimental activities were carried out in the upper part of the Re della Pietra catchment, Tuscany Apennines, Central Italy. The hillslope is roughly 110 m long and 60 m wide, has a mean slope of 30°, and is dominantly covered by European beech trees. The TF experimental plot consists of 126 throughfall collectors divided in two square grids of 144 m2 with 49 collectors at the bottom and the top of the hillslope, and a transect of 28 collectors from the bottom to the top grid. TF was manually measured from the collectors approximately monthly and compared with gross precipitation. Moreover, five automatic gauges were installed along the hillslope to increase the temporal resolution. Topographic surveys were conducted to measure the main physiological characteristics (diameter, height and age) of the trees in the TF plot. Leaf Area Index (LAI) was estimated using a ceptometer above each sampler in four dates in the dormant and in the growing season.

The 40 manual measurements revealed a large spatial and temporal variability of the TF/precipitation ratio (mean 68%, standard deviation 37%). In the growing period, the TF/precipitation ratio showed higher spatial variability compared to the dormant season (66±29% and 85±31%, respectively), suggesting that the crown expansion can be an important control on TF variability. Moreover, TF was consistently lower in the bottom plot, characterized by larger tree size compared to the top grid indicating a control by trees size. Event-scale data from the gutter gauges show a rainfall intensity control on TF but showed no correlation between TF and hillslope position.

To corroborate the preliminary observations on crown and tree size, in early March 2023 a UAV survey will be conducted to determine the crown architecture and lateral expansion, and relate this parameters to the observed TF. Furthermore, LAI ground measurements will be compared with LAI data derived from Sentinel-2 data to establish a relation between ground measurements and satellite observations. This relationship will be then use to upscale LAI and its possible associate control on TF variability from the hillslope to the small (0.3 km2) catchment scale.

How to cite: Verdone, M., Llorens, P., Massari, C., van Meerveld, I., and Penna, D.: Identifying controls on throughfall variability at the hillslope scale through satellite data and UAV-assisted techniques, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-69,, 2023.

GC8-Hydro-103 | Poster | Session 2

Assessment of UAV-based LiDAR and photogrammetry data in crop morphology monitoring for advanced irrigation 

Attila Nagy, Erika Buday-Bódi, Andrea Szabó, Zsolt Zoltán Fehér, and János Tamás

Most of the climate scenarios forecast increased water scarcity in semi-arid and arid areas, such as Hungary. Since only 2% of Hungary’s agricultural land is irrigated where mostly outdated irrigation technology is applied, there is a huge need for act to enhance advanced irrigation. The general aim of the present research was to develop the basis of variable rate irrigation for a water-saving precision sprinkler irrigation system on an maize site (85 ha) located in the reference area of the Tisza River Basin. There are limited available water resources at the site, therefore alternative water sources utilization system was set up for irrigation to adapt to climate change and reduce fertilizers. As the alternative water resource for irrigation, inland excess water, treated wastewater, and biogas fermentation sludge are collected in a water reservoir with a capacity of 114,000 m3. For proper irrigation scheduling, heterogeneity of topography, hydrological, soil and crop conditions have to be explored and monitored. For this reason, UAV-based surveys were carried out with high spatial and temporal resolution by which DEM, DSM, multispectral vegetation data was conducted both on irrigated and non-irrigated parts of a maize field in Hungary this site. Supplementing these data with physically based modelling of the soil and crop status, and the water balance surveying is tested to use for accurate irrigation scheduling.

In the surveys we used a DJI Matrice 300 RTK UAV drone equipped with a Zenmuse L1 LiDAR payload with integrated RGB Surveying Solution and a DJI Zenmuse H20T thermal camera, which measures in the spectral range from 8000 to 14,000 nm. A DJI Mavic 2 Zoom drone equipped with a Sentera Double 4K sensor that can calculate NDVI (Normalized Difference Vegetation Index) and NDRE (Normalized Difference Red-Edge Index) by filtering out red and NIR wavelengths was used for the multispectral research. These data enables the monitoring of crop height and biomass and the assessment of the thermal properties and the photosynthetic activity of the crop, respectively. A crucial work phase is the data management of these remotely sensed data by which we gain point-cloud and raster from semi-raw formats and photogrammetry analysis can commence. For validation, the results of field measurements for crop height, general status and chlorophyll content were applied by virtue of the high spatial resolution provided by the sensors. Based on the results, the considerable relation was found between the field and RS based data to survey the surface, the height and health status of the maize, which contributes to the mapping of a proper vegetation patterns fostering variable rate irrigation prescription maps.

The abstract was funded by European Union’s Horizon 2020 “WATERAGRI Water retention and nutrient recycling in soils and steams for improved agricultural production” research and innovation programme under Grant Agreement No. 858375. This research was supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences

How to cite: Nagy, A., Buday-Bódi, E., Szabó, A., Fehér, Z. Z., and Tamás, J.: Assessment of UAV-based LiDAR and photogrammetry data in crop morphology monitoring for advanced irrigation, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-103,, 2023.

GC8-Hydro-107 | Poster | Session 2

Monitoring water turbidity with camera: a real scale experiment 

Domenico Miglino, Khim Cathleen Saddi, Francesco Isgrò, Seifeddine Jomaa, Michael Rode, and Salvatore Manfreda

Turbidity is one of the most critical metrics in water quality monitoring.  High turbidity in river basins can be an indicator of both organic and inorganic material presence. Improving existing river monitoring techniques is essential, given the growing presence of critical factors, such as climate change, population growth, and pollution in recent years.

In this study, a real scale experiment has been conducted in Selke River within the Bode catchment in Germany. The Bode basin is one of the best-instrumented catchments in Central Germany, managed by UFZ Helmholtz Centre for Environmental Research. In this experiment, the level of turbidity has been artificially increased by adding kaolin clay into the river, upstream enough from the monitored river cross-section to ensure the complete mixing between clay and water.  Kaolin is usually exploited to prepare turbidity standard solutions. In addition, it is a harmless, easy to handle, and low-cost clay mineral, which is also an abundant silicate in soils and sediments.

The monitoring field campaign has been conducted using different instruments, such as an optical camera, a multispectral camera mounted on fixed positions and a drone, which have been used to describe, from different points of view, the synthetic turbidity event generated. Different types of camera and installation settings have been investigated to understand the full potential of this technology for water quality monitoring. The gathered optical data was compared to the recorded turbidity of the UFZ sensors, which has been currently installed in the Selke river cross-section.

The final goal of this work is to build a reliable image processing procedure for the development of a camera system that could support existing monitoring techniques and increase the temporal and spatial resolution in  river monitoring.

Keywords: camera, UAS, river monitoring, sediment transport, image processing, spectral indices, remote sensing, drones, water quality assessment

How to cite: Miglino, D., Saddi, K. C., Isgrò, F., Jomaa, S., Rode, M., and Manfreda, S.: Monitoring water turbidity with camera: a real scale experiment, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-107,, 2023.

GC8-Hydro-106 | Poster | Session 2

Utilizing Unmanned Aerial Systems in River Water Quality Variability Monitoring 

Khim Cathleen Saddi, Domenico Miglino, Seifeddine Jomaa, Michael Rode, Francesco Isgro, and Salvatore Manfreda

Traditional water quality monitoring in River Systems is both labor intensive and expensive. However, in order to better understand the different phenomena occurring in river systems, it is vital to have robust data available. Satellite observations have been successful in monitoring different environmental systems, but generally, current available spatial resolutions and cloud cover in inland waters limit the monitoring of rivers. Recent developments in the use of Unmanned Aerial Systems (UAS) highlighted the potential to address this gap in environmental monitoring. 

In this study, UAS and image processing techniques were utilized to gather an overview of the water quality variability, specific to turbidity level and pollutant transport, along the Sarno River, which is the most polluted river in Europe, and the river pollution has long been subject to disputes between many sectors. Preliminary findings highlighted the potential of image processing and allowed to identify the  variability in river water quality along the main river by adopting a sampling protocol in several points of the Sarno River. While there were few observations of plastic in river banks, organic transport was mostly observed and interestingly, there is a water quality spatial mixing in the river mouth, which is difficult to observe using traditional in situ point measurements. This study only covers the initial phase of the river monitoring activities. 

Keywords: UAS river monitoring, sediment transport, image processing, spectral indices, remote sensing, drones, water quality assessment



Miglino, D., Jomaa, S., Rode, M., Isgro, F., & Manfreda, S. (2022). Monitoring Water Turbidity Using Remote Sensing Techniques. Environmental Sciences Proceedings, 21(1), 63.

How to cite: Saddi, K. C., Miglino, D., Jomaa, S., Rode, M., Isgro, F., and Manfreda, S.: Utilizing Unmanned Aerial Systems in River Water Quality Variability Monitoring, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-106,, 2023.

GC8-Hydro-11 | Poster | Session 2

Using Sentinel-2 multispectral imagery to assess flow-intermittency in non‑perennial rivers 

Carmela Cavallo, Maria Nicolina Papa, Giovanni Negro, Giuseppe Ruello, Massimiliano Gargiulo, and Paolo Vezza

Non-perennial rivers are characterized by periods with dry bed or chains of isolated ponds. Given the extremely high biodiversity and various ecosystem services, these environments require careful management. The main obstacle to the implementation of correct management practices is related to the lack of information about the duration and frequency of zero-flow periods, that are the primary determinants of ecosystem processes in this kind of streams.

In many cases, the presence of non-perennial reaches within the river network is unknown. Given the high extension of the network of non-perennial rivers and their strong spatial inhomogeneity, traditional gauging systems are not adequate to provide measures with adequate spatial coverage. Moreover, point measures cannot capture the space-pattern of presence/absence of water. On the other hand, field surveys of water patterns have a limited temporal resolution and therefore lack in capturing the regime’s time-patterns. In this context, satellite data can make a key contribution thanks to the possibility of monitoring large areas with high temporal resolutions. Their use for monitoring the regime of non-perennial rivers has so far been limited by the availability of images with adequate resolution and accessible costs.

In this work, we explored the potential of medium-resolution multispectral Sentinel-2 data to identify non-perennial rivers and to assess their degree of intermittency. Examining the spectral signatures of water, sediment and vegetation covers, the bands in which these classes are most differentiated were identified. Exploiting these bands, we generated false-color image in which the pixels covered by water stand out from the background. From the false-color composite images, it was possible to identify the three distinct flowing status of non-perennial rivers: “flowing”, “ponding” and “dry” . The classification of flowing status was checked against ground truth, showing very good agreement. To enable a wider audience to identify flowing status along non-perennial rivers, we have developed and made freely available a code on the Google Earth Engine platform. For all the archive images (since 2015) we identified one of the three possible flowing status: flowing, ponding and dry bed. The obtained dataset allowed to train a random forest (RF) model able to predict the daily occurrence of a specific flowing status using as predictors spatially interpolated rainfall and air temperature data. The analysis was performed for 5 reaches of the streams Sciarapotamo, Mingardo and Lambro (Campania region, Italy), for which a RF model was calibrated. Classification RF models performed well in terms of accuracy (ranging from 82% to 97%) and true skill statistic (ranging from 0.65 to 0.95). All the studied reaches showed a no-flow condition during the observation period. Three of the five reaches resulted to have a dry bed condition each year while the other two reaches never dry up completely. With its ability to monitor the presence and absence of water in a cost-effective manner, this method has the potential to significantly improve the management and the conversation of non-perennial rivers, enabling a better understanding of their ecological status, as required by the European Water Framework Directive 2000/60/EC.

How to cite: Cavallo, C., Papa, M. N., Negro, G., Ruello, G., Gargiulo, M., and Vezza, P.: Using Sentinel-2 multispectral imagery to assess flow-intermittency in non‑perennial rivers, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-11,, 2023.

GC8-Hydro-52 | Poster | Session 2

UAS Hydrometry – Contactless airborne measurements of water level, depth, flow velocity and discharge in rivers and streams 

Peter Bauer-Gottwein, Daniel Olesen, Karina Nielsen, Alexander Rietz, Monica Coppo Frías, Alexey Dobrovolskiy, Alexey Kadek, Niksa Orlic, Tomislav Grubesa, Tom Hiller, Henrik Grosen, Sune Nielsen, Angelica Tarpanelli, Daniele Giordan, Silvia Barbetta, David Gustafsson, Daniel Wennerberg, Markus Disse, Fabian Merk, and Laia Romero and the UAWOS project team

High-resolution monitoring of rivers is important because rivers are severely affected by climate change and both frequency and magnitude of extreme events are changing rapidly. Advanced in-situ monitoring technologies need to be combined with satellite Earth Observation (EO) to provide accurate, reliable, and spatio-temporally resolved information for effective decision support, risk assessment, investment analysis for climate change adaptation, and operational forecasting/surveillance.

Traditional hydrometric monitoring of rivers is in-situ and station-based. In-situ monitoring networks lack spatial resolution, have been declining in many regions, and data accessibility is increasingly restricted because of growing conflicts between countries over water resources allocation. To solve this problem, hydrometric monitoring using satellite earth observation needs to be combined with drone-borne hydrometric monitoring technology for validation, deployment in remote and inaccessible regions, and for reliable and accurate estimation of river discharge.

The Horizon Europe UAWOS project develops an Unmanned Airborne Water Observing System to provide key hydrometric variables (bathymetry, velocimetry, water surface elevation) at high spatial resolution/coverage, and data-based products/services to support management and decision making. UAWOS integrates airborne data streams with Copernicus water bodies and water level services for cross validation and to estimate river discharge from satellite EO data.

This contribution outlines the UAWOS work programme and reports first results of airborne surveys using (i) radar altimetry for water surface elevation mapping, (ii) water penetrating radar and sonar for bathymetric mapping and Doppler radar for surface velocity monitoring. The combination of these datasets for river discharge estimation as well as for validation and enhancement of satellite radar altimetry datasets will be discussed.

How to cite: Bauer-Gottwein, P., Olesen, D., Nielsen, K., Rietz, A., Coppo Frías, M., Dobrovolskiy, A., Kadek, A., Orlic, N., Grubesa, T., Hiller, T., Grosen, H., Nielsen, S., Tarpanelli, A., Giordan, D., Barbetta, S., Gustafsson, D., Wennerberg, D., Disse, M., Merk, F., and Romero, L. and the UAWOS project team: UAS Hydrometry – Contactless airborne measurements of water level, depth, flow velocity and discharge in rivers and streams, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-52,, 2023.

Over the last decades, numerous models for sediment transport prediction have been proposed with application to littoral transport. However, the morpho-dynamic interactions that occur at the river mouth are still largely unexplored given different concurring phenomena, deriving from both river hydraulics and marine hydrodynamics. Against the high technical-scientific interest, the calibration of the hydrodynamic models of coast-mouth interaction presents,a lack of possible observations, due to both the spatial extension of domains and to their strong two-dimensional pattern.

To overcome this, the present work investigates the possibility of using satellite images, as tools for calibrating and validating hydrodynamic numerical models, an approach already successfully used over the years in the field of hydrological modelling.

For this purpose, hydrodynamic model (TELEMAC2D) were used to simulate the hydrodynamic components and the relative sediment transport  components (SISYPHE), and the pattern of the superficial velocities fields is compered with the remote sensing images.

In this study two different cases study in Adriatic Basin ware analysed. The River Piave (220 km), which flows from the eastern Italian Alps to the North Adriatic Sea, and a river in the southern part of Italy, Ofanto River (134km). The configuration of the Adriatic basin has such a shape as to generate particular tidal and wave conditions, which is why it is important to carry out a hydrodynamic study upstream, using the various drivers both on the river side and on the seaside, such as water discharge, tide, wind, etc. Then, depending on the results obtained from the hydrodynamic model, the dispersion of sediment during a flood event is analysed.

Early results show potential for using satellite images of suspended sediment plumes as calibration targets for numerical models.

How to cite: Menzione, A. and Mancini, M.: Satellite images potentiality for calibration of hydrodynamic model in estuaries and coastal areas, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-78,, 2023.

Session 3 – Data assimilation, artificial intelligence, and hydrological observations

Over the last 40 years remote sensing has significantly changed the way we observe and predict the Earth system, particularly in the oceanographic and meteorological sciences. Today, every General Circulation model (GCM) relies upon advanced and well-established data assimilation (DA) techniques, and Land Surface Models (LSMs) – which are integral components of GCM – have been increasingly using DA to constrain the LSM model predictions with available remote sensing data of hydrological, carbon and energy cycles.

Despite this, the use of DA into hydrological models (HMs) is still operationally limited and the reasons for that lie in 1) the considerable variability between different HMs, with much uncertainty in their respective representations of processes (often conceptual) and their sensitivity to changes in key variables, 2) the contrast between the scale of application of HMs (often smaller than LSMs) and the coarse-scale information provided by remote sensing along with their associated accuracy and, 3) the variety of the data assimilation setups, specificity of the study areas, and pre-processing used by a plethora of studies on the topic which provide a blurred picture on the real benefit of DA of relevant hydrological variables into HMs (e.g. soil moisture, precipitation, snow, terrestrial water storage anomalies).

The recent exponential grown of high-resolution remote sensing data (the European Union's Earth observation Programme Copernicus with the constellation of the Sentinel satellites is a notable example) has potentially opened new opportunities for improving our HMs also for small scale applications.  However, their usefulness is still limited by our ability to analyse and integrate efficiently a large volume of observations with current hydrologic models. In other words, most of the issues mentioned above have been not overcome with a consequent under-exploitation of potentially useful information to constrain HMs.

This contribution aims to summarize the main challenges and opportunities of DA into HMs from a hydrological perspective in light of the availaiblity of new and more skillful Earth observations. It identifies and explains critical challenges by using published literature by the author on European catchments as well as on-going studies, and offers insights for a productive research based on new available models and observations as to build a comprehensive hydrologic data assimilation framework that is a critical component of future hydrologic observation and modelling systems.

How to cite: Massari, C.: Data assimilation of remote sensing observations into hydrological models: challenges and perspectives in light of a new era of Earth observations, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-6,, 2023.

GC8-Hydro-21 | Orals | Session 3

Assimilation of Sentinel-1 backscatter data into AquaCrop v7 for soil moisture and biomass updating over Europe 

Shannon de Roos, Louise Busschaert, Michel Bechtold, Zdenko heyvaert, Sujay Kumar, Hans Lievens, Jonas Mortelmans, Dirk Raes, Samuel Scherrer, Maxime Van den Bossche, Elias Fereres, Margarita Garcia-Vila, Pasquale Steduto, Theodore Hsiao, Lee Heng, Maher Salman, and Gabrielle De Lannoy

Recent advances in gridded crop modeling and satellite observations help to improve the monitoring of crop growth and water requirements. In this contribution, we use AquaCrop v7 within the NASA Land Information System (i) to produce spatially distributed estimates of soil moisture, biomass and backscatter, and their uncertainty, and (ii) to assimilate backscatter observations from the Sentinel-1 satellite mission to improve soil moisture and biomass via state updating, at 1 km resolution over Europe. The results are evaluated against in situ observations of soil moisture and satellite-based vegetation products. We will discuss the opportunities and challenges of high-resolution gridded crop models and satellite-based active microwave data for agricultural applications. 

How to cite: de Roos, S., Busschaert, L., Bechtold, M., heyvaert, Z., Kumar, S., Lievens, H., Mortelmans, J., Raes, D., Scherrer, S., Van den Bossche, M., Fereres, E., Garcia-Vila, M., Steduto, P., Hsiao, T., Heng, L., Salman, M., and De Lannoy, G.: Assimilation of Sentinel-1 backscatter data into AquaCrop v7 for soil moisture and biomass updating over Europe, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-21,, 2023.

GC8-Hydro-64 | Orals | Session 3

Landslide Early Warning System based on Machine learning and radar data 

Giovanni Francesco Santonastaso, Pasquale Marino, Daniel Camilo Roman Quintero, and Roberto Greco

In the area of Casamicciola, on the island of Ischia, in the Gulf of Naples, on November 26, 2022, heavy rain triggered landslides that killed people and caused great damage to buildings and roads. Rain gauges on the island recorded heavy rainfall starting at midnight on November 25. The 6-hour cumulative rainfall (between 00:00 on 25/11 and 06:00 on 26/11) resulted 126 mm. The peak hourly rainfall at the two nearest rain gauges was 51.6 mm in Forio and 50.4 mm in Monte Epomeo, attained just before the triggering of the major landslide. The attainment of critical rainfall depth was so sudden, that rain gauges recordings did not allow deploying timely risk mitigation measures. In this context, an effective Landslide Early Warning System (LEWS), based not only on rain gauges, would be an important tool to mitigate the impact of landslides. The goal of a LEWS is to provide timely information to individuals and organizations, so that they can take appropriate actions to reduce the risk. These systems typically use a combination of monitoring networks and modeling techniques, to issue real-time warnings when the probability of a landslide becomes high. A well-designed LEWS can save lives, reduce property damage, and minimize the economic impact of the events.

In this paper, a novel approach to LEWS, based on machine learning and radar data, is proposed. Specifically, a random forest model is trained to define pre-alarm thresholds based on radar measurements available on the portal MISTRAL (Mistral portal Meteo Italian SupercompuTing poRtAL), and on rainfall measurements from four rain gauges on the island of Ischia. Two concentric monitoring areas around the island of Ischia are divided into 16 sectors, and the model evaluates every five minutes the percentage of nodes in each sector where the rainfall height detected by the radar exceeds assigned thresholds, corresponding to pre-alarm stages. Preliminary results show the prospects of using machine learning in LEWS.

How to cite: Santonastaso, G. F., Marino, P., Roman Quintero, D. C., and Greco, R.: Landslide Early Warning System based on Machine learning and radar data, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-64,, 2023.

GC8-Hydro-42 | Orals | Session 3

Optimizing irrigation parameters to improve land surface model irrigation simulations: an example over the Po Valley, Italy 

Sara Modanesi, Gabriëlle J. M. De Lannoy, Michel Bechtold, Louise Busschaert, and Christian Massari

Improving the knowledge of agricultural water uses is in the spotlight of hydrologic sciences and water management authorities due to an increasing amount of water used for irrigation. An efficient water management system has a crucial role also considering the climate change projections scenario and the large increase in the frequency, duration, and severity of droughts, especially over the Mediterranean basin, which has been recognized as a hotspot of extreme weather events. However, simulating irrigation through large scale land surface models is not trivial, because the simplistic model parameterization do not necessarily resolve field scale conditions. In particular, the main challenge is to reproduce the amount and timing of irrigation applications by farmers, because these are often not physically-based and effectively driven by water policies instead of root zone soil moisture conditions.

Some recent approaches have demonstrated the utility of remote sensing observations to either derive irrigation directly, or indirectly via their assimilation into land surface and hydrological models. Indeed, high resolution remote sensing offers an unprecedented opportunity to observe the soil/vegetation system and to consequently detect irrigation. However, although both methods seem promising, irrigation quantification and detection are still at their infancy due to limitations of both satellite data and models. In particular, recent data assimilation experiments have shown the crucial role of an accurate land surface model parameterization to optimally integrate models and satellite observations.

The aim of this study is to test the benefit of directly optimizing the irrigation parameters of a sprinkler irrigation module embodied in the Noah MP land surface model running within the NASA Land Information System framework. The experiment was conducted over a highly irrigated area in the Po Valley (Italy) using synthetic irrigation benchmark data and at a spatial resolution of 0.01°. The improvement of the poorly-parameterized sprinkler irrigation scheme through a proper calibration is intended to be a valid alternative to quantify agricultural water uses.

How to cite: Modanesi, S., De Lannoy, G. J. M., Bechtold, M., Busschaert, L., and Massari, C.: Optimizing irrigation parameters to improve land surface model irrigation simulations: an example over the Po Valley, Italy, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-42,, 2023.

Due to soil moisture and vegetation's critical role in controlling land-atmosphere interactions, detailed and accurate hydrological and ecological information is essential to understand, monitor, and predict hydroclimate extremes (e.g., droughts and floods), natural hazards (e.g., wildfires and landslides), irrigation demands, weather, and climate dynamics. While in-situ soil moisture and vegetation biomass measurements can provide detailed information, their representativeness is limited, and networks of sensors are not widely available. Multispectral satellite observations offer global coverage, but retrievals can be infrequent or too coarse to capture the local extremes. This observation data gap limits the use of such information to adequately represent land surface processes and their initialization conditions for seasonal to sub-seasonal (S2S) prediction models. To bridge this gap, the assimilation of remote sensing observations into land surface models at hyper-resolution spatial scales (< 100 meters) provides a pathway forward to (i) reconcile model and observation scales and (ii) enhance S2S hydroclimate predictability in Earth System Models.

To this aim, we introduce a scalable approach that leverages advances in machine learning, radiative transfer modeling, and in-situ observations to assimilate satellite observations into unstructured tile-based land surface models. In this approach, a machine learning model is trained to harness information from big environmental datasets and in-situ observations to learn how the physical model and satellite biases are related to specific hydrologic conditions and landscape characteristics and how these biases evolve over time. We demonstrate the added value of this approach for improving soil moisture and vegetation dynamics at the hyper-resolution scales by assimilating MODIS Leaf Area Index and NASA’s SMAP brightness temperature observations into the LM4.0 – the land model component of the NOAA-GFDL Earth System Model. To this end, we performed stand-alone LM4.0 simulations between 2000 to 2021 over the Continental United States, with the MODIS and SMAP assimilation performed from 2002 and 2015, respectively, until the present day. Soil moisture estimates are evaluated against independent in-situ observations. To quantify the approach added value for S2S predictability, we compare the impact of soil moisture and vegetation data assimilation on root zone soil moisture, runoff, vegetation biomass, surface temperature, and evapotranspiration.

How to cite: Vergopolan, N.: Leveraging advances in hyper-resolution soil moisture and vegetation land data assimilation for S2S hydroclimate applications, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-82,, 2023.

GC8-Hydro-44 | Orals | Session 3

From observations towards operational site-specific soil moisture ensemble forecasting 

Richard Hoffmann, Klaus Görgen, Heye Bogena, and Harrie-Jan Hendricks-Franssen

The use of numerical models for real-time management of water resources is becoming increasingly popular as the increasing frequency and intensity of extreme weather events negatively affect society, agriculture and crop yields. Prolonged droughts are becoming the new normal, which, among other things, increase the need for operational, site-specific soil moisture forecasting. A model that provides accurate site-specific soil moisture forecasts can support agriculture by contributing to precision irrigation and the provision of important information for crop planning, yield maximization and the coordination of field operations. Soil moisture assimilation has proven potential to provide appropriate initial conditions for such a forecast model. However, the operational estimation of an initial condition requires model-specific protocols for continuously incorporating new observational data into models for hydrological, crop, land surface, vadose zone, or subsurface processes that are not yet widely available. In this study, we present an automated data pipeline for operational, site-specific soil moisture ensemble forecasting based on the Community Land Model Version 5.0 (CLM5) taking the TERENO agricultural research station "Selhausen" in western Germany as an example. CLM5 simulates vegetation states, carbon and nitrogen pools prognostically. We compare land surface model prediction quality (e.g., soil moisture, crop yield) with and without weather forecasts and with and without near real-time soil moisture data assimilation. Climatological mean time series and 10-day ensemble weather forecasts from the German Weather Service, aggregated to the grid cell, are the atmospheric forcings in simulating future states. Forecasts start from the states of the last simulation time step with on-site measurements of precipitation, wind speed, air temperature, air pressure, relative humidity, and global radiation as the atmospheric forcings. In parallel with forward simulations from 2011-2021 (open loop experiment), soil moisture assimilation is being performed for 2018-2021 to generate site-specific initial conditions for the land surface model with reduced uncertainty. Forecasts starting from initial conditions based on soil moisture assimilation are more reliable as model bias is reduced. Preliminary results show that the inclusion of site-specific weather forecast uncertainties in the model improves the simulation of soil moisture dynamics at the plot scale and is thus important for optimizing irrigation schedules while keeping crop productivity stable.

How to cite: Hoffmann, R., Görgen, K., Bogena, H., and Hendricks-Franssen, H.-J.: From observations towards operational site-specific soil moisture ensemble forecasting, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-44,, 2023.

GC8-Hydro-53 | Orals | Session 3

Identification of hydrological controls of slope response to precipitations using machine learning techniques 

Daniel Camilo Roman Quintero, Pasquale Marino, Giovanni Francesco Santonastaso, and Roberto Greco

The assessment of the response of slopes to precipitations is important for several applications: from drought associated problems to the evaluation of the occurrence of threatening events such as floods and landslides (Bogaard & Greco, 2016). This study aims at identifying the most important variables, that can be monitored in the field, suitable to describe the initial conditions that control the capability of a slope to store infiltrating water at the end of precipitation events. The case study of the slopes near the town of Cervinara, southern Italy, is presented, where field observations and laboratory experiments allowed the understanding of the water processes at different scales (Marino et al., 2020). A synthetic dataset, simulating the major hydraulic processes observed in the field, was generated to enrich the available data. It was built by simulating the response of the slope to a 1000-year long synthetic rainfall series, generated with the NSRP model, with a physically based model coupling the unsaturated flow in the coarse granular soil cover with the shallow aquifer hosted by the uppermost part of the underlying fractured limestone bedrock (Marino et al., 2021). The hydraulic behavior of the soil cover is modelled with the 1D Richards’ equation, while the aquifer, connected to the soil cover through its lower boundary condition, is modelled as a simple linear reservoir.

Two variables expressing underground antecedent conditions, one hour before any rainfall event, were analyzed: mean water content in the uppermost meter of the soil cover and aquifer water level. The slope response was quantified as the fraction of rainwater remaining stored in the soil cover at the end of any rainfall event. The non-linear relationships linking the three variables were studied with clustering and random forest techniques, allowing the identification of three major hydrological conditions. The first one is linked to dry seasons, when the lowest aquifer water level coincides with soil water content below field capacity: in this condition, rainwater tends to remain completely stored in the soil at the end of rain events. Once the soil cover overcomes the field capacity, two different conditions are found. When the aquifer water level is high, active drainage through the soil-bedrock interface limits the increase of water stored in the soil cover. Conversely, when the aquifer water level is low, it corresponds to impeded drainage, i.e., there is little leakage from the soil cover to the bedrock. In this condition, most rainwater tends to remain stored in the soil cover even when it is already wet at the beginning of the rain event.




Bogaard, T., & Greco, R. (2016). Landslide hydrology: from hydrology to pore pressure. Wiley Interdisciplinary Reviews: Water, 3(3), 439–459.

Marino, P., Comegna, L., Damiano, E., Olivares, L., & Greco, R. (2020). Monitoring the hydrological balance of a landslide-prone slope covered by pyroclastic deposits over limestone fractured bedrock. Water (Switzerland), 12(12).

Marino, P., Santonastaso, G. F., Fan, X., & Greco, R. (2021). Prediction of shallow landslides in pyroclastic-covered slopes by coupled modeling of unsaturated and saturated groundwater flow. Landslides, 18(1), 31–41.

How to cite: Roman Quintero, D. C., Marino, P., Santonastaso, G. F., and Greco, R.: Identification of hydrological controls of slope response to precipitations using machine learning techniques, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-53,, 2023.

GC8-Hydro-77 | Orals | Session 3

Assimilation of measurements from hydrological observatories for better terrestrial system model predictions: experiences and challenges 

Harrie-Jan Hendricks-Franssen, Fang Li, Lukas Strebel, Haojin Zhao, Heye Bogena, and Harry Vereecken

The hydrological observatory for the Rur catchment (2400 km2) in Germany is highly equipped including 15 Cosmic Ray Neutron Sensors (CRNS) to measure soil moisture content, 6 eddy covariance stations with measurement of land-atmosphere exchange fluxes and further micrometeorological observations, and additional monitoring stations for river discharge and groundwater levels, amongst others. In addition, 3 intensive research sites at representative locations have been implemented with distributed soil moisture and temperature monitoring. These measurements allow for a better local verification of terrestrial model predictions, and the improvement of model predictions by model-data fusion methods. We did a series of studies on the assimilation of observations from the Rur observatory to improve predictions with the Terrestrial Systems Modelling Platform (TSMP), which models water, energy, carbon and nitrogen cycles of the land surface and subsurface. The data assimilation algorithm was in most cases the Ensemble Kalman Filter, but also the Particle Filter and Markov Chain Monte Carlo were used. Assimilated observations included soil moisture (from FDR-probes, CRNS or remote sensing), groundwater levels and net ecosystem exchange. We found that assimilation improved the characterization of the measured variable, also at verification locations. However, states and fluxes of variables that were not assimilated, such as evapotranspiration, often were not better characterized. The results suggest the importance of the joint assimilation of measurements for different variables, including remotely sensed information and vegetation information.

How to cite: Hendricks-Franssen, H.-J., Li, F., Strebel, L., Zhao, H., Bogena, H., and Vereecken, H.: Assimilation of measurements from hydrological observatories for better terrestrial system model predictions: experiences and challenges, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-77,, 2023.

Data assimilation techniques allow for optimally merging remote sensing observations in ecohydrological models, guiding them for improving land surface flux predictions. Nowadays freely available remote sensing products, like those of Sentinel 1 radar, Landsat 8, and Sentinel 2 sensors, allow for monitoring land surface variables (e.g., radar backscatter for soil moisture and the normalized difference vegetation index, NDVI, for leaf area index, LAI) at unprecedented high spatial and time resolutions, appropriate for heterogeneous ecosystems, typical of semi-arid ecosystems characterized by contrasting vegetation components (grass and trees) competing for water use. An assimilation approach that assimilates radar backscatter and grass and tree NDVI in a coupled vegetation dynamic-land surface model is proposed. It is based on the Ensemble Kalman filter (EnKF), and it is not limited to assimilate remote sensing data for model predictions, but it uses assimilated data for dynamically updating key model parameters (the ENKFdc approach), the saturated hydraulic conductivity, and the grass and tree maintenance respiration coefficients, which are highly sensitive parameters of soil water balance and biomass budget models, respectively. The proposed EnKFdc assimilation approach facilitated good predictions of soil moisture in an heterogeneous ecosystem in Sardinia, for 5 years period with contrasting hydrometeorological (dry vs wet) conditions. Contrary to the EnKF-based approach, the proposed EnKFdc approach performed well for the full range of hydrometeorological conditions and parameters, even assuming extremely biased model conditions with very high or low parameter values compared to the calibrated (“true”) values. The EnKFdc approach is crucial for soil moisture and LAI predictions in winter and spring, key seasons for water resources management in Mediterranean water-limited ecosystems. The use of ENKFdc also enabled us to predict evapotranspiration and carbon flux well, with errors less than 4% and 15%, respectively, although the initial model conditions were extremely biased.

How to cite: Montaldo, N. and Corona, R.: On the Assimilation of Remote Sensing Data for Soil Moisture and Leaf Area Predictions Using an Ensemble-Kalman-Filter-Based Assimilation Approach in a tree-grass Mediterranean Ecosystem, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-71,, 2023.

GC8-Hydro-15 | Poster | Session 3

A Swiss-wide network of hydro(geo)logical observatories 

Christian Moeck

In recent years, important water-relevant research results have been achieved and numerous emerging issues have been identified. The posed challenges have to be elaborated, and solutions and measures must be developed. In this context, there is a great need to ensure a continuous competence building and to promote an exchange of results, protocols, infrastructure, and equipment as well as hydrological data. Among the different fresh water sources, groundwater is expected to play a key role in a resilient water future. For this reason, hydrogeological observatories are more necessary than ever.

Several existing, long-term hydrogeological observatories within Switzerland are currently being organized into a long-term national hydrogeological observatory network with the support of the Swiss groundwater network (CH-GNet; The current hydrogeologic observatories are complementary in terms of elevation, geology, use, and scientific as well as practical objectives. These observatories are managed by research groups or practice partners to ensure long-term operability. The observatories are heavily instrumented for long-term hydraulic and chemical water monitoring and are supplemented by field experiments and investigations. It is envisioned that synergies will be created to promote joint and future experiments by a large number of research groups with different expertise. In addition, these observatories are and will be an important tool to train students. National and international research groups have the opportunity to further develop approaches and improve their knowledge under "real" working conditions, as well as to develop and validate modelling and predictive numerical tools. The hydrogeological observatories are constantly further developed and we are open for any suggestions, remarks, and new partners. In our contribution, we present the already existing observatories, goals and the way forward.

How to cite: Moeck, C.: A Swiss-wide network of hydro(geo)logical observatories, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-15,, 2023.

GC8-Hydro-114 | Poster | Session 3

Spatial patterns for canopy drainage translate into soil moisture dynamics – empirical evidence 

Anke Hildebrandt, Christine Fischer-Bedtke, Johanna Clara Metzger, Gökben Demir, and Thomas Wutzler

Heterogeneity in below canopy precipitation has often been hypothesized to induce spatial variation of soil water content especially in forests. However, we are not aware of any observational study relating the spatial variation of soil water content directly to net precipitation or alternatively to deep percolation. Here, we investigate whether throughfall patterns affect the spatial heterogeneity of soil water response in the main rooting zone. We assessed rainfall, throughfall and soil water contents (two depths: 7.5 cm and 27.5 cm) in a very dense observation network on a 1‐ha temperate mixed beech forest plot in Germany during two growing seasons. Because throughfall and soil water content cannot be measured at the same location, we used kriging to derive the throughfall values at the locations where soil water content was measured. 

Throughfall spatial patterns were related to canopy density. Although spatial auto-correlation decreased with increasing event sizes, temporally stable throughfall patterns emerged, leading to reoccurring high and lower input locations across precipitation events. A linear mixed effect model analysis showed, that soil water content patterns were only poorly linked to throughfall spatial patterns, and it was rather shaped by unidentified but time constant factors. Instead the increase soil water content after rainfall corresponded more closely to throughfall input patterns. Furthermore, soil water patterns additionally affected how much water was stored, and ancillary data suggest that this was related to preferential flow. 

In this comprehensive study we show that throughfall patterns imprint less on soil water contents and more on soil water dynamics shortly after rainfall events, therefore only partly confirming previous modelling with data. Our findings highlight at the same time systematic patterns of times and locations where the capacity to store water is reduced and water probably conducted quickly to greater depth. Our results indicate percolation patterns may already be triggered in the canopy.

How to cite: Hildebrandt, A., Fischer-Bedtke, C., Metzger, J. C., Demir, G., and Wutzler, T.: Spatial patterns for canopy drainage translate into soil moisture dynamics – empirical evidence, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-114,, 2023.

GC8-Hydro-17 | Poster | Session 3

Assimilation of soil moisture data from cosmic-ray neutron sensors into the integrated Terrestrial System Modeling Platform TSMP (case study: Rur catchment in Germany) 

Fang Li, Heye Reemt Bogena, Bagher Bayat, Wolfgang Kurtz, Harry Vereecken, and Harrie-Jan Hendricks Franssen

Cosmic-ray neutron sensors (CRNS) measure soil moisture in real-time at the field scale, bridging the gap between in situ measurements and remote sensing products. This is promising and has the potential to enhance hydrological model predictions through the assimilation of CRNS data and improve the estimation of model parameters. In this study, soil moisture measurements from a network of 13 CRNS in the Rur catchment (~2000km2, Germany) were assimilated into the integrated model Terrestrial System Modelling Platform (TSMP) by the ensemble Kalman filter (EnKF). In total 128 ensemble members were generated by perturbing atmospheric forcing variables and soil textures to account for the uncertainties. The data assimilation experiments (with and without soil hydraulic parameter estimation) were carried out in both a wet year (2016) and a dry year (2018), and later validated using an independent year (2017) without assimilation. The objectives of this study were to investigate the potential of CRNS assimilation for improving soil moisture and evapotranspiration (ET) characterization, estimation of soil hydraulic parameters at the catchment scale, and analysis of whether the data assimilation performance differs between wet and dry years. The data assimilation experiments showed that soil moisture estimation was significantly improved during the assimilation period at measurement locations, with a root mean square error (RMSE) reduction (compared to open loop simulations without assimilation) in the range of 36-60% either in the dry or wet year, and the improvements were limited by the measurement error of CRNS (0.03 cm3/cm3). The joint state-parameter estimation gives better performance than state estimation alone (more than 15% RMSE reduction), and 9% RMSE reduction in the verification period with the updated parameter. The jackknife experiments revealed that the measurement network (~1 site per 200 km2) was insufficiently dense because soil moisture characterization at independent verification locations only improved marginally with large differences between wet and dry years (with an RMSE reduction of 40% in 2016 and 16% in 2018). The improved predictions from the jackknife experiments, however, imply that the assimilation of soil moisture data from a CRNS network still has the potential to improve the soil moisture characterization on the catchment scale by updating the spatially distributed soil hydraulic parameters of the subsurface model. The comparison of simulated ET with the data from eddy covariance (EC) stations demonstrates that it is challenging to achieve great improvements in ET simulations through CRNS soil moisture assimilation (with the RMSE reduction of monthly ET ranging between 6% and 21%).

How to cite: Li, F., Reemt Bogena, H., Bayat, B., Kurtz, W., Vereecken, H., and Hendricks Franssen, H.-J.: Assimilation of soil moisture data from cosmic-ray neutron sensors into the integrated Terrestrial System Modeling Platform TSMP (case study: Rur catchment in Germany), A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-17,, 2023.

GC8-Hydro-93 | Poster | Session 3

An observatory to monitor long-term eco-hydrological changes in Alpine environments: the LTER Matschertal/Val di Mazia. 

Giacomo Bertoldi, Georg Niedrist, Alessandro Zandonai, Nikolaus Obojes, Veronika Fontana, Stefano Brighenti, Francesco Comiti, and Ulrike Tappeiner

The Long Term (Socio-) Ecological Research LT(S)ER site IT25 - Val Mazia/Matschertal is a catchment covering an elevation range between 900 and 3700m a.s.l., in South Tyrol (Italian Alps). While nivo-glacial processes dominate runoff production, lower sideslopes have a relatively dry climate, (ca. 500 mm at 1500m a.s.l.), mainly as summer convective precipitation, and therefore the site is appropriate for space-to-time substitution experiments for understanding mountain eco-hydrologic processes along climatic gradients.

For a better understand of the ecological, hydrological, and climatic processes in the catchment, a spatially distributed micro-meteorological network has been installed since 2009. The measurement infrastructure consists of about 20 stations among all dominant land-use types (grassland, forest, river, proglacial area) covering an elevation range from 1000 to 2700 m a.s.l.. The parameters monitored are mainly related to the 1) Microclimate (air temperature, humidity, wind) 2) Hydrological cycle (soil moisture, soil water potential, runoff, evapotranspiration, solid/liquid precipitation) 3) Energy balance (short/longwave/net radiation, surface heat fluxes) 4) Optical reflectance (Phenocam, NDVI/PRI Sensors). 5) Vegetation (sap-flow. O-H stable isotope monitoring).

The talk will focus on the capability of the collected observations to clarify if the water used by vegetation is coming from snowmelt or mainly from summer precipitation, which is one of the key open research questions in the perspective of a future elevational increase of the rain-snowfall transition zone.

In this contribution, we would like to highlight the potential of the site in a network of hydrological observatories in Europe that allows the testing of hydrologic hypotheses for different environments and climatic regions.

How to cite: Bertoldi, G., Niedrist, G., Zandonai, A., Obojes, N., Fontana, V., Brighenti, S., Comiti, F., and Tappeiner, U.: An observatory to monitor long-term eco-hydrological changes in Alpine environments: the LTER Matschertal/Val di Mazia., A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-93,, 2023.

GC8-Hydro-102 | Poster | Session 3

Twenty years of hydrological observations at Fiumarella of Corleto basin: experimental data, analysis and modeling 

Silvano Fortunato Dal Sasso, Maria Rosaria Margiotta, Beniamino Onorati, Biagio Sileo, Alonso Pizarro, Salvatore Manfreda, Ruggero Ermini, and Mauro Fiorentino

Hydrological observations provided by in situ monitoring networks are essential to better understand hydrological processes and to improve water resource management. This is even more precious for small basins where large spatial coverage or remotely sensed data are not enough to represent hydrological behavior in space and time. In addition, the availability of several years of hydrological data is particularly useful for the application of hydrological models that usually requires long calibration data series in order to provide reliable results. Starting from 2002 and continuing for the subsequent two decades, the "Fiumarella of Corleto" basin, which spans an area of 32.5 km2 and is situated in the Basilicata region of Southern Italy, has been under observation (Manfreda et al., 2011). The basin is located on two slopes with differing land use patterns: the left slope is mostly comprised of agricultural land, while the right slope is predominantly covered by forests. The hydrometeorological network consists of three automated weather stations equipped with various sensors to monitor rainfall, snow depth, temperature, wind speed and direction, air temperature, relative humidity, solar radiation, atmospheric pressure, and hydrometric data. From 2006, a TDR100 system connected to 22 probes located at 11 different sampling sites was used to monitor soil moisture in the sub-basin. The system was set up along a transect measuring approximately 60 meters in length, with probes located at two different depths of 30 and 60 cm. In addition to this, a high-resolution (1x1 m) DSM of the basin was derived using LiDAR to provide a detailed characterization of the morphology of the two slopes. The catchment pedology was investigated through field campaigns and laboratory measurements to identify the primary soil types and units in the basin (Romano et al., 2002; Santini et al., 1999). Monitoring activities were conducted with reference to two different spatial scales: the entire basin (32.5 km2) and the sub-basin (0.65 km2). Hydrological signatures were used to characterize the hydrological behavior of the two drainage areas. Peak flow analyses were performed to define lag-time, soil moisture conditions before flood events evidencing the different hydrological responses of both basin and sub-basin. Some flow indicators (e.g., base flow and recession constant) were used to constrain a semi-distributed hydrological model in order to optimize performances in calibration and validation. In this contribution, an overview of the main results of hydrological data analyses and modeling obtained at different spatial scales is presented.

How to cite: Dal Sasso, S. F., Margiotta, M. R., Onorati, B., Sileo, B., Pizarro, A., Manfreda, S., Ermini, R., and Fiorentino, M.: Twenty years of hydrological observations at Fiumarella of Corleto basin: experimental data, analysis and modeling, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-102,, 2023.

GC8-Hydro-104 | Poster | Session 3

Mobile photogrammetric raster clouds to apply classification of time series data 

János Tamás, Zsolt Zoltán Fehér, Nikolett Kiss, Dávid Pásztor, and Attila Nagy

Vehicle-mounted, wide-angle cameras combined with deep learning algorithms are proving to be a powerful mapping tool (e.g. Google Street View). Such tasks include facilitating adaptation to the increasingly common extreme rainfall events attributed to climate change. Repeatable rapid surveys of agricultural parcels have the potential to combine ground and satellite information over large areas, enabling cost-effective planning of cultivation tasks such as more efficient nutrient supplementation, pest management, irrigation water use. In this paper we describe our experience with a photogrammetric data acquisition system (FODAR).

The vehicle mounted Geometer device takes images every two metres along the routes travelled, which can be evaluated on its cloud-based geographic information platform. The geospatial data can then be displayed and evaluated interactively. On-the-move survey control is also provided. A powerful on-board computer can be used to monitor the recording during fieldwork. After the survey, the software automatically converts the recording metadata for cloud-based processing. It is also possible to determine the geographic position of point objects and measure distances and areas. The artificial intelligence used by the system uses deep learning algorithms to recognize and pinpoint with high accuracy on the map various objects on the surveyed road sections, such as traffic signs, but also fire hydrants, sewer covers, stormwater drains and other objects related to urban hydrology.

The use of such equipment in precision agriculture is not yet widespread, despite the fact that due to its vehicle mountability also can be used for mapping of ploughs or orchards and for effective assessment of crop growth. Our aim in using the tool was to build a prototype workflow to evaluate the data set that is expected to become available in the near future.

Patterns in the data, such as vegetation health, that are present in the data and have not been investigated so far, could lead to an increase in the profitability of management decisions by including the near-infrared band in photogrammetric analyses. In contrast to teaching deep learning algorithms, the object detection and image classification itself can be done with relatively little hardware effort, but future trends must be taken into account. For processing a large number of images submitted by cloud-connected vehicles, it may be worth considering a dynamically scalable hardware infrastructure. In addition, objects of agricultural interest identified by the technology could also serve as calibration data for aerial or even spaceborne imagery.

The abstract was funded by European Union’s Horizon 2020 “WATERAGRI Water retention and nutrient recycling in soils and steams for improved agricultural production” research and innovation programme under Grant Agreement No. 858375. Project no. TKP2021-NKTA-32 has been implemented with the support provided from the Na-tional Research, Development and Innovation Fund of Hungary, financed under the TKP2021-NKTA funding scheme.

How to cite: Tamás, J., Fehér, Z. Z., Kiss, N., Pásztor, D., and Nagy, A.: Mobile photogrammetric raster clouds to apply classification of time series data, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-104,, 2023.

Soil drainage flux is crucial for determining agrochemical loading and groundwater recharge. Because soil drainage is difficult to measure, it is typically predicted using soil moisture models. However, different soil moisture models have been shown to produce different drainage values although they all respected the same soil measurements well, leading to a non-uniqueness problem. To address this issue, this study used groundwater level, stream flow, and tile drainage measurements along with soil moisture data to constraint soil drainage estimation through a coupled soil and groundwater modeling framework in the Cross River watershed in Prince Edward Island, Canada. A 1D Richards equation model, LEACHM, was developed to predict soil drainage and calibrated using soil moisture data. A 3D watershed-scale MODFLOW model was built and calibrated against groundwater level data. The two models were loosely coupled using the soil drainage predicted by LEACHM as recharge. Forward coupled LEACHM and MODFLOW simulations were performed until simulated daily soil moisture, groundwater level, baseflow, and tile drainage values simultaneously matched the 2011–2014 observed values within prescribed error ranges by fine tuning the hydraulic parameters in coupled models. The coupled models were then verified using 2015–2016 data. The resulting LEACHM simulations matched the soil moisture data with less than 15% error, and MODFLOW simulations matched the groundwater level and base flow data, except for a few short periods when LEACHM overestimated soil drainage under deep snow cover. Although the timing of simulated soil drainage corresponded with the occurrence of tile drainage, the simulated soil drainage was generally higher than the tile drainage, which is considered reasonable because tiles intercept only a portion of the overall soil drainage. This exercise demonstrates that the coupled modeling respected multiple hydrological data sources instead of soil moisture alone, and thus enhanced soil moisture estimation.

How to cite: Jiang, Y. and the Yefang Jiang: Using multiple hydrological data sources to reduce uncertainty in soil drainage modeling, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-30,, 2023.

GC8-Hydro-87 | Poster | Session 3

Observing soil moisture dynamics on starch potato fields for improving irrigation management based on hydrological simulations 

Jan Lukas Wenzel, Christopher Conrad, Thomas Piernicke, Kristin Haßelbusch, Falk Böttcher, and Julia Pöhlitz

In the view of global freshwater availability and an increasing water demand in agriculture to secure world nutrition, efficient water use is a key factor for sustainable irrigation management. Irrigation decision support systems often show a lack of awareness on intra-site and variety-specific optimum ranges of plant available water content, which enhances the ineffective use of irrigation water. In potato production, all phenological stages are sensitive to insufficient water supply, with optimum soil water contents ranging between 40% and 90% plant available water content. Hence, observations and simulations of soil moisture dynamics are crucial information for irrigation management. In a study to be presented we aim (i) to assess the optimum irrigation level for starch potatoes in terms of plant available water dynamics, and (ii) to compare the suitability of three different model environments for simulating soil moisture dynamics.

Four test plots (each 172 m x 72 m) were installed during the growing seasons 2021 and 2022 on two loamy sands (27 ha and 35 ha) in Mecklenburg-Western Pomerania, Germany, within one gun sprinkler irrigation lane. In each test plot, one irrigation level was applied: the longtime used irrigation level of the local farmer (100%), two deficit irrigation levels (80%, 90%), and one abundant irrigation level (120%). The 100% irrigation level was 119.2 mm in 2021 and 132.8 mm in 2022. The soil hydraulic properties determined in laboratory are typical for a loamy sand with soil moisture of 0.196 m3 m-3 at field capacity and 0.038 m3 m-3 at permanent wilting point. Hourly and daily simulations of root-zone (0-60 cm) soil moisture dynamics were performed using the evapotranspiration-based “Agrarmeteorologisches Modell zur Berechnung der aktuellen Verdunstung” (AMBAV) model and the soil hydraulic properties-based HYDRUS-1D and HYDRUS-2D model environments. In-situ soil moisture measurements, observed in three-time replicates per test plot in 10 cm increments up to a depth of 60 cm, were used for validation.

Field measurements confirmed that all irrigation levels impacted plant available water contents. They ranged between 25% and 65% at the 80% irrigation level, between 42% and 94% at the 90% irrigation level, between 50% and field capacity at the 100% irrigation level and between 64% and 109% at the 120% irrigation level. All three model environments provide reliable simulation results at all irrigation levels, with an average coefficient of determination (R2) of 70.13% (AMBAV), 76.62% (HYDRUS-1D) and 81.13% (HYDRUS-2D). Simulated soil moisture dynamics varied stronger in topsoil than in subsoil layers, mainly due to the soil hydraulic properties of a potato dam and the effects of evapotranspiration.

The in-situ measured soil moisture dynamics confirm the capability of a 90% irrigation level for starch potatoes. AMBAV´s lower input parameter requirements ensure a greater dispersion of simulated soil moisture dynamics, when compared to more precise estimations by both HYDRUS environments. The inclusion of soil hydraulic properties in irrigation scheduling provides practice-relevant information, e.g., the actual irrigation demand of a specific crop, and enables the use of hydrological models for irrigation scheduling instead of in-situ measurements.

How to cite: Wenzel, J. L., Conrad, C., Piernicke, T., Haßelbusch, K., Böttcher, F., and Pöhlitz, J.: Observing soil moisture dynamics on starch potato fields for improving irrigation management based on hydrological simulations, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-87,, 2023.

GC8-Hydro-68 | Poster | Session 3

GIS-based Framework and AI Approaches to support Decision Makers in Implementation of Climate-adaptive Design Solutions 

Vittorio Miraglia, Maria Fabrizia Clemente, Valeria D'Ambrosio, and Ferdinando Di Martino

Urban and metropolitan settlements, due to the growing impacts of climate change, are highly at risk from critical hydro-meteorological hazards (HMHs), such us floods and heatwaves.
Future climate change scenarios require the implementation of resilient design solutions taking into account the climate projections, as well as vulnerability and exposure. In this context, we propose a GIS-based framework aimed at supporting decision-makers in designing long-term climate adaptive design solutions. The framework is developed starting from input data assimilation; then, using AI machine learning and decision-making techniques, are executed aggregations and classifications of urban physical features in order to assess the spatial distribution of vulnerability and risk indicators.
In particular, it is proposed a method to verify the resilient efficacy of nature-based solutions in reducing potential economic damages produced by coastal floods events, and simultaneously improving the open spaces heatwave vulnerability.

How to cite: Miraglia, V., Clemente, M. F., D'Ambrosio, V., and Di Martino, F.: GIS-based Framework and AI Approaches to support Decision Makers in Implementation of Climate-adaptive Design Solutions, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-68,, 2023.

GC8-Hydro-62 | Poster | Session 3

Evapotranspiration partitioning over irrigated wheat in a semi-arid region using in-situ measurements and AquaCrop model. 

El houssaine Bouras, Abdelhakim Amazirh, Zoubair Rafi, Lionel Jarlan, Said Khabba, Olivier Merlin, and Salah Er-Raki

Accurate estimation of the partitioning of actual evapotranspiration (ETa) into plant transpiration (Tr) and soil evaporation (E) is difficult but important for assessing biomass production and the allocation of increasingly scarce water resources. This work aims to evaluate the performance of the AquaCrop model to estimate actual crop ETa and its components (Tr and E) over drip irrigated wheat fields in the semi-arid region of Morocco. Field experiments were carried out during 2016-2017 season on an irrigated winter wheat field in semi-arid region of Morocco. Wheat ETa and its partitioning components (Tr and E) were measured by using the eddy covariance (EC) system and the sap flow system (SF). The obtained results showed that the AquaCrop model adequately simulated canopy cover (CC), ETa and wheat biomass. The coefficient of determination (R2) between observed and measured CC, ETa and biomass were 0.98, 0.72 and 0.98 respectively. With regard to the ETa partitioning, the results indicate that the estimate of Tr using the AquaCrop model is well consistent with those of the in-situ measurements with SF. The Root mean square error (RMSE) between the observed and simulated Tr was about 0.60 This work demonstrates that the AquaCrop model has reliable accuracy in simulating wheat growth, production and ETa partitioning. As a result, this model provides a technical means of application to formulate optimal irrigation schedules.

How to cite: Bouras, E. H., Amazirh, A., Rafi, Z., Jarlan, L., Khabba, S., Merlin, O., and Er-Raki, S.: Evapotranspiration partitioning over irrigated wheat in a semi-arid region using in-situ measurements and AquaCrop model., A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-62,, 2023.

GC8-Hydro-70 | Poster | Session 3

A comparison of multi-source actual evapotranspiration estimates to derive a combined dataset over Italy 

Carmelo Cammalleri, Chiara Corbari, and Marco Mancini

Actual evapotranspiration (ET) is one of the key quantities of the hydrological cycle, with a central role in many applications including crop water stress assessments, analysis of green water scarcity and studies on drought conditions. Due to the sparseness of ET measurements, large scale estimates are often based on models, which outputs are usually validated only on a limited number of sites. This results in a large variety in the estimates, with differences in magnitude that can limit engineering applications based on volumes. In this study, five ET datasets are compared over Italy, with the final goal to design a strategy for a robust assessment of a combined product over the climatological reference period 1991-2020 at monthly scale and at a moderate spatial resolution (i.e., 1-km). The datasets analyzed in this study include estimates from: 1) the BIG BANG water balance project; 2) the MODIS satellite product MOD16; 3) the LSA SAF product based on Meteosat; 4) the CEMS-LISFLOOD hydrological model; and 5) the SSEBop simplified surface energy balance. Preliminary results show a good spatial coherence between all the datasets over winter (DJF) and summer (JJA) – mainly driven by the marked north-south gradients during these months – but also non negligible systematic differences in the modeled ET magnitudes. A good consistency between anomaly values is also observed for many datasets. With the aim to preserve both the inter-annual variability and the temporal consistency of the time series, a strategy based on the separation between the climatological dynamic and the monthly anomalies is proposed for the combined dataset.

How to cite: Cammalleri, C., Corbari, C., and Mancini, M.: A comparison of multi-source actual evapotranspiration estimates to derive a combined dataset over Italy, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-70,, 2023.

Session 4 – Using O-H stable isotopes for studying hydrological process understanding and the history of flowing waters

GC8-Hydro-101 | Orals | Session 4

Towards the mechanistic understanding of plant-source water isotopic offsets 

Adrià Barbeta, Teresa Gimeno, Lisa Wingate, and Jérôme Ogée

In recent years, the widespread use of laser-based analyzers of the isotopic composition of water (δ18O and δ2H) resulted in an increase in the temporal and spatial resolution of measurements of plant water and their sources. Such datasets revealed previously undetected mismatches between the isotopic composition of subsurface water pools and bulk xylem water usually extracted by cryogenic distillation. To understand the underlying cause of these isotopic mismatches, plant ecophysiologists and ecohydrologists have conducted numerous experiments to address a range of hypotheses. Measurement artifacts produced by water extraction techniques in both bulk xylem water and soil water were claimed to be behind the observed mismatches. However, there is not yet a consensus on a sole mechanism to explain all cases. On the other hand, our research demonstrated the existence of isotopic heterogeneities between the water in different xylem compartments, which also have contrasting degrees of hydraulic connectivity with the transpiration stream. Analogous isotopic patterns were observed in soil water pools and attributed to physicochemical interactions with soil particles. Altogether, it seems that the water pools that are measured matter, and that not all isotopic mismatches can be attributed to methodological artifacts. Given the widespread occurrence of these isotopic mismatches, it is urgent to identify the cause, either natural, artificial, or both. This will allow us to make informed choices of the extraction techniques in each situation and eventually, we could be able to correct potentially biased old datasets. In this regard, we will summarize the most recent findings and suggest research strategies to unravel the underlying mechanisms of isotopic mismatches. In addition, we will outline how such strategies can also provide important insights for closely related disciplines such as plant hydraulics or isotopic analyses of tree-ring archives.

How to cite: Barbeta, A., Gimeno, T., Wingate, L., and Ogée, J.: Towards the mechanistic understanding of plant-source water isotopic offsets, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-101,, 2023.

GC8-Hydro-109 | Orals | Session 4

Xylem water isotopic variability in Fagus sylvatica L.: potential impacts for ecohydrology 

Christophe Hissler, Alessandro Montemagno, Richard Keim, and Laurent Pfister

Understanding water dynamics in the Critical Zone is key for designing better water management strategies, particularly in the light of climate change. Of specific interest in this context is the large amount of water exchanged between regolith and trees in forest ecosystems. In the coming years and decades, the frequency of droughts is likely to increase during vegetative periods. The lack of understanding of how and where tree water uptake is taking place across different regolith layers becomes a critical economic and social issue – spanning from water resources to forest management, even in temperate ecosystems.

Stable isotopes of water have been largely used as tracers in ecohydrology, contributing enormously to the development of various hypotheses and interpretations on tree water uptake dynamics and evapo-transpiration fluxes. However, many issues remain when using O-H stable isotopes to trace the origin of the tree water uptake. The lack of standard protocols for tree water sampling and analysis, alongside the little attention given to the effect that tree physiology and biochemistry may have on the isotopic composition of xylem water, is a limitation to the use of these tracers in the regolith-tree continuum.

In this work, we present tree sap O and H isotopic data collected during three years with two different techniques: (i) an in-situ vacuum extraction of the sap flowing in the xylem vessel and (ii) the well-known cryogenic vacuum distillation applied on wood cores. Nine beech trees were sampled at different heights in the root-twigs continuum along a hillslope in the Weierbach Experimental Catchment in Luxembourg. The O-H isotopic signatures of the samples were then compared for observing differences proper to the techniques and/or to potential effects of internal tree processes controlled by either (1) the retention and mixing of water of different ages and/or (2) water exchange in xylem tissues. The isotopic signatures of the xylem water were also compared with the potentially available water sources in the regolith.

We observed a significant difference between the isotopic signatures in water collected with the two different techniques. The water sampling protocol from the root with the in-situ vacuum extraction appears to be more appropriate for the identification of the potentially absorbed water source. We conjecture that roots are the first tree organ that interacts with the regolith water and in which a lesser impact from the internal tree processes can be expected. Our results also show a progressive 18O and 2H enrichment in the xylem water along the root-twig flow path for all studied trees. This enrichment seems to be closely related to the travel-distance inside the xylem: the longer the water is exposed to the internal tree processes, the stronger the modification of its isotopic signature. Finally, the range of the water isotopic signature obtained via cryogenic vacuum distillation is closely related to the tree compartment from which the water was collected from – questioning the contribution to internal tree process understanding from data obtained via this technique.

How to cite: Hissler, C., Montemagno, A., Keim, R., and Pfister, L.: Xylem water isotopic variability in Fagus sylvatica L.: potential impacts for ecohydrology, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-109,, 2023.

GC8-Hydro-19 | Orals | Session 4

How do four-year-old intercropped trees share soil water with wheat in temperate alley-cropping experimental site: evidence from 2H2O artificial labeling? 

Claire O'Connor, Caroline Choma, François Delbende, Bernhard Zeller, Aichatou Ndiaye, Hélène Desmyttère, Eric Manouvrier, Ali Siah, Christophe Waterlot, and Kasaina Sitraka Andrianarisoa

Despite numerous studies investigating competition and/or facilitation for soil water resources in alley-cropping systems (AC), share of water at the early stage of trees establishment in AC has been poorly examined. This work aimed to explore the water share between crops and trees after four years of tree establishment in AC at the Ramecourt block design alley-cropping experimental site. In mid-spring, we injected 300 mL of a 10 % deuterated water at 30, 50 and 100 cm soil depth at 1.5 m distance from a referent tree (alder, hornbeam or wild cherry) in AC, in pure-forest control plot with ryegrass (FC) and in a randomly chosen area in monocrop wheat control (CC) plots. The tracer uptake was monitored by collecting tree leaves and wheat and ryegrass (RG) whole-plant samples every two weeks in labeled and unlabeled area. For deuterium natural abundance analyses, the global mean of δ2H was significantly lower for wheat (- 44 ± 4 ‰) than RG (- 27 ± 6 ‰) and trees (- 20 ± 3 ‰), indicating that the most active sites of water absorption were different between these species. The mean wheat δ2H was 2481 ± 523 ‰, 715 ± 218 ‰, and 133 ± 68 ‰ at 30, 50 and 100 cm labeling depth respectively. It was significantly higher in AC (2883 ± 585 ‰) compared to CC (1131 ± 274 ‰) only at 30 cm labeling depth. For trees, the δ2H of labeled samples remained negative unlike wheat. Particularly in AC, alder and wild cherry presented significant higher δ2H 15 and 45 days after labeling, respectively from 50 and 100 cm labeling depth, compared to unlabeled samples. We concluded that trees and wheat took up their water in upper soil layer but in AC, they favored wheat water absorption in topsoil and were able to flexibly shift their water source from deep layer in case of low water availability in the upper soil layer.

How to cite: O'Connor, C., Choma, C., Delbende, F., Zeller, B., Ndiaye, A., Desmyttère, H., Manouvrier, E., Siah, A., Waterlot, C., and Andrianarisoa, K. S.: How do four-year-old intercropped trees share soil water with wheat in temperate alley-cropping experimental site: evidence from 2H2O artificial labeling?, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-19,, 2023.

GC8-Hydro-92 | Orals | Session 4

Tracing stemflow infiltration with a simple experiment using geophysical surveys and stable water isotopes 

Giulia Zuecco, Chiara Marchina, Matteo Censini, Diego Todini Zicavo, Giorgio Cassiani, and Marco Borga

In forested catchments, stemflow affects the amount of precipitation reaching the soil, how water infiltrates and transports nutrients into the soil. Recently, the ecohydrological community has shown a renewed interest towards the methods used to quantify the stemflow infiltration area. Stemflow infiltration area is generally estimated based on the ratio between stemflow input rate and the mean soil infiltration capacity, whereas direct observations are rare. Direct estimations of stemflow infiltration areas are usually made by the application of dye tracers, which have proven to be useful for monitoring double-funneling. On the contrary, there are still few observations based on the application of electrical resistivity tomography (ERT) and isotopically-labelled water.

In this study, we present a simple experiment carried out for a beech tree, in a forested hillslope in the Italian pre-Alps. The aims of the experiment were to simulate stemflow by using salt and isotopically-labelled water, and to quantify stemflow infiltration area and volume.

The experiment was performed during a dry period in September 2022, in order to observe marked changes in the isotopic signature of soil water, as well as in electrical resistivity. Stemflow was simulated with a rainfall depth and intensity similar to typical summer storms in the catchment, and by using salt water with an isotopic composition very different compared to the composition of soil water during summer months. Before, during and after the stemflow application, 9 ERT surveys were performed to capture the infiltration dynamics. The collection of soil samples for isotopic analysis was carried out after the experiment, at different distances from the stem and at different depths (e.g., 0-15, 15-30, and 30-45 cm). Soil moisture was also measured at 0-6 and 0-12 cm depths at different distances from the stem.

Preliminary results showed a rapid infiltration of stemflow along the root system of the beech tree, and 24 hours since the start of the experiment the labelled water had infiltrated up to 80 cm into the soil. This simple experiment showed the usefulness of using time lapse ERT surveys, as well as isotopically-labelled water to simulate stemflow and trace double-funneling.



Keywords: stemflow, electrical resistivity tomography, stable water isotopes, soil water, forested catchment.

How to cite: Zuecco, G., Marchina, C., Censini, M., Todini Zicavo, D., Cassiani, G., and Borga, M.: Tracing stemflow infiltration with a simple experiment using geophysical surveys and stable water isotopes, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-92,, 2023.

GC8-Hydro-40 | Orals | Session 4

Reproducing in-situ measurements over a high-elevation grassland using HYDRUS-1D and a snow isotope model 

Alessio Gentile, Davide Gisolo, Davide Canone, and Stefano Ferraris

Stable water isotopes are increasingly used for tracking water fluxes in the critical zone offering new possibilities for model calibration and validation. Past studies revealed that the main discrepancies between simulated and measured values in a soil profile can occur when snow-related processes are under investigation. Indeed, the amount and timing of infiltrated meltwater and its isotopic composition remain largely unexplored to date.

In this work we use HYDRUS-1D (H-1D) to simulate water flux and isotope transport in a soil profile and in vegetation over a high-elevation (2600 m a.s.l.) grassland located in Valle d’Aosta (Italy). The H-1D inputs deriving from snow-related processes are computed in two steps: i) the amount of snowmelt is obtained through a classical degree-day model ii) the meltwater isotopic composition is simulated with a recently proposed snow isotope model which further assumes that any rainfall on a pre-existing snowpack mixes with the water stored in the snowpack. Model results have been compared with in-situ observations, including isotope measurements in both soil water and xylem water.

Our results show a satisfactory correspondence between model outputs and observations, but the raised discrepancies indicate other potential processes at play, e.g., soil freezing and thawing, preferential flow, isotopic fractionation, that will demand future attention. In addition, is still an open challenge to collect both meltwater samples for isotopic analysis and snowmelt measurements to validate the results deriving from models that attempt to reproduce the inputs intended for other models.

How to cite: Gentile, A., Gisolo, D., Canone, D., and Ferraris, S.: Reproducing in-situ measurements over a high-elevation grassland using HYDRUS-1D and a snow isotope model, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-40,, 2023.

GC8-Hydro-4 | Poster | Session 4

MOSES Campaigns to Study the Evolution of Hydrological Extremes in the Mueglitz Valley 

Andreas Wieser, Uta Ködel, Andreas Güntner, Christian Rolf, Theresa Blume, Peter Dietrich, Jan Handwerker, Dina Khordakova, Martin Kohler, Erik Nixdorf, Marvin Reich, and Heiko Thoss

MOSES (Modular Observation Solutions for Earth Systems) is a research initiative comprising nine Helmholtz research centres which are part of the research field “Earth and Environment”. MOSES focuses on 4 research areas covering Ocean Eddies, Permafrost Thaw, Heat Waves, and Hydrological Extremes. Highly flexible and mobile observing systems, combining the expertise of the involved Helmholtz Institutes, were developed to study effects along full event chains in highly dynamic situations (such as floods or droughts) as well as the long-term trends in environmental systems.

To study Hydrological Extremes, the Elbe river basin in Germany was selected as investigation area during the implementation phase of MOSES. The measurements in headwater catchments of the Elbe river includes several campaigns, coordinated by the Karlsruhe Institute of Technology (KIT). These campaigns took place in the Mueglitz Valley in the Eastern Ore Mountains, Germany, aiming at the investigation of the effects of extreme rainfall events along an entire process chain from the origination in the atmosphere, over the land-surface and the subsurface including their storage dynamics, up to flood generation in the contributing sub-catchments. The Institute for Meteorology and Climate Research - Department Tropospheric Research (IMK-TRO) of KIT provides essential data on the formation and evolution of heavy precipitation events, as well as high resolution measurements of precipitation distributions and evaporation. The Research Centre Jülich (FZJ) study the handover of water vapour and trace substances into the upper troposphere and even into the lower stratosphere.

The Helmholtz Centre for Environmental Research (UFZ) and the German Research Centre for Geosciences (GFZ) studies the catchment storage dynamics and runoff generation during flood and drought events by absolute and relative gravimeters, soil moisture monitoring with wireless sensor networks as well as with stationary and roving Cosmic Ray measurements, and river water level and discharge monitoring.

The presentation will explain the research questions and introduce the field and monitoring set up and the methods applied.

How to cite: Wieser, A., Ködel, U., Güntner, A., Rolf, C., Blume, T., Dietrich, P., Handwerker, J., Khordakova, D., Kohler, M., Nixdorf, E., Reich, M., and Thoss, H.: MOSES Campaigns to Study the Evolution of Hydrological Extremes in the Mueglitz Valley, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-4,, 2023.

In steep humid catchments with a low permeability soil layer close to the surface, lateral flow at or near the soil surface is an important runoff mechanism. In these catchments overland flow and shallow (i.e., near-surface) subsurface flow also play a crucial role in nutrient and sediment mobilization and transport, and thus affect stream water chemistry. However, due to the lack of data on the spatial and temporal variability in the occurrence of overland flow and shallow subsurface flow and their isotopic signature, it is still poorly understood how rainfall event- and site characteristics affect the onset and mixing of these near-surface flow pathways.

We installed 14 small (1 m wide) runoff plots in a 20-ha headwater catchment in the Swiss pre-Alpine area that is underlain by Gleysols and Flysch bedrock. We coupled hydrometric measurements and stable water isotope data to infer the source (groundwater, soil water, and rainfall) of overland flow and shallow subsurface flow during rainfall events during the snow-free seasons of 2021 and 2022. Rainfall was sampled sequentially at two locations. The isotopic composition of pre-event water was determined based on the soil and groundwater samples taken at each plot prior to the event. Preliminary isotope hydrograph separation results for five rainfall events indicate a median event water fraction over all plots and events of 87% for overland flow and 58% for shallow subsurface flow and a very large variation in the event water contributions (30100% for overland flow and 9100% for shallow subsurface).

In this presentation, we will provide an overview of these new data on the temporal and spatial variability of isotopic composition in overland flow and shallow subsurface flow and describe how the event water fractions depend on rainfall event- and site characteristics (topographic position, vegetation cover, and antecedent moisture conditions). 

How to cite: Leuteritz, A., Gauthier, V., and van Meerveld, I.: Event water fractions in overland flow and shallow subsurface flow in a pre-Alpine headwater catchment in Switzerland, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-45,, 2023.

GC8-Hydro-13 | Poster | Session 4

Reconstructing the history of flowing waters from freshwater mussels in the context of interdecadal climate variability 

Turk Guilhem, Laurent Pfister, Bernd Schöne, Christoph Gey, Frankie Thielen, Christophe Hissler, François Barnich, and Loïc Léonard

The ongoing intensification of the hydrological cycle calls for the identification and assessment of factors controlling catchment resilience to climate change. Stable isotopes of O and H in streams and precipitation are cardinal tools in this respect – notably for investigating questions related to water source, flowpaths and transit times. However, the spatial and temporal variability of these tracers remain largely unknown – essentially due to the limited availability of long historical time series of O-H isotope signatures in stream water, as opposed to the multi-decadal records in precipitation of the IAEA’s GNIP database (

Based on their quality as natural archives of in-stream environmental conditions, freshwater mussels have been recently used for complementing stream water δ18O isotope records. With an average life span of ca. 10 years (up to 200 years for the freshwater pearl mussel), their potential is significant, considering the fact that nearly 1200 freshwater bivalve species inhabit a large variety of river systems and lakes around the globe (Pfister et al., 2018). Our proof-of-concept work has shown that δ18O values extracted from their shells closely mirror the variance of the measured stream water δ18O – both showing a strong damping of the precipitation signal. In our follow-up study, we leverage prior work by Schöne et al. (2020) on potential links between the NAO index, precipitation isotope signatures and subsequent interdecadal variabilities in reconstructed stream water δ18O signals for three catchments located in Sweden. Using freshwater bivalve shell δ18O as a proxy of stream water δ18O signatures, we hypothesize that interdecadal shifts in atmospheric circulation patterns translate into modifications of δ18O isotope signatures in precipitation and subsequent stream water δ18O signals – the latter potentially revealing changes in young stream water fractions related to fast flow paths. In parallel, we stipulate that the long-term δ18O signal in precipitation can be retrieved from historic records and reanalysis data of climate variables, as well as from synoptic atmospheric circulation classifications.

Here we focus on findings gained from a unique dataset of 5 years-worth of sub-daily precipitation O-H isotope data from the Belvaux (L) meteorological station, comprising 1443 rainfall samples. We investigated the links between local climate variables, the rainfall amount, atmospheric circulation patterns, and the precipitation δ18O signal. Our results show (i) an anticipated strong temperature-induced seasonality of the δ18O signal, characteristic for semi-continental sites, (ii) a weak but significant amount effect, (iii) a circulation type-dependant influence of local climate variables on the δ18O signal, and (iv) a high variability at the event-scale – indicating the influence of complex frontal systems and moisture recycling. We leveraged these findings for building a multiple linear regression model, explaining up to 50 percent of the variability of the δ18O signal at sub-daily resolution and closely matching the isotopic signal when applying moving averages over periods within a monthly range.

How to cite: Guilhem, T., Pfister, L., Schöne, B., Gey, C., Thielen, F., Hissler, C., Barnich, F., and Léonard, L.: Reconstructing the history of flowing waters from freshwater mussels in the context of interdecadal climate variability, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-13,, 2023.

GC8-Hydro-81 | Poster | Session 4

Flow pathways, transit time, and tree water sources: linking ecohydrological processes with stable isotopes in a small forested catchment 

Daniele Penna, Stefano Brighenti, Marco Borga, Francesco Comiti, Andrea Dani, Ginevra Fabiani, Julian Klaus, Francesca Sofia Manca di Villahermosa, Chiara Marchina, Laurent Pfister, Federico Preti, Paolo Trucchi, Matteo Verdone, Giulia Zuecco, and Konstantinos Kaffas

A holistic understanding of ecohydrological processes that regulate the variability of tree water use, water flow pathways through the soil and to groundwater and the stream, and the transit time of water at the catchment scale is still challenging. In this work, we rely on an integrated dataset of isotope tracers and hydrometric data to show new evidence on the main ecohydrological processes and their controls that link runoff origin, sources of tree water uptake, and water transit time in a small mountain, forested catchment in central Italy.

The Re della Pietra experimental catchment is located in the Tuscan Apennines. The catchment is 2 km2 in size and ranges in elevations between 650 and 1280 m a.s.l.. Forests cover more than 95% of the area, and the main tree species are beech and oak trees, with a much smaller proportion of conifers. Mean annual precipitation is around 950 mm. We collected water samples from April 2019 to January 2023 from precipitation, throughfall, soil, groundwater, springs, stream at different sections, and xylem of beech trees, and determined their isotopic composition. Weather data, streamflow, soil moisture, groundwater level, and throughfall were monitored in a 0.3 km2 headwater sub-catchment. Stream stage and electrical conductivity as additional tracer were measured in three stream sections from the headwater sub-catchment down to the Re della Pietra outlet. Streamflow, groundwater, spring flow, and soil moisture are characterized by a marked seasonality, reflecting the strong seasonal variability in the meteorological forcing, typical of the Mediterranean climate.

Based on field observations and preliminary data analysis, we aim to test the following hypotheses:

  • i) Trees growing along a steep hillslope in the headwater sub-catchment use different water sources (soil water vs. shallow groundwater) as a function of their topographic position.
  • ii) Hillslope soil water is an important contributor to streamflow only during wet conditions (i.e., in winter, late fall, and early spring).
  • iii) Spring water flows through shallow pathways and is a negligible contributor to streamflow, especially during dry conditions.
  • iv) Water transit time increases as a function of increasing catchment size (i.e., increasing drainage area).

The results will contribute to the conceptualization of the interrelated ecohydrological processes driving water fluxes in Mediterranean forested catchments.

How to cite: Penna, D., Brighenti, S., Borga, M., Comiti, F., Dani, A., Fabiani, G., Klaus, J., Manca di Villahermosa, F. S., Marchina, C., Pfister, L., Preti, F., Trucchi, P., Verdone, M., Zuecco, G., and Kaffas, K.: Flow pathways, transit time, and tree water sources: linking ecohydrological processes with stable isotopes in a small forested catchment, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-81,, 2023.

An experimental headwater catchment has been setup in a typical monsoon-influenced semi-humid mountainous forest of North China and long-term field measurements of hydrological processes have been conducted. Samples were collected for isotope (δ18O and δ2H) and hydro-chemical analysis since 2014. Based on long-term hydro-chemical and isotopic data, the principal components of streamflow were defined and fractional components of stream flow separations were estimated, the result shows that groundwater and streamflow isotopic compositions are very similar and streamflow is controlled by a deep groundwater system that is recharged only in one or two large events (or clusters of events) each year. The two-component isotope hydrograph separation has been applied in 6 intensively sampled events, the results suggest that groundwater makes up 63-94% of the storm runoff,event water plays a relatively tiny role. Based on numerical modeling and statistics methods, impact of rainfall and hydraulic conductivity heterogeneity on Hortonian overland flow patterns have been analyzed, possibilities of Hortonian overland flow occurrence have been estimated in different climatic and underlying occasions, the result shows due to high permeability and low rainfall intensity, in more than 95% of total events, Hortonian overland flow couldn’t occur in the study area. Runoff generation mechanism in semi-humid mountainous catchment have been revealed based on multi-scale measurements and numerical modeling, when rainfall intensity and duration are lower than certain threshold, surface runoff generation is consisted of groundwater runoff, direct rainfall on channel and saturation overland flow. Onsite observation shows that surface runoff contributing area in the watershed mainly distributed in riparian zone, and our result shows saturation overland flow is the dominant type of surface runoff generation in most summer rainfall events.

How to cite: Tian, F. and Zhao, S.: Runoff generation mechanism in a headwater experimental catchment with semi-humid monsoon climate in North China, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-2,, 2023.

GC8-Hydro-75 | Orals | Session 4

The study of stable O-H isotopes to assess the features of the genesis of artesian waters in the sedimentary basins of South Kazakhstan based on

Dr. Malis Absametov, Dr. Erkebulan Zhexembayev, Dr. Yermek Murtazin, Dr. Jay Sagin, and Dr. Dinara Adenova

GC8-Hydro-94 | Poster | Session 4

Application of the stable isotope compositions of water for quantifying evaporative losses 

Nariman Mahmoodi, Christoph Merz, and Michael Schneider

Comprehension of the hydrological process and accurate estimation of major water balance components are substantial for a prosperous hydrologic model application. Analyses of changes in the stable hydrogen and oxygen isotope composition of surface water and groundwater can be employed to estimate evaporation losses and to define the origin of water and the way it moves in a specific region. This study aims at a better understanding of the water cycle of lowland lakes (Groß Glienicker See, Sacrower See) in Berlin-Brandenburg state, Germany, using stable water isotopes (oxygen-18, deuterium). To get that done, an isotopic mass balance model (HydroCalculator) was applied to compute the evaporative losses over inflow from the lakes’ water bodies under a steady-state hydrologic regime condition. The isotopic signatures of precipitation, water samples from eight observation wells, and from different depths of the lakes’ water within the time period of September 2022 to Jan 2023 classify the lakes into flow-through types which are fed by shallow groundwater. The estimated fractional water loss by evaporation is slightly higher in Groß Glienicker See (35%) in comparison to Sacrower See (33%). This is due to the different depths and areas of their water bodies.

How to cite: Mahmoodi, N., Merz, C., and Schneider, M.: Application of the stable isotope compositions of water for quantifying evaporative losses, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-94,, 2023.

GC8-Hydro-14 | Orals | Session 4

Combined use of multiple tracers to identify water flow dynamics and pollutant transport 

Christian Moeck, Andrea Popp, Matthias S. Brennwald, Rolf Kipfer, and Mario Schirmer

Assessing hydrological processes, water ages and mixing ratios is crucial for sustainable water management. The surface and subsurface heterogeneity necessitate the application of multiple tracers to quantify uncertainty when identifying the above mentioned processes and observational tools operating at high temporal resolutions are required. Although a variety of tracers exists, their interpretation can differ considerably due to the mentioned heterogeneity, underlying tracer assumptions, as well as sampling and analysis limitations. 

For our urban hydrological observatory, we used stable water isotopes (e.g., 2H and 18O), chlorinated solvents (e.g., perchloroethylene (PCE)), dissolved gas concentrations (e.g. He, Ar, Kr, N2, and O2), dye and heat tracers, chemically (persistent) anthropogenic markers (e.g., artificial sweeteners) and  3H and tritiogenic 3He concentrations to assess water flow paths and mixing between artificially infiltrated surface water and groundwater. Moreover, we explain the origin and spatial distribution of PCE contamination found at our study site with our multi-tracer approach.

Especially, the recent developments of portable field-operated gas equilibrium membrane inlet mass spectrometer (GE-MIMS) systems provide a unique opportunity to measure dissolved gas concentrations, such as 4He with a high temporal resolution at relatively low costs. Although the GE-MIMS are not capable of providing apparent water ages, 4He accumulation rates are often obtained from 3H/3He ages and it has been shown that non-atmospheric 4He concentrations determined in the laboratory (e.g., by static (noble gas) mass spectrometry) and by field-based (GE-MIMS) methods closely agree. This agreement allowed us to establishing an inter-relationship between 3H/3He apparent water ages and the non-atmospheric 4He excess (e.g., calibrating the 4He excess in terms of residence time).

We demonstrate that the 4He excess concentrations derived from the GE-MIMS system serve as an adequate proxy for the experimentally demanding laboratory-based analyses. We combined the obtained water ages with hydrochemical data, water isotopes (δ18O and δ2H), and PCE concentrations to understand water flow dynamics and applied a developed Bayesian model to a tracer set, which includes the 4He analyzed on-site to determine water-mixing ratios. We demonstrate that important information about flow and transport during changing boundary conditions (e.g., infiltration rates) can only be identified with a high temporal resolution data set and that the gained information from multiple tracers and methods offered more insight and accuracy than from a single tracer.

How to cite: Moeck, C., Popp, A., Brennwald, M. S., Kipfer, R., and Schirmer, M.: Combined use of multiple tracers to identify water flow dynamics and pollutant transport, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-14,, 2023.

Session 5 – Quantifying regional hydrological change impacts

As communities prepare for the impacts of climate change, policy makers and stakeholders increasingly require locally-resolved projections of future climate. Statistical downscaling uses low-resolution outputs from climate models and historical observations to both enhance the spatial resolution and correct for systematic biases. By examining the downscaled rainfall over land, we show that although bias corrections are effective in reducing biases in the current climate, they do not reduce the intermodel spread in future rainfall projections. This failure stems from the strong dependence of future rainfall change upon the current climatological rainfall patterns. Even after bias corrections are applied, the downscaled projections of precipitation change retain this dependence upon their native climatology. However, we show that this dependence can be exploited; even very simple methods to sub-set models according to their ability to resolve the observed rainfall climatology can substantially reduce the intermodel spread in rainfall projections.

How to cite: soden, B. and Zhang, B.: Constraining Climate Model Projections of Regional Precipitation Change, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-9,, 2023.

GC8-Hydro-3 | Orals | Session 5

Building reliable hydrological models for climate change studies

Marco Dal Molin and Fabrizio Fenicia

Riparian corridors act as thermal and moisture refugia for a range of plant and animal species, particularly in water-limited environments. Declining water tables, increasing temperatures, and an increase in extreme hydrologic events due to climate change threaten the diversity of life these landscapes support. Successful adaptive conservation management strategies require an understanding of how species are responding to climate change and an ability to anticipate how changing patterns of water resource availability and demand will alter vegetation patterns and processes. 

Here, we investigate dryland riparian plant responses to fluctuating water availability and atmospheric demand using a novel drone-based approach for estimating transpiration. Integrating thermal imagery, structural data, and a suite of environmental sensors mounted on an unmanned aerial vehicle (UAV) platform, this approach was specifically designed to capture fine-scale functional data and variation in individual-level plant functional traits within riparian ecosystems and allows for efficient calculation of evapotranspiration for a site solely using data collected from the UAV. Using UAV-based measurements of transpiration across seasonal, diurnal, and spatial gradients of water stress, we quantify individual-scale hydraulic sensitivity to fluctuating water availability and atmospheric moisture demand. Finally, we highlight how these fine-scale estimates of plant water use facilitate understanding of how ecologically important plants respond to the increasingly variable hydrologic regimes that sustain them, yielding valuable insights into how such ecosystems will evolve in the face of global environmental change.

How to cite: Morgan, B. and Caylor, K.: Assessing the vulnerability and resilience of riparian vegetation to water stress, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-96,, 2023.

Many operational drought indices use precipitation and temperature data together with vegetation conditions obtained with advanced remote sensing technologies. However, there are only a few indices that use actual evapotranspiration (ET) but still do not address the effect of precipitation. In this work, we brought actual ET using enhanced complementary relationship method to include precipitation and vegetation conditions when depicting drought conditions.  We compared the proposed drought index with the U.S. Drought Monitor (USDM) which is widely used within the United States. The results of this study showed that the drought patterns from the proposed drought index are consistent with USDM, and the use of an accurate ET method improved its performance as a drought index. The key strengths of this study are that the proposed index can serve as an indicator of rapid droughts developing over a few weeks, and uniquely describes the drought conditions with vegetation conditions which have large impacts on predictions compared to other drought indices.

How to cite: Kim, H. and Kaluarachchi, J.: Drought Monitoring using the Enhanced Complementary Relationship of Evapotranspiration and Remote Sensing, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-29,, 2023.

GC8-Hydro-35 | Poster | Session 5

A Climate Based-Projection of Future Drought in Aegean Region of Turkey 

Mir Jafar Sadegh Safari, Mustafa Nuri Balov, and Babak Vaheddoost

The frequency, intensity and duration of drought events are expected to increase during the coming years. Hence, the resilience against climate changes and water deficit would be of concerns to ensure agro-food and energy safety. To address this issue, the outputs of general circulation models (GCM) under various emission scenarios are used to generate two meteorological and hydrological drought indices for a number of meteorological stations scattered in three major basins namely Buyuk Menderes, Kucuk Menderes, and Gediz located in the western Turkey (the Aegean Region). The biases in the outputs of GCMs were corrected using linear scaling method with respect to the reference period (1990-2020). The results were assessed in two 30-years period as mid-time future (2041-2070) and late future (2071-2100). Afterward, the well-known standard precipitation index (SPI) together with the streamflow drought index (SDI) are determined based on the outputs of the climate scenarios for the allocated time periods. The results of the study showed a significant increase in the number and severity of the drought events by the end of the century under all emission scenarios.  

How to cite: Safari, M. J. S., Nuri Balov, M., and Vaheddoost, B.: A Climate Based-Projection of Future Drought in Aegean Region of Turkey, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-35,, 2023.

GC8-Hydro-88 | Orals | Session 5

Future drought and groundwater availability in the Netherlands: a growing concern 

Victor Bense, Adriaan Teuling, Syed Mustafa, and Martine van der Ploeg

Groundwater depletion from aquifers worldwide is of increasing intensity and this is reason for serious societal concern especially in areas of continuing population growth and where future dry periods are predicted to be more frequent in a changing climate. Groundwater depletion will occur, and groundwater development eventually unsustainable, where groundwater withdrawal rates exceed the groundwater recharge flux. However, the limited ability to assess groundwater recharge conditions gravely hampers effective groundwater resources management to avoid their overexploitation leading to groundwater depletion. Hence, mapping and quantifying groundwater flows is therefore increasingly recognized as one of human societies grand challenges. The Veluwe area is of the few topographically elevated areas in the Netherlands to enable appreciable groundwater recharge. Therefore, it hosts the largest fresh groundwater system of the Netherlands covering a surface area of approximately 1100 km2. The 2018 and subsequent 2021-2022 summer droughts led to a strongly increased demand for drinking water across the Netherlands which brought some groundwater abstraction licenses, set by regulatory government bodies, across the Veluwe area close to being exceeded. This cunningly demonstrated that, similar to many areas globally, in periods of water stress groundwater resources often are of crucial importance in maintaining a reliable supply of domestic water, and to meet agricultural and industrial demands. However, the relation between climate and groundwater drought is complex, in particular for areas with deep unsaturated zones such as the Veluwe, yet needs to be understood in the face of projected climate change. For this reason, already prior to 2018, the Veluwe area was listed as a nationally strategic water reserve, and as such should receive ample attention in considerations of National Security on the long term. However, since the mid-1990s the regional hydrogeological system of the Veluwe has not been subject of extensive experimental academic study as result of which it is highly questionable whether we can now reliably assess groundwater availability across the area in the decades to come. In this presentation, we outline ongoing and future efforts to monitor water fluxes in the Veluwe region. Past measurements have been focussing on water table fluctuations and soil-water modeling to estimate recharge. Current plans include establishing a drought observatory consisting of a precision lysimeter array complemented by eddy covariance observations of ET, that transects the from the high sandy grounds with deep groundwater tables to the seepage areas with shallow groundwater tables.

How to cite: Bense, V., Teuling, A., Mustafa, S., and van der Ploeg, M.: Future drought and groundwater availability in the Netherlands: a growing concern, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-88,, 2023.

GC8-Hydro-43 | Orals | Session 5

Catchment-scale analysis of hydrological and agricultural impacts of small reservoirs 

Jérôme Molénat, Cecile Dagés, Nicolas Lebon, and Delphine Leenhardt

Small reservoirs are dams built to intercept and store runoff water. Small reservoirs can be a resource for farmers by providing water for crop irrigation. In agricultural areas, small reservoirs are seen as a way to sustain agriculture in times of drought. Changes in rainfall patterns due to climate change, with higher rainfall in some seasons and longer droughts in others, and the need to maintain or even increase agricultural productivity are also prompting some stakeholders to promote the development of small reservoirs. The proliferation of small reservoirs in a catchment can put pressure on the water cycle and have a cumulative impact on river flows and other hydrological components, which in turn can affect other water uses and the quality of downstream aquatic environments (Habets et al., 2018). There is a need to better understand and quantify both the cumulative hydrological impacts and the agricultural benefits of small reservoirs.

We present here an analysis of the cumulative impact of small reservoirs on hydrology and crop yield in an agricultural catchment. This analysis is based on the modeling of a 20 km² catchment in southwestern France. We used a new agro-hydrological model called Mhydas-Small-Reservoirs, a model coupling hydrological and crop processes with farmers' water management decisions (Lebon et al., 2022). Several catchment situations were considered. These situations combine different levels of reservoir use (current situation with 26 reservoirs of which only 13 are exploited for crop irrigation, a situation with no reservoirs at all, a situation where reservoirs currently not exploited are used for irrigation) and different climatic years (dry year, wet year, and year with average rainfall). The simulations were analyzed in terms of crop yields and different water balance terms (flow, ET, irrigation withdrawal). From the preliminary results, we show the interest and the need to take into account the interactions between hydrological and agricultural processes to quantify the impacts due to small reservoirs. We also identify the need for observations in agrohydrological modeling applied to catchments with small reservoirs.


Habets F., Molénat J., Carluer N., Douez O., Leenhardt D., 2018, The cumulative impacts of small reservoirs on hydrology: A review, Science of The Total Environment, 643, 850-867,

Lebon, N., Dagès, C., Burger-Leenhardt, D., Molénat, J. 2022, A new agro-hydrological catchment model to assess the cumulative impact of small reservoirs, Environmental Modelling & Software, Volume 153,2022, 105409,

How to cite: Molénat, J., Dagés, C., Lebon, N., and Leenhardt, D.: Catchment-scale analysis of hydrological and agricultural impacts of small reservoirs, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-43,, 2023.

GC8-Hydro-41 | Poster | Session 5

OMERE: A Long-Term Observatory of Soil and Water Resources, in Interaction with Agricultural and Land Management in Mediterranean Hilly Catchments 

Jérôme Molénat, Damien Raclot, Rim Zitouna, Jean Albergel, and Marc Voltz and the OMERE Team

This communication is dedicated to the Mediterranean agro-hydrological observatory OMERE (Mediterranean Observatory of Rural Environment and Water). It aims to explain the observation strategy and to highlight how this strategy and the associated research have contributed to a better understanding of the impact of agricultural and land management on water and soil resources in Mediterranean catchments.

OMERE is a Franco-Tunisian observatory based on two agricultural catchments, one in northern Tunisia and the other in southern France, representing the diversity of agricultural and ecosystem situations in hilly Mediterranean regions. The observatory was created more than twenty years ago to answer key scientific questions concerning the impact of global changes on soil and water resources (Voltz and Albergel, 2002). More specifically, the motivation has been to study how hydrological processes involved in water cycles and in the mass transport, such as contaminants and sediments, are affected by changes in farming practices and landscape management . The processes underlying these changes may be slow, such as in land use or contaminant dynamics, or infrequent over time, such as erosion. Understanding these processes and their relationship requires long-term observations to capture slow dynamics or infrequent events, which motivated the OMERE observatory.

The OMERE observatory belongs to the French national network OZCAR, dedicated to the observation of the critical zone. The observation strategy is motivated by monitoring the flow of water, sediments and contaminants and hydrological and climatic variables at different spatial scales from cultivated plots and landscape elements to the catchment scale (Molénat et al., 2018). These measurements were made with fine temporal resolution on a long-term scale and examining land use, agricultural practices and soil surface characteristics. The long-term observation strategy aims to support multidisciplinary integrative research to elucidate the conditions that improve soil and water management and the provision of ecosystem services in the Mediterranean context of rain-fed agriculture. The observatory helped to address three scientific questions: (i) better understand water flows, erosion and contaminants, in particular pesticides, and their natural and anthropogenic factors in the short and long term; (ii) analyze the overall effects of agriculture and land management on mass flows at different scales, from the plot to the watershed or the landscape; and (iii) develop new scenarios for sustainable agricultural management and better delivery of ecosystem services. Some of the main scientific advances of research conducted using the observatory obtained through OMERE are presented. The main perspectives in matter of the observation strategy are also drawn.


Molénat, J., Raclot, D., Zitouna R., ...., Albergel, J., and Voltz M., 2018, OMERE: A Long-Term Observatory of Soil and Water Resources, in Interaction with Agricultural and Land Management in Mediterranean Hilly Catchments, Vadose Zone J., 17:180086. doi:10.2136/vzj2018.04.0086

Voltz, M., and A. Albergel. 2002. OMERE: Observatoire Méditerranéen de l’Environnement Rural et de l’Eau- Impact des actions anthropiques sur les transferts de masse dans les hydrosystèmes méditerranéens ruraux. Proposition d’Observatoire de Recherche en Environnement. Minist. Français Rech., Paris

more information at :

How to cite: Molénat, J., Raclot, D., Zitouna, R., Albergel, J., and Voltz, M. and the OMERE Team: OMERE: A Long-Term Observatory of Soil and Water Resources, in Interaction with Agricultural and Land Management in Mediterranean Hilly Catchments, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-41,, 2023.

Flood properties are known to be sensitive to spatial and temporal patterns of precipitation, which in turn are affected by global warming. In this study, we investigated the effect of global warming on properties of heavy precipitation events (HPEs) in the eastern Mediterranean, focusing on hydrologically-important characteristics, including total precipitation amount, coverage area, precipitation duration and the distribution of rain rates for different durations. Then, we quantified how changes in precipitation due to global warming affect resulting flood properties for small-medium catchments in the study region.

We used the weather research and forecasting (WRF) model to simulate 41 HPEsin present and future (end of 21st century; RCP 8.5 scenario) climate conditions and output the precipitation fields at high resolution (1 km2, 10 min). The calibrated GB-HYDRA distributed hydrological model (<60 s, 100 m) was utilized to simulate floods from those HPEs in 4 small-medium-size basins (18–69 km2). To account for the rainfall spatial uncertainty in the simulations, spatial shifts were applied to the simulated HPEs in a range of 20 km north and south.

We found a major decrease in precipitation accumulation (−30% averaged across events) in future HPEs. This decrease results from a substantial reduction of the rain area of storms (−40%) and occurs despite an increase in the mean conditional rain rate (+15%). In addition, the duration of the HPEs decreases (−9%) in future simulations. The above changes were consistent across events.

These changes have opposite directions, suggesting that flood properties changes are not trivial. Our simulations indicate a future decrease in both flood volume (-27%) and peak discharge (-20%, non-significant) at the outlet of the catchments. On the other hand, peak discharge is increasing in the future for small sub-catchments (< 5 km2). We currently expand this research to account for expected changes in future antecedent soil moisture conditions and land-use.

To conclude: with global warming, HPEs in the eastern Mediterranean are becoming drier and more spatiotemporally concentrated. Consequently, small and larger catchments respond differently to this change, with the former reacting to the increase in rain rates and producing higher flood peak discharge, while the latter reacts more to the reduction in total rainfall, area and duration, and results in lower flood volumes and peaks.

How to cite: Morin, E., Rinat, Y., and Armon, M.: Quantifying global-warming-induced changes in spatial and temporal patterns of heavy precipitation events and the implications to flood properties in Mediterranean catchments, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-12,, 2023.

GC8-Hydro-50 | Poster | Session 5

GIS—based application of Benfratello's method to estimate the irrigation deficit and its variability in the Capitanata plain under climate change 

Marco Peli, Muhammad Faisal Hanif, Stefano Barontini, Emanuele Romano, and Roberto Ranzi

Benfratello's Contribution to the study of the water balance of an agricultural soil (Contributo allo studio del bilancio idrologico del terreno agrario) was firstly published in 1961. The paper provides a practical conceptual and lumped method, based on climatic forcings and on the field capacity, to determine the irrigation deficit in agricultural districts. It generalizes the previous Thornthwaite (1948) and Thornthwaite and Mather (1955) water balances thanks to the application of a dimensionless approach introduced by De Varennes e Mendonça (1958), and of a power—law desiccation function. Since then, it has been used in many semi—arid areas in Southern Italy.

Due to its simplicity and to the small number of required parameters, Benfratello's method could be regarded to as an effective tool to assess the effects of climatic, landuse and anthropogenic changes on the soil water balance and on the irrigation deficit, both at the climatic scale and in real time.

In previous EGU—GA contributions (Barontini et al., 2021, 2022) we presented a GIS—based implementation of Benfratello's method to assess the irrigation deficit in the Capitanata plain (4550 km2), and a theoretical development of the method to estimate in closed form the interannual variability of the calculated irrigation deficit, once known the variability of temperature and precipitation.

In this contribution we present the results obtained by applying the GIS—based Benfratello framework to assess the irrigation deficit and its variability in the Capitanata plain under different climate change scenarios.

The scenarios were generated with the following procedure: (i) evaluation of different GCMs (CNRM-CM5, CMCC-CM and IPSL-CM5A-MR) in comparison with the historical data, (ii) correction of systematic biases, (iii) application of the same biases to the corresponding IPCC RCP4.5 and RCP8.5 scenarios, (iv) statistical downscaling of the obtained models to estimate future time series for the meteorological stations of interest in the considered case study and (v) spatial interpolation with ordinary Kriging.

How to cite: Peli, M., Hanif, M. F., Barontini, S., Romano, E., and Ranzi, R.: GIS—based application of Benfratello's method to estimate the irrigation deficit and its variability in the Capitanata plain under climate change, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-50,, 2023.

GC8-Hydro-76 | Orals | Session 5

On the potential cross-mixing of Lake Bogoria and Baringo in the Rift Valley of Kenya 

Mathew Herrnegger, Pierre Kray, Gabriel Stecher, Nelly Cherono, and Luke Olang

The Rift Valley lakes of Kenya are biodiverse ecozones, classified not only as RAMSAR wetlands of international importance, but also as UNESCO World Heritage. In the last decade, starting in 2010, several Kenyan lakes have experienced significant rises in water levels. The consequences have been severe. Inundations of the riparian areas have not only flooded homes, schools and hospitals, but also the basis for the local livelihoods and economy such as agricultural fields, national parks or tourism infrastructure has been destroyed. Nearly eighty thousand households with 400,000 people are affected according to a governmental report published in 2021.

There is fear of an ecological catastrophe, should the water levels of the alkaline Lake Bogoria continue to rise. The result would be an overflow and mixing with the freshwater Lake Baringo, the basis of the local community supporting drinking water provision, agriculture, tourism and fisheries. Currently no analysis exists to understand the topographical conditions between the two lakes and the potential flow paths. It is unclear, what climatic rainfall conditions are necessary to lead to an overflow and sustained flows from Lake Bogoria towards Baringo. This analysis therefore assesses (i) the overflow or sill point location and potential flow paths towards Lake Baringo, (ii) the required lake water volume changes, until the sill point is reached and (iii) the mean rainfall conditions, which would be necessary to provide the required volume and a sustained flow towards Lake Baringo. The analysis relies on satellite altimetry-based lake levels and lake volume variations, remote sensing-based rainfall data and lake areas but also high-resolution space-borne and UAS-based DEMs. Field surveys and electrical conductivity measurements used as a proxy to understand flow paths in the flat and swampy Loboi plain between Bogoria and Baringo complement the data basis.

To reach the sill point elevation, the lake level of Bogoria would have to increase by 3.5-4 m, compared to the water levels of 2020. This translates to an additional water volume of around 0.17 km³. To put this into perspective: From 2009-2014, lake levels increased by 3 m (or 0.11 km³), and after a recession phase, from 2017-2020 by 2.3 m (0.10 km²). If the sill point would be reached, the rainfall conditions in the last decade would have allowed for a permanent flow towards Baringo, at least in single years. These preliminary results suggest that it is feasible that the sill point can be reached and that a permanent flow from Bogoria towards Baringo can be sustained, if wetter conditions – as we have observed in the last decade - persist for a longer period.

How to cite: Herrnegger, M., Kray, P., Stecher, G., Cherono, N., and Olang, L.: On the potential cross-mixing of Lake Bogoria and Baringo in the Rift Valley of Kenya, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-76,, 2023.

GC8-Hydro-74 | Poster | Session 5

Historical and future changes on water resources in the Flumendosa basin, Sardinia. 

Roberto Corona, serena Sirigu, and Nicola Montaldo

In Mediterranean climates during the winter months much of the precipitation recharges sub-surface and surface reservoirs. However, in the late winter and early spring, when vegetation growth conditions are favorable, much of the precipitation can be depleted by transpiration and, furthermore, runoff reduced directly by the increased vegetation cover. In the Mediterranean regions there is the evident effect of climate changes that it is causing several problems on the water resources availability. Several scientists have shown a strong decreasing trend in winter precipitation amounts and an evident shift in how the precipitation is distributed across the winter and spring months. Considering that most of the runoff to surface reservoirs occurs in the winter months and that spring hydrologic response is likely to be influenced strongly by vegetation, these precipitation changes can be considered hydrologically important. Case study is the Flumendosa basin (Sardinia), which is one of the case studies of the ALTOS European project, characterized by a reservoir system that supplies water to the main city of Sardinia, Cagliari. Data are from 42 rain gauges stations (1922-2021 period) over the entire basin and data of runoff are available for the same period. In the Flumendosa reservoir system the average annual input from stream discharge in the latter part of the 20th century was less than half the historic average rate, while the precipitation over the Flumendosa basin has decreased, but not at such a drastic rate as the discharge, suggesting a marked non-linear response of discharge to precipitation changes. We developed and calibrated a distributed hydrological model at basin scale which predicts runoff, soil water storage, evapotranspiration and grass and tree leaf area index (LAI). Hydrometeorological variables provided by the future climate scenarios predicted by Global Climate Model (CMPI-6 MPI-ESM1-2-LR downscaled) have been used as input in the model to predict soil water balance and vegetation dynamics under the future hydrometeorological landcover scenarios. The historical observations highlighted strong negative trends in precipitation series and in the number of wet days (examined using the Mann-Kendall trend test). The results from model application showed that tree dynamics are strongly influenced by the inter-annual variability of atmospheric forcing, with tree density changing according to seasonal rainfall. At the same time the tree dynamics affected the soil water balance. We demonstrated that future warmer scenarios would impact the forest, which could be not able to adapt to the increasing droughts. In addition,  future scenarios predict a reduction of the runoff, which is crucial for the dam reservoir recharge. The water resources system planning needs to carefully takes into account the effect of future climate change on water resources and vegetation dynamics.

How to cite: Corona, R., Sirigu, S., and Montaldo, N.: Historical and future changes on water resources in the Flumendosa basin, Sardinia., A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-74,, 2023.

Groundwater overdraft is a global problem demonstrating a general inability of modern civilization to manage groundwater demand. Climate change only makes this problem more acute and challenging. A key reason for chronic overdraft is the relative invisibility of groundwater and pumpers’ effects on it. Here I assert (1) the need for real-time monitoring of an overlooked metric – change in groundwater storage (Δs), (2) its transformative potential for groundwater management and (3) a simple yet new approach to monitor Δs in real time. The hydrology community has failed to learn a key lesson from the impressive successes of measuring sub-continental scale Δs with GRACE satellite technology. The lesson: monitoring Δs (rather than simply changes in groundwater levels, Δh) increases dramatically peoples’ awareness of groundwater overdraft and their motivation to better manage groundwater. Unfortunately, the sub-continental resolution (~400 km) of GRACE makes it ineffective as a tool for monitoring and managing groundwater at a functional basin scale, which is typically on the order of 10’s of km and rarely as large as ~400 km. Although monitoring of Δs in shallow, unconfined aquifers is relatively simple, it is much more challenging in most sedimentary basins that contain most of the world’s major aquifer systems, and where myriad, interbedded aquifer and aquitard layers create depth-variable degrees of semi-confinement that complicate the relationships between Δs and Δh. Here I demonstrate a simple approach in which a calibrated groundwater flow model is used to translate data on Δh into real-time estimates of Δs, despite massive (104) spatial variations in the effective storage coefficients (Δs/Δh). This meta-modeling approach means that it is feasible today to monitor Δs with conventional hydrogeologic data and tools, highlighting missed opportunities for more effective, science-based groundwater management. I will also articulate the need for much greater research emphasis on new methods for monitoring Δs, including combined use of machine learning methods leveraging diverse datasets along with conventional data and models.

How to cite: Fogg, G. and Flores, C.: Monitored Groundwater Storage Change:  An Overlooked, Essential Driver of Groundwater Management, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-98,, 2023.

GC8-Hydro-80 | Poster | Session 5

TVET SUDS MAR opportunities for water sustainability  

Raushan Amanzholova, Dr.Catalin Stefan, Dr. Jana Sallwey, M.Sc. Nurlan Ongdas, Dastan Sarbassov, Akgulim Sailaubek, and Dr.Jay Sagin

Floods and droughts are widespread emergency event (EE) issues in Central Asian (CA) countries. Water sustainability and efficient use of water resources are connected to complicated problems in CA. SustDrain ( )  will be reasonable to expand in an application for the proper water management, collection, and efficient use of flood water. We are working on the potential expansion in applications of the TERESA project for CA, TERESA is a nature-based solution for urban catchments by combining the advantages of sustainable urban drainage (SUDS) and MAR systems. The vulnerability to flooding and the growing demand for drinkable water are complicated issues for CA regions. Integrated water management, which integrates surface water management (stormwater catchment, flood protection) and groundwater management, is required to address both issues simultaneously (recharge measures, recovery for different uses). The development of multifunctional solutions should reduce stormwater runoff and increase groundwater recharge for the mitigation of flooding and protection of groundwater-dependent ecosystems. Some of the complexities to expanding the TERESA project applications are related to the acceptance of this approach with the expansion of the connected TVET (technical and vocational education and training) programs among the CA communities. The current customs, community attitude, and legislation system will be reasonable to update in combination with water efficiency technologies, modeling, and prediction analysis. For example, snow in urban Kazakhstan areas is categorized as “ waste”, and municipalities usually collect snow and damp snow by moving out by the big tracks in the garbage collection sites, without proper localized SusDrain MAR approach, as the TERESA project implementation program suggests. The current status of the TVET SUDS MAR activities for CA communities will be presented during the conference

How to cite: Amanzholova, R., Stefan, Dr. C., Sallwey, Dr. J., Ongdas, M. Sc. N., Sarbassov, D., Sailaubek, A., and Sagin, Dr. J.: TVET SUDS MAR opportunities for water sustainability , A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-80,, 2023.

GC8-Hydro-66 | Orals | Session 5

The role of agriculture irrigation on the Po river basin hydrological balance 

Giovanni Ravazzani, Marco Mancini, Mouna Feki, and Alessandro Ceppi

Changes in climate can have profound effects on river systems and cause important variation in availability of water, with significant impacts on uses highly dependent on the hydrological regime, such as hydropower production and agricultural irrigation. Under this circumstances, current amount of water used for irrigation could not be sustainable in the future. This work presents insight into the Po river basin hydrological balance, investigating the impact of irrigation on water resources availability.

The extreme complexity and heterogeneity of processes involved in river basin hydrology requires the use of integrated modelling approaches for water resources planning and management. In this work the FEST-WB model was employed, that is an integrated spatially distributed physically based hydrological model capable to keep into account anthropogenic structures and management practices that interact with natural hydrological cycle such as artificial regulated reservoirs and agricultural irrigation, and interaction of stream and groundwater.

The study is performed in two steps: first, the hydrological model FEST-WB is calibrated and validated against discharge observations; second, the impact of irrigation is assessed through the simulation of different scenario of irrigation strategies.

How to cite: Ravazzani, G., Mancini, M., Feki, M., and Ceppi, A.: The role of agriculture irrigation on the Po river basin hydrological balance, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-66,, 2023.

GC8-Hydro-110 | Poster | Session 5

Reconstruction of annual flood series in Southern Italy 

Manuele Messina, Salvatore Manfreda, Angelo Avino, Teresa Pizzolla, and Awais Naeem Sarwar

In the last few years, several studies have detected changes in the rainfall regime which may have an impact on hydrological extremes and water resources availability. In addition, the lack of continuous observations as well as the significant transformations of river basins limits our ability to fully characterize hydrological response. Therefore, it is urgent to update current methods and tools in order to shed light on the expected hydrological changes.

In the present study, we try to construct a detailed description of extreme flow patterns in Southern Italy in the period 1920-2020. For this reason, the dataset of annual maximum discharges was constructed using all available records and extended using indirect measurements (e.g., daily discharge and water levels). The data before 1980 were collected in the SIMN Special Publication No. 17 and in the SIMN Hydrological Yearbooks, which provide the annual maximum flow rates and the annual rating curves. Hydrological observatory have been transferred to the regional Department of Civil Protection, but only water level observations are available for the most recent period.

Dataset from different sources requires a significant effort to reconstruct reliable timeseries. In order to extend the historical series of floods annual maxima, we tried to transform mean daily maxima into peak flow values by means of a conversion factor proposed by Taguas et al. (2008). Additionally, the database was also integrated with the most recent data converting water level measurements in annual floods by using the annual maxima flow rating curve. Such rating curve turned out to be quite stable over time as demonstrated by Claps et al. (2010) and it was verified using also hydraulic numerical models.

The present study results complement the outcomes of the recent study by Blöschl et al. (2017), who investigated flood trends over the last five decades in Europe. This study provided a clear overview on the recent tendencies in Europe except for southern Italy because of the limited and discontinuous data availability. Therefore, the study allowed to reconstruct a relevant number of timeseries representative of the entire southern Italy. The homogeneity of the reconstructed data have been verified using the Kolmogorov-Smirnov test. Then, the obtained series were analysed in order to detect possible trends by using the Mann-Kendall non-parametric test. Results highlights the dynamics of flood production over the entire southern Italy.



Blöschl G., Hall J., Parajka J., Perdigão R.A.P., Merz B, Arheimer B., Aronica G.T., Bilibashi A., Bonacci O., [...], Živković N. (2017). Changing climate shifts timing of European floods. Science, 357, pp. 588-59.

Claps P., Ganora D., Laio F., and Radice R. (2010) Riesame ed integrazione di serie di portate al colmo mediante scale di deflusso di piena, Atti del XXXII Convegno Nazionale di Idraulica e Costruzioni Idrauliche, Idraulica e Costruzioni Idrauliche, Palermo, 14-17 settembre 2010.

Taguas E.V., Ayuso J.L., Pena A., Yuan Y., Sanchez M.C., Giraldez J.V., and Pérez R. (2008) Testing the relationship between instantaneous peak flow and mean daily flow in a Mediterranean Area Southeast Spain, Catena, 75, pp. 129-137.

How to cite: Messina, M., Manfreda, S., Avino, A., Pizzolla, T., and Naeem Sarwar, A.: Reconstruction of annual flood series in Southern Italy, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-110,, 2023.

Regional hydrology vibrates to the rhythm of the weather intercepted by the soil-vegetation continuum and controlled by human abstraction and managements.
How can we interpret the observations? Does an observed trend is a signal of climate change? or natural variability ? Is the absence of trend associated to compensating trends?

To do so, long-term observations are indeed a key issue. I’ll show a study on the Seine basin, for which we wanted to assess the impact of the Atlantic Multidecadal Variability on the river & groundwater flows. To do so, 60-years is barely enough, and it was necessary to cover all the XXth century. There are few research networks on such long period, and the required observations come mostly from the public survey. Several issues were to face: data rescue, re-interpretation of the data (from river level to river discharge) and  the combined study of modeling and observations. It remains hard to interpret all the observed variations, especially due to the strong artificialization of the basin. However, it helps interpret the impact of natural variability, and how it could impact the basin in the next decades.

Long term lysimetric observations can help interpret the impact of land cover change and agricultural practices change on the regional hydrology. By using a 60-year lysimeter data set with several crop rotations and a bare soil, we were able to assess the impact of climate change and the impact of catch crop on the groundwater recharge. Unfortunately, such data set are not that common, and it is one of the objectives of the OneWater French research program to help building a lysimeter long term network in France.

Another challenge is to estimate the effect of human management on the water resource.  For groundwater and river abstraction, most of the time, the observations are partial and most often at an annual time scale. Among the human impact, those associated to large reservoirs are difficult to hide. If in Spain, there is free access to the associated data, it is more difficult in France if they are devoted to hydroelectricity or irrigation.  Small dams are far more numerous, but their direct and cumulative effects are not easy to quantify, especially, since there are few information on how the reservoir fill and spill, and how the water is used. I’ll show some elements on how the combination of biotic and abiotic data can be used to assess the impact of small reservoirs and how their impact can change with climate change.

The results were achieved in collaboration with Remy Bonnet & Julien Boé, Antoine Sobaga, Bertrand Decharme & Nicolas Beaudoin, Jérôme Molénat, Nadia Carluer, Elodie Philippe, Patrick LeMoigne & Claire Magand

How to cite: Habets, F.: How to quantify regional hydrological change impact: some examples from France, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-118,, 2023.

GC8-Hydro-111 | Poster | Session 5

Phenomena of Intense Climatic Changes over the Territory of Ukraine and a Vision for the Extension of the Climatic Monitoring System 

Boris Faybishenko, Mikhail Romashchenko, Roman Saydak, and Sebastien Biraud

The purpose of the presentation is to present evidence and analyze the temporal-spatial changes in the climatic zonation of the territory of Ukraine based on the evaluation of the following metrics of meteorological and water balance parameters for the period from 1945 to 2021: temperature, precipitation, relative humidity, evapotranspiration (ET), Standard Precipitation Index (SPI), and Standard Precipitation Evapotranspiration Index (SPEI). We then performed multivariate and univariate (ET and SPEI) hierarchical clustering and Principal Component Analysis (PCA) for periods before and after the temporal structural breaks/breakthroughs, which were used for zonation and 2D mapping of the territory of Ukraine. These data indicate a remarkable pattern of the spatial and temporal variability of climatic changes within the territory of Ukraine, which apparently exceeded the averaged trend of global warming. The most significant increase in temperature occurred in January–March and July–August periods. Almost in all regions of Ukraine, with the exception of central and northern parts, annual precipitation slightly increased, with the most significant increase in precipitation during the September–October period. Despite of a slight increase in precipitation, the level of moisture supply within the territory of Ukraine, resulting from the increased evaporation, has significantly worsened. However, the obtained 2D spatio-temporal data are insufficient to explain the impact of climatic processes on land-atmosphere processes in Ukraine. We hypothesize that an extension of the FLUXNET global network of micrometeorological tower sites (based on the application of eddy covariance methods) over the territory of Ukraine is needed to measure and calculate vertical turbulent fluxes within atmospheric boundary layers. This will help construct reliable 3D climatic models, which will help explain the impact of observed climatic changes on water cycle in Ukraine and surrounding European regions.

How to cite: Faybishenko, B., Romashchenko, M., Saydak, R., and Biraud, S.: Phenomena of Intense Climatic Changes over the Territory of Ukraine and a Vision for the Extension of the Climatic Monitoring System, A European vision for hydrological observations and experimentation, Naples, Italy, 12–15 Jun 2023, GC8-Hydro-111,, 2023.