Moritz Shore
Adviser
Authors
M.R. Eini M. Piniewski P. Braun E.A. Chiaradia Csilla Farkas L. Honzak P. Kassai R. Kolcsár S. Plunge L. Sanguanini C. Schürz Moritz Shore B. Szabó M. Volk C.I.H. Wittekind M. StrauchAbstract
Climate change is intensifying floods, droughts, and nutrient export from agricultural landscapes, threatening water security under increasingly non-stationary hydroclimatic conditions. Although landscape-scale water-retention measures are widely promoted as nature-based solutions, their combined effectiveness under future climates remains poorly constrained, particularly across contrasting hydroclimatic settings. Here, we evaluate the capacity of distributed retention portfolios to buffer climate-driven hydrologic and water-quality change using a harmonized, field-explicit Soil and Water Assessment Tool Plus (SWAT+) framework applied to five European agricultural catchments spanning a pronounced hydroclimatic gradient. Portfolios, co-designed with local stakeholders, were simulated under historical and late-century climates drawn from bias-corrected Coordinated Regional Climate Downscaling Experiment over Europe (EURO-CORDEX) simulations. Impacts were assessed for flood peaks, low flows, soil-moisture drought duration, and nutrient or sediment export. Climate change consistently amplifies hydrologic extremes and pollutant loads, particularly under wetter future conditions. Retention portfolios reduce flood peaks and pollutant export across all catchments but provide only limited improvements in low flows and drought duration. However, portfolio effects rarely offset climate-driven changes, indicating that retention primarily functions as a risk-reduction strategy rather than a means of restoring baseline conditions. Portfolio effectiveness showed weak associations with the catchment dryness index and varied among catchment-specific portfolios. Because hydroclimate, catchment properties, measure composition, and spatial placement covary in this comparative design, their independent effects cannot be separated. The results nevertheless identify measure-pathway alignment and hydrologic connectivity as plausible design considerations. Responses were predominantly co-beneficial across indicators, indicating that portfolios can deliver multiple co-benefits with limited trade-offs. These findings position distributed retention portfolios as a useful but inherently limited component of climate adaptation, underscoring the need to combine retention with complementary strategies to manage residual risks.
Authors
Csilla Farkas Moritz Shore Agota Horel Agota Horel Gökhan Cüceloglu Dorota Mirosław-Świątek Maria Eliza TurekAbstract
Within the OPTAIN project, the effects of Natural/Small Water Retention Measures (NSWRMs) on water regime, soil erosion and nutrient transport are evaluated at both catchment- and field-scales for present and future climate conditions. The goal of this deliverable report D4.3 is to perform an integrated, model-based assessment of the effectiveness of NSWRMs at the field scale and to use these results for cross-validating the outputs obtained from the catchment-scale modelling. The assessment is based on the adaptation of a field-scale mathematical model (SWAP) to seven pilot sites across three European biogeographical regions and on combined analyses of NSWRM and projected climate scenarios. The scenarios are designed to evaluate the efficiency and potential of different NSWRMs in improving soil water retention and reducing flash floods and the loss of soil and nutrients under changing climate conditions. This report contains a detailed description of the SWAP modelling workflow, from input data preparation, model setup and harmonisation, model calibration and application in climate and NSWRM scenario runs. It presents calibration and NSWRM scenario results from seven OPTAIN case studies from three different biogeographical regions (Boreal, Continental and Pannonia). The report also describes i) the new approaches and tools developed within the OPTAIN project that facilitate the implementation of the scenarios and the interpretation of the modelling results, ii) the methods used to cross-validate the SWAP and SWAT+ models, and iii) the issues faced during the implementation of this work. The SWAP model was calibrated for all the pilot fields with good or satisfactory results. The impact of four in-field NSWRMs - reduced tillage, shifting to grassland, afforestation and drought tolerant crops - on the water balance elements was evaluated. The scenario results indicate that the effects of measures on soil water retention and other water balance elements have some regional pattern, but can be strongly dependent on local conditions (e.g. soil, crop, slope). According to the scenario results, for most of the cases the studied NSWRMs contributed to reducing evaporation, surface and subsurface runoff and percolation to deeper layers, which results in increased soil water retention or plant water uptake within the fields. The cross-validation of the field scale SWAP and catchment-scale SWAT+ models was a challenging task and could only be performed for selected water balance elements (evaporation, transpiration and drainage outflow). Comparable results were obtained in most of the cases for the baseline scenario, but the differences between the soil water balance elements simulated by the two models increased when implementing the different measures. The increased differences, however, could also reflect the differences in measure implementation, as these were constrained by the model’s structure and parameters. We concluded that the implementation of the SWAP field-scale model in the scenario analysis and cross-validation could positively contribute to i) better understanding the effects of NSWRMs at field level and ii) evaluating the outputs of the SWAP and SWAT+ models in a wider context. We concluded that NSWRMs can contribute to water retention within the landscape, and that this effect seems to decrease and increase in the future for measures related to management and land use change, respectively. The cross-validation of the water balance elements of the two models showed that the SWAP and SWAT+ simulation results were comparable for the status quo (present situation, for which the models have OPTAIN D4.3 Assessment of NSWRM effectiveness at field scale 6 / 143 been calibrated), but differed for the NSWRMs scenarios, depending on how the measures were implemented in the two models.
Authors
Hannu Marttila Joy Bhattacharjee Katrin Bieger Brian Kronvang Mikołaj Piniewski Svajunas Plunge Ignacy Kardel Marek Giełczewski Csilla Farkas Moritz Shore Mojtaba Shafiei Arturs Veinbergs Ieva Siksnane Kaspars Abramenko Ainis Lagzdins Kristina Mårtensson Sara Sandström Katarina KyllmarAbstract
This document describes comparison of SWAT+ model with national/regional hydrogeochemical models as well as graphs and maps of the most relevant outputs documenting the model performance and comparison. Case and demonstration study-specific model descriptions and inputs are in the report as appendices.
