Moritz Shore
Adviser
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.
Abstract
Reducing diffuse nutrient losses to water bodies remains a major problem in the agricultural areas of the Nordic countries. The transition towards a bioeconomy and ongoing climate change raise questions on the future of water quality and freshwater ecosystems and what kind of adaptation strategies could be implemented to maintain both food and environmental safety. The objective of our study was to evaluate the effectiveness of Natural Soil Water Retention Measures (NSWRMs) under current and future climate conditions in retaining water, soil particles and nutrients within the landscape. The hydro-biochemical model SWAT+ was implemented in the Krakstad catchment in southern Norway using the novel approach developed within the EU H2020 project OPTAIN. This approach enables an improved spatial representation of NSWRMs in the landscape. Available discharge and water quality monitoring data were used as reference data for model calibration. The effectiveness of reduced tillage, grassed waterways, sedimentation ponds established in the forested areas and buffers on water retention and nutrient loads was evaluated. Our simulation results indicate that conservation tillage, which maintains stubble on the soil surface during winter, has the strongest impact on reducing soil and nutrient losses towards surface water bodies. Grassed waterways, established in existing erosion prone gullies, could also significantly contribute to water and nutrient retention within the landscape. The implemented NSWRMs did not appear to increase the soil moisture content in early spring even under future climate conditions, which is an important aspect for ensuring soil trafficability and the timing of sowing spring cereals
