River Dviete Basin: Catchment area – 254 km²; Annual runoff – 0,057 km3; Length – 37 km; Slope of the riverbed – 4 m/km at the upland and 0,2 m/km at the lowland; The Dviete floodplain area is also a Natura-2000 site (5000 ha): Main nature values are the eutrophic floodplain meadows, which provide nesting sites for the corn-crake (Crex crex) and other rare bird species. Local partnership building: Union of the Dviete Valley Municipalities (DSPA) founders are five municipalities (Bebrene, Dviete, Eglaine, Pilskalne and Sedere parishes). Many projects have developed in close cooperation between the Daugavpils University and this NGO.

The Csorsza case study is located in Veszprém County, Hungary. The size of the study site is 21.3 km2, where 29% of the total catchment area is forest, 29% orchards and vineyards, 17% shrubs, 13% is arable land, 6% is grassland, and 5% is urban.

Some selected analysis are performed at the Felső-Válicka catchment, too. The Felső-Válicka study site is located in Zala County, flows in south-north direction into the River Zala. The size of the catchment is 131 km2. 27% of the total catchment area is forest, 35% is cropland, 11% is grassland, 3% is wetland and 11% is urban.

Both study sites are located in the catchment of Lake Balaton, therefore state of the environment and nature in these small catchments influences the touristic and economic potential of the Balaton region. Their water and nutrient management affects water quantity and quality of the lake. Extreme weather events will increase the environmental and social conflicts in the region.

Main challenges identified in both sites are decreasing soil erosion and nutrient load, preventing flash floods, and implementing integrated water resources conservation.

OPTAIN project aims to identify effective combination of the NSWRMs and optimize their allocation, in order to improve water and nutrient retention in the soil and the catchments. Emphasis will be put on suitable options to foster the resilience of agricultural production to climate change.

The Cherio River basin is located in the eastern part of Bergamo province, Lombardy region. It extends from the pre-alpine reliefs to the irrigated plain area, down to the confluence of Cherio River into Oglio River. The catchment area is about 153 km2, broken down mainly into forest (42%) and agricultural (39%) land. The territory is vulnerable to overflows and flooding events, which requires constant reclamation activities. Moreover, the increasing water withdrawals from Cherio River for industrial and agricultural purposes compromises the possibility to ensure environmental flows, especially during summer and drought periods. Pollution from nitrogen, phosphorus and wastewaters finally contributes to deteriorate the overall water quality.

OPTAIN seeks the involvement of local actors to identify strategies and solutions for an efficient water management, aimed at ensuring quali-quantitative standards to safeguard natural and aquatic habitats and to support an agricultural system deeply dependent on water resources.

The case study area “Petite Glâne” belongs to the Broye catchment in the southwestern part of the Swiss Plateau. The river Petite Glâne is about 30 km long, repeatedly crosses borders between the cantons of Vaud and Fribourg, and has a catchment area of 94 km2. Its upper reaches have remained fairly natural and are lined with forest, whereas its lower reaches in the Broye plain have been canalized and straightened. The soils and climate here are highly suitable for arable farming. Overall, the catchment of the Petite Glâne is strongly characterized by agriculture: nearly three quarters of its area consists of pastures and cropland. However, the region is increasingly experiencing water shortages in summer, and there is often not enough water in the Broye and Petite Glâne to irrigate the fields. Climate change will further aggravate the situation. Farmers are therefore considering new options to mitigate the increasing drought events – for example an irrigation project using water from Lake Neuchâtel.

Against this background, OPTAIN explores efficient land use and land management strategies as well as technical measures that increase the capacity of soils to absorb and store water while improving nutrient retention and decomposition. These natural and small water retention measures (NSWRMs) are discussed and evaluated jointly with regional stakeholders. Based on model calculations, OPTAIN works to determine the maximum possible water and nutrient retention potential that can be achieved with NSWRMs if they are optimally combined and positioned in the catchment. Although the focus is on the Petite Glâne, the case study extends to the entire Broye catchment when it comes to modelling and stakeholder involvement.

The OPTAIN project will support the case study team with identifying and developing efficient land management strategies and small technical solutions to improve the soils’ infiltration and water holding capacities as well as its capacity to filter, buffer and transform pollutants.

The study site is the sub catchment of Tetves, is considered a priority area in terms of water protection. The size of the study site is 68 km2. 49% of the total catchment area is forest, 39% is arable land, 1% orchards, 1% vineyard, 1% is grassland and 2% is urban.

The study site is sensitive to nutrient and nitrate loss. Extreme weather events, the presence of loose parent material and a lack of best management practices in some part of the study site increase soil degradation, especially gully erosion. The water and nutrient management of this small catchment affects water quantity and quality of Lake Balaton. Extreme weather events will increase the environmental and social conflicts in the region.

The most pressing issues recognized in the study site are: revise the aspects considered for the delineation of soil erosion prone areas, wider application of measures that efficiently decrease soil erosion and nutrient load, and implementation of integrated water resources conservation.

OPTAIN project aims to identify effective combination of the NSWRMs and optimize their allocation, in order to improve water and nutrient retention in the soil and the catchments. Emphasis will be put on suitable options to foster the resilience of agricultural production to climate change.

The Wimbe basin is about 112 km2 in size and is classified as a continental bioregion. The basin consists of the water bodies LE8-10. The municipalities within the basin are Daverdisse, Wellin, Beauraing, Gedinne and Rochefort. The basin’s land use is 2% urban, 21% arable, 11% pasture and 66% forest. The region where the stream flows is representative of the Famenne schisteuse and the landscape is open. The region is vulnerable to both floods and low flows. The area is also vulnerable to nitrate concentration in water that is exceeding or is likely to exceed 50 mg/l, may have undergone or likely to undergo eutrophication.
The OPTAIN project will support the case study team with identifying and developing efficient land management strategies and small technical solutions to improve the soils’ infiltration and water holding capacities as well as its capacity to filter, buffer and transform pollutants.

The Schwarzer Schöps case study is located in the East of Germany. The catchment area is about 136 km2, most of which is used as cropland (54%) and grassland (20%). The area is facing an increase in severe floods, soil erosion, and droughts, with negative implications for crop yield stability. In addition, the downstream reservoir Quitzdorf suffers more often from low water tables and high phosphorus pollution which is causing blue-green algae bloom and threatening its multiple services, in particular its important role for nature protection, recreation, and maintaining downstream environmental flows.
The OPTAIN project will support the case study team with identifying and developing efficient land management strategies and small technical solutions to improve the soils’ infiltration and water holding capacities as well as its capacity to filter, buffer and transform pollutants.