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.