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 Cechticky stream catchment case study is located at the Central Bohemian Region of the Czech Republic. The catchment area is about 72 km², most of which is used as agricultural land (69%). Fifty nine percent of which is cropland. Čechtický stream catchment is a part of the Želivka river basin, which includes the Švihov drinking water reservoir. The reservoir is currently facing persistent problems with poor water quality linked to phosphorus, nitrogen and pesticide pollution. The area is also threatened by soil erosion in large fields as well as poor soil quality linked to dehumidification, soil compaction and increasing periods of drought. Tile drainage is common in the area and issues linked to technical failures, unintended runoff and poor quality are increasing.

OPTAIN aims to develop strategies and advanced tools for designing and evaluating the effectiveness of Natural Small Water Retention Measures taking into account the principles of their feasibility in small agricultural river basins in terms of increasing water accumulation and retention and improving water quality. Emphasis will be placed on measures on agricultural drainage systems in terms of possibility of their modernization, regulation, professional elimination.