Year of Issue 2024 General National Id NO Site name Hobølelva River Summary The Kråkstadelva catchment, as case study area, is located within the Hobølelva watershed, located ca. 30km S-SE of Oslo, Norway. The area of the Kråkstadelva catchment is approximately 51 km2. Agricultural land covers ca. 43% of the catchment (22km2) and it is dominated by cereal production. Forest covers ca. 45% of the catchment. Heavy clay soils dominate in the area (up to 80% of clay content). Mean annual temperature is 5.3°C and average annual precipitation is c.a. 864 mm. Floods of varied magnitude occur frequently in the catchment, typically during spring snow melt and autumn rainstorms. The main challenge in the area is water quality (incl. high phosphorus pollution) and soil erosion (incl. riverbank erosion and quick-clay landslides). There is already high focus on environmental mitigation measures, for example reduced tillage (no tillage in autumn), buffer zones, grass-covered water ways, constructed wetlands and the use of catch-crops. OPTAIN project will support the case study team in identifying new land management strategies, including the best combination and allocation of measures in the catchment as well as implementing new (combinations of) measures, in order to improve water retention in the soil and the landscape and as a result reduce the risk of flooding, and improve water quality downstream. Light or indepth? In-depth The in-depth description of the case study 10_Hobol_NIBIO.pdf RBD code NO011 Transboundary 0 Data provider Nibio NWRM(s) implemented in the case study Sediment capture ponds Stream bed re-naturalization Low till agriculture Buffer strips and hedges Optain's measures Small retention ponds in the forest Grass or stubble in areas prone to flooding and erosion Grass buffer zones alongside waterways in cropland Grassed waterways Site information Climate zone cool temperate moist Mean annual rainfall 600 - 900 mm Mean rainfall Annual precip. (1993-2004): 651-1305 mm.yr-1(avg. 864 mm.yr -1) Mean rainfall unit mm/hour Average temperature Mean temp.: 5.3°C (annual), -4.8°C (Jan/Feb), 16.1°C (July). Mean runoff 4.7 m3.s Remarks runoff imperviousness Avg. water discharge: ca. 4.7 m3.s (max: 102 m 3.s). Type Case Study Info Average slope range Elevation range: 25 - 346 m a.s.l. Vegetation class In the North: mainly forested with Pre-Cambrian bedrock. The land use is 79% forest, 16% agriculture and 5% water areas. Monitoring maintenance Monitoring impacts effects 0 Design & implementations Public consultation 0 Contractural arrangements 0 Design contractual arrangement Arrangement type Responsibility Role Comments Name Design consultation activity Activity stage Key issues Name Comments Design land use change Land use change type Design authority Authority type Role Responsibility Name Comments Lessons, risks, implications... Financing mechanism 0 Success factor(s) Success factor type Success factor role Comments Financing Financing type Comments Barrier Barrier type Barrier role Comments Driver Driver type Driver role Comments Financing share Financing share type Share Comments View Policy, general governance and design targets Policy description Local involvement has been extensive since around 1990 as catchment has been used as a study site in many projects, e.g., EU FP7 Refresh, EuroHarp, H2020 Recare). NIBIO has arranged many workshops with stakeholders of this catchment: - Farmers and land owners; - Water boards: local (for the catchment) and regional (for the river basin of Glomma); - Municipalities; - Boaters, canoes (mainly in the lake), local communities; - Drinking water supply company (MOVAR); - Environmentalists (f.ex., SABIMA); - Hunting and fishing associations; - Tourist association (Turistforeningen);etc. Part of wider plan 0 Policy target Target purpose Erosion Control Peak-flow reduction Pollutants Removal Policy pressure Pressure directive Relevant pressure Policy area Policy area type Policy area focus Name Comments Policy impact Impact directive Relevant impact Policy wider plan Wider plan type Wider plan focus Name Comments Policy requirement directive Requirement directive Specification Photo gallery Full Context Area(aka Level or Site) ALL Crosslinks Pair Record Reduced tillage: no tillage in autumn Destination Context NSWRM(Sections) - Default view - ALL - 7487 Crosslink Type Proximity with Pair Record Small constructed wetland Destination Context NSWRM(Sections) - Default view - ALL - 7462 Crosslink Type Proximity with Destination Context Learn About - Real-world Examples - Detailed Case Studies - 462 Crosslink Type Proximity with