The project area is situated in the southern part of County of Halland at the Swedish west coast. We have selected 11 agricultural drainage areas in which we have identified > 1 000 constructed wetlands (CWs) in GIS-layers. We deployed water level meters in 9-14 constructed wetlands in each drainage area. In each drainage area we have water level meters also in the water courses. In addition, we have water level meters in ca 15 CWs outside of the 11 drainage areas. In total we have 112 water level meters in wetlands and 12 in water courses. The map shows the 11 drainage areas.