The Agricultural Catchment Monitoring (LOOP) is part of the Danish Environmental Protection Agency's National Monitoring Program for Aquatic Environment and Nature (NOVANA). In LOOP, the focus is on the trends in losses of nutrient to the aquatic environment. Information on agricultural practices is collected through an annual interview survey of farmers in six well-defined agriculturally dominated catchments, and is measured in the water seeping through the root zone (soil water), drainage water, the upper groundwater and the stream water in five of the areas.
The Danish Environmental Protection Agency is responsible for the implementation of the monitoring with professional support from the Topic Center for transport of nutrients to surface waters at Århus University and the Topic Center for Groundwater and Boreholes at GEUS.
GEUS’ role in the LOOP program
GEUS provides scientifically based advice regarding monitoring, in relation to the quality and quantity of the upper groundwater in five LOOP catchments.
The nitrogen content of groundwater is measured in monitoring wells (groundwater nests), with screens between approx. 1.5 and 5 m below ground and for a single locality in LOOP 4, Lillebæk, where the groundwater wells are up to 7 and 11 m deep.
The quality of the upper groundwater in each of the five LOOP catchments is monitored in approx. 20 monitoring points, which are sampled up to six times a year. The groundwater is analysed for various nitrogen and phosphorus compounds, and it is also analysed for the other main constituents of the groundwater, however with a lower sampling frequency.