Nutrient leaching in Rönne å River - Problem Solving

The study aims to evaluate the amount of nutrient leaching from diffuse sources and estimates the operational costs for the problem-solving.

Eutrophication is a result of organic material increase in aquatic ecosystems due to high levels of Phosphorus (P) and Nitrogen (N) in water. This process reduces the water transparency,  can lead to a lack of oxygen, and even the death of fish (SMITH, 1998). 

ArcGIS Mobel Builder was used in this project and showed to be an effective tool to analyze environmental issues. Moreover, the GIS software usage through map-making also makes it easier for the general public to visualize and spatialize the data, helping in environmental planning.


In order to quantify which source contributes the most to the eutrophication process, land use data was joined to a coefficient table that contained how many Tons/year of P and N are leached from those different sources.

Nutrients leached to the aquatic ecosystems

Despite covering 26.5% of the drainage basin, cultivated areas are responsible for leaching to aquatic systems 1758.6 tons of Nitrogen (74.6%), and 20.1 tons of Phosphorus (61.5%) per year

Since cultivated lads are the main source of nutrient leakage, protective zones along the contributing stream in those areas can be created to reduce the damage. Those zones have the capacity to stop the leaching of P at a rate of 4 kg/ha/year. Here, a 20-meter buffer was suggested.


However, to create those areas, some costs must be taken into account:


The protective zone covers 808.57 ha in cultivated lands, thus It was estimated a reduction of 19.7 million kg/ha of P leaching per year.

The operational cost was estimated at over 14 million SEK, being 97.7% of the value designated funds for construction, and 2.3% to compensation costs.