Murån river, drainage and ecology

Several studies conducted at the Bolmen Research Station indicate that the local impact of the Murån river in the southwestern lake Bolmen results in significant browning of the Bolmen water, which is used for drinking water after treatment at the Ringsjöverket facility. This has a significant environmental impact and is cost-intensive.

Additionally, the lake’s ecology undergoes changes as a consequence of increased browning. Measures aimed at reducing browning in Bolmen thus have both short-term and long-term positive effects on drinking water safety. The project aims to map the origin of browning in the Murån river basin, how concentrations vary over time, and the climatological and hydrological factors that increase or decrease browning. The value of restored wetlands for capturing browning before humic substances reach the lake will be particularly investigated. The project is carried out at Halmstad University as a doctoral project by PhD student Jasmin Borgert.


  • Identify the main causes of browning in the water of Kafjorden and at the intake to the Bolmen tunnel
  • Understand why and when soils release organic material and humic substances
  • Examine the consequences of an increasing concentration of organic material and humic substances for the ecosystem of Lake Bolmen
  • Investigate the possibilities for constructed wetlands to reduce browning and how these wetlands should be designed in terms of depth, vegetation, and hydraulic residence time if they are to be effective