The impact of mitigation work in quick clay zones – An example from Skjelstadmark, Norway

Quick clay landslides pose significant threats to human lives, infrastructure, and the environment. This paper summarizes nearly three decades of mitigation work in the Skjelstadmark region in mid Norway, where extensive measures were implemented to reduce landslide risk along 28 km of river channels and tributaries. The mitigation strategy combined erosion control, slope relief, and counter fills, resulting in a substantial decrease in sediment transport and landslide activity. Environmental benefits included improved water quality and enhanced fish habitats. Socio-economic benefits were also significant, safeguarding lives, protecting infrastructure, and preserving agricultural lands. The cost-benefit analysis demonstrates the economic viability of these measures, highlighting the importance of proactive risk management. This study provides valuable insights into effective mitigation strategies for quick clay landslides, emphasizing the need for continued monitoring and maintenance to ensure long-term effectiveness.