Practical Sediment Management in Urban Areas. The Success Story of Ishøj Lake, Denmark
WODCON XXIII - Dredging is changing - The Practice. The Science. The Business.
G. van den Berg, M. Seehuusen, Jan K. Pedersen
"Tube dewatering technology can be the key to local re-use of contaminated sediments. This paper will discuss in detail how this worked out in an innovative project in Denmark. It will highlight how the removal of sediment from a lake in an urban environment as a city park, traditionally seen as tedious and costly, can turn into an opportunity to enhance nature, boost water quality and stimulate recreation, while achieving these results in the fastest possible way without nuisance for the people in the area and with least carbon footprint possible. Ishøj Lake is an artificially constructed but nowadays protected lake in the heart of the city of Ishøj, south of Copenhagen. As a result of road water supplied from Baldersbækken and Lille Vejle stream, Ishøj Lake filled up, over the years, with clay, sand, and organic particles. During summer months the situation was so bad that the consequences for fish and birds, which enjoy the wetlands, were quite severe. A decision needed to be made about the lake's future role in the community. In close collaboration Ishøj Utilities Company, the specialists of TenCate Geotube(r) and its representatives in Denmark, EnviDan, worked out a plan to dredge the lake in an environmentally friendly way, removing the sediments and the accumulated nutrients and use them in a revolutionary way never used in Denmark before, to remodel the recreational landscape of the park. An efficient work process with the least possible environmental impact. The work was executed within the time frame and ticked all the boxes. Apart from an in-depth discussion on the technical preparation, the execution and the results, the paper will discuss the road towards this success and offer key elements for other communities to keep in view in the decision-making process."
Keywords: city lake, dredging, tube dewatering, environmentally friendly.