Lossen Regulating Weir

Client: Ljusnans Vattenregleringsföretag
Main contractor: DAB Group AB
Main works: Enhancement of weir safety
Project dates: 2013–2016

The project in brief
Lossen regulating weir was built in 1952–1962 where Lossen lake runs into the Ljusnan river. This contract entailed safety enhancement at the weir, including a new spillway. DAB was in charge of the project and of all building works.

Project and solution
• New concrete spillway with a capacity of 610 m³/sec.

• The spillway was fitted with two 13-metre-wide segmented compartments.
• 3,000 m³ concrete for the spillway.
• Inlet and outlet channel, total length 550 m.
• The outlet channel from the spillway comprises a 130-metre-long concrete channel.
• Approx. 3,000 m³ concrete – which then runs into a rock channel.
• Earth excavation 760,000 m³.
• Rock excavation 60,000 m³.
• A new concrete road bridge was built over the rock channel.
• Reinforcement of the dam’s downstream slope with support embankment.
• 42,000 m³ stone filler.
• 18,000 m³ coarse filter.
• 20,000 m³ fine filter.
• Reinforcement of the existing erosion protection on the upper part of the embankment dam’s upstream slope, extending 400 metres
• A 180-metre-long pier with a crest width of approx. 10 metres on the southern shore of Lake Rörhån.
• Laying of excavated rock and earth masses for the pier and dam abutment reinforcement in Lake Rörhån.
• Kraftverksbyggarna Söderhamn was the subcontractor, performing all land and rock works.