Projekt Byälven – efter översvämningen hösten 2000 / The Byälven project – after the flood of year 2000
During autumn year 2000 a severe flood hit the Byälven river system in the western parts of Värmland, Sweden, causing damages of about MEUR 25–30. Afterwards local municipalities and the county board decided to investigate the possibilities of mitigating future floods and initiated the Byälven Project. What caused the flood and a number of flood protection measures were looked into in the first stage of the project. Some measures that proved environmentally or economically unfeasible were rejected whilst some remained interesting. In the
second stage a detailed hydraulic model of the river was developed and used to study the effectiveness of different flood protection measures. Places along the river reach where protective measures would be effective were identified and the attained reductions of water level were calculated. In the third stage more detailed simulations and economical calculations were made for the most interesting measures in order to estimate cost effectiveness. The investigation highlights a number of technical protective measures that considerably reduces risk-cost coupled with floods. The step by step carrying through of the project made it possible to economize on investigating resources and thereby to study the most interesting protective measures more in depth.The method proved to be successful considering protective measures now are being realized.