Installing Flap Gates at Sagnfossen to Increase Available Head

摘要

During renovation of its 6.2-MW Sagnfossen plant on the Trysil River in Norway, owner Eidsiva Energi decided to boost the generating capacity of the project by increasing available head by 2 meters. This was accomplished by lowering the tailwater level by 1 meter and installing flap gates on the crest of the dam to add 1 meter in height. This was the first Norwegian use of these gates, which are raised and lowered using air bladders. The gates, installed in 2005, continue to operate successfully, including during icy conditions and spring floods.