Prairie du Sac dam repairs continue through 2026
Prairie du Sac dam repairs continue through 2026
KEVIN MURPHY For the News Republic Jan 8, 2022
Concrete spillways allow water to bypass turbines at Alliant Energy's Prairie du Sac dam on the Wisconsin River. The dam's gates are being rebuilt in a $25 million project. Alliant's license requires the utility to maintain the level of Lake Wisconsin within a range of about 7 inches.
STATE JOURNAL ARCHIVE
KEVIN MURPHY For the News Republic
MADISON Alliant Energy continues repairs to its 107-year-old hydro dam at Prairie du Sac as it will replace all 41 spillway gates during the next five years. ... The steel gates are original to the dam since it went into service and help control water flow used to generate electric power.
A 2016 inspection found some buckling in some of the gates. The Federal Energy Regulatory Commission, which licenses the dam, then required Alliant to further review and evaluate this issue, according to Jan. 4 letter the utility sent to the Public Service Commission.
An inspection conducted from 2017 to 2019 determined that all of the gates needed to be repaired or replaced. Since the gates were nearing the end of their useful life, Alliant decided to replace them all. Six gates will receive additional components designed to increase dam safety and water flow during winter months.
The gates are referred to as Tainter gates, named after a Wisconsin engineer who invented the convex shaped floodgate in 1886. Since then, they have been used worldwide, including 321 installations alone on the Mississippi River. ... The estimated $25 million project at Prairie du Sac will replace six to 10 gates per year from 2022 to 2026.
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