Beers Sisters Reservoir Dam Repairs
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Main Dam Embankment – After the reservoir was drained, an earthen coffer dam was constructed around the area of construction to maintain a dry working area. An 8” HDPE pipe managing incidental water flows around the construction area. Approximately 2,000 CY of the dam embankment and core was removed to reconstruct the outlet works. Riprap lining of the upstream side of the embankment was replaced with new riprap.
Spillway – A new overflow weir was constructed along the reservoir’s edge at the start of the spillway to define the spillway crest. A new spillway channel was constructed outside of the embankment toe. The spillway channel is protected from scour with riprap, intermittent boulder check/grade control structures, and vegetation. In addition to the riprap protection, a riffle boulder structure has been included at the downstream end of the stilling basin prior to the flows returning to the existing Coon Creek drainage channel.
Outlet Works – The existing reservoir drain pipe was removed and replaced with 18” & 30” Concrete Encased RCP. A new inlet tower was constructed at the upstream end of the pipe that will be used to control the 2-year storm event flows into the pipe. A drain intake structure was constructed at the bottom of the reservoir. The final primary outlet works will consist of both the 30” RCP and the new spillway. A stilling basin was constructed at the outfall of the RCP. Storm flows more than the 2-year storm event will spill into the new spillway channel prior to being conveyed into Coon Creek.
Pedestrian Trail – The existing asphalt trail on the existing dam embankment was removed and replaced with a concrete trail. A prefabricated pedestrian bridge was installed to cross the spillway.