Caples Creek Channel Maintenance Flow Assessment and Caples Lake Spillway Stabilization Plan

Client: El Dorado Irrigation District

Location: Sierra Nevada, CA

Summary: Cardno ENTRIX conducted two studies associated with the post-compliance FERC relicensing for the Caples Creek hydroelectric project in the Sierra Nevada, CA. The first study is an assessment of annual high flow releases that are mandated for the maintenance of geomorphic, riparian, and aquatic habitat conditions. Cardno ENTRIX evaluated the transport of spawning gravels, bank stability, and regeneration of riparian vegetation on a floodplain surfaces. The study included field measurement of bed material transport, assessment of geomorphic conditions, and hydraulic modeling and assessment. The second study was an evaluation of the Caples Lake spillway stability and preparation of a plan for stabilization. The Caples Lake spillway is a natural drainage channel that has become enlarged and incised due to large, episodic over flows. Cardno ENTRIX prepared a feasibility assessment for a range of conceptual bioengineering treatments and associated costs.