Shaver Lake Dam had been performing safely and effectively for almost 100 years; however, freeze thaw cycles, escalated extreme load conditions (seismic and flood), required retrofitting, calcium carbonate buildup and structural restrictions impacted maintenance efforts necessary to respond to deterioration and ultimately led to the degradation of the dam. A PVC geo-composite liner that waterproofed the entire upstream face of a dam was proposed for application to reduce dam leakage and increase dam viability. The associated reservoir required draining, fish rescue and mitigation for fish mortality and stream sedimentation were required prior to application of the 100 mil (3.0 mm) PVC geomembrane liner. Bathymetric surveying was conducted to find benthic stream flow and reservoir depths. We deployed a benthic UAV and calculated sediment build-up adjacent to the upstream face of the dam. Developed and negotiated mitigation measures for the IS/ MND which ultimately was accepted by CDFW, the Lead Agency for the project. Project required FERC, DSOD, SHPO, USFWS, CDFW, USACE, SWB