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 the 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 mils (3.0 mm) PVC geomembrane liner. Bathymetric surveying was conducted to find benthic streamflow and reservoir depths. Soar Environmental staff supported the deployment of a benthic UAV and calculated sediment build-up adjacent to the upstream face of the dam. Our team supported the development and the negotiated mitigation measures for the IS/MND which ultimately was accepted by CDFW, the Lead Agency for the project. The project required FERC, DSOD, SHPO, USFWS, CDFW, USACE, SWB