Phoenix Lake Preservation and Restoration Plan

Horizon Water and Environment (Horizon) is assisting the Tuolumne Utilities District to develop the Phoenix Lake Preservation and Restoration Plan (PLPRP). Constructed in 1852 and now used as a water supply reservoir, the storage capacity of Phoenix Lake has decreased substantially due to sedimentation. In addition to decreased capacity, the lake’s water quality and wetlands have degraded due to excessive sediment and nutrient loading. Horizon is conducting several technical studies, including monitoring streamflow and lake levels, sampling and analyzing water and sediment quality, mapping lake bathymetry, identifying watershed sediment sources, and evaluating wetlands and aquatic resources. Based on this lake and watershed assessment, Horizon is developing a lake plan to increase water supply capacity through sediment removal and control, improve water quality, reduce watershed sediment sources, and enhance wetlands. The overall goal of the District is to improve the lake’s water storage and supply reliability while also enhancing its natural resources. Horizon is also assisting the District with outreach efforts to the local lake task force and supporting grant coordination with the Sierra Nevada Conservancy who is helping fund the project.