Mountain Meadows Reservoir, referred to locally as Walker Lake, reportedly lost all of its water during the second week of September sometime after a clogged intake supplying the 4.8-MW Hamilton Branch hydroelectric facility was cleared of debris, according to published reports.
Mountain Meadows Reservoir is on Hamilton Creek in the Sierra Nevada Mountains of Northern California. It is a catchment operated by Pacific Gas & Electric Co. (PG&E) in its Feather River hydroelectric system. Mountain Meadows Dam, a steel frame and timber face dam 26 feet in height by 264 feet in length, impounds the 5,800-acre reservoir.
The reservoir has a storage capacity of 24,800 acre-feet and it supplies flow to Hamilton Branch located on the east shoreline of Lake Almanor in Plumas and Lassen counties.
Current federal regulations do not require that the dam, reservoir and powerhouse hold a Federal Energy Regulatory Commission license.
The dam was originally constructed in 1924 and later reconstructed in 1962. PG&E relies upon permitted and prescriptive water rights for 24,000 acre-feet of water storage in Mountain Meadows Reservoir.
PG&E claims riparian rights for a direct diversion of 200 cubic feet per second of water into Hamilton Branch Flume below Mountain Meadows Reservoir; additional flows diverted at Spring Creek Feeder, 15 cfs; Clear Creek Feeder, 30 cfs; and Red Bridge Pump at 35 cfs, according to state documents. The company holds irrigation rights at Mountain Meadows Reservoir and at Hamilton Branch Flume.
After power generation at Hamilton Branch, flow is released downstream into Lake Almanor and into PG&E’s other North Fork Feather River projects. Each year the Feather River hydroelectric power projects deliver irrigation water to regional farms between March 31 and October 31.
Utility Dive reports, hydroelectric producers throughout the west have struggled with four years of drought, leaving the region’s snowpack — the chief supplier of reservoir water — at just 3% of typical conditions for spring 2015.
According to the latest NASA estimates, about 11 trillion gallons of water are needed to alleviate California’s four-year drought and the agency anticipates El Nino’s impact on winter weather could restore some of the water level in the region.