SCH Number 2016052036

Title: Hell Hole Dam Core Raise Project
Description: At the request of the California Department of Safety of Dams (DSOD), PCWA Investigated the permeability of Hell Hole Dam above the impervious dam core in the event of a Probable Maximum Flood (PMF). The PMF is the theoretically largest flood resulting from a combination of the most severe meteorological and hydrologic conditions that could conceivably occur in a given area. Investigations identified that the PMF over tops the dam core for a distance fo approx. 700 feet adjacent to the left abutment and approx. 700 feet adjacent to the left abutments and approx. 700 feet adjacent to the right abutment. To meet DSOD and Federal Energy Regulatory Commission (FERC) requirements, PCWA is proposing to raise the dam core to ensure that seepage that could occur above the core under PMF loading is safely controlled.

4 documents in project

Type	Lead/Public Agency	Received	Title
NOD	Placer County Water Agency	7/11/2019	Hell Hole Dam Core Raise Project
NOD	Placer County Water Agency	5/20/2019	Hell Hole Dam Core Raise Project
NOD	Placer County Water Agency	7/22/2016	Hell Hole Dam Core Raise Project
MND	Placer County Water Agency	5/13/2016	Hell Hole Dam Core Raise Project