Sediment Transport & Erosion Control

Poe Reservoir Sediment Study | Plumas County, California

View of Poe Dam
View of Poe Dam
Pacific Gas and Electric Company
Project Description:
The Poe Reservoir Project is one of 10 hydroelectric projects in the North Fork of the Feather River drainage basin, upstream of Lake Oroville. Poe Dam diverts flow through a 7-mile long power tunnel to the Poe Powerhouse.

Pacific Gas and Electric Company (PG&E) is currently evaluating various options for the radial gate repair. Because of the environmental concern associated with the drawdown operation, one option of interest was to construct a suitably sized coffer dam, which would allow access to repair or reinforce the gates while minimizing the potential erosion and possible sediment release that occur during the project drawdown operation.

As part of the Project Team, WRECO is responsible for the sediment study. The purpose of the sediment study is to assess the trends of sediment erosion and deposition and the suspended sediment concentrations in the reservoir based on varying coffer dam heights (which would allow varying drawdown levels in the reservoir) under different inflow conditions. The study results would enable PG&E to conduct evaluation on the engineering aspects, their associated costs, and their potential environmental and generation impacts/mitigations based upon the recurrence intervals for the short-term versus the long-term needs. Additionally, the results would provide guidelines to assess how the coffer dam heights may affect the operation of the power tunnel.

WRECO is also tasked with evaluating the trends and volumes of sediment erosion and deposition in Poe Reservoir for different flows and different drawdown levels for the water surface in the reservoir for a simulation time of two months. The different drawdown levels corresponded to a required coffer dam height to achieve that drawdown. Seven coffer dam heights and nine constant inflow rates are being evaluated.

Key Tasks:
Reservoir and River Sediment Study and Sediment Transport Modeling
Poe Reservoir 2010 Bathymetry
Poe Reservoir 2010 Bathymetry
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