Presentation Title

Modelling the Effects of Reservoir Operation on Lower Capilano River Temperature: A Case Study

Session Title

Challenges and opportunities related to habitat enhancement, restoration, and ecosystem productivity in the Salish Sea

Conference Track

Habitat

Conference Name

Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type of Presentation

Poster

Abstract

Capilano reservoir, located in the coastal mountains of southern British Columbia, is one of the three main sources of drinking water in the greater Vancouver region. The Lower Capilano River, located downstream of the reservoir, provides valuable spawning and rearing habitat for Salmonids and other fish species, and discharges into the Burrard Inlet. Construction of a dam has implications in changing the temperature regime of the downstream river, e.g. lower than normal water temperature in summer. Such a change tends to affect the growth of juvenile fish, which is largely regulated by the water temperature.

The increasing water withdrawal and the change of future reservoir operation, which include a new pumped intake and a proposed hydropower plant operating during the wet season, could alter the reservoir thermal structure and hence affect the lower Capilano River temperature. A 1-D hydrodynamic model (DYRESM) is used to predict the consequences of future operation. The model prediction under the increased future demand shows that hydropower operation from late fall to spring contributes to the increase of overall reservoir water temperature by taking out the cold deep water and reducing the spilling of warmer surface water. This operation in conjunction with increased drinking water demand led to the lowest river temperature increase from 6o to 8oC, even in a cold and wet summer. Power generation might have more profound water quality implications by triggering earlier turnover in the fall and changing of reservoir stratification regime from the current dimictic to monomictic.

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Language

English

Format

application/pdf

Type

Text

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Modelling the Effects of Reservoir Operation on Lower Capilano River Temperature: A Case Study

2016SSEC

Capilano reservoir, located in the coastal mountains of southern British Columbia, is one of the three main sources of drinking water in the greater Vancouver region. The Lower Capilano River, located downstream of the reservoir, provides valuable spawning and rearing habitat for Salmonids and other fish species, and discharges into the Burrard Inlet. Construction of a dam has implications in changing the temperature regime of the downstream river, e.g. lower than normal water temperature in summer. Such a change tends to affect the growth of juvenile fish, which is largely regulated by the water temperature.

The increasing water withdrawal and the change of future reservoir operation, which include a new pumped intake and a proposed hydropower plant operating during the wet season, could alter the reservoir thermal structure and hence affect the lower Capilano River temperature. A 1-D hydrodynamic model (DYRESM) is used to predict the consequences of future operation. The model prediction under the increased future demand shows that hydropower operation from late fall to spring contributes to the increase of overall reservoir water temperature by taking out the cold deep water and reducing the spilling of warmer surface water. This operation in conjunction with increased drinking water demand led to the lowest river temperature increase from 6o to 8oC, even in a cold and wet summer. Power generation might have more profound water quality implications by triggering earlier turnover in the fall and changing of reservoir stratification regime from the current dimictic to monomictic.