Water Stewardship Information Sources

Citation Trow Associates. 2007. Temperature Monitoring Lower Coquitlam River Project - Year 1 Report. Prepared for BC Hydro.
Organization BC Hydro
URL https://www.bchydro.com/content/dam/hydro/medialib/internet/documents/environment/pdf/wup_temperature_monitoring_lower_coquitlam_river_project.pdf
Abstract/Description or Keywords Coquitlam Lake is a natural lake that was enlarged by the construction of a dam at the head of the
Lower Coquitlam River. Waters from Coquitlam Lake are diverted through tunnels to Buntzen
Lake, a reservoir that supplies water for two hydroelectric generation stations on Indian Arm, and
to the Greater Vancouver Regional District’s (GVRD) drinking water system. Releases of water
are also directed to the Lower Coquitlam River to maintain the features and functions of this
stream and its associated riparian habitat.
BC Hydro’s Coquitlam-Buntzen Water Use Plan, Monitoring Plan Terms of Reference – January
2006 specifies that an adaptive management program be carried out to assess the effects of
reservoir operations on downstream river temperatures in order to guide decisions made regarding
the balancing of the three main demands on the Coquitlam-Buntzen system. As identified, the
demands are habitat (primarily fish habitat) on the Lower Coquitlam River, domestic water
supply, and hydroelectric power generation. Two components of the CBWUP adaptive
management program are infrastructure upgrades at the Coquitlam Reservoir, to allow regulated
and variable flows from the low level outlets, and a series of monitoring programs, that will allow
the assessment of various flow regimes being implemented over a nine year period.
The Lower Coquitlam River Temperature Monitoring Program (the Program), one of those
programs, has the objective of determining if and how water temperatures in the Lower
Coquitlam River are influenced by reservoir operations. The Program will run for three years
(2006, 2007 and 2008) and culminate in an analysis that will answer two questions:
1) Is there a significant correlation between lower Coquitlam River temperatures and Coquitlam
Reservoir operations? and
2) Is there a significant difference between the reservoir to river temperature gradient and lake to
river temperature gradient(s) in similar but unregulated lower Fraser River tributaries?
The Program was initiated in November, 2005 with the installation of five water and one air
temperature data loggers in the Lower Coquitlam River. Together with operations data (water
releases to the Lower Coquitlam River) and water temperature data for Coquitlam Lake, obtained
from the GVRD, these data will be used to answer the first question. In 2006 a search was
conducted to locate data on water temperatures from one or more unregulated lake-river
tributaries on the lower Fraser River. Candidate systems included the Harrison, Pitt, Chilliwack,
Chehalis and Cultus systems. Data from the unregulated systems would be analyzed with lake
and river water temperature data from the Coquitlam system to answer the second question. See
Figure 1 for the location of the Coquitlam system in the lower Fraser Valley and Figure 2 for
details of the sampling locations in the Coquitlam system.
Information Type report
Regional Watershed Lower Fraser
Sub-watershed if known Coquitlam River
Aquifer #
Comments
Project status complete
Contact Name
Contact Email