Cheakamus Project Water Use Plan Monitoring ... - BC Hydro

Cheakamus Project Water Use Plan
Monitoring Programs Annual Report: 2011
4.6.4 Interpretation of Results
The maximum acceptable level of stranding (MALS) established by DFO and MoE
was defined as a relative order of magnitude and established as dozens of fish
stranded as opposed to hundreds of fish stranded. A total of 35 stranded fish
(27 salvaged, 8 mortalities), including 12 rainbow trout, were found by the field crew
that conducted the fish salvage operation during and immediately after the ramp
down in flows. A direct comparison of the total number of stranded fish found (i.e.,
35 fish total) to the MALS confirmed the acceptance of the first impact hypothesis
(i.e., the rate of resident fish stranding downstream of the dam does not exceed the
MALS).
The second impact hypothesis (i.e., the rate of stage change between Daisy Dam
and Rubble Creek is less than 2.5 cm/h when flows are reduced from 7 m 3 /s to
3 m 3 /s on November 1) was rejected. The maximum rates of stage change exceeded
the target rate of 2.5 cm/hour at both upstream and downstream water pressure
transducer monitoring locations.
The results confirmed that the prescribed ramping rate of 1 m 3 /hour is acceptable to
prevent a high level of fish stranding during the November 1 ramp down.
4.7 CMSMON-6: Monitoring Groundwater in Side Channels of the Cheakamus
River
4.7.1 Management Questions
The key management questions addressed by this monitoring program are:
1) To what extent does seasonal NVOS and TH floodplain shallow groundwater flow
direction, and selected water quality parameters (temperature, dissolved oxygen,
and pH) vary in response to Cheakamus River mainstem flows ≤ 40 m 3 •s -1 ?
2) To what extent does seasonal NVOS and TH side channel hydrology depend on
groundwater flow interactions with Cheakamus River mainstem flows
≤ 40 m 3 •s -1 ?
3) To what extent do key fish habitat variables related to flow (average depth,
average velocity, discharge) and water quality (temperature, dissolved oxygen,
and pH) in NVOS and TH side channels depend on groundwater flow interactions
with Cheakamus River mainstem flows ≤ 40 m 3 •s -1 ?
4) To what extent does salmonid production vary in NVOS and TH side channels in
relation to groundwater flow interactions with Cheakamus River mainstem flows
≤ 40 m 3 •s -1 , and to what extent has the implementation of the WUP affected
salmonid production in the NVOS and TH side channel habitats compared to the
pre-WUP state?
4.7.2 Overview
Both the Cheakamus River Water Use Plan (WUP) Consultative Committee (CC)
and the Fisheries Technical Committee (FTC) have identified monitoring of
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