Stave River Water Use Plan - BC Hydro

Stave River Water Use Plan
Monitoring Terms of Reference June 13, 2005
Overview
Monitoring Program
Stave River Water Use Plan:
Monitoring Program Terms of Reference
The Stave River Water Use Planning process was completed in the fall of 1999
with the release of a consultative committee report (Failing 1999) and the submission of
draft water use plan (WUP) to the provincial Comptroller of Water Rights. The water use
planning process, which involved consultation with a committee of interested
stakeholders to identify water use values and objectives, the completion of several
ecological studies and a gaming procedure to develop balanced operational alternatives,
resulted in substantial knowledge gains about the Stave lake watershed. Despite this
considerable effort and the successful development of what the consultative committee
(CC) considered to be a balanced WUP for the Stave Lake project (Combo 6 WUP
operating strategy), a number of knowledge gaps and uncertainties remained.
Conditional to the general acceptance the WUP by the CC was the development and
implementation of monitoring program that addresses these shortcomings.
At the conclusion of the WUP consultation process, the consultative committee
(CC) were able identified three general areas of uncertainty. The first was the extent to
which the productivity levels in both Stave and Hayward reservoirs would change when
operations specified in the WUP are implemented. The productivity indicators of interest
included seasonal nutrient levels, seasonal levels of photosynthetic carbon (an indicator
of general lake productivity), seasonal levels of littoral periphyton production at various
water depths, and a general assessment of fish biomass. The latter indicator was
deemed to be the one of greatest interest, but was also the most difficult and expensive
to obtain. The CC anticipated an increase in all indicators of reservoir productivity as a
result of the WUP. However, the premise with which this expectation was based was
rather tenuous and the CC was uncertain as to whether the productivity benefit would be
realised.
The second area of uncertainty dealt with the potential impacts of flow
fluctuations on the reproductive cycle anadromous salmonids downstream of Ruskin
Dam. These flow fluctuations arise because of peaking operations and can be very
large. In some cases these fluctuations were viewed as a positive impact by limiting the
extent of spawning activity along the river margins where there is a high likelihood of
redd stranding during the incubation period. This may be offset however, by increased
stranding of gravid adults. There is also a potential increased risk to fry stranding when
peaking operation extend into the fry out-migration period. By studying the diel timing of
this out-migration, the CC felt that it might be possible to find ‘windows of time’ during
which changes in discharge could occur with minimal fry stranding.
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