Peace Project Water Use Plan - BC Hydro

Peace Project Water Use Plan
Annual Report: 2010
Contractor: This work is being conducted by Northwest Hydraulic Consultants Ltd.
(NHC). NHC has conducted similar work for BC Hydro on other systems.
ToR Status: In January 2010 the CWR approved a resubmission of the
GMSWORKS#6 ToR with updated project implementation costs. The project
complies with the revised ToR; no further resubmission is anticipated at this time.
There is currently a financial variance, a plan is in place to address this variance —
see Table 6.1 for details.
5.1.6.2 Contractor’s Report
This study was initiated by BC Hydro to fulfill the recommendations of the Peace
River Water Use Plan (WUP) Committee to monitor water levels and develop stagedischarge
relations for the Peace River mainstem downstream of the Peace Canyon
Dam (PCN) to the Pine River confluence. The purpose of this project is to develop
more accurate models of flow attenuation downstream of the dam, and to gather data
that will enable side channel inundation levels to be determined during ramping and
spill events.
The Peace River has been regulated by W.A.C. Bennett Dam since 1967, and its
characteristics are influenced by the operation of this dam and PCN. Flow regulation
has altered the annual hydrograph, daily flow patterns, temperature regime, and
water quality of the Peace River. The average post-regulation annual maximum daily
flow (under the ‘normal’ operating regime) is 31% of the pre-regulation value at
Hudson’s Hope and 37% of those values near Taylor, BC.
Hydrometric stations were installed for long term flow monitoring at five locations
along the Peace River to assist in the ongoing operation of BC Hydro’s G.M. Shrum
(GMS) and PCN facilities, and to determine effective flow ramping rates for various
project discharges that will reduce the risk of fish stranding in both side channel and
mainstem habitats. The hydrometric stations installations and monitoring are in
compliance with Grade A standards as set by the BC Ministry of Environment (MOE)
Resources Information Standards Committee (RISC) Hydrometric Standards (RISC,
2009).
Discharge measurements for stage-discharge (rating curve) development at each
hydrometric site began concurrently with the installation of the hydrometric stations,
with VIASAT Data Systems Inc. conducting installation of the satellite linked real-time
hydrometric stations, and Northwest Hydraulic Consultants Ltd. (NHC) leading
discharge measurements, river cross-section surveys, and data analyses. Rating
curves were successfully developed for each hydrometric station, allowing for
accurate continuous discharge estimates at the five sites along the river mainstem,
and the determination of flow wave attenuation from ramping events at PCN dam.
This data is continuously collected by BC Hydro’s GOES system.
Rating curve development and analyses meet or exceed RISC (2009) Grade A
hydrometric standards. Rating curve analyses have included the computation of
confidence limits, cumulative discharge calculations, and gauge comparisons with
existing Water Survey of Canada (WSC) gauges on the river. The hydrometric
stations were initiated on October 7th, 2009, following the beginning of the reduced
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