The 2011 BC Hydro Cheakamus Project Water Use Plan involves ten monitoring programs specific to salmonids and their habitats. This article describes the monitoring programs implemented in 2011 and the key management questions addressed by them.
Juvenile salmonid counts
Downstream trapping methods are used to estimate the level of juvenile salmonid outmigration from the Cheakamus River annually. Target species include coho, Chinook and steelhead smolts and pink and chum fry. Presence of other life stages and species captured will also be documented.
This monitoring aims to investigate the habitat capacity for salmonids of the Cheakamus River, including the mainstem and side channels. It aims to explore the relationship between juvenile salmonid production and water discharge and whether the implementation of the water use plans influences salmonids habitat capacity, productivity or production.
Spawning groundwater survey and escapement monitoring of chum salmon
This monitoring program uses a mark-recapture method to ascertain the spawning escapements of chum salmon. Groundwater levels are also monitored to assess the relationship between river discharge and groundwater flow. This data is used to investigate the relationship between spawning site selection, incubation conditions and river discharge. It will allow assessment of the effectiveness of the water use plan models in calculating spawning area, site selection and available spawning habitat and identify if spawning habitat could be represented by alternative metrics.
Monitoring Trout Abundance
Electrofishing is used to sample juvenile rainbow trout and a standardized angling effort is used sample adult rainbow trout. This monitoring program is designed to investigate a relationship between trout abundance and operations of the Daisy Lake Dam.
Resident trout abundance downstream of the Daisy Lake Dam is considered to be a critical component of the water use plan due to its inherent value to local people and its role as an ecosystem health indicator. It is thought that trout may be sensitive to flow release changes in the Daisy Lake Dam.
Monitoring Steelhead Abundance
Snorkel counts and electrofishing are used to collect data on the number of fry, adult and juvenile steelhead to investigate the relationship between flow and steelhead production in the Cheakamus River. The program monitors four life stages; young of the year in fall, young of the year in spring, spawners and parr to improve understanding of how flow affects the steelhead seasonally and at different life stages.
Monitoring Stranding
Assessment of stranding downstream of the Cheakamus generating station and downstream of the Daisy Lake Dam will determine whether there is a significant impact of fish populations and inform the decision to mitigate. The monitoring program uses models to assess the magnitude of risk of fish stranding in the tailrace channel and to determine the life stages and time of year that the risk is highest. At the Daisy Lake Dam, the effects of base flow changes on stranding risk are also being investigated.
Monitoring Groundwater in Side Channels
Measurements of side channel groundwater levels and hydrology are used to investigate the effects of flow on fish habitat and production.
Monitoring the Benthic Community
In order to fill gaps in scientific knowledge and inform the water use planning process, an assessment of the biomass, abundance and composition of benthic invertebrates is undertaken. The results of this assessment are used to explore the impact of flow release on benthic communities.
Monitoring the channel morphology
GIS analysis and aerial photos are used to monitor channel morphology over time and assess the effectiveness of the water use planning process on channel features. This information is used to evaluate fish habitat, specifically the availability of spawning substrate, fish access to the channel and suitability of the channel for fish utilization.
Monitoring recreational angling access
This program monitors the angling activity and identifies important areas for angling between January 1st and March 31st. This allows the investigation of optimum flow release rates to improve recreational angling locations on the Cheakamus River.
- Source BC Hydro. December 2011. BC Hydro Cheakamus Project Water Use Plan, Monitoring Programs Annual Report: 2011. Available at : https://www.bchydro.com/content/dam/hydro/medialib/internet/documents/planning_regulatory/wup/lower_mainland/2011q4/cms_annual_report.pdf [Accessed 03/2021].