GMSWORKS-3 Peace River Side Channel Restoration - BC Hydro

The middle side channel is ephemeral and subject to dewatering, and the north channel is
inactive within the current flow regime. Restoration would include deepening sections of the
middle channel to make it free flowing and open. Wood complexes could be installed to benefit
rearing habitat for salmonids in this cold water reach. The north channel would be excavated
into a closed channel providing backchannel refuge and rearing habitat. The close proximity of
this site to PCN will limit sediment infilling. Localized sediment removal at the outlet of the third
channel could increase flows.
Proposed restoration for this site includes:
1. Excavation of a closed channel 10‐25 m wide, 1‐2 m deep on the north side of the bar;
2. Excavation of the inlet bar and selective thalweg excavations in the middle secondary
channel;
3. Large wood complexing of the middle channel at 10‐15 sites along the channel with 25‐
40 m 2 jams; and
4. Boulder complexing of the main south secondary channel.
Total estimated excavation and fills are approximately 74,000 m 3 depending on the depth of
cut, and would result in the development of 50,000 m 2 of open continuous side channel
habitat. Fills would be placed along bar edges to form raised bar areas that would be live staked
and allowed to re‐vegetate naturally. Estimated costs for the KM 5.0R site in concept are
$1.54M including contingencies.
7.2 River KM 8.1R
The side channel at River KM 8.1R is shown on Map sheet 2 of 11. The main side channel at this
site is presently used by fish populations belonging to the cold water fish assemblage and
habitat limitations are minimal. The ephemeral secondary channels do not appear to provide
access to fish at most flows and appear to dewater regularly, fish use is therefore unlikely.
If the secondary channels were targeted for restoration the sites would mimic fish habitats
provided in the main side channel (run/riffle complexes). The area is dominated by the cold‐
clear water fish assemblage; therefore, bull trout (juveniles and adults), mountain whitefish
(all), rainbow trout (juveniles and adults), and slimy sculpin (fry, juveniles, and adults) would
benefit from restoration. With restoration of the secondary side channels, cold water
temperatures may preclude the use of this area for spawning/egg incubation by most species
(mountain whitefish is the exception).
Access to the site is provided from the upstream property and would cross the upstream end of
the bar with a culvert crossing or small‐span bridge. The larger secondary channel on the south
side of this bar complex may be subject to low flows and excavation of sediment infilling at the
inlet may help increase flow input and habitat area. The smaller secondary channel to the north
is ephemeral and would be excavated and lowered to form an open side channel. In the cold‐
clear water reach of the Peace River, wood complexing will improve rearing habitat for bull and
rainbow trout.
Peace River Side Channel Restoration 24