Canimred Tributary Weir Construction 535 Road

 

Objectives

The primary objective of this project was to construct a weir to allow fish passage through existing culverts increasing the quantity of available habitat.

FRBC Region/ MELP Region/ MoF Region

Cariboo-Chilcotin/Cariboo/Cariboo

Author

Ken MacKenzie

Proponent

Weldwood of Canada Ltd.

100 Mile House Operations

Location:

The crossing is located 0.5 km down a side road at 17 km on the Bowers FSR at an unnamed stream that flows into Canimred Creek.

Introduction

Canimred Creek has high densities of rainbow trout and may be an important spawning stream for Canim Lake. The streams affected by this project have high spawning and rearing habitat potential.

Assessments and Prescriptions

This barrier to fish was identified during a field inspection by Weldwood staff. It was determined during the site plan preparation that the existing culverts were sufficiently large to accommodate the Q100 flows. The primary barrier to fish was caused by the 20 cm outfall at the downstream end of the culverts and increased water velocity during high flow periods (fig 2-1). Constructing weirs to eliminate the outfall drop barrier was determined to be the most cost effective solution.

Rehabilitation Work

To minimize environmental impacts during the weir construction, the following steps were taken:

• Only clean rock was used for construction of the weir to reduce sediment input into the stream.
• An environmental monitor was on site for all phases of construction

Structure Details

Two weirs were built to eliminate the outfall drop from the culverts. The first weir raised water levels at by approximately 30 cm slowing water velocities through the culverts and eliminating the outfall drop. An additional benefit from the weir construction is the significant deepening of the plunge pool for overwintering habitat. A second smaller weir was built downstream from the first to reduce the gradient of the stream and provided better fish passage.

Cost Summary

Site Plan Preparation $2,000

Rip rap supply $4,500

Supervision $2,000

Machine Time $1,500

TOTAL $10,000

Environmental Benefits

6.2 km of habitat is now available to migrating rainbow trout.

For Further Information Contact:

Ken MacKenzie
P.O. Box 97
Weldwood of Canada Ltd.
100 Mile House Operations
100 Mile House, BC
V0K 2E0
Tel. (250)395-8280

 

Figure 2-1. Culverts prior to weir construction

Figure 2-2. Culverts backflooded after weir installation.