Associated Environmental was retained in April 2018 to develop a soil bioengineering design using native woody vegetation to stabilize the north bank and upland slopes of the Wapiti River near the drinking water facilities that supply over 63,000 residents of Grande Prairie. Live balsam, poplar, and willow cuttings were planted during dormancy (spring and fall) to grow an interlocking network of roots. Configurations of cutting size and spacing were selected based on an erosion assessment.
Rough and loose soil treatments were used to create mounds and depressions in wide, open disturbance areas (e.g. Off-Highway Vehicle trails), interrupting runoff, and loosening the soil matrix by creating pockets and mounds, to allow natural propagation of the existing seed bank
Associated Environmental provided advisory services throughout construction:
- Total Area of Live Staking on Gravel Bar and Upper Slopes: 22,000 m2
- Total Live Silt Fence Design Length: 150.5 m
- Total Rough and Loose Design Area: 56,380 m2
Soil bioengineering techniques provide permanent erosion control by restoring native woody vegetation species, protecting soil from increasing river flows and surface runoff, while requiring minimal disturbance and equipment for completion.