Bioengineering Techniques for Revegetation of Riparian Areas at the Colomac Mine, NWT

Factors such as nutrient poor soils, harsh climate, remote locations, and high costs make revegetating disturbed areas in northern environments a challenge.  We present a case study where novel bioengineering and project planning techniques were employed to revegetate and remediate riparian areas at Colomac Mine, an abandoned gold mine 220 km north of Yellowknife, NT.  The revegetation plan focused on establishing pioneer species and facilitating natural recovery and succession.  A 'rough and loose' technique was used to allow the soil to capture and retain moisture, trap windborne seed, promote easy root penetration and prevent erosion.  Harvesting and planting of local willow cuttings, alder seeds, and sedge plugs ensured that the vegetation at these sites was adapted to local climate and soils.  Multi-year monitoring was initiated which included vegetation counts and photographic documentation. Initial results have shown success rates of 60-100% plant survival on the majority of areas where bioengineering techniques were used. In contrast, poor revegetation success rates of 8-33% plant survival were experienced in areas where techniques were either used incorrectly or implemented too late in the season.  The bioengineering techniques implemented at Colomac Mine provided a successful, cost effective, and local approach to revegetation in a northern environment.