of Accelerated Gully Erosion on Pipeline Right-of-Way
AURORA T-PIT HILL PROJECT
Lease of Syncrude Canada Limited, near Fort McMurray,
reduce accelerated surface erosion occurring on the
T-Pit Hill section of Syncrude Canadaís Aurora inter-site
pipeline right-of-way by establishing vegetation using
soil bioengineering techniques.
T-Pit Hill site is a 120 m long section of pipeline
right-of-way. Slope gradients range from 10 to 60%.
The soil texture is fine to medium sand, which when
dry is highly hydrophobic. Prior to treatment, extensive
rill and gully erosion occurred with gullies up to 1.15
m in depth. In October 2005 Terra Erosion Control Limited,
in association with Fort McKay Environmental LP, was
retained to carry out a field assessment, develop an
erosion control prescription and carry out the implementation.
The prescription developed included the use of brush
layers and straw wattles to provide deep root formation
and physical barriers to reduce surface erosion.
of the prescription was carried out in two phases: 1)
collection and cold storage of live materials (April
2006), and 2) installation of erosion control measures
(June 2006). The live cuttings (Salix bebbiana /
exigua / scouleriana) were harvested locally, while
dormant. Care was taken to maintain moose habitat values
in the harvest area by leaving clumps of willow standing.
to installation of erosion control measures, the slope
was re-con toured to fill in rills and gullies. Planting
of brush layers was machine-assisted, using an excavator
in conjunction with manual labour. Straw wattles were
installed to help reduce surface rill erosion. Local
muskeg, used as mulch, was spread over the site. The
site was also planted with native shrubs, broadcast
seeded with native grasses and fertilized.
implementation was proceeding, assessment of the surface
runoff during heavy rainfall showed that the soilís
highly hydrophobic nature (impeding water infiltration)
was exacerbating soil erosion. An agricultural soil
wetting agent was therefore applied to help ameliorate