Syncrude Canada Alpha Swale W1 Project

Placement of cuttings in trench and covering middle of sill with fine branch trimmings, April 2004.

Repair and Maintenance and Additional Work in 2005 and 2006:

Survival and growth of the brush sills and fascines during the summer of 2005 was assessed as good. The trial section, where contour fascines were installed above the brush sills, did, however, perform much better than the brush sill structures alone at dispersing water. Also, based on water-flow patterns and minor rilling development, additional structures were found to be required in some areas. Sections of some brush sills had poor survival due to undermining by flowing water.

Measures to address these problems were implemented in October 2005. Additional contour fascines were installed above all existing brush sills. Some new brush sill structures with adjacent fascines were also installed at this time, along with re-planting of brush sill sections showing high mortality, and live staking in the centre of the swale. Muskeg-filled burlap sacks were used to prevent further erosion in areas where brush sills were undermined and channelization of water had occurred. Broadcast seeding of native grass mix and mycorryzae incocullant was carried out .

Minor maintenance work was also required after the spring 2006 snowmelt. Implemented in June 2006, this consisted of placing additional muskeg-filled burlap sacks in areas of new channel formation, manually filling rills, removal of sediments deposited over structures, and some re-seeding of native grasses and fertilization.

Monitoring observations:

2006

Growth of the erosion control structures within the swale was considered excellent when assessed in the spring and fall of 2006. In the depressional area at the top of the swale, a diverse wetland plant community was developing (as a result of the seed bank contained within the muskeg placed here).

2007

The growth of erosion control structures was considered excellent overall when monitored in July 2007. There was no need for additional maintenance treatments at that time; the work has therefore been successful in preventing accelerated gully formation in the swale through establishment of native vegetation and is expected to improve with time as vegetation becomes more established. A frog and numerous bird tracks were also observed in the created wetland area at the top of the swale (a report was also received of a moose sighting in the swale that spring).

2009

The growth of erosion control structures was considered excellent overall when monitored in July 2009. There was a minor requirement for maintenance at that time (see minor surface erosion photo) and treatments such as muskeg or compost filled burlap sacks, in conjunction with seeding, are planned in order to prevent further erosion in these areas.   The work is scheduled to take place later in the 2009 field season.  Overall the work was considered to be successful in preventing accelerated gully formation in the swale through establishment of native vegetation, as well as creating wildlife habitat and improving the aesthetic of this mine site.