.... Specialising in reducing accelerated erosion

Control of Soil Erosion in Re-Constructed Waterway on Alberta Oil Sands Overburden Dump

Syncrude Canada Alpha Swale W1 Project

 

Go To:

Initial Erosion Control Measures

Repair and Maintenance

Monitoring Observations

Monitoring Observations 2010 to 2014 / Habitat Creation

 

Modified Design Trial Applied to 2009 W1 Alpha 02 and Beta 01 Swales

 

Location: Syncrude Canada Limited Base Mine, Fort McMurray, Alberta

Client: Syncrude Canada Limited

Objective: To disperse precipitation water flow and reduce surface erosion that could lead to gully formation, within a re-constructed waterway (swale) built on Syncrude Canada s W1 overburden dump. Establishment of vegetation and creation of wildlife habitat

In 2003 the Alpha swale was designed and retrofitted into Syncrude Canada s W1 overburden dump. The swale is approximately 600 m long, averages 30 m in width, and is two to four metres in depth. The slope gradient averages 7 %. The substrate within the swale consisted of approximately 20 cm of muskeg (organic material) placed over 80 cm of clay capping. This overlies oil-sands tailings.

In the spring of 2004 rill erosion was noticed in the swale as a result of snowmelt. Terra Erosion Control Limited, in association with Shane Vincenzi, Environmental Program Coordinator with Fort McKay Environmental LP, was retained to carry out a field assessment and develop an erosion control prescription. The fieldwork was implemented in spring 2004. Monitoring of the site led to maintenance and repair work in 2005 and 2006.

 
 
Alpha swale, spring 2004, prior to treatment

Alpha swale in spring 2004 prior to treatment

 

Alpha swale connected with lateral swales drawing (Syncrude Canada Ltd)

Alpha swale connected with lateral swales drawing

Initial Erosion Control Measures (April/May 2004):

Soil bioengineering structures were installed across the swale in the spring of 2004, these consisted of 29 brush sills. Live cuttings used in the structures consisted of Willow (Salix bebbiana / exigua / scouleriana) , Black Cottonwood (Populus balsamifera ssp. trichocarpa) , and Red-Osier Dogwood (Cornus stolonifera). These were all collected during dormancy within the local area. In the middle of each sill (lowest portion) additional cuttings of smaller diameter were used to improve water dispersion. As a trial, contour fascines were installed across the swale in two locations above the brush sills.

Locally available muskeg (organic mulch) was spread between the brush sills during installation. The swale was fertilized and broadcast seeded with a nurse crop of barley. In the upper portion of the swale a wet depressional area (created wetland), located at the confluence of two minor lateral swales, was planted with live stakes (muskeg also applied here). The site was monitored in August 2004 survival of brush sill cuttings was estimated at approximately 70%, with shoot growth averaging 60 cm.

View of Alpha swale, April 2004
(Photo: Syncrude Canada Ltd)

View of Alpha swale April 2004

Collection of live cuttings, April 2004

Collection of live cuttings in April 2004

   
Brush sill construction, preparation of trench
April 2004

Brush sill construction (preparation of trench)

Brush sill construction, April 2004

Brush sill construction

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

Placement of cuttings in trench and covering middle of sill with fine branch trimmings

 
Backfilling of trench, April 2004

Backfilling of trench

Completed brush sill, April 2004

Completed brush sill

Depressional area in upper portion of swale
(created wetland), with live staking, April 2004

Depressional area in upper portion of swale, with live staking

 
Fascine installed above brush sill as trial,
April 2004

Fascine installed above brush sill as trial

Growth on brush sill, August 2004

Growth on brush sill in August 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.

 

Additional work completed, October 2005

 

Additional work completed

Installed muskeg-filled burlap sacks in eroded channel, October 2005

Installed muskeg-filled burlap sacks in eroded channel

 

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 (partially as a result of the seed bank contained within the muskeg placed here and natural propagation methods such as wind, birds and mammals).

 

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.

 

Alpha swale, June 2006

Alpha swale, June 2006

Alpha swale, June 2006

Alpha swale, June 2006

 
Alpha swale, June 2006

Alpha swale, June 2006

Alpha swale, July 2007

Alpha swale, July 2007

Wetland at top of Alpha Swale, July 2007

Wetland at top of Alpha Swale, July 2007

Alpha swale, July 2007

Alpha swale, July 2007

 
Growth from live cuttings, July 2007

Growth from live cuttings July 2007

Brush sill growth in Alpha Swale, July 2007

Brush sill growth in Alpha Swale, July 2007

 
Alpha Swale, July 2007

Alpha Swale, July 2007

Alpha Swale, July 2007

Alpha Swale, July 2007

 
Aquatic plant establishment, July 2007

Aquatic plant establishment, July 2007

Establishing wetland upper Alpha Swale, July 2009

 
Created wetland, note Salix axigua and Populus balsamifera surrounding established aquatic species, July 2009

 

Alpha Swale, July 2009

   
Alpha Swale, July 2009

Alpha Swale looking south, July 2009

 
Frog within Alpha Swale, July 2009

Minor surface erosion found, July 2009

Monitoring Observations 2010 to 2014 / Habitat Creation:

 

The site was monitored further in 2010, 2013 and the fall of 2014.  Vegetation has become well established and there have been no signs of further erosion since the maintenance carried out in 2009. 

 

Aquatic species such as sedge (Carex spp.) and cattail (Typha spp.) have become well established in between the installed brush sills and contour fascines. These aquatic species have colonized partially from the seed bank contained within the muskeg material used for capping and from natural propagation methods such as wind, birds and mammals.  The aquatic species types colonizing the various micro sites depends on the depth of the water table. After two years the aquatic species are out competing the native grasses and legumes initially seeded (personal communication with Eric Girard, Syncrude Canada Limited). It was also observed that the combination of pioneer deciduous and coniferous species, originally planted in conjunction with the newly established aquatic species, are contributing to the creation of a wetland habitat which is highly desirable in these disturbed mine sites.

Burlap bags filled with muskeg, used to repair the eroded depressions caused by splash erosion, have been noted to work very efficiently. 

>>Control of Localized Splash Erosion from 2005 to 2014

 
Field visit, May 2010

 

   
Field visit, looking north at swale from bottom,
June 2013

 

 
Swale prior to treatment, spring 2004

 

   
Field visit, looking at swale across from berm,
June 2013

 

 
Field tour, September 2014
 
Ten years of growth on willow cutting in brush sill, September 2014

 

 
Swale looking south, September 2014

 

   
Native spruce, naturally seeded, September 2014

 

Wetland created in upper swale, September 2014
 
Control of Localized Splash Erosion from 2005 to 2014:
Burlap bags filled with muskeg, placed in eroded areas, 2005

 

Native vegetation growing through burlap while controlling splash erosion, 2006

 

   
Native vegetation growth becoming established, 2007

 

Established native vegetation within repaired area, 2014

 

   

Modified Design Trial Applied to 2009 W1 Alpha 02 and Beta 01 Swales

 

After five years the findings at the trial site established in 2004 were reviewed and the soil bioengineering design was adjusted.  The revised design used larger diameter contour fascines (30 cm) and no brush sills and was applied over two newly constructed swales (waterways) in the spring of 2010.  These newly constructed swales (09 Alpha 02 and 09 Beta 01) have a combined catchment basin of approximately 66.5 ha and are located within the W1 overburden mine dump. Implementation work for the 09 Alpha 02 and 09 Beta 01 Swales project were completed in May 2010. Growth of the vegetation (i.e. seeding, seedlings and live cuttings) was monitored during the summer and fall of 2010.  Minor repairs and maintenance were implemented in 2011 using burlap sacks and muskeg to fill in eroded cavities. Additional inspections were also carried out after significant rainfall events. Further monitoring took place in 2012 and no erosion was noted. Establishment of aquatic species within the applied muskeg was significant, taking over the initially applied seed mix. The site was assessed as good to excellent in regards to native vegetation establishment and control of surface erosion. 

09 Alpha Swale 02 and 09 Beta 01 Swales, Spring 2010

 

   
Clay cap and muskeg placement

 
Collection and processing of live cuttings
 
Implementation, spring 2010
Implementation, spring 2010
   
Contour fascines installed
   
Contour fascines installed
 
Growth, fall 2010
   
Growth, fall 2010
   
Aquatic species colonizing site, fall 2014
   
Aquatic species colonizing site, fall 2014
Growth, fall 2014
   
Swale construction, fall 2009
Fall 2014

home

Copyright © 2010 Terra Erosion Control Ltd.

Industrial Reclamation ~ Soil Erosion