STAFF REPORT #RWSC 2002 - 31
REGIONAL WATER SUPPLY COMMISSION
17 APRIL 2002
SUBJECT: SOOKE RESERVOIR EXPANSION PROJECT - ENVIRONMENTAL SITE
ASSESSMENT OF CNR RAIL BED
In 1997, as part of the site preparation component of the Sooke Reservoir Expansion Project, the Water
Department conducted a preliminary assessment of the contaminants in the abandoned CNR rail grade and
Highway 117. No contaminants were detected in the soils from Highway 117. However, a number of
contaminants were found in the rail bedding soils in contact with the ties. No contaminants originating from the
rail grade were detected in drinking water samples.
To provide a clear indication of the extent of these contaminants, in August 2001, the Department commissioned
Golder Associates Ltd. to conduct a detailed assessment and provide technical advice on the management of
these soils. Technical direction and oversight for this detailed assessment were provided by a Technical
Working Group whose members included a specialist in chemical contaminants from the CRD Environmental
Services Department, a representative of the Chief Medical Health Officer for the Vancouver Island Health
Authority and Water Department staff.
Based on operational maps and air photo interpretation, the preliminary assessment estimated that approximately
1000 m of the rail grade may be under the influence of the rising waters. More accurate and detailed field
surveys of the rail grade structure (including the rail bed and underlying fills) now show that some 4400 m of
the rail grade will be in the future water contact zone and subject to erosion from wave action.
A copy of the Executive Summary from the Golder report on Environmental Site Assessment of CNR Rail Bed at
Sooke Reservoir, Greater Victoria Water Supply Area is attached. The complete report is available to
Commission members upon request and a copy will be posted on the CRD website.
The environmental site assessment was conducted using the formal provincial sampling and analysis protocols
for the assessment of industrially contaminated soils. As in the preliminary assessment, detectable levels of
pentachlorophenols, dioxins and furans were found in the rail bed soils. The detailed assessment showed that
these contaminants occurred only in the upper 20 cm (8”) of the rail bed. This was not unexpected given that
these chemicals were residues of the preservatives used on the rail ties. Some petroleum residues were also
detected in a former siding area. These residues, while detectable, were below the Agricultural Use Standard in
the Contaminated Site Regulation. No metal contamination was detected.
The contaminated soils from the rail bed will be transported out of the Sooke Reservoir catchment area and
deposited in an area further down the railway line in off-catchment lands owned by the CRD. The levels of
contaminants detected in these soils are acceptable for placement on non-agricultural land without a
Contaminated Soils Relocation Agreement.
Protective Strategies and Techniques
In consultation with the Chief Medical Health Officer, the Water Department is taking an extremely
conservative approach to this phase of the expansion project and will be incorporating a number of very
protective strategies and techniques in dealing with the contaminated soils. The following strategies and
techniques go beyond the recommendations of the Environmental Site Assessment and provide assurance of
public health and environmental protection.
1. Remove all of the contaminated soils from that portion of the rail grade lying within the future water contact
zone and place them outside the reservoir catchment area. This will include the top 30 cm of the rail bed
(i.e. an additional 10 cm below the 20 cm contaminated layer) and 1.5 m down the sides of the rail grade.
2. Remove the roots of any vegetation growing within the upper 30 cm of the rail bed and dispose of them in
the off catchment storage location. This will ensure that the potential uptake of contaminants by vegetation
is managed in the same manner as the contaminated soils.
3. Treat all areas showing visible staining as a ‘hot spot’ and specifically dig out these areas as required. This
will ensure that the areas of hydrocarbon contamination are removed entirely.
4. Provide close supervision of the equipment operators to ensure that the appropriate quantities of soil are
removed and the ‘hot spots’ are dealt with immediately.
5. Once the top 30 cm of rail bed have been removed from that portion of the rail grade in the water contact
zone, use confirmatory testing to ensure that no contaminants remain.
6. In the off catchment storage location, cover the contaminated soils according to a geotechnical design and
plant appropriate vegetation to protect against erosion. This will ensure that the contaminated soils are not
eroded even in the off catchment areas.
The removal of the contaminated soils is estimated to cost approximately $100,000 and is included in the budget
for the Site Preparation Component of the Sooke Reservoir Expansion Project.
That the Regional Water Supply Commission receive the staff report for information.
Stewart Irwin Joel Ussery, M.R.M.
Manager, Water Quality Division Superintendent, Resource Planning
Watershed Management Division
J. A. (Jack) Hull, P.Eng., MBA
General Manager, Regional Water Supply