This page has been archived on the Web

Information identified as archived is provided for reference, research or recordkeeping purposes. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. Please contact us to request a format other than those available.

Lower Sooke River Watershed Non-Point Source Assessment: Impact on the Sooke River Estuary


British Columbia has generally succeeded with regulating “end-of-pipe” pollution, and it now recognizes that non-point source pollution is the significant contributor of water pollution (Ministry of Environment, Lands and Parks, 1999). Sources of non-point source pollutants can include stormwater, agricultural, urban, and forestry run-off, sewage and on-site septic systems, and land development activities (Ministry of Environment, Lands and Parks, 1999).

The inputs of non-point source pollutants into the Sooke River and their subsequent effects on the estuary are not fully understood. To begin addressing these particular issues, Integrated Environmental Consultants began a study of non-point source pollution in the lower regions of Sooke River and De Mamiel Creek.

Water quality directly impacts economic activity in Sooke. The shellfish industry in Sooke has been closed due to fecal coliform levels. In addressing non-point source concerns in the Sooke watershed direct economic benefits may be accrued for the community.

The first objective of this study was to determine the state of water quality in the Sooke River and De Mamiel Creek. Preliminary analysis was used to infer possible non-point sources of these parameters. The second objective was to ascertain the relationship between the Sooke River and the estuary. The third objective was to compile the results of the study into a digitized format Geographic Information System. The final objective was to examine the results in order to suggest preliminary recommendations for improved environmental management.

Research and water sampling for fecal coliforms and nutrients were combined to fulfill these objectives. Sampling was done five times over thirty days for two sampling runs. There were four sampling sites on the Sooke River, four sites on De Mamiel Creek, and one in the Sooke River estuary. Control sites were established on the upper reaches of both watercourses.

Fecal coliform, in situ tests, and quality control samples were collected weekly. Nutrient testing for nitrate and nitrite, ammonia, and total dissolved phosphorus was conducted during weeks three and four of each sampling run.

Results demonstrated that fecal coliform levels are a problem with respect to drinking water quality. Fecal levels were not proven to be a concern for recreational and livestock uses but the data indicate that this may change with seasonal variation. Based on the results of this study, nutrient levels are not a water quality problem in the Sooke River and De Mamiel Creek. Nitrate/nitrite and total dissolved phosphorus levels indicate that they may become a problem given different seasonal variations in water flow and human activities.

The data also indicate that the water entering the estuary from the Sooke River does impact the water quality of the estuary. However, it should not be assumed that the Sooke River discharge is a primary detriment to the health of the Sooke Harbour and Basin, and the associated shellfish industry, until further research is done. This may determine the extent of the impact, which has not yet been established.

As the river, estuary, harbour, and basin are interconnected, the entire Sooke River watershed must be managed for water quality. Stormwater and sewage treatment alternatives as management options are recommended for consideration. Community based initiatives such as public education, with a focus on school children may increase awareness and facilitate the reduction and avoidance of non-point source pollution.

Geographic Information System allows for an integration of information and resources in order to preserve natural ecosystems. In order to utilize the full potential of the package, more information needs to be incorporated.

This study was a ‘snapshot’ of water quality within the lower Sooke River watershed and provides baseline data for future studies. By extending the sampling periods, tests, and locations enough data could be collected to determine the sources of non-point source pollution in the lower Sooke River watershed.

Copy of report available by request at

Date modified: