The primary current source of contamination in the Gorge is in runoff from impervious surfaces (e.g. roads, buildings, parking lots) in the surrounding area. Instead of soaking into the ground, rainwater runs across these surfaces picking up pollutants and carrying them into the waterway, either directly or through storm drains. Some of this surface runoff contains contamination from industrial sites within the watershed, but “non-point source” pollution, particularly from vehicular traffic, is a major contributor.
In the lower Gorge (the Selkirk Water), copper, mercury, zinc and polycyclic aromatic hydrocarbons are present in quantities known to harm marine life. Although sewage contamination, through cross-connections with storm drains, has been much reduced in recent years, it is still a potential concern in the Gorge.
Despite this legacy, the water quality in the Gorge has improved since the 1990s, thanks to infrastructure improvements (e.g. sanitary sewers and some storm water treatment systems), and ongoing community clean-up efforts. Water quality is a high priority with local and regional governments that are working together to establish water quality objectives specific to the Gorge and the other harbours in Greater Victoria. Storm drains and creeks that discharge into the Gorge are monitored and tested regularly for a variety of contaminants, and elevated levels are investigated to locate and address problems.
The Vancouver Island Health Authority (VIHA) is the agency responsible for determining safety of public swimming beaches. VIHA tests the water at beaches regularly during the summer, and the water is usually found to be safe for swimming. Click here
for beach reports.
Loss of Intertidal Habitat
Much of the Gorge consisted of rocky shorelines before foreshore areas were altered with seawalls and in-filling. The rough texture and complexity of natural shorelines greatly increase the available surface area, providing nooks and crannies in which creatures can shelter. Smooth surfaces such as seawalls provide little habitat in comparison. Many small estuaries and salt marshes along the Gorge were lost when the shoreline was filled in. Pollution also contributed to habitat loss, because certain areas became too toxic for marine life.
Past sawmilling and log booming operations in the Selkirk Water has left an accumulation of wood debris on the seafloor. Wood debris causes habitat loss by burying bottom-dwelling plants and animals, and by altering the chemical composition of the sediment. Decomposition of wood debris by bacteria can also rob the surrounding water of oxygen. Some areas seem to be recovering from this impact, as shown by the recent expansion of eelgrass beds in the Gorge.