Gorge Waterway - Concerns
Pollution
The Gorge is heavily affected by runoff from impervious surfaces (i.e. roads, buildings, parking lots) in the surrounding area. Instead of soaking into the ground, rainwater runs across these surfaces and carries pollutants into the waterway, either directly or through storm drains. Industrial sites within the watershed also contribute to contamination, primarily due to surface runoff. In the lower Gorge (the Selkirk Water), copper, mercury, zinc and polycyclic aromatic hydrocarbons (PAHs) 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.
Loss of Intertidal Habitat
Much of the Gorge consisted of rocky shorelines before the shoreline was altered with seawalls and in-filling. The roughness and complexity of natural shorelines greatly increase the available surface area, and provide nooks and crannies in which creatures can shelter. Smooth surfaces such as seawalls provide little habitat in comparison. 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.
Saw milling and log booming operations, conducted in the past in the Selkirk Water, caused wood debris to accumulate on the bottom. 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.
