Map of Colquitz River Watershed (large PDF version)
The watershed supports a wide variety of uses including rural and urban residential, agricultural, commercial, institutional and industrial land uses. For almost 50 years prior to 1925, Elk/Beaver Lake supplied most of the drinking water for the Victoria area. Some water licenses on the river for irrigation and rural residential purposes are still active. Water quality in the Colquitz watershed has been negatively impacted by urbanization, agricultural and industrial land uses over many decades (see Colquitz Proper Functioning Condition Assessment
Channelization, ditching and dredging, draining of wetlands and flood plains, increased impervious cover from roads and roofs, septic field infiltration and contaminants entering the creek in runoff from roads and farms have all contributed to degradation of the creek and its tributaries. Some of the historical salmon spawning habitat in the upper reaches of the watershed is no longer available to salmon due to creek obstructions and dam building. Despite these impacts, there continues to be a run of 200-400 coho salmon that enter the Colquitz system each fall, as well as several dozen chum salmon. Since the 1970s the District of Saanich has had a policy of purchasing riparian lands along the creek, and a linear park and trail system now extends along most of the creek corridor. This policy has resulted in improved riparian habitat for wildlife, birds and insects and for humans as well.
Swan Lake/Swan Creek
The Swan Lake watershed includes drainage from Swan and Blenkinsop creeks, an area totalling 12km2. Swan Creek is the 2.3km long outflow stream that enters the lower reaches of Colquitz Creek near Interurban Road and Violet Avenue.
Swan Lake is part of the 47ha Swan Lake/Christmas Hill Nature Sanctuary
, established in 1975. The sanctuary includes the marshy lowlands surrounding Swan Lake, and the Garry oak
forest and meadows at the top of adjacent Christmas Hill. Below the sanctuary, Swan Creek has been extensively dredged and channelized for land drainage. Land uses in the lower areas of this sub-watershed include residential, commercial activities and some agriculture. In 2012, after a series of oil spills into Swan Creek, a restoration project has been initiated on this creek by a local conservation group
and community volunteers.
Blenkinsop Lake/Blenkinsop Creek
According to maps dating from 1858, there was not originally a direct connection between Blenkinsop Lake and Swan Lake. The man-made partially culverted ditch that exists now was constructed in order to drain a large wetland at the south end of Blenkinsop Lake. There are two dams on this stretch of creek, and water levels are regulated. Some of this man-made creek was enhanced and ecological function restored in 2001.
Since the late 1800s, agriculture has been the dominant land use on the Blenkinsop Valley, leading to many changes in vegetation and habitat. By the mid-1950s, most of the original vegetation had been cleared for farmland and for the construction of a power transmission line in the area.
Viaduct Creek/Viaduct Flats
This tributary lies roughly between Interurban, Wilkinson and West Saanich roads, and includes two significant wetlands: Quick’s Bottom and Viaduct Flats. The land in this sub-watershed, including the area that is now Viaduct Flats, was farmed until 1993, when the agricultural lease expired. Around the same time, a beaver dam appeared that blocked off the outlet channel and created an area that remained flooded year-round. This hydrological change created wetland habitat that was soon being used by many birds and other wildlife species as well as aquatic/marsh vegetation. For this reason, two weirs were installed at the outlet of the wetland to maintain water levels, and the area is now preserved as municipal parkland. It is a popular bird-watching area, and a viewing platform has been installed there by the Victoria Natural History Society (accessed from Interurban Road). This change in hydrology has meant that there are lower flows than in the past in Viaduct Creek.
The reach of Viaduct Creek between the Flats and Quick’s Bottom is sometimes referred to as Goward Springs A Creek.
The Durrell Creek watershed is a sub-watershed of the Colquitz. This small stream begins in the hills of Francis King Park, and flows south and east, mainly through farmland and residential areas, before joining Colquitz Creek near Wilkinson Road. Although the stream channel and the surrounding landscape have been extensively modified over the years, the watershed still provides wildlife habitat, recreational opportunities and agricultural land that are important to the local community.
For more details, please see Durrell Creek