Posted on March, 01 2012

Boosting biodiversity with constructed wetland

In Abbotsford, one of Canada's highest-precipitation cities, a gorgeous nature park helps solve a serious problem with water runoff exacerbated by suburbanisation. The Fishtrap Creek Nature Park features wetlands and an enlarged creek for storm-water detention and bio-filtration. It also boosts biodiversity by providing habitats for among other creatures, the Salish sucker fish, while providing recreation and education opportunities.



Keywords: runoff, storm-water, biofiltration, storm-water detention, restoration ecology

Suburban land-use and stormwater solutions are often blamed for undermining natural ecosystem services – and the traditional suburbs of Abbottsford were no exception. Serious runoff, flooding and pollution were even threatening nearby agricultural land of high value. Stormwater runoff can contain a range of contaminants, particularly from cars and home-lawn chemicals. Abbotsford high annual precipitation levels among cities in Canada (1.5 metres/year) prompted it to search for a solution and made it a forerunner in the work with wetlands.

Restoration ecology
The Fishtrap Creek Nature Park was created in the 1990s as a form of restoration ecology. First, the park provided a stormwater detention facility to reduce flooding (see also Auckland). This was primarily done by creating a large wetland, enlarging and reshaping an existing creek, and adding large amounts of mainly native vegetation – meadow, forest, wetland and riparian plantings. Bio-filtration by plants and bacteria improves the water quality, as do sediment traps on the storm-flow inlets to the wetlands.

This multi-stakeholder and multiple-award-winning project also managed to integrate a wide range of other benefits. The park has multiple types of natural habitats, and is regarded as an important remediation of the effects of land-clearing for agriculture in the area (see also Emscher Park). Fishtrap is also designed for nature-oriented recreation like bird watching. Learning/interpretive opportunities have also been created, focused on the local ecology and cultural history, e.g. on pioneer homesteads.

Multiple benefits
The presence of endangered fish species (the Salish sucker and Nooksack dace) was crucial to the development of the runoff solution, not least by engaging environmental agencies in the project. Also, wetlands are increasingly recognised as an effective way to solve a range of problems, including conservation of highly biodiverse nature near cities (see also Brisbane and New Orleans). The multiple benefits make the introduction of wetlands more attractive in both urban and rural settings.


References
Catherine Berris, ”A stormwater wetland becomes a nature park (British Columbia, Canada),” in Robert L . France (editor), Handbook of Water Sensitive Planning and Design, CRC Press 2002

Bev Betkowski / University of Alberta, 2009, Price point established for restoring wetlands, University of Alberta Research Services Office, http://www.uofaweb.ualberta.ca/rso/news.cfm?story=91969

Kelly Greig, 2011, ”Building a better storm drain”, Canadian Geographic, http://www.canadiangeographic.ca/magazine/jun11/fishtrap_creek_nature_park.asp

Key data are retrieved from the UN Demographic Yearbook 2011 http://unstats.un.org/unsd/demographic/products/dyb/dyb2011.htm

Text by: Aaron Thomas