Wetland Creation

Keffer Marsh

Langstaff EcoPark is an area of natural regeneration located along a 2 km stretch of the west Don River as it flows through the Langstaff industrial park. When completed, Langstaff EcoPark will comprise the mid-portion of the Bartley Smith Greenway, a 15-kilometre trail system. The highlight of Langstaff EcoPark is the Keffer Marsh Complex, named after one of the original pioneering families to settle in the area. Keffer Marsh is a 2-hectare wetland complex at the mouth of Westminster Creek, a highly urbanized sub watershed of the west Don River that includes a deciduous swamp and a marsh wetland.

Water is supplied to the marsh though a diversion system that uses the hydrology of Westminster Creek to provide a suitable source of water for the wetland. The diversion structure is a large concrete dam that with three outlets. One outlet diverts base flow into the smaller marsh wetland and is designed to convey 6 litres per second of base flow while preventing the accidental infiltration of spills into the marsh wetland. A second outlet is designed to convey major flows through the existing gabion channel. The remaining outlet feeds water to the swamp.

The base flow outlet feeds water to a marsh complex that maximizes water quality improvements and habitat features. Water flows into a steep-sided settling pond designed to drop out coarse sediments and promote the development of submerged aquatic macrophytes. The water then flows through a cattail thicket that is situated on a thick bed of pea-sized gravel. The cattail thicket/gravel bed promotes sub surface flow of water and aids in nutrient uptake. The water then flows into a large marsh feature and through another cattail thicket and a porous rock weir designed to cool the water before it enters the West Don River.

The deciduous swamp is designed to capture peak flows during major storm events or the spring freshet. During an average year, this swamp area will collect water four to six times and is designed to hold in excess of 8,000 M3 during each event. There is no designed outlet except for a spillway for major flows. The water dissipates from the swamp through infiltration, evaporation or is used by the plant material.

The area is rapidly colonizing with both plants and animals. Initial plantings were conducted to inoculate the complex with the desired species of plants, and many community groups have supported the project by planting trees and building the trails. The site is now home to green frogs, American toads and a wide variety of birds.