Evaluation of City of Regina Stormwater Retention and Treatment Pond Performance
Abstract
Municipal storm water retention ponds are required to protect property, reduce negative
water quality characteristics and impacts of first flush materials on receiving waters, and
mitigate against peak flow challenges for treatment systems and receiving waters under
high precipitation or spring flow conditions. To that end, research was completed to
review the current operating performance and identify potential concerns with water
quality outflows from several of the City of Regina municipal ponds. Additionally,
optimization and maintenance suggestions are made to improve performance, where
appropriate. The research focuses on retention ponds that are designed to serve as
constructed wetlands, as these tend to be relatively new to Saskatchewan and potentially
challenging under the climatic conditions presented. The results indicate that the
constructed wetlands are strongly influenced seasonally, with concentrations of dissolved
oxygen and nutrients fluctuating with air temperature, winds, and precipitation events.
All constructed wetlands, at some point in the monitoring program, exceeded water
quality thresholds for the protection of aquatic life or general surface water quality
management. The pond most often out of compliance was North Windsor, with Windsor
also experiencing a significant number of compliance issues. The results further show
that the majority of ponds are nitrogen-limited, with one exception (North Windsor),
suggesting that management schemes to limit nitrogen (or enhance bioavailable
phosphorous) will be most effective for minimizing algal growth in the ponds.
Maintenance and management programs that include trigger points (performance
thresholds) are recommended to avoid aesthetic and health-related concerns.