By Norman Dewar
Rain gardens are a simple and effective landscaping tool to reduce surface water runoff in urban areas through on-site retention and absorption of rainwater. It is often overlooked by property owners as a stormwater control option in favour of quick drainage off-site. The Spring Park Home and School Association (SPHSA) installed a demo rain garden just off the main entrance Spring Park Elementary School in Charlottetown in September 2018. By eliminating a surface water runoff problem specific to this site, the project provided a practical demonstration of how to use stormwater runoff to create an attractive landscape feature and at the same time, reduce a winter hazard created by water runoff flowing across the sidewalk.
The project has worked exactly as designed based on daily observations recorded by Norman Dewar, the project coordinator. To date, the rain garden has never overflowed, and the water retained disappears in 48 hours or less. This was despite record-breaking rainfalls this fall and early arrival of winter. As the plants and shrubs grow, the ability of the rain garden to absorb water will increase over time unlike hard infrastructure such as storm drains.
Over 2 dozen parents and children showed up to plant the rain garden, and the project was followed on the Spring Park Home and School Facebook page. The night the project was completed, hundreds attended a large public-school branch public meeting at the school. Many parents commented on how good the project looked. One of the members of the public school board was so impressed by the project, they asked the school principal to introduce them to the project coordinator, so they could personally extend their congratulations. The project is still be noticed by parents and others visiting the school. Principal Terry MacIsaac has had some people come up to him and inquiring if he noticed the big puddle of water at the front of the school so more education is needed for people to understand how a rain garden functions. An as-built sign showing the landscape plan and providing some background on the project, and rain gardens, in general, is needed. It is anticipated because of the relatively late planting, not all the plants will survive or will prove suitable for the location. Hence an “as built” sign will be installed in 2019.
This project has proven that rain gardens or similar structures can be an effective stormwater runoff control tool. Ellen’s Creek Watershed Group would like to repeat a similar project at another location and lead the installation of a bio-swale project as an integral part of the City’s stormwater drainage system. A bio-swale is in concept a rain garden but where a rain garden’s principal function is stormwater retention, a bio-swale also filters and remediates stormwater runoff.