A good rainfall often comes with a hefty tab.
Consider the recent case of Montreal, where record rainfall last month caused extensive flooding, damaging infrastructure and affected more than 1,000 homes – 60 of which were deemed uninhabitable after inspection. The Red Cross provided $3 million to the province to deal with the aftermath.
And that was just one incident. The total annual cost associated with municipal flooding in Canada is in the billions of dollars.
Stormwater comes with other hazards, as well. A region’s overall water quality – from rivers to lakes – is affected by road runoff. In municipal areas, like London, stormwater is full of chloride on account of salt thrown on the roads in winter. We don’t want to see that water going directly into the rivers, noted Engineering professor Clare Robinson.
Robinson recently partnered with the City of London to reduce the likelihood of flooding, reduce the amount of stormwater going into rivers and improve overall water quality. Her project, Assessment of the Performance of Bioswale Bioretention Systems in Reducing Nutrient Loading to Tributaries from Urban Stormwater, aims to determine the effectiveness of stormwater management technologies in reducing the amount of potentially harmful nutrients, such as phosphorus and nitrogen, transferred to rivers and lakes in Ontario.
Robinson’s effort was one of 17 environmental projects that received support through the Province of Ontario’s Best in Science program. Announced in April, the projects will receive a total of $800,000 in grants over three years. Established in 2004, the Best in Science Program has provided approximately $10.5 million to support 129 environmental research projects.
“In urban areas, stormwater management is a big issue, both in terms of managing the amount of stormwater to prevent flooding, as well as managing the quality of the stormwater,” Robinson said.
“My focus is looking at urban stormwater, particularly low-impact development technologies. Traditionally, stormwater just goes into a drain and then into the rivers. But the Ministry of Environment has a big push on low-impact development technologies, which reduce the amount of stormwater runoff you have, and can also improve the quality of the stormwater before it reaches the stream or the river.”
In working with the City of London, Robinson will be looking at bioretention cells, a popular stormwater management technology, being installed on Sarnia Road. When it rains, road runoff, instead of going into the drain and then into the river, is absorbed in the cell and filtered through soil. When the water percolates through soil, its flow slows, while its nutrients are filtered out, improving water quality.
Robinson and her research team will be looking at monitoring these systems as well as trying to optimize their functionality.
In this region, managing phosphorus in lakes is a major concern, and the governments of Ontario and Canada are collectively trying to reduce phosphorus load by 40 per cent.
“Around Ontario, there’s a big push with stormwater, for more environmentally friendly stormwater management infrastructure, such as these bioretention cells,” Robinson continued.
“I look at water quality issues. I’m trying to reduce phosphorus loading and nutrient loading into the lakes to prevent algal blooms. I do work in agricultural areas, too, and look at septic systems and how they can deliver pollutants into the lakes or streams. This (Best in Science-supported) project is just focused on the urban stormwater problem.”
Stormwater management has been a focus in recent years in London, she explained. There are a number of green roads around Western, as well as green roofs, and the city is looking at how effective these are in managing stormwater. Managing road runoff through green infrastructure, such as rain gardens, bioswales, infiltration galleries, or urban trees in the rights-of-way, reduces storm water volumes and storm water pollution.
“We have a lot of water issues in this area, a lot of concerns about the water quality, in particular in the Great Lakes. What happens in the Great Lakes is determined by what happens here,” Robinson said.
There are a few bioretention cells around London already. However, Robinson will be looking at new systems. The three-year project will start next year.
“We want to improve these technologies because across Ontario, when we look at urban stormwater infrastructure, it’s really moving towards these low-impact development technologies. We need to know how these systems work and how we can improve them.”