The water that flows up through the pipes in your home, out of your faucet and into your glass is clean and healthy to drink—but it didn’t start out that way.
Before our drinking water becomes drinking water, it starts off as precipitation. Some of this water is absorbed into the ground, which acts as a sponge, but some of it flows down from rooftops and over driveways, roads, sidewalks, parking lots and lawns and, instead of soaking into the ground, flows into surrounding streams and lakes. This is called urban surface water runoff and it occurs most often in the urban and suburban areas of our watershed.
As the water flows over these impermeable surfaces, it can pick up and transport sediment and contaminants, such as commercial and residential pesticides and fertilizers, industrial chemicals and household products as well as pathogens, such as bacteria and viruses, which can spread disease.
After travelling over these impermeable surfaces and being transported by sewers, channels and streams, this water is discharged into a large body of water. In our watershed, that body of water is Lake Ontario. This water is then collected back from Lake Ontario and transported to one of three Halton Region water treatment plants, where these contaminants and sediment are removed or reduced so that safe, clean drinking water can then be distributed.
The water purification process is a bit of a delicate balance and water treatment plants can be unprepared for a sudden increase in a particular contaminant. This is why, even though water purification is an important process, reducing the contamination of surface water runoff is an important first step for clean drinking water.
In 2001, the National Water Research Institute in Burlington named urban surface water runoff one of the worst threats to drinking water quality in Canada, and urban expansion as one of the greatest contributors to this threat. Our watershed is no stranger to urban expansion. From 2011 to 2016, the population of Halton Hills increased 3.6 percent, the population of Burlington increased 4.3 percent, the population of Oakville increased 6.2 percent and the population of Milton increased by an unprecedented 30.5 percent. Before that, from 2006 to 2011, the population of Milton surged by 56.5 percent. In 2016, the population of Halton Region was about 548,400 and is expected to grow to 624,000 by 2021, to 752,500 by 2031 and to 1 million by 2041.
As our communities grow, there are more home and business owners spraying their lawns, more drivers leaking oil on the roads, more sidewalks being salted, more industrial pollution being produced and more agricultural pesticides being used to feed a growing population. But even more importantly, this growth means that more and more permeable soil is being replaced with impermeable, paved surfaces, which increases the flow of surface water runoff.
This is why, before a neighbourhood is built within our watershed, Conservation Halton works with the municipalities and developers to ensure that requirements stormwater management are met. For years, stormwater ponds have been the most common form of stormwater management, however more municipalities are now integrating low impact development.
“To slow down surface water runoff, Conservation Halton is working with its partner municipalities to find more opportunities for low impact development in urban areas” says Barb Veale, Director of Planning and Regulations at Conservation Halton.
Conservation Halton has been collaborating with the City of Burlington and Cootes to Escarpment to implement a low impact development project to manage surface water runoff in the Brighton Beach community. For years, the Brighton Beach community has relied on roadside ditches to transport urban surface water runoff through the neighbourhood, to the nearby ravine and into Hamilton Harbour. Not only does this cause erosion of the ravine but it degrades the quality of the water in Hamilton Harbour. The project that Conservation Halton and Cootes to Escarpment will be implementing this summer will include two bioswale features, which will absorb surface water runoff and filter this water before it reaches Hamilton Harbour.
“The Brighton Beach community has been involved in the planning, location, design and implementation of this project from the beginning,” says Kestrel Wraggett, Stewardship Technician at Conservation Halton. “Several meetings and workshops have been held and the community continues to contribute a wealth of knowledge on water concerns within the area.”
As an urban watershed resident, there are things you can do to decrease surface water runoff and reduce contamination to keep our drinking water clean.
- Plant rain gardens on your property to encourage water to soak into the ground.
- Use permeable materials, such as gravel or woodchips, instead of concrete and asphalt.
- If there is sloped ground on your property, even it out to slow the flow of water.
- If you live on a shoreline, plant native species along the shore to help filter contaminants.
- Use a rain barrel to collect the water that flows down from your eaves trough and then use this water on your lawn and garden.
- Use an absorbent to clean up and dispose of any spilled chemicals instead of washing them away.
- Only use fertilizers when necessary and at the recommended rate and do not use them if you know it is about to rain.
- During the winter, try alternatives to road salt or only salt your sidewalk and driveway when necessary.
- Always clean up pet waste, which can carry organisms that can transmit diseases or infections to humans.
- Use good housekeeping practices to keep your yard free of hazardous materials and waste.
Last modified: September 5, 2017