Stormwater ponds in Niagara Falls need millions in maintenance; PCs' rapid housing plan could put more municipalities in the same situation
In Niagara Falls, 14 of the City’s 25 stormwater management ponds are becoming clogged with dirt and debris and desperately need to be cleaned out to continue providing valuable water filtration and flood protection. The critical work will not come cheap for the municipality with it estimated to cost about $18 million over the next few years.
As part of the 2021 Capital Budget, the City of Niagara Falls allocated $150,000 for a Stormwater Pond Assessment and Cleanout Program. Last year, the City approved an additional $500,000 for undertaking the assessment and cleaning out one pond. The City is currently working in conjunction with the Federation of Canadian Municipalities (FCM) to develop a plan for cleaning out the others that have shown signs of sediment build-up. A spokesperson for the City told The Pointer in an email the $18 million cleanout of all 14 ponds is expected to be spread out over the next few years and “cost estimates will be refined as the City proceeds to the detailed design phase of pond rehabilitation.”
The City will be receiving assistance from Infrastructure Canada through the Municipal Asset Management Program (MAMP). The MAMP provides municipalities and partner organizations funding to promote sustainable asset management. The City of Niagara Falls is eligible for $50,000 in funding through MAMP to support work on the Stormwater Pond Assessment and Cleanout Program. The City has not yet received the funds but the spokesperson said the grant money will help offset the original capital cost of the $150,000 study.
In the City’s approved 2023 capital budget, $3.3 million is allocated for stormwater management. However, none of this money is currently being put towards cleaning out ponds as this cleanout program is still in the planning phases, the City says.
Stormwater management ponds are common neighbourhood features in modern subdivisions and while they can be aesthetically pleasing, they hold municipal runoff that often contains contaminants.
(Alexis Wright/The Pointer)
The concern with stormwater management is increasing at a time when there is a dramatic move to build more homes across the province following the approval of the PC’s Bill 23 housing plan. Niagara Falls has been allocated a target to build 8,000 new homes by 2031 under the legislation, but it is not the only municipality that will struggle with stormwater management as a result of the construction of 1.5 million homes across Ontario.
“One of the reasons that we're starting to talk to everybody about overmanned stormwater treatment is because we're seeing a lot of new developments, and we're expecting a lot of new developments,” Cathy Blott, a habitat restoration biologist with 8Trees, said. 8Trees is an environmental consultancy that has a group of scientists and students working together to support ecological restoration, mentorship and public outreach.
Urban and suburban development interferes with the natural transfer of water as part of the hydrological cycle. Paved surfaces block water from being absorbed into the earth, which not only creates flooding issues during large rainfall events as water has nowhere to go and municipal wastewater infrastructure becomes overwhelmed, but can also lead to increased pollution in lakes and waterways as this rainfall or snowmelt washes over the pavement, collecting road salt and other pollutants. Stormwater ponds are a staple of GTA subdivisions and serve the vital function of collecting and filtering stormwater before it is released into local waterways. With 1.5 million homes planned for construction across Ontario in the next eight years, most of which will be concentrated in Southern Ontario, municipalities will need to pay particular attention to proper stormwater management practices to prevent flooding catastrophes as the urban landscape expands, gobbling up more greenspace and farmland. This is particularly concerning as experts have already pointed out that Ontario municipalities are far behind the 8-ball when it comes to guarding themselves against flooding.
In November, Ontario Auditor General Bonnie Lysyk published a damning audit that concluded the province of Ontario is doing very little to help save municipalities from flooding catastrophes and is providing miniscule amounts of funding for stormwater infrastructure. The findings came at a time when the risk for flooding is increasing due to changes in the climate and weather patterns. According to data from Natural Resources Canada, the number of heavy precipitation days across the country—defined by the accumulation of greater than 10 millimetres of rain in 24 hours—increased from 135 days in the 1950s to 158 days in the 2000s. All the while, the Province is focusing on increasing the amount of impervious surfaces by building more homes and associated roads and other infrastructure.
“Our audit found that the Province does not have effective systems and processes to reduce the risk of urban flooding, nor to provide homeowners, municipalities and other decision-makers the guidance and information they need to reduce their risks of urban floods,” Lysyk wrote in her audit.
Stormwater management is a key process that can help to prevent flooding catastrophes, which will only increase with a changing climate. Stormwater management ponds collect runoff from storm events, but also from rain and melting snow. In more rural areas, water is able to pass naturally through grasslands and other natural systems, but in areas carpeted with impervious surfaces, like roads, sidewalks and parking lots, the stormwater needs to be diverted to prevent pooling and flooding. This water is collected into underground pipes and redirected to a central facility, more commonly known as a stormwater management pond.
There are two main types of stormwater management ponds: dry detention basins and wet retention ponds. The major difference between the two is the permanent presence of a pool of water in the latter. Dry systems work by providing a large area for water to collect which slowly drains through an outlet at the bottom of the basin. Dry systems are less commonly used because they can detract from property values. The more common system is the use of a wet pond which can add to property value with the aesthetic of nearby water. Wet ponds collect stormwater and use natural processes to work to remove pollutants. Large amounts of water are able to enter the pond while the outlet emits small amounts to maintain levels.
Without effective stormwater management many municipalities will experience more flooding events as rainfall and storm events increase due to climate change.
(Alexis Wright/The Pointer)
Anne Yagi, a conservation biologist and founder of 8Trees, said she is concerned that a stormwater management pond has become just one thing on a checklist for developers, without really considering the costs or more effective alternatrives.
“Why do you have to have a stormwater pond is not even mentioned anymore,” Yagi said. “It's not always the best thing, unless there's a true commitment to cleaning it out.”
There are a myriad of concerns with both dry and wet ponds that have to do with property value, drowning hazards and insect breeding. But the main concern for some environmentalists is the concentration of contaminants in a single location. In the drainage process, stormwater picks up sediments, nutrients and contaminants from the urban landscape.
“The reality is these open water ponds attract wildlife to them,” Yagi said. “And it's a sink for contaminants that are coming off the roads, coming off urban areas, natural areas, and rural agricultural areas. And they bioaccumulate in animals, or they persist long enough to the point where they cause damage to the animal's reproductive systems, because the animals are attracted there, they can't help it.”
Yagi noted that engineers and developers are not always aware of the negative effect these ponds can have on the species attracted to them. She pointed to a development in Thorold, west of Niagara Falls, where the engineers were discussing the possibility of frogs inhabiting the proposed stormwater pond and the benefits it could serve to the species. Yagi and community members got involved, expressing concern that the stormwater pond would actually not be safe for frog species.
“It's interesting that the engineers thought that they were actually making a frog pond when they built the stormwater pond,” she said. “That's the wrong message, because those ponds are horrible places for these animals, but they will be attracted to it.”
Contaminants like chloride—road salt—are collected by melting snow and rainwater to be washed into stormwater management ponds. Chloride persists in the environment, creating dead zones in lakes and ponds.
When animals are attracted to stormwater management ponds it puts them at risk of consuming contaminants that have runoff into the water. These animals then get eaten by others and the contaminants bioaccumulate up the food chain, sometimes even making their way to humans.
Yagi and Blott are working hard to promote other options for stormwater management , but say not enough municipalities are aware of valuable alternatives called overland stormwater treatment systems.
These systems are built like a network of converging streams and tributaries. They have small collection channels that transition into creeks and streams as they gather more water from other collection channels. During the process, the water passess through natural features that filter out sediments and contamination.
“You're using natural vegetation, native vegetation, you're using that to assimilate and clean the rainwater as soon as possible after it hits the ground,” Blott explains.
Blott pointed to the example of the Humber Flats neighbourhood in Richmond Hill. Humber Flats was built over 20 years ago using an overland stormwater system that functions similar to a network of streams. It is used across the province as an example of potential sustainable alternatives to large stormwater ponds.
A map of the interconnected stormwater management system of the Humber Flats neighbourhood in Richmond Hill.
(City of Richmond Hill)
The benefits of these sustainable systems extend beyond their improved ability to filter out contaminants and benefit wildlife. Blott says there are economic benefits for developers to use overland systems as well.
“It's very expensive to build a stormwater treatment that is underground, because it's using pipe, it's using plastic, it's using cement, it's using metal, these are becoming more rare resources.”
Using an overland system does not require the same length of underground piping meaning housing can be built differently. The lack of an underground pipe system and not having a large space needed for a retention pond means more housing can be built, potentially increasing density.
Blott and Yagi are tirelessly working to expose the negative impacts of stormwater management ponds which have traditionally been thought of as environmentally beneficial due to their deterrence from flooding. Through 8Trees and working with municipal partners, both scientists are using the example of Humber Flats to promote more sustainable development across the province.
“Today's policy for stormwater treatment does allow for overland stormwater treatment,” Blott said. “There's no barriers. It can be done today if anybody wants to start doing it. And I think that what we've found is that nobody's proposing it and nobody's asking for it…I think because people just don't realize that it's out there.”
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