“Safe, reliable storm water infrastructure is crucial to city building,” wrote Bonnie Crombie, Mayor of Mississauaga, in the May/June 2016 issue of Water Canada. Billed to Mississauga properties as part of the water bill, the fee will collect revenue that will permit the creation of a reliable storm water infrastructure.
“A property owner’s contribution to the funding of the storm water program will no longer be based on the value of their property. Instead, it will be based on the extent of hard surfaces,” wrote Crombie. This is more fair, says Crombie, since the impact a property has on storm water is unrelated to land value and more to the percentage of impermeable surfaces on it. “Commercial, industrial, institutional and multi-residential buildings will be charged for the area of hard surface—such as buildings and parking lots—covering the property.”
Crombie also mentioned the city’s additional programs that engage landowners in storm water management. This includes a credit program in which properties that demonstrate efforts to significantly reduce the impact of storm water runoff from their property (e.g., by planting trees and other best practices in green development) will be rewarded. Crombie also mentioned education and outreach programs, which will help residents understand drainage as part of the water cycle and strategies to best manage the environment of their property.
Urban runoff is any kind of surface runoff of rainwater created by urbanization. Mostly in the form of contaminated storm water runoff, it is a major source of urban flooding and water pollution in urban communities worldwide; urban runoff is also recognized by governments as the leading source of water quality problems in urban settings.
Urbanization changes the local hydrological cycle, mostly through decreasing natural vegetation cover and by increasing impervious surfaces. The effect is catastrophically compounded: 1) as infiltration (and filtration) of water into groundwater decreases—because it can’t get there or it rushes too fast across hardpan—the groundwater aquifer doesn’t recharge; 2) less vegetation to softly absorb rainwater results in shorter travel time between water phases and less evapotranspiration back into the atmosphere. These increase the volume and intensity of runoff while decreasing groundwater recharge. It’s as if the frenzied urban pace of has spawned a frantic water pace.
Trees make rain. Less trees; less rain. And when it comes, it’s unruly, overwhelming the capacity of a city’s drainage systems and causing flash floods, storm surges and overbank flooding. Impervious surfaces (like rooftops, streets, parking lots and driveways) promote floods and lower the water table. Water rushes like a banshee on a rampage; the city is literally in a drought-flood scenario. Most municipal storm sewer systems discharge untreated storm water to streams, rivers and bays. The excess water can also flow into people’s properties through basement backups and seepage through building wall and floors.
Runoff from impervious surfaces picks up gasoline, motor oil, heavy metals, trash and other pollutants from roadways and parking lots. Polycyclic aromatic hydrocarbons (PAHs), are combustion byproducts of gasoline and other fossils fuels. Heavy metals such as nickel, copper, zinc (from galvanized gutters), cadmium, and lead are often part of urban runoff. Lawns, parks and golf courses may also leach fertilizers, such as nitrates and phosphorus, and pesticides. Runoff will also pick up sundry pollutants, including sediments, from poorly maintained construction sites, undermining the health of the water systems that ultimately receive them. Effects include smothering of bottom-dwelling biota, eutrophication from increased nutrients and reduction in oxygen with consequences to fish and other biota.
Recent floods in Mississauga and elsewhere suggest a need for better urban water and flood management. Crombie’s gutsy—and possibly unpopular initiative—may be one of the best working solutions because it aims at the level of the citizen. If it doesn’t work at the individual level, it won’t work.