Storm water (stormwater) starts as precipitation and snow/ice melt. When it falls in a city, whether it soaks into the soil (infiltrate), remains on the surface and evaporates, or ends up as contaminated urban runoff that flows into a nearby water body depends on that city’s infrastructure.
Urban runoff is mostly contaminated storm water runoff and is a major source of flooding and water pollution in municipalities worldwide; urban runoff is also recognized as the leading source of water quality problems in cities.
Urbanization & the Water Cycle
Urbanization changes the local hydrological cycle, mostly by decreasing natural vegetation cover and 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 has spawned a frantic water pace.
Municipalities typically use property taxes or a portion of the water utility bill to charge for storm water services. “But these methods are not fair,” write Sara Jane O’Neill and Stephanie Cairns in Water Canada. This is “because there is no relationship between property value or water consumption and the volume of stormwater generated by a site.” High-value properties may be paying for stormwater services they are not using; likewise, properties that consume much less (e.g., parking lots) but generate a high volume of runoff are not paying their share.
Stormwater user fees as a tool in municipal stormwater management are gaining momentum in Canadian municipalities, write O’Neill and Cairns. A user-fee based on the calculated amount of stormwater generated from a property creates an equitable assignment of cost. It also better addresses the “polluter pays principle”. This is much like putting a toll on a new highway; those using the highway logically pay for it.
A stormwater service fee encourages conservationist action and helps reduce stormwater runoff in two main ways: 1) economic incentive and 2) greater awareness and transparency.
Economic Incentive: Researchers have shown that when utilities price drinking water based on consumption, people use less water; the same is true for stormwater. Property owners can reduce stormwater fees by implementing creative ways to reduce stormwater runoff on their property. This may include various creative means, such as planting trees, rain gardens, using impervious surfaces for driveways, installing green roofs, etc.
Increased Awareness & Transparency: “Experience has shown that charging specifically for stormwater sparks a conservation,” write O’Neill and Cairns. Property owners will learn about the water cycle and how green infrastructure (e.g., trees, rain gardens, permeable pavement, green roofs, etc.) helps balance and restore the water cycle, ultimately benefiting the community and the watershed they live in.
The user-fee redistribution of cost will likely shift the cost toward non-residential property owners (e.g., commercial businesses, parking lots, apartments, condominiums and town homes), given the traditionally high permeable surfaces. Credit and discount programs provide incentive for these property owners to reduce the fee and help the environment at the same time. This is a win-win scenario.
The city of Mississauga, Ontario, has recently adopted a user-fee and credit structure for managing its stormwater.
“Safe, reliable storm water infrastructure is crucial to city building,” writes 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.”
What this and related user-based programs does is shift both environmental knowledge and environmental responsibility to the individual, where it belongs. And where we, as individuals, can make a difference.