Solutions to Stormwater Runoff

photo: stormwater drain,

Stormwater runoff is the single largest contributor of non-point source pollution to Michigan’s waterways. While separating our sanitary sewers from storm sewers will do a great deal to protect our water from raw or partially treated sewage overflows, we have to pursue other policy options to deal with stormwater where it lands. Stormwater runs off of our driveways, lawns, parking lots, roofs, and other gray infrastructure. In most cases, this water then drains into combined pipes where it mixes with sewage before heading to a wastewater treatment plant. In some cities, like Grand Rapids, these stormwater and wastewater pipes have been separated. This separation eliminates combined sewage overflows. In both cases, the stormwater is carrying with it oils, anti-freeze, fertilizers, dog feces, and myriad other dangerous chemicals it comes in contact with. In both instances, when the system is working properly and not exceeding its capacity, the water goes first to wastewater treatment plants before then being discharged back into the water table.

During heavy rainfall events however, our sewers often exceed their intended flow capacity, and untreated stormwater, carrying all the same dangerous pollutants, gets deposited directly into lakes, rivers, and streams. The fertilizers carried by stormwater from suburban lawns is a huge problem. These fertilizers and nitrates contribute to the toxic algae blooms that pollute Lake Erie as well as many inland lakes in Michigan.

This problem is only getting worse as urban, suburban, and exurban areas continue to expand in population and square mileage. Many of these gray infrastructure systems are not being upgraded at the same rate, and end up allowing for overflows and discharges that are harmful to our local rivers and streams. Climate change contributes to the problem too as Michigan continues to see more frequent and more extreme weather events.

There is a simple way to solve this problem. The best way to treat stormwater is to treat it where it falls, as it falls. When green infrastructure is put in place, stormwater re-enters the water table without picking up harmful chemicals from nonporous surfaces. Native plants helps to act as a sponge, soaking up water where it falls. The water is then filtered naturally through roots and soil before then making its way back into aquifers. This is why raingardens, wetlands, bio-swales, porous pavement, and other green infrastructure upgrades go a long way toward solving this major water quality issue.

Most lawns, especially the popular and widely used Kentucky bluegrass, are invasive to Michigan (meaning it isn’t native to our state). Unlike native plants which tend to have deeper roots and allow for much greater water infiltration during rainfall, Kentucky bluegrass and most other lawn species have shallow root structures that don’t allow for much infiltration, meaning that rain does not infiltrate the ground well enough and ultimately runs off the lawn into sewers, carrying with it fertilizer and all the other pollutants it comes in contact with on the way.

Individual households can make a big difference by adding green infrastructure to their property. Some green infrastructure upgrades include things like: raingardens, rain barrels, and buffer strips. By utilizing native Michigan grasses and plants in your yard, you are helping to capture rain where it falls and keep it from polluting our local waterways. By capturing stormwater in rain barrels on your property, you save water (and money) as this water is easily reused to maintain your flowerbeds and vegetable gardens. For more information on easy green infrastructure upgrades you can make at home, check out this resource from EPA.

One way to implement green infrastructure on a larger scale is by allowing for municipalities to create stormwater utilities. A stormwater utility would charge property owners fees based on how much stormwater their property contributes to municipal stormwater systems. These fees would then be used by the municipal utility to make upgrades, invest in infrastructure and maintain existing systems. Those fees could be reduced or eliminated when a property owner installs green infrastructure that reduces or eliminates runoff from their property. This does two really positive things. First, it gives municipalities the funding necessary to deal with our expanding stormwater problem. Second, it creates incentive for property owners to be proactive in installing green infrastructure and eliminating runoff from their own properties.

To find out more about our work on stormwater issues, or to volunteer with us, click here.