From Runoff to Renewal: How Low-Impact Development Can Reduce Stormwater Runoff and Protect Water Quality

From Runoff to Renewal: How Low-Impact Development Can Reduce Stormwater Runoff and Protect Water Quality

What is stormwater?
The water that flows down rooftops, sidewalks, parking lots and streets after rains and during spring runoff.

Where is stormwater a problem?
When rain and snow fall to the ground in undeveloped, vegetated areas, the water percolates through the soil and is taken up by plants. What isn’t used by the plants saturates the soil; this is the natural system that eventually helps recharge our groundwater supplies. However, in areas where we have covered the ground with buildings and parking lots and removed plants, stormwater cannot enter the soil and therefore has to “runoff” into a storm drain or nearby water body.

Rain is natural, why does stormwater cause concern?
As it flows across human-made surfaces, water gathers everything from sediment to pesticides and toxic chemicals and mainlines them into our waterways. In some areas, this runoff also overwhelms outdated sewage infrastructure, spilling raw or partially-treated sewage into waterways and the Great Lakes.

What can we do to protect our lakes, rivers, wetlands and groundwater from stormwater contamination, combined sewer overflows and erosion?
Fortunately, there are easy and affordable solutions communities and individuals can use to reduce runoff from development. Low-impact development (LID), one set of techniques, is at heart a strategy to make the built environment function like the natural environment. It involves low-cost practices as well as site planning and design to take into account on-site, natural features, to maintain an area’s predevelopment hydrology.

Some examples of LID practices include:

  • Vegetated roofs,
  • Permeable paving,
  • Rain gardens,
  • Rain barrels, and
  • Soil amendments.

 

LID also involves site planning and design, such as:

  • Preserving natural vegetation,
  • Clustering development & preserving open space, and
  • Designing buildings and roads to minimize impervious surface cover.

 

How is Low-Impact Development different from traditional development?
While traditional development treats stormwater as a waste product, creating more runoff by removing native vegetation, and covering the natural landscape with concrete, asphalt and buildings that make the ground less able to absorb water and filter pollution, LID utilizes this water as a resource.

What tools can local communities utilize to turn their stormwater into a resource? Master plans, zoning ordinances or bylaws, and stormwater ordinances can explicitly endorse and encourage practices such as LID techniques that residents and local leaders find desirable, while revising older parts of ordinances that inhibit effective stormwater management.

The key features of any LID stormwater ordinance should include:

  • A standard of no net runoff from new development,
  • Flexibility for developers to use a wide range of non-structural LID practices to achieve the standard, and
  • Revision of outdated requirements that interfere with LID, such as requirements for excessively wide streets, large setbacks or traditional stormwater infrastructure.

 

Are stormwater issues isolated to particular areas?
Polluted stormwater is a significant and growing problem throughout the Great Lakes Basin. However, numerous opportunities exist within the developed landscape to control stormwater flows close to the source. Reducing stormwater runoff is simpler and cheaper than building expensive stormwater infrastructure, and more effective at protecting our waterways and the Great Lakes.

Where can resources and information be found?
One resource for groups and individuals looking to promote LID in their community is the Public Interest Research Group in Michigan’s (PIRGIM) website, www.pirgim.org, where you can find the report,Waterways at Risk, as well as an LID fact sheet, model ordinance and media toolkit. GLAHNF will also be developing additional stormwater tools this summer.

For more stormwater related resources, see pages 12 and 13 of this newsletter.

For more information:
Abby Rubley, Great Lakes Advocate
Environment Michigan
103 E. Liberty St., Ste. 202, Ann Arbor, MI 48104
Ph: (734) 662-9124 • E-mail: arubley@pirgim.org

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Images courtesy of Steven Huyser-Honig,
West Grand Boulevard Collaborative, & Yellow Dog Watershed Preserve.