projects

Low Impact Development (LID) Design Manual Development

South Burlington, Vermont

Client: City of South Burlington, Vermont

Services

  • Consultation
  • Manual Development

Project Summary

The City of South Burlington faces a number of challenges relating to surface water quality. Approximately 65% of the land area in the City drains to one of five streams that the Vermont Agency of Natural Resources (ANR) lists as impaired primarily due to uncontrolled stormwater runoff. The ANR is preparing first in the nation stormwater Total Maximum Daily Loads (TMDLs) that will require the construction of stormwater treatment practices to achieve aggressive flow reduction targets in these impaired watersheds. The ANR recognizes that in some cases the stream flow reduction goals set in the stormwater TMDLs will not be achieved through installation of traditional stormwater treatment practices (e.g. detention ponds) alone. Additional intervention will be necessary to reduce the amount of runoff that is eroding stream banks and causing impairment.

In 2009, the City responded to these challenges by creating a Stormwater Management Overlay (SMO) district within the City’s Land Development Regulations. Within the SMO district, all projects resulting in a sufficient amount of land disturbance or impervious area are required to implement Low Impact Development (LID) techniques. LID practices are a set of site development techniques designed to reduce the amount of stormwater runoff and associated pollutants leaving a site. LID practices reduce the impact that development has on natural water resources by mimicking existing drainage patterns and retaining stormwater runoff onsite, commonly allowing for infiltration of precipitation into the soil. It is the City’s expectation that implementation of LID techniques, in conjunction with construction of large scale stormwater treatment projects, will help the municipality meet the requirements of the new TMDLs and result in healthier streams.

As part of this effort, Hoyle, Tanner worked with the City on the modifications to the Land Development Regulations and developed a LID Guidance Manual as a resource for applicants(homeowners, business owners, developers, and designers) within the SMO district. Since the development of the manual, multiple project sites located outside of the SMO district have voluntarily implemented LID practices utilizing the design guidance.

City staff and Hoyle, Tanner staff prepared a paper on this topic and presented their findings at a national stormwater conference in August 2009.

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