Shaping Our Future - Stormwater Regulations Review
How to Engage with this ProjectWant to share your thoughts? Check out the survey in the middle of this webpage.Information about past and future public meetings is at the bottom of this webpage.Project...
How to Engage with this ProjectWant to share your thoughts? Check out the survey in the middle of this webpage.Information about past and future public meetings is at the bottom of this webpage.Project Background
The Town of Chapel Hill is reviewing the current post-construction stormwater management regulations in response to a petition from several Council members. As part of this review, the project consultant, SRF Consulting Group and Orion Planning & Design, will
lead the Town through a process to identify updates to the current stormwater regulations within the Land Use Management Ordinance (LUMO), which will include internal and external stakeholder engagement, andwrite recommendations for possible updates to the current stormwater management regulations.What is Stormwater?
Water from rain or snow that does not soak into the ground is called stormwater runoff. In undeveloped landscapes, rain falls into bodies of water or gets soaked up into the ground. When water flows over hard surfaces like driveways, rooftops, and roads into the storm drains, it makes its way through the environment untreated.
Storm drains are not connected to the sanitary sewer system and they drain to our creeks, drinking water supplies, and Jordan Lake. When our creeks and storm drains cannot handle high volumes of runoff from storms, we face flooding issues.
What are Post-Construction Stormwater Requirements?
Post-construction stormwater management in areas undergoing new development or redevelopment is necessary because runoff from these areas has been shown to significantly affect local waterways.
New developments are generally required to temporarily store and treat excess runoff by installing stormwater control measures (SCM’s). Have you ever seen a pond in a new neighborhood or behind a shopping center? Then you have seen stormwater control measures.
Engineers design stormwater control measures based on the amount of hard (impervious) surface and average rainfall amounts for common storms. Under the Town’s current requirements, the rate of stormwater runoff cannot exceed predevelopment conditions for that site for the 1-, 2-, and 25-year storms within a 24-hour period.
So how much rain are we talking about? In Chapel Hill, these storms bring approximately 2.78 to 6.53 inches of rain in 24-hours, depending on the type of storm and how saturated the soils are when it arrives.
Stormwater Regulations for a Complete Community
The Chapel Hill Town Council initiated a Complete Community Strategy to identify shared interests around a new approach that clarifies where and how to build to be an inclusive, sustainable, and an economically competitive community. Updating the current stormwater regulations helps operationalize the Complete Community Strategy.
In a June 2021 petition, several members of Council requested that “areas of review would include, but not be limited to, assessing whether:
“The storm events addressed by the regulations are still appropriate“The rainfall timeframes are adequate“The methods for stormwater management that are approved (BMP’s, etc.) are state of the art and include green stormwater infrastructure and low-impact design“Amounts of impervious surface permitted are appropriate for various development types, ground conditions, downstream issues, and topography“Watershed and sub-watershed plans include an appropriate range of evaluation criteria including natural flood protection and habitat preservation as well as engineering criteria."
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