Brookhaven, GA, March 4, 2016 – by Trey Benton – In response to the city’s and public concern regarding stormwater run-off that is coming from infill single family residential development, Brookhaven’s City Engineer and Public Works Director, Bennett White, gave a presentation recently proposing revisions to the city’s stormwater management ordinance. The aim is to make the ordinance apply to more infill housing construction projects than the ordinance does presently.
This is particularly significant in certain neighborhoods such as Brookhaven Fields, a community that has experienced numerous issues resulting from run-off including wash-outs, flooding and insufficient mitigation. With the amount of infill development that has taken place over the last few years, the amount of surface area providing an absorption effect has also been significantly reduced.
According to White, the current ordinance applies to development activities that involve the creation or replacement of at least 5,000 square feet of impervious surface. The contemplated revision, would lower the impervious surface threshold down to 3,000 square feet.
White gave 3 primary reasons why 3,000 square feet is being recommended as the new threshold:
- The vast majority of the infill new home applications that come in propose less than 5,000 square feet of impervious surface
- The vast majority of new home applications that come in now are at or above a 3,000 square foot threshold of impervious surface
- Home additions and smaller projects fall under 3,000 square feet of impervious surface, so the smaller projects around the city would not be negatively impacted by a lowering of the threshold
White explained the State requires all communities in the metro-area to adopt stormwater management ordinances, that are at least as strict as a “model ordinance”. Its threshold is set at 5,000 square feet – where Brookhaven’s ordinance is at currently. The model ordinance also exempts single-family construction that is not part of a new subdivision, for example. Brookhaven does not exempt those single-family homes, making the city’s current ordinance a bit stronger, although with the problems occurring citywide, it’s being found to not be strong enough.
When the City of Brookhaven incorporated, the city adopted generally the same ordinance DeKalb had in place for stormwater management applicability. Where the difference lies, is how Brookhaven interprets some of the language in the ordinance.
“There is a paragraph, a section, that says Community Development can require stormwater management if there is a known drainage issue or flooding issue downstream of the project,” White told the Council. “My inference is that DeKalb County said that we’re just going to require it everywhere on that basis. Our judgement was that was perhaps more arbitrary, than what we should be doing…if we do know of an issue…then we could impose that. We chose not to do that uniformly.”
White says choosing to lower the threshold to 3,000 square feet of impervious surface, would catch nearly all of the new homes being constructed around the city, and thus require them to make allowances for stormwater management. He said the types of homes going up in Brookhaven almost invariably involves around 3,000 square feet of impervious.
The most common technique to address stormwater management in single family construction, according to White, is the installation of a dry well, and the size of the well is calculated to handle a certain amount of run-off created by the impervious surfaces on a particular project. What that does is provide a place for the run-off to collect, and allows for gradual dispersion into the surrounding soil.
Other ways to address the run-off include infiltration trenches, bio-retention rain gardens and water capture systems that can later be used for irrigation.
White says that his team will prepare a draft stormwater management ordinance incorporating the proposed changes for Council to discuss at an upcoming Council work session. The Post is told that discussion may take place during a work session in the latter part of March.