A city advisory group is in the process of reviewing the city’s stormwater management policies and hopes to encourage more developers to include Low Impact Development features.
The term Low Impact Development, or LID, can be applied to many different aspects of planning and development, but in this case it is being used to describe practices relating to managing stormwater runoff and how that water affects Raleigh’s streams and creeks.
While the city already has policies in place regulating stormwater, Stormwater Management Advisory Commission Chair Kevin Boyer said these regulations don’t go far enough to protect the city’s degrading streams and lakes from sediment, pollution and erosion.
While not all of Raleigh’s streams and creeks flow into our drinking water supply, ultimately, those streams and creeks flow into someone’s supply downstream. The Neuse River, for example, supplies water for downstream communities such as Goldsboro.
Likewise, Durham’s stormwater ends up coming out of Raleigh’s faucets.
Boyer explained that healthy streams are also important to the general food and life cycle.
Ben Brown, the city’s stormwater development supervisor, said with the current stormwater management system, stormwater runoff in, say a residential subdivision, is funneled to and treated by a central stormwater device, like a wet pond, and then released into creeks and streams.
Homeowners Associations are responsible for the maintenance of those devices and send the city an annual report confirming that the maintenance has been done.
An exception to this would be subdivisions that are located in more forested parts of the city that have large lots, which “counteract the impervious surfaces,” Brown said.
Part of the city’s hesitation on implementing LID practices is putting the maintenance responsibility on individual homeowners.
“We’re a little squirrely about having all of these individual homeowners in charge of all this maintenance,” Brown said.
It would be similar to homeowners who have cesspools in their backyard who are responsible for its care and upkeep.
On the roadways, stormwater is funneled into drains, which lead directly to the nearest creek or stream.
Boyer said LID would treat the stormwater as close as it could to where it hits the ground.
“[LID] treats [rainwater] on site using features that, as much as site design can allow, mimic the way nature would handle the rainfall if it were an undeveloped site,” he said.
While it sounds fancy and complicated, it’s actually quite simple. Stormwater would be soaked up by the ground, grass and plants and filtered and cleaned by the earth.
The key to LID is lessening the impervious surfaces on a site. Impervious surfaces are anything that water can’t filter through, such as a house, driveway or street. Using special concrete or pervious pavers to create streets and driveways that allow the water to be filtered naturally would decrease the amount of water, and subsequent pollutants, ending up in Raleigh’s streams.
Instead of the curb-and-gutter system the city uses now, Boyer said he would recommend grassed swales that would slow the rainwater and filter out the sediments and pollutants as it headed toward the street.
Another option would be to intentionally route water into landscaped bumpouts, which the city already uses as a traffic calming method.
Boyer said it would be virtually impossible to change Raleigh’s regulations to require LID practices in the near future, but he hopes the city would allow for some incentives that would entice developers to include LID in their plans.
Incentives could include an expedited permit process and reduced permit fees. Or, trade offs. Developers who include some LID features would be allowed to have fewer parking spaces than policy dictates.
While LID has been on the commission’s work plan for the past couple of years, the group is just tackling it now.
When asked why the group is finally looking at it now, Boyer said that in a volunteer commission it takes or someone who is willing to move it forward. He added that he believes the commission now has the right mix of people that want to see the work get done.
The group will spend the next year reviewing LID practices and what has been successful in other cities that have strong LID regulations, such as Portland, Ore.
The commission will also be meeting with stakeholders to find out what keeps developers from already implementing these practices and what it would take to get them to do it.
How the UDO Comes Into Play
As the Unified Development Ordinance, the rewrite of Raleigh’s zoning code, slowly makes its way through the review process, Boyer said it is unlikely that the commission’s recommendations will be ready by the time it is adopted. While the commission isn’t completely absent from the UDO conversation, it won’t make any recommendations until its report is complete.
“Had the commission gotten a start on this two years ago, perhaps we’d be in a position to offer real firm detailed recommendations for council to consider in the draft UDO they’re working on now,” Boyer said.
While some of the new specifications in the UDO seem to be inconsistent with LID practices, Boyer said that the two can work together.
He said the UDO requires larger sidewalks, which would increase the amount of impervious surface on Raleigh’s streets. But, developers could be given the option to use permeable materials, planters and other LID methods that would also meet the new UDO requirements.
“So they’re still walkable, but the stormwater doesn’t run off, at least not 100 percent,” Boyer said. “Some of it soaks into the ground.”
City planner Travis Crane said until the commission releases its recommendations, it’s hard to say how they will affect the UDO. But, he said planning staff believe that LID issues need further attention and evaluation.
After the UDO is adopted, any new standards would be included through a text change process, just as it is done now with the current code.