County stormwater shift to promote more ‘green'

Friday, Feb. 5, 2010

The preservation of Charles County's natural landscape and the promotion of conservation-friendly drainage systems is the way Charles County development will be headed in the coming months.

In other words: Less gray and more green.

Prompted by shifting state requirements and temporarily aided by federal dollars, the county will be making some adjustments of its own to the local stormwater management ordinance.

Residential, commercial and industrial developers alike will be obliged to design systems that promote the natural landscape and discourage any plans or materials that would create a negative impact on the land and water resources that is more than necessary.

The proposed changes at the county level are the result of the adoption of the Maryland Stormwater Management Act of 2007.

Amendments will go into effect May 4, which means that any project that does not have stormwater management and erosion and sediment control plan approval on or before that date will not be grandfathered through the process and will have to meet the new standards, county officials said.

"The act requires that all projects' designed stormwater management [water quality] portions use an environmental site design technique to the maximum extent practicable," said Robert Harrington, a stormwater management engineer for the county, during the Jan. 26 county commissioners' meeting.

"Environmental site design has the goal to treat stormwater runoff closer to the source; as close to where rainfall falls and runoff occurs," said Michael Clar, a project consultant from Ecosite who's worked on the management ordinance environmental site design manual. "Our traditional stormwater management strategies have often combined centralized structural practices for pollutant removal with channel erosion or flood controlling poundments. These designs are less able to mimic predevelopment conditions because they focus on managing large volumes of polluted storm water rather than treating runoff closer to the source."

The county's Director of Planning and Growth Management Chuck Beall explained to the county commissioners that all local jurisdictions were provided with a model of the state ordinance which Charles County mostly copied for its own plan but made some adjustments for "local uniqueness."

Harrington explained that that included quantity requirements which are handled at the county level and are already included in the current ordinance.

"We'll see a lot more porous pavement … a lot more landscaping as [developers] integrate storm water management as part of their design, which is now required," Harrington said. "It doesn't mean you won't see a pond because these [projects] also produce quantity discharge. There might be some quantity [ponds]. These environmental site design practices should even minimize the size of those because what they're doing is taking more water and infiltrating into the ground. There's still going to be ponds but it's going to be a lot more soft practices."

Charles County commissioners' President F. Wayne Cooper (D) had concerns about the impact on residential and commercial developers and whether there would be an effect on the wallet of the county government once the grant from the National Fish and Wildlife Foundation was finished.

The $63,000 grant which was won with the partnership of the county and the towns of La Plata and Indian Head, will go toward implementation of low-impact development — environmental site design —Karen Wiggen, a county planner, said.

It will terminate in April, which is close to the deadline for plan approval before ordinance changes take effect.

"ESD is the same thing as low-impact development. It includes the optimizing conservation of natural features … and minimizing the use of impervious surfaces," Harrington said.

Beall said he did not think there'd be an additional cost to the county, as the review fees are paid by the applicant.

"… [W]hat we're doing is just changing the means and methods in which stormwater management has to be provided," Beall said. "I don't envision that the cost of the review in the long run is going to ultimately be more onerous than it presently is. There's always a learning curve on both sides of the table any time you change any regulations, but I don't envision a fiscal impact."

Clar explained to the board that some EPA studies have shown that money can be saved when a developer makes an effort to take the surrounding environment of his project into consideration.

"… [I]n general, applying environmental site designs [is] reducing costs on a subdivision-by-subdivision basis," Clar said. "In the past your landscaping was often just landscaping, but in the future landscaping that's required by subdivision regulations becomes a part of the stormwater system."

The planners and consultant outlined for the commissioners what site design practices would be seen around the county and how the three-step approval process will work.

The approval process, Beall said, is the result of careful review and corresponding feedback from the planning and growth management advisory board and the Maryland-National Capital Building Industry Association. The latter is comprised of 15 different categories of representatives including members of the engineering community, surveyors, developers, attorney representatives and homeowners' association members.

"… Initially a planner will come in with a concept plan which we have to review and approve before they move on to step number two," Harrington said. "Step number two, which is a more detailed plan and includes calculations, is the site development plan. After that is reviewed and approved then a developer may go ahead and submit their final stormwater management plan which would be our normal planning process at that point."

The environmental site design techniques can be broken down into three categories: Alternative surfaces, nonstructural practices and micro-scale practices. What will be used for a project will be done case by case, Clar said, which will be similar to picking the most appropriate choice from a menu of items.

Alternative surfaces include such things as green roofs and permeable surfaces, the latter of which is already in use throughout Southern Maryland.

A green roof is a roof that is predominantly covered in grass or other plants. Along with providing a natural habitat often in an unlikely urban setting, green roofs provide a productive way to absorb rainwater. The National Aquarium and Maryland Department of the Environment building in Baltimore both use green roofs.

Permeable surfaces allow rainwater to move around and through the material it's made with, which helps cut back on erosion and runoff and promotes water seepage back into soil. The La Plata Starbucks uses porous asphalt.

Nonstructural practices cover the options of disconnected rooftop runoff and nonrooftop runoff.

Clar explained that these types of runoff allow water "the chance to get back into the ground rather than just entering a storm drain and overtaxing the storm drain system."

Micro-scale practices run the gamut from swales, rain gardens and rain barrels, to dry wells and submerged gravel wetlands, according to the presentation.

Clar told the board that microbioretention practices — part of the third site design category — will be some of the most commonly seen techniques around Charles County because they are so versatile and adaptable to the surrounding landscape of a proposed project.

"Microbioretention practices capture and treat runoff from discrete impervious areas by passing it through a filter-bed mixture of sand soil and organic matter," Clar explained. "The filtered stormwater is returned to the conveying system or partially infiltrated into the soil."

Commissioner Gary V. Hodge (D) asked the county staffers about the discussions going on in Annapolis about whether there are any limits the new stormwater management changes could have on smart growth and redevelopment in existing urban areas.

While Beall said that every regulatory requirement at some point adds a degree of difficulty to promoting smart growth, Clar told the commissioner that while there's a balance that needs to be kept when attempting to look for higher density in urban corridors and at the same time restoring impaired watersheds, redevelopment offers "one of the best opportunities to address stormwater issues from the past," and also avoids an expensive retrofit loan that will come out of tax funds.

"It may provide some incentive for a local government to partner with developers to see how much of the stormwater requirements they can provide or perhaps make some incentive to work with them," Clar said.

As far as any legislation that could come down for the stormwater management ordinance, Clar said there's a good chance of seeing something about pushing back the May 4 deadline and making the requirements for grandfathering in a development proposal more flexible.

Following the public hearing, work sessions and adoption process, there will be a Feb. 19 seminar held at the College of Southern Maryland for engineer and inspector training, Beall said, which will cover the generic topic of low-impact design rather than specific regulations, but will stay in step with the state's stormwater management ordinance of 2007.

msomers@somdnews.com