More than four years after the advent of Phase II of the National Pollutant Discharge Elimination System (NPDES), awareness of stormwater management has significantly increased, notes Brian Roberts, director of the Water Resources Learning Center in Fairfax, VA.
“Until recently, the focus was on some of the softer issues, such as public outreach and education and more erosion control,” Roberts says. “Now most of the permit programs are at the five-year point, and people are having to figure out what BMPs [best management practices] are appropriate for post-construction, how well they work, and how to pay for them, maintain them, and design them.
“Now’s the point where the rubber hits the road and they have to start building permanent BMPs. This is a critical phase. It’s also a wake-up call as to how much these really cost and how much space they take up on the site,” Roberts says.
The Water Resources Learning Center provides training, continuing education, and professional development in such areas as post-construction stormwater management measures, watershed planning and management, regulatory aspects, erosion and sediment control, hydrology, hydraulics, and computer modeling.
Some states—such as Virginia, Maryland, North Carolina, and Florida—have been engaged in assertive stormwater management planning for more than 20 years, Roberts notes.
“Conventional BMPs such as retention, detention, and infiltration have always been and will always will be around; they are the foundation,” Roberts says. “The hot issue right now is low-impact development [LID].”
Low-impact development has been defined as modifying development to maintain natural hydrological function—water is treated on the lot where it falls and is allowed to infiltrate back into the ground.
Often, traditional stormwater management methods are designed to quickly move water offsite to a centralized pond or local tributary, whereas LID keeps rainfall onsite to maintain hydrological function through such methods as rain gardens, green roofs, and porous pavements.
Stormwater management plans also take into account BMPs connected to the six minimum control measures outlined by the federal rule: public education/outreach, public participation/involvement, illicit discharge detection and elimination, construction-site runoff control, post-construction runoff control, and pollution prevention/good housekeeping for municipal operations. Post-construction BMPs are especially critical for long-term stormwater management.
Roberts says he teaches those who take his course to “look for opportunities on a site to do stormwater management, as opposed to forcing a solution. In the past, we would worry about stormwater or post-construction measures last or we’d grade the whole site and make it drain to a low point and squeeze in a pond.”
Now people are concentrating more on how to distribute BMPs, Roberts says. “How do you take advantage of the existing landscape for a better blended solution and take advantage of natural processes like vegetation and infiltration in soils?”
Retrofitting—incorporating stormwater management measures or BMPs into an existing site—is another hot area, Roberts notes. “Where there are intensely developed sites and a high percentage of impervious areas, it is more of a challenge to do those things,” he says. “There are still some opportunities, but in industrial sites and areas like that, you might be looking more toward filtration and things that don’t take up as much space.”
He says it’s not easy to design a site and implement BMPs so the post-construction hydrology is no worse than the predevelopment hydrology in that no more water and no more pollutants—and preferably less of both—are leaving the site than before.
“It’s difficult to mimic the predeveloped conditions,” he points out. “We can try to get it closer to that and in some cases you might actually be able to do it, but you are dealing with volumes of runoff, peak rates, and flow durations. Anything you do to a site is going to affect all of those. It’s extremely difficult to try to meet all three things. In many cases, you can get close to it, but you are dealing with quantitative and qualitative issues. The conventional approach is focused on releasing at predeveloped peaks for larger storms. We are finding that clearly doesn’t solve all the problems.”
There is no “silver bullet” type of BMP, Roberts notes.
“What might work well in one environment wouldn’t work well in another,” he says. “Green roofs are exciting, and I’ve seen obvious places where this is really a good idea, such as parking garages. I’ve also heard people say residential homes should have green roofs, but I don’t see that happening. The structural aspects have to be evaluated. It has to be leak-proof. But there are engineering solutions.”
Every region has its inherent challenges, he says. “In one way, there are some differences, but at the end of the day, it’s the rainfall runoff process,” Roberts says. “There’s more interaction today—people from all over the country are talking to each other.”
The goal for stormwater needs to be centered on developing better design criteria. “We’ve taken a loose approach on what to design for and the research we have needs to be better incorporated into the design methodologies,” he says.
One problem he notes is that most states have recently released a design manual or are working on one and once the manual comes out, it has a “shelf life” of about 10 years before it needs changes. “You’ve got to be really careful about what you put in that manual,” he says. “States are doing similar things and it tends to be driven more by looking at what surrounding states have done.”
Dealing With Many Variables in Georgia
Issues such as dwindling space, zoning, the impact of hurricanes, and the Endangered Species Act are of primary concern to the clients of Dave Briglio, a principal water resource engineer at MACTEC Engineering and Consulting. Based in the firm’s Atlanta, GA, office, Briglio is responsible for business development and supervising regional and state water resources projects for the company.
Georgia is in its fifth year of the NPDES Phase II permit.
“What’s happened after five years?” Briglio questions. “It depends on how aggressive the citizens of any community want to be. Some are putting funding into place and discussing it, which then enables them to do quite a bit more in terms of public involvement as well as the good housekeeping control measures in the spectrum of putting in BMPs.
“I believe the majority of the Georgia Stormwater Management Manual has in itself enabled them to adopt model ordinances and make sure we have good erosion/sediment control, which is in the state law, and use the manual to select and implement BMPs. That has helped a lot with the Metropolitan North Georgia Water Planning District having put together a plan that provided model ordinances for communities to adopt.”
MACTEC’s clients are trying to develop stormwater management for new development and redevelopment. “When it comes to new development, they get into a lot of coordination with state requirements, which could get into buffers and setbacks,” says Briglio. “They also get into zoning issues and how much room they have to put in these BMPs. For commercial, it could be the number of minimum parking spaces or building setbacks. It is much more sophisticated with having to put in more controls.”
Space is an issue of increasing concern. “They need to work with various other departments to figure out if one requirement—minimum number of parking spaces, for example—is good in this situation and see if some variances may be beneficial for all,” notes Briglio.
While the Georgia Stormwater Management Manual offers a lot of guidance on the pros and cons of BMPs, Briglio notes it’s geared toward new development that better accommodates the space and can meet requirements for the performance level of 80% total suspended solids (TSS) removal. The 80% removal requirement for BMPs has been adopted by a number of states and regulatory agencies.
“If you are redeveloping, more than likely that parcel didn’t have any water-quality components to it, so any improvement is just that—an improvement—but it may not be able to get 80% because the parcel is landlocked,” Briglio points out.
That calls for municipalities and developers to determine whether a project should proceed and also for a conversation between communities and regulatory groups, which may give the green light even without a total 80% TSS removal, “because it‘s better than it was before when it was an unused site with no controls in place,” he says.
“If they are not able to get the 80% removal rate, the developer is simply not going to change it,” Briglio says. “Not only do you have an ineffective parcel in terms of economics, but it’s still going to be contributing the same additional and likely polluted runoff it had before with no improvement. It takes a lot of interested parties to come together to figure out what is the best thing.”
One approach that’s gaining favor in Georgia is LID, because “more thought on the front end requires less cost in construction maintenance on the back end,” Briglio says. “That’s ideally what we want to do, but the reality sometimes comes into play that you’re just not able to do that.”
One of the discussions surrounding that issue centers on BMP effectiveness, Briglio says. One of the challenges in the metropolitan Atlanta area is trying to determine BMP requirements and to what extent they live up to vendor claims, he adds.
“We know they do their research and work at validating and backing up the performance they claim for their products,” Briglio says. “That’s a big issue as well, because as you get toward redevelopment, you are getting away from the types of BMPs we have the best research on, which would be more natural features, whether they be vegetated swales, filter strips, detention ponds, or others.”
Another issue is that proprietary BMPs such as an inlet device or vortex separator are being examined for space-limited sites, “which can be not too expensive for the installation but could be for the upkeep, and whose responsibility is that?” Briglio points out. “Yet that may be the only option based on space limitations.”
Another consideration in Atlanta-area development is taking into consideration the Endangered Species Act, thus involving more strict regulations in areas where habitat can be protected or restored.
The Etowah River Habitat Conservation Plan covers northwest Georgia’s Etowah River watershed. Two dozen groups and government entities are working together to develop a plan protecting Etowah’s water quality and conserve aquatic species. The amber darter and Etowah darter—both native aquatic species—are listed as endangered. The Cherokee darter is listed as a threatened species.
The goal of the plan is to ensure the least possible impact of development on water quality and aquatic habitat. Thus, the stormwater concerns not only involve runoff rate but runoff volume as well.
“It’s is more difficult than following the Georgia Stormwater Management Manual—holding that one-year event for longer periods of time and still allowing more volume runoff, maintaining or decreasing the peak,” Briglio says.
The conservation plan indicates there cannot be an increase in runoff volume, “which means that water has got to get into the ground, and in Georgia’s soils that’s a big challenge,” he says. “It is not going to be as easy as it may be in some lower parts of the state or in Florida, where you have infiltration as a much more viable countermeasure.”
Northern Georgia’s proximity to mountains means a variable topography, which is not conducive to water infiltrating the ground but rather running downhill and into the streams, Briglio points out.
In an effort to ease the process and avoid individual permitting for the Endangered Species Act, some communities have banded together to adopt their own development regulation that follows the best-known established guidelines.
In stormwater management, one must put into perspective the type of storms anticipated, Briglio says. “It’s one thing to keep the peak the same for the large and less frequent events, but know there is more runoff volume,” he says. “When you get to the smaller ones, you have to look at how you release the rates for the one- and two-year storm events over 24 hours and sometimes longer.
“The post-development peak can be lower than the predevelopment, but because of all that extra volume, we’re trying to avoid having it run at its previous peak so much longer and tearing up the banks.”
As MACTEC’s clients work to address the six minimum control measures of Phase II, not only are they considering funding and staffing in the implementation, but also their priorities shift, Briglio points out.
Case in point: Just as municipalities were digging in to their Phase II programs, the impact of a round of hurricanes pushed water quantity to the top of the priority list.
“We’ve got several communities where nonpoint-source pollution is important, but it had to take a backseat to culverts being washed out and the need for better floodplain mapping in the area,” he says. “In the metropolitan Atlanta area, there’s a requirement to do more extensive floodplain mapping for future conditions, which is another drain on resources. We have the issue of quantity versus quality, and in many cases quantity is more visible, more immediate and obvious in its impact to homeowners.”
Construction Requirements in Washington
The State of Washington has taken a unique approach to stormwater management through its Certified Erosion and Sediment Control Lead requirement, says Nathan Hardebeck with Clear Water Compliance Services in Auburn, WA. “A lot of NPDES construction permit holders now have to come up with a person on sites 1 acre or larger or hire a third party to do the construction’s inspection service on their behalf,” he says. That person is required to make sure the site stays under compliance and on some of the larger sites needs to take water-quality samples at discharge locations.
Another issue of concern to Clear Water Compliance Services’ clients is BMP use. The company does a lot of work on large-scale projects where there are high volumes of water having to move at significant flow rates off the system.
“When the conventional BMPs such as silt fence and straw wattles cannot meet water-quality standards because the receiving water has a certain TMDL [total maximum daily load], or just based on not being able to get turbidities down, we offer them construction-site water treatment, mostly using chitosan-enhanced sand filtration,” Hardebeck says.
Phase II regulations have increased stormwater awareness in Washington, and while the state’s Department of Ecology sent out letters to municipalities in an effort to get everyone on board, a lack of funding stymied the follow-through process, Hardebeck notes.
“The Department of Ecology did get some funding and is starting to build an inspection and enforcement team,” he says. “Phase II municipalities are also creating stormwater divisions that are inspecting and monitoring construction and industrial sites, shutting down projects not in compliance.”
There also are more third-party lawsuits brought against developers and industry not in compliance with their permits by people “who are starting to run out of what they consider their patience level in terms of enforcement, so they are taking matters into their own hands and suing based on the Clean Water Act,” says Hardebeck.
He sees a push for LID “as well as other more efficient, more environmental ways of rebuilding” in redevelopment projects, but he doesn’t see redevelopment projects get as scrutinized for NPDES requirements as new construction.
Like many municipalities, the clients of Clear Water Compliance Services do not necessarily have the staff or funding to implement all of the six minimum control measures in-house, so with measures such as public education, they are outsourcing the work.
New Strategies in Florida and Texas
Meanwhile, in Florida, consulting firms also are noting increased compliance enforcement.
“Contractors are catching up on that,” says Mike Howe, a senior ecologist for Boyle Engineering’s Orlando, FL, location. “There’s a lot of training for erosion and sediment control being done around the state by the state agencies, so the contractors are being educated more to that process.”
With municipalities jointly initiating programs in NPDES Phase II and TMDLs, “a lot of our clients are either starting to plan their stormwater activities better through a master plan or are looking at outdated or older master plans and wanting to update them,” says Sue Woodbery, senior engineer for Boyle. “Not only is the component looking at flooding, but it’s also looking at water quality. A lot of our BMP activities are driven by water-quality issues today.”
Howe says “clients tend to want design engineers to prepare the stormwater pollution prevention plan these days, so more of that is incorporated into the design, especially in regards to post-construction—it’s usually a lot more in the design phase than contractors coming on board and signing on to a stormwater pollution prevention plan that is already in place. Designs may be modified. That’s been the biggest shift.”
Woodbery says through a Basin Management Action Plan that is TMDL-driven, her company notes a large push from the state’s water management districts to go to LID.
“The developers are getting on board with individual ponds at homes or going back to the large swales,” she says. “There’s a big push for parking lots with impervious pavement. A lot of new vendors are showing us their products, and we’re starting to consider using them for a reduction of stormwater runoff for after development. It doesn’t necessarily have to do with anything during the construction side, like NPDES requires with the SWPPP.”
As more university research is done on existing and emerging BMPs, “you are getting regulatory agencies to buy into the fact that the impervious pavement will reduce stormwater runoff,” says Woodbery. “Before, we weren’t getting credit for it and it was a more expensive technology, so why would your municipality use it if it requires more maintenance and you don’t get credit for it?
“They want credit for it so they can reduce the size of land they have to have for a stormwater pond, for the additional control that the impervious pavement may or may not handle for you.”
Michael Bloom agrees with those from other consulting firms that there’s been an increased emphasis on water quality as NPDES Phase II progresses. He also points out that Phase II has brought a new group of municipal and transportation department entities to the table that had not previously been regulated, so it’s becoming a learning process for them. Bloom is a senior engineer and a stormwater expert for the Houston, TX, office of PBS&J.
As communities go through cycles of dealing with flooding issues, municipal officials and residents are becoming more aware of water quality and quantity, he points out. “But there are some folks who think of Phase II regulations as being just a federal mandate they have to do and don’t really see it as an opportunity to do more with quality of life or recreational facilities,” he adds.
Individual property rights are highly valued in some parts of Texas as in other parts of the country, “so some communities—not all by any means—are more reluctant to regulate land development,” Bloom says. “But there are other communities like Portland that have been very assertive in regulating land development. It depends on the politics of the location.”
Most of PBS&J’s Texas clients are municipalities that regulate development, and while there is a lot of interest in LID—for example, in the Houston metropolitan area—“there is a lot of concern about whether it would work in our location because we are very flat and have clay soil, low permeable soils, and a lot of rain.”
There is a typical list of BMPs being selected for development, he adds. “Generally speaking, for post-construction, municipalities will have an action item in their five-year plan to develop some sort of ordinance that would require either structural or non-structural controls.
“There are a lot of Texas locations that are not necessarily going to commit themselves to structural controls,” he adds. “For illicit discharge, there’s generally an ordinance to prohibit those discharges and plan to use visual and odor observations to identify those illicit discharges. Generally, Phase II cities are not going to commit to a rigorous amount of field sampling where they get water chemistry results. They might rely on water chemistry results for any kind of enforcement proceeding, but just to identify any particular concerns, they’ll just use their eyes and their nose.”
In guiding its clients to effective non-proprietary BMPs, PBS&J leads them to sources such as the International Stormwater Best Management Practices database (www.bmpdatabase.org). For proprietary BMP information, PBS&J relies on the USEPA’s Environmental Technology Verification program (www.epa.gov/etv/).
From Planning to Implementation
Mark McCabe, the Cleveland, OH–based stormwater program manager for URS in San Francisco, CA, says his company’s clients are requesting assistance in moving from the planning to the implementation part of NPDES Phase II.
“Their knowledge tends to be somewhat limited,” he says. “They’ve got a general knowledge of the hydraulics dealing with stormwater conveyance system designs, but the overall management tends to be limited since this is new to a lot of folks.”
How to align municipal separate storm sewer system permits with construction permits is another issue with which URS clients wrestle, McCabe says. “In certain states, the requirements tend to be different. They tend to collide from time to time in terms of what their outputs are and what they are allowed to do under certain permits and conditions.”
As for the six minimum control measures, most municipalities tend to have a handle on public education outreach, construction-site runoff in terms of sediment and erosion control, and pollution prevention in documenting procedures, McCabe says.
“The inventory component of the illicit discharge is fairly straightforward and tends to be driven by a budget issue,” he says. “Moving from the actual inventory to developing an illicit discharge program tends to give them a little bit of a concern, because that could entail a large effort to identify, trace, and remove illicits as well as understanding how that program ties into the TMDL requirement.”
Clients are also struggling with the post-construction measure in terms of site criteria, where to place a BMP, and who’s responsible for maintaining it, McCabe says.
LID tends to be a coastal issue that midwestern states are just beginning to consider, he believes. “Like anything new, it’s going to take awhile before it actually takes hold and becomes institutionalized. I think the green initiatives and green infrastructure programs some of the cities have in place probably will expedite LID, but I think it’s a fear of the unknown—they just don’t know what’s all involved and what it means.”
Looking ahead as NPDES Phase II unfolds, the United States is now at the point where Phase II is on the books, but every so often, a weather event or other factors serve as a reminder that there are other issues that demand attention as well, Briglio points out.
“There’s the struggle where the rain cycle reminds us every so many years that it’s not just water quality,” he says. “Sometimes the dollars do have to go to replacing undersized pipes.
“That’s the real struggle because regulators don’t come down on the local entities to see how they are doing in replacing pipes. They come down to see how they are doing as far as the six control measures.”