Low-impact-development stormwater management approaches are gaining in popularity and are being increasingly written into permitting requirements. While a number of barriers to implementation continue to come into play, advocates are finding more solutions to those obstacles, according to experts across the country.
“We cannot just trumpet the wonderful qualities of LID without also hearing about the barriers, understanding them, and trying to address them,” observes Bruce Wulkan, senior policy advisor of the Puget Sound Partnership. “That’s what we’ve tried to do for years.”
The Puget Sound Partnership, a state agency created in 2007 to mobilize public and private resources to restore and protect the 1.6-million-acre body of water and its 2,500 miles of shoreline, defines the process and goal of low-impact development as “developing land and managing stormwater to imitate the natural hydrology (or movement of water) of the site.” Among its benefits, according to the Partnership’s website, are helping to reduce flooding and protecting property, helping to protect human health by more effectively removing pollutants from stormwater, protecting drinking water supplies by ensuring rainwater infiltrates where it can recharge aquifers, providing cost-effective alternatives to system upgrades, and even increasing public safety. (“One of the hallmarks of LID is more narrow streets. Studies show that when vehicle traffic is slowed, there are fewer pedestrian accidents and fatalities.”)
“It’s something that everyone needs to be fluent with at this point in order to meet basic requirements with stormwater permits,” explains Amie Broadsword, LEED AP, a civil engineer and project manager with Kirkland, WA-based PACE Engineers.
Broadsword, Wulkan, and others divide barriers into nine categories:
* Local code limitations
* Preconceived notions
* Perceived and real costs
* Soil and meteorological conditions
* Risk and liability
* A lack of federal investment in research
* Mounting demands and diminished resources at the local level
* Multi-departmental interaction
Even within her own professional circle, Broadsword acknowledges, she encounters a “spectrum of perspectives from colleagues as to how far to implement LID approaches.”
Permeable pavers in a parking lot
Looking at the Big Picture
Neil Weinstein, executive director of the Low Impact Development Center in Beltsville, MD, explains that LID approaches began to emerge in the 1990s as a response to the shortcomings of traditional grey infrastructure. Its implementation is being fueled by the growing green movement and government mandates.
“What’s happening is people understand the way we’ve built infrastructure and maintain it is draconian. A lot of stormwater approaches are not very well thought out. They’re just meeting regulatory standards, but that’s it. The proof of that is you have some estuary programs that have been in place for many years and you still see degradation, so we really need to be rethinking approaches,” says Weinstein. “We have to ask, “˜What’s the best outcome and economic performance you can get out of a system?’ That’s what we really focus on–how to create that system.”
Weinstein says the application of environmental technology calls for an evolution that requires looking beyond traditional methods. “Rather than just saying, “˜Build a pond,’ you say, “˜Here’s a pollution problem; here’s the hydrology we’re trying to create,’ and you go from there. So, we’re getting people to say two widgets may meet the standard, but it might not be the best thing. We might not know all the answers, but we want to move to a performance-based process. It’s not “˜grey’ all the time or “˜green’ all the time. There are hybrid approaches,” he explains.
Broadsword began working with LID techniques after a 2002 British Columbia Water and Waste Association Conference on LID “really opened my eyes.” She was a presenter at the 2010 ASCE International Conference on LID.
Wulkan notes that because low-impact development remains a relatively new way to develop land and manage stormwater, “you have to go into the local codes, regulations, and standards and change them so a developer doesn’t have to go back and request a waiver.”
As a result, the Puget Sound Partnership teamed with AHBL, an engineering and community planning firm with offices in four Washington cities, to initiate the LID Local Assistance Project in 2005. The Partnership and AHBL staff reviewed municipal ordinances for barriers to LID implementation and developed new and revised code language for 36 local governments around Puget Sound during 2005 to 2009. “Removing barriers in the local code is a huge step forward,” says Wulkan. “It’s a necessary place to start.”
Wulkan advises communities interested in encouraging or requiring LID to review the Partnership’s 2012 guidebook on changing applicable code language, and then either use internal staff or a consultant to update municipal codes.
Broadsword and Wulkan agree that municipalities in western Washington have benefited from state funding that made code updates possible. Lawmakers have also appropriated funds for competitive grants for LID retrofits, hastening an understanding and implementation of such facilities.
Broadsword adds that numerous jurisdictions have more stringent LID guidelines than currently required by the Washington Department of Ecology, which enforces the federal Clean Water Act in the state. The result is that engineers and planners who work with those communities are “getting fluent with LID techniques ahead of state-mandated compliance.”
Danny Bowden, who began as a stormwater engineer for the City of Raleigh, NC, in the 1980s and now manages a utility that serves 405,000 people over 180 square miles, adds, “The EPA is pushing low-impact development. My take is we need to get ready with some sort of LID program, because somewhere down the road it’s probably going to be required. It already is for some cities with consent decrees.”
No Slam Dunk
Broadsword cites the Brickyard Park and Ride, a 200-space expansion of an existing parking lot in unincorporated King County, as an example of overcoming obstacles to implementation of LID techniques even in a jurisdiction with numerous LID facilities.
“There are still, certainly, code barriers. I needed to get a variance for that project,” recalls Broadsword. “It wasn’t a slam dunk per the local governing jurisdiction.”
The parking surface featured pervious asphalt with distributed detention storage in a shallow underground arch pipe system and a biofiltration swale for water-quality treatment.
“There were interesting lessons to be learned with the contractor on that hybridized stormwater system. I don’t believe the contractor had worked with the arch pipe storm system before. They loved it and said how easy it was. The contractors said, “˜If we’d known how easy it was, we would’ve bid cheaper.'”
The asphalt crew might not have shared those sentiments because of the extra energy expended working with the sticky consistency of the pervious material during installation. The crew also had to protect the subgrade from excessive compaction. “That’s true on all projects where you’re trying to get the water back into the ground. It adds an extra level of caution that the contractor has to use to make sure the site is treated properly, so that’s a little extra work for them and it has to be spec’d out, so it also requires an extra level of detail from the design team to make sure it’s done right,” she adds.
Broadsword says the project was a case in point to counter one of the largest barriers to LID: persistent concerns about perceived and real costs. “I see it on the owner side and even on the design side. Some engineers who have not gotten onboard will say, “˜Oh, that’s going to cost too much,'” she notes.
While the pervious asphalt and washed, crushed base were more expensive than traditional materials, the LID system eliminated the need for a giant underground vault, associated earthwork, catch basins, and some piping. The result: an $88,000 (3.8%) savings in the construction budget.
The answer to cost objections, Wulkan finds, is to maintain a list of current studies that document price comparisons. “It’s very important to have documented evidence at your fingers to say, “˜This is really cost effective.’ I never say it’s always going to be cheaper, but it’s important to have accurate information,” he explains.
The perception that LID approaches won’t work in some soils, like Washington’s glacial till, continues to be a barrier to implementation. “I point to different projects around western Washington that have put in rain gardens and pervious pavement on very tight soil,” says Wulkan. “Guess what? Designed and correctly, it still works.”
Nevertheless, Wulkan and Broadsword acknowledge that soil conditions, slopes, and elevations do create barriers to implementation, especially in the Pacific Northwest where heavy rains fall during the cold season. Those cooler temperatures and saturated soil conditions slow water absorption, evaporation, and transpiration rates in native plants. “We’re basically going through drought conditions in the summer, and plants have to accept a lot more water in cold months, so we have to work with plants that handle those conditions,” explains Wulkan.
In the southeastern United States, an opposite problem exists, according to Bowden. He notes that street sand is an obstacle to the success of some LID facilities in the Southeast. The city has tackled the problem by employing high-efficiency street sweeping equipment. He adds, “Once educated on LID, people will see its benefits, not only from a viewpoint of protecting the environment, but also the economic savings that can result in many cases.”
Personal Preference and Prejudices
Individuals involved in a particular project can also pose an impediment to LID techniques. From property owners, contractors, and private engineers to public works staff and elected officials, one reluctant person can stop things in their tracks. “Say it’s a small or medium-sized jurisdiction, if the public works director doesn’t think it’s going to work, then there are still barriers. Not everyone is OK yet with pervious asphalt,” acknowledges Broadsword.
Adds Weinstein, “When you’re talking codes and public money, you have to couch things in terms of risk and certainty. It’s important to work that out, because a lot of times people in the public sector will say, “˜Prove it works for me and that my permit is still in compliance.'” He notes that a barrier to implementation can sometimes be as simple as an objection about the potential for mosquito breeding.
Wulkan says, “The problem is often either unfamiliarity or incorrect information. That’s something every local government permit desk has to deal with and overcome.”
He laments the negative publicity generated by a single project–the Ballard Rain Garden–in a city that has long embraced and been very successful in using low-impact development. He contends project construction was rushed and not all needed studies were completed in order to utilize federal stimulus funding. “Parts of the project failed, and that continues to stick in the media’s eye and with the public. Seattle has done multiple beautiful, award-winning stormwater green infrastructure projects, yet you get this one project with problems and the perception of many is, “˜There you go, it won’t work,'” says Wulkan.
He notes that local stormwater managers often list another issue–worries about maintenance–as their primary concern. Experienced managers have maintenance of grey infrastructure pretty well figured out, but LID systems have different maintenance needs that can lead to anxiety.
That leads to a broader issue: Local governments are being pushed to adopt LID approaches at the very same time that many are being hit with stricter National Pollutant Discharge Elimination System (NPDES) requirements, mounting maintenance demands, and tighter budgets.
“There have been a lot of cutbacks during the recession,” says Wulkan. “Local governments have had to do more things with fewer people. It’s hard to take on a new paradigm shift and maintain this new infrastructure at the same time you’re dealing with all these other issues. That’s a barrier,” he observes.
He encourages local stormwater professionals to seek more state support to finance code updates and demonstration projects–just as municipalities did in Washington state.
Weinstein, meanwhile, favors an even greater federal focus on LID research. “We’re doing a lot of innovative things. We don’t necessarily have 20 years or 30 years of data, but we’re basing them on sound engineering principles. We really need to have an adaptive management approach that bases things on new techniques and modifications to existing designs or we’re not going to advance the ball,” he says. “For instance, we would benefit from a federal green roof research center or clearing house. It’s been universities getting grants, and developers and vendors that have recognized a market, that have moved us forward.”
Applying It in the Right Places
In Raleigh, stormwater utility senior engineer Scott Bryant says LID and balanced green infrastructure approaches are a deliberate component of a comprehensive strategy to build a world-class city. “At the staff level, we see LID and green infrastructure as important tools in the tool box. It needs to be part of a balanced and fitting approach,” he says.
Bryant notes that minimum roadway widths–an unobstructed width of not less than 20 feet exclusive of shoulders, according to North Carolina fire code–have to be factored to ensure safe access for fire and other emergency provider equipment. And road designs must also take into account basic considerations such as placement of residents’ solid waste and recycling containers on pickup days.
“Reaching out to internal and external stakeholders is crucial,” says Bryant. “If we were just looking solely at stormwater management goals, the benefits are obvious where LID and green infrastructure techniques apply and are fitting, but when you look at public safety, emergency services, solid waste and recycling collection, private property issues, and other factors, you have to bring people into the conversation early to develop a balanced solution for the community.”
Bowden notes that this process has taken some time in Raleigh, but “we are beginning to see better interdepartmental cooperation because of education and the realization that pollution prevention is better than reactivity.”
Wulkan agrees that interdepartmental cooperation is an obstacle that requires focus. “Public works has to work with the roads department like never before. The fire and safety department has to be involved. So do the utilities, because you might be locating utilities in ways you never have before,” he explains.
Working with the city council and budget staff is also a critical step.
Bryant notes that the Raleigh stormwater utility provides financial incentives for property owners who install LID facilities such as a green roof or pervious paving that go above and beyond normal requirements, but acknowledges “relatively few participants” take advantage. One reason is that a developer might bear the cost of LID facilities, but the eventual owner will receive the credit via a reduced stormwater utility fee.
Bowden adds, “In current economic times, developers say it’s hard to make that investment up front.”
A Healthy Skepticism
Hector Cyre, an early leader in the US stormwater management field with four decades of experience in the industry, confesses to some skepticism about some of the practices and proposed practices under the LID umbrella. He believes stormwater management professionals should exercise skepticism about every LID project.
“I try to reassure myself every day, “˜I’m not a cynic; I’m a skeptic.’ Some people take it as a personal affront when you’re skeptical, but skepticism is healthy,” explains Cyre. “You always have to look at the downside.”
He continues, “We have had enough experience with some stormwater management practices that can pass for LID measures, which were adopted beginning mostly in the 1970s, to know that aging and reliability can be a big issue over time. I generally don’t see enough attention paid to designing and building LID stormwater elements with the objective of achieving long-term reliability. There isn’t a suitable recognition that measures need to remain functional even if they don’t get appropriate maintenance, which is often not performed for financial or other reasons.”
Cyre has concluded that a “surprisingly large portion of this generation’s environmental advocates, many of whom have embraced LID as a cause, don’t grasp the importance of reliability in context of conditions that are highly variable–that is, stormwater.”
He says, “They also don’t realize that the systems need to continue to function over time without excessive and sometimes very costly maintenance or monitoring being required, or the likelihood of abandonment increases. From the simplest to the most elegant, LID practices are imposed on a highly dynamic environment. Yet even the engineers sometimes overlook that simple fact in their LID solutions. Then, within just a few years, someone, often the public, is saddled with a system that doesn’t work and either has to be repaired or replaced. And that isn’t always easy in a post-development setting. It may simply not be possible in some cases.”
Cyre says a critical barrier is the fact the private sector is often expected or required to bear the cost of publicly developed LID facilities. Property owners may decide to avoid the added costs by simply ignoring maintenance. He says, “The only way to ensure low-impact development will function in the long run is to have a public entity responsible for it. Now, you have new issues with going on private property, maintenance agreements, easements, and access.”
Wulkan acknowledges that reality, underscoring the importance of well-defined local ordinances to address the issue before it becomes a problem in the future.
“We’re cognizant of this because we do hear stormwater managers’ concerns, and we’re still working on it. We came up with new language to insert into local codes giving public works directors that authority and access. It also requires coming up with a good checklist on how to visually inspect an LID facility to determine when it does need maintenance or corrective action,” acknowledges Wulkan.
Weinstein suggests the argument that municipalities fund LID system maintenance ignores current financial realities. “A lot of times, they aren’t maintaining [traditional] systems right now. So, if they don’t maintain those systems or these systems, they still function fairly well,” he concludes.
“I remain convinced that people simply aren’t considering the long-term financial implications all of that involves, and that worries me more than the immediate costs,” argues Cyre.
Bowden adds, “The long-term costs generally fall to the public entity and ultimately to the stormwater utility ratepayers.”
Cyre contends that, at a minimum, the consequence of failure due to lack of maintenance, poor design, poor installation, or extreme storm conditions must be a principal design consideration. “I don’t think that it is,” he adds. “A lot of folks don’t seem to appreciate the implications of lost functionality or outright failure, either.”
Cyre was incorporating LID systems into his local system in the 1970s as stormwater manager in Bellevue, WA. “I don’t want to douse cold water on it, but I’m a ways away from true believer status. It’s not in its infancy anymore, but it still has a long way to go,” he insists.
He continues, “That doesn’t mean you don’t try new things. It just means you should always be skeptical. There are a lot of aspects of it that make a lot of sense. If you’re able to do it in an efficient manner, it does have a marginal impact on stormwater problems. But, the important word in that sentence is “˜marginal.’ It doesn’t mean you don’t do it, but you have to be realistic.”
Cyre points out several aspects of low impact development that he likes.
“I like the level of involvement that it creates with citizens. Somebody with a rain garden or bioswale thinks about stormwater differently than somebody who hasn’t gone to that trouble. That has extraordinary value, because it’s in the minds of people that you begin to achieve the changes that affect water quality and stormwater management,” contends Cyre.
“I like the idea in the hydrological sense. I like the ideas of trying to retain and make use of the resource. That has beneficial effects offsite as well as for individual properties. I also like the idea it increases the service level of other systems,” he explains. “But my philosophy is different than some others in that it doesn’t reduce service demand; rather it gives me a margin on top. That’s a critical difference. The degradation of LID functionality is often greater over time. That’s why I don’t think the LID concept should be an excuse or rationale for making reductions in the design or capacity standards of your centralized system.”
A self-confessed “belt-and-suspenders guy,” Cyre says instead of creating a centralized stormwater system predicated on the assumption that LID facilities will always be functional and reduce the service demands of a given design event, he operates under the assumption that none of those green assets will perform as expected. When the LID systems do reduce flows, the central system is able to handle a larger margin. “Maybe the system actually handles a 27-year event instead of a 25-year event if everything functions properly. That’s the benefit,” according to Cyre. “In terms of water quality, an additional degree of pollutant load reduction may be attained over and above that attainable solely through mitigation measures incorporated into centralized drainage systems.”
Which raises the point of some advocates who say that LID systems can in fact reduce the size and cost of centralized facilities. “The savings some would represent that could be gained through low-impact development is not reality,” says Cyre. “You have to take those claims with a healthy dose of skepticism.”
Weinstein contends low-impact development should be viewed as much more than a stormwater management approach. “Up until five years ago, people weren’t paying attention to grey infrastructure and LID, so they just did what was in the regulations,” he says. “The best thing that’s going to happen is you’re going to have hybrid approaches. Not everything can be LID, especially if you’re retrofitting urban systems.”
But, he insists, LID offers substantial advantages in the close quarters of a city’s limits or a military base. “When you’re in an urban area and you want to do infill, you have to look to increasing pervious surfaces and building LID systems. You don’t get more land, so you have to make the best use of what you have. If you build a [retention basin], that takes up real estate that can be built on. So, you have to first say, “˜What is my objective? Is it stormwater management? Is it economic development?’ You have to look at the bigger picture,” says Weinstein.
Bryant suggests an added benefit for LID or green infrastructure approaches is the public support they foster because they don’t resemble traditional stormwater control systems. “In the past, we’d simply place pipes in the ground and possibly route runoff into a central detention pond. Now, we are understanding better that managing runoff as close to its source as possible has many benefits, both to water quality and quantity control,” he notes. “At the same time, there will always be a need for balance, practicality, and ensuring long-term system maintenance and performance.”
Broadsword also recommends starting small. “A half-acre access road was my first project. You get to see what issues come up with construction. That’s pretty helpful to someone who wants to get started but doesn’t have a lot of experience,” she offers.
She favors the creation of highly collaborative teams, including suppliers and builders, early in the project. “Not just when you’re starting out, either, but for every project. It’s important for mitigating risk, but it’s also a smart way to design all projects. As an engineer you may have learned quite a bit about soils and hydrology but not about soil ecology and plant communities and understanding the entire ecosystem. When you’re building a mini-ecosystem it’s important to collaborate with other professionals who have other pieces of the puzzle so you put it all together,” elaborates Broadsword.
She also suggests participation in continuing education, conferences, seminars, and webinars as another avenue to mitigate risk. And she strongly recommends the use of LID-specific contract language as a key to risk management.
Bowden agrees that engineers should lean heavily on landscape architects who understand local flora and its traits. Bryant suggests stormwater utility managers may also need to turn to parks employees and private contractors whose expertise could be a better fit than the public work crews when it comes to maintaining bioswales and rain gardens. “We’re really ramping up in that area. We don’t have the full-time people or equipment,” he acknowledges.
Ultimately, even barriers to implementation can provide benefits of their own.Cyre sums it up, “I don’t see skepticism as a barrier but as a refinement mechanism. I see it as a means to make it better as you go. It will create hurdles along the way, but there’s a difference between a hurdle and a barrier. A barrier keeps you from getting there. There are very few outright barriers to what we want to do. A hurdle is something you have to go over or around, and maybe you learn something along the way.”