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But it was worse when it rained. “There were some erosion issues for the railroad embankment,” Shepherd said, a sensitive issue since increased sediment flows could degrade the creek’s aquatic wildlife habitat and large storm flushes could wash out streambed habitat for aquatic invertebrates. And any silt and pollutants that entered the stream ended up in Beaver Lake — the source of Fayetteville’s drinking water.
The remedy came in 2007, when Place Properties purchased the land and hired Appian Centre for Design, a Fayetteville-based landscape planning and architecture company, to work on a student housing proposal. Appian hosted community meetings, which pinpointed water quality concerns, as they worked on the project’s landscape design and decided to employ low impact development for Hill Place as a result.
Low impact development (LID) uses or recreates natural landscape features to mimic predevelopment runoff patterns and allow water to slowly percolate into the subsoil, thereby treating storm water as a resource, not a waste product. “Con ventional development focuses on flood control” using concrete pipe and retention ponds, said John Coleman, Sustainability Director for the City of Fayetteville’s De partment of Sustainability. “LID focuses on water quality and water shed protection.
It also has some biodiversity benefits. It catches fertilizers, nitrogen, phosphorous, and holds them on-site, preventing them from going downstream.” A scientific analysis for Hill Place estimated that a low impact design system would reduce annual phosphorous runoff by 53 percent, nitrogen by 27 percent and sediment by 22 percent as compared to conventional gutter, pipe, and pond stormwater controls.
Typical bio-friendly stormwater management techniques might include rain gardens, bioswales, infiltrations islands and wetlands. Rain gardens, for example, are depressions planted with plant species that increase the soil’s ability to absorb rainwater. Bioswales are wide shallow ditches with vegetation or riprap; they are designed to slowly filter pollutants out of stormwater. Infiltration islands are basically rain gardens planted in parking lots, where they can clean up significant amounts of vehicular pollutants.
After a 2008-09 retrofit, three rain gardens and five bioswales now slow stormwater flow and filter water at Hill Place. Six infiltration islands filter parking lot runoff. A wooded riparian buffer lines the creek running through the property. In all, 24,000 square feet of LID greenery surrounds the apartment complex, which opened in August 2009 and comprises 16 buildings with 288 units.
Construction of low impact design features is fairly basic — a homeowner could put in a rain garden — although there are certain techniques and plant species considerations, said Todd Jacobs, Appian’s Director of Design. Financially, LID might save a developer 10 percent to 40 percent compared to installing a traditional pipe system, depending on parameters such as topography and site density. With lots of green space available for bio-systems, for example, savings might be closer to 40 percent. A dense urban site might see savings closer to 10 percent.
However, Jacobs acknowledges that savings can be a wash if local ordinances favor traditional stormwater management, resulting in additional regulatory considerations and fees for the LID team. In Fayetteville, Place Properties was willing to commit to the extra design fees.
“If you can get away from the concrete, pipe and curb, and shift that to design fees, you can alleviate some of the design costs,” since traditional concrete features cost more to install than LID features, Coleman said. In 2008, the university received a grant for research on stormwater in Northwest Arkansas communities. “[The City of] Fayetteville is now taking that research and looking at the possibility of implementing LID,” he said. “It means [city ordinances] would allow for rain gardens and bioswales, where in the past, developers didn’t get credit for it.” Water quality in the Beaver Lake watershed is the driver behind the city’s efforts to make the transition to LID-friendly ordinances, he said. That would ultimately lower the planning costs for LID systems.
In fact, the Arkansas Department of Environmental Quality’s stormwater permitting language directs municipalities to “evaluate their existing codes and planning procedures to remove impediments to low impact development and green infrastructure.” Ron Tyne, managing member of Rocket Properties, which incorporates LID into its Little Rock development, said there’s been increasing acceptance of LID in the past 10 to 15 years. “There’s a whole lot of education that needs to be done, but once cities know the benefits, they more readily accept it and accommodate it.”
In terms of maintenance, costs are comparable to more traditional systems, according to Jacobs. “If the area wasn’t a bioswale, then it’d be a lawn needing to be fertilized and cut and mulched,” he said. “So the maintenance cost isn’t much more than a typical lawn situation.”
Meanwhile, there’s no denying the higher aesthetic appeal of green spaces incorporated into development design. The Environmental Protection Agency’s Web site lists increased property values, increased marketing potential and faster sales as benefits to the open green spaces of LID. “LID has been around, but when we look at mentor cities, we look at Seattle, Northern Virginia,” Coleman said. “It’s not really widespread — we’re pretty early in the process. You want to look at an existing project like Hill Place and try to learn the positives and negatives before you jump off.” It’s this kind of forward-thinking by the Hill Place team that earned the Appian Centre for Design a 2009 Award for Urban Planning & Design from the Arkansas Chapter of the American Society of Landscape Architects.
In making the award, the ASLA wrote, “We applaud the client for having the courage in undertaking such a project and suspect that the future success of the project will encourage other developers to follow suit.” Coleman and Jacobs are working in Fayetteville toward making that a reality.