Rethinking the Built Environment - A Solution for Florida's Water Woes?
By Mary Kelley Hoppe
After decades of engineering ways to move water off land as quickly as possible, or pipe it to a pond for nominal treatment, water managers are rethinking the ground rules for development. Some say the answer lies in low impact development (LID) principles that employ a variety of “green” technologies think grassy swales and berms, porous paving materials, even vegetated rooftops to reduce stormwater runoff and treat it closer to the source.
At River Forest in Bradenton, developer Joe King designed streets and homesites to minimize pavement and maximize native vegetation. Such low impact design principles are gaining favor as an increasing number of developers and architects pursue sustainable building practices that minimize the environmental footprint of development.
The problem is that existing stormwater rules and local government building codes, established to meet other objectives, discourage such practices. To satisfy permit requirements, engineers construct systems that convey stormwater as quickly and directly as possible to the street or to manmade retention or detention ponds, instead of retaining it longer on site with smaller features distributed throughout the landscape.
That’s led to decreased recharge of groundwater, increased stormwater runoff and water pollution.
“Short of barring all development, unless we change the way we develop the land and treat stormwater, we’re never going to be able to restore our creeks, rivers and estuaries,” says Sarasota County Commissioner Jon Thaxton, a panelist at an LID workshop held in conjunction with the 31st Annual Conference on Water Management in September at Tarpon Spring’s Innisbrook Resort.
Thaxton calls LID common sense development. Most of the principles are so basic, so common sense, so intuitively right that we know we should be applying them, he says. “Frankly, the way we’ve done it in the past has led us to the problems we have today.”
“Our rules have served us well, but now we recognize that to address nutrient water quality problems we need to do more,” says Eric Livingston, Chief of the Florida Department of Environmental Protection’s Bureau of Watershed Management. A useful analogy, he says, is when the region went from secondary to advanced wastewater treatment. “To make that happen for stormwater we’ve got to bring in the nonstructural toolbox.”
Current state stormwater rules require an 80% reduction of total suspended solids (TSS), which is typically achieved by constructing large retention or detention ponds. While stormwater treatment ponds are effective at controlling sediments, they remove less than 30% of nutrients such as nitrogen, a key contaminant of concern in Tampa Bay. Additionally, because existing rules address only peak stormwater discharges, the volume of runoff has continued to increase as developers pave over lands that once allowed rainwater to soak into the ground.
Even with the addition of wet detention treatment ponds, for instance, nitrogen loadings from developed sites with 25% impervious surface are more than twice that of undisturbed lands.
State regulators hope to correct those deficiencies by revising the state stormwater rule next year. The new stormwater rule will promote LID and give developers flexibility and incentives to implement low impact features to reduce stormwater loadings and the pollutants they carry.
Elie Araj has studied the stormwater problem from both sides. As environmental program manager for Hillsborough County’s Stormwater Section from 1990 to 2000, he witnessed an evolution in the local government mindset from “digging a ditch here, putting a pipe there” to addressing underlying water quality problems. “When I started with the county, the concept was if we got a permit and followed the rules, we were doing the right thing,” he says. “But at the same time, people were calling to complain about water quality in creeks and lakes, and asking what we were going to do about it.
“When we studied water quality in basins developed with water management district (stormwater) permitting criteria, we found elevated levels of nitrogen we realized that even though we were in compliance we were still negatively impacting the environment.
Low Impact Development is a flexible, environmentally progressive approach to site planning and design that employs a variety of techniques sharing these common goals:
• To help maintain a site’s natural hydrology;
• To reduce pollution in runoff by treating stormwater as close as possible to where it falls to the ground, relying on smaller natural features, such as swales and berms and rain gardens, distributed throughout the landscape;
• To reduce impervious surfaces for parking lots, roads and roofs by using pervious paving materials or other design features that reduce the footprint of hardscapes;
• To treat stormwater as a resource to be reused for irrigation where possible rather than discarded.
• To preserve as much native vegetation as possible.
LID offers builders a way to achieve significant savings by enabling them to add value-enhancing features and increase developable space by eliminating or reducing the size of stormwater treatment ponds.
“We began looking at what more we could do this led us to LID and cooperative projects to demonstrate how to treat stormwater volume and quality,” adds Araj, who started his own firm, Applied Sciences Consulting Inc., in 2005 to promote low impact design.
“Today, (the standard approach to development is) we clear, we fill, we grade, we add infrastructure, we revegetate, and then we leave. We need to turn that thinking on its head and embrace a new philosophy the less we do to the landscape, the more we benefit,” says Araj.
While that may sound logical enough, in practice, it’s difficult to implement. Environmental consultants and developers point to multiple rules and one-size-fits-all building codes and regulations that dictate everything from street width, curbs and gutters to parking spaces and access for emergency vehicles requirements that invariably lead to more pavement and more runoff.
“It’s an incremental process that eats at your idea of doing LID, and however much you have left over at the end, there are always things you just acquiesce to so you can get on to the next step,” says urban ecologist Tom Levin of Ekistics Design Studio, another panelist at the water management district workshop. “There’s a disincentive for the developer to spend the extra money to get a variance, and even when they say it’s worth it, there’s the hassle of getting it approved,” Levin adds.
Roadblocks to Redevelopment Foster Sprawl
Current regulations also create roadblocks to redeveloping sites constructed before stormwater rules were enacted, panelists argued. Bringing an old building up to modern stormwater codes can make redevelopment economically unviable, says Commissioner Thaxton, who is also a real estate developer. “You have two choices either you abandon the project and build elsewhere, often contributing to urban sprawl, or you forge ahead at great cost knowing that today’s lawful stormwater projects remove only a fraction of the nutrients and pollutants threatening our waterways,” he says.
“We’re simply remodeling the old Edsel,” Thaxton says.
“We want to have mixed use development, we want to bring residential uses into these outdated strip malls, but we can’t because of stormwater and at present LID concepts are not allowed. We need to start giving credits for LID so we can redevelop sites into more viable spaces and avoid additional sprawl,” he adds.
Livingston says current rules allow offsite stormwater mitigation, but developers may be unaware of that flexibility or local governments may not offer that option.
Rule to be Revised
Although a schedule for the revised rule has not been finalized, Livingston says the state expects to draft a conceptual rule with local water management districts by the end of this year. A technical advisory committee will be convened next, with the hope of adopting a final rule by the end of 2007. As an added bonus, the new rule will standardize stormwater requirements for developers, eliminating multiple sets of rules now in force.
To promote LID, regulators anticipate adding incentives or permitting credits for preserving native vegetation and minimizing soil compaction; topsoiling and tilling to increase soil permeability; incorporating distributed natural features such as swales and berms, and green roofs; and utilizing porous paving materials.
Environmental managers and developers alike hail the proposed changes as good news for communities committed to sustainable development. For Thaxton, saving our bays and estuaries comes down to a basic choice. “Either we come up with a new paradigm for stormwater treatment or we continue fouling our own nest.”
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