Agreement Sets Stage for Controlling Nutrients in Stormwater

By Victoria Parsons

A landmark agreement in October between the state’s Department of Environmental Protection and the five water management districts has set the stage for stormwater treatment regulations that will restrict nutrients in post-development runoff from exceeding those in runoff from raw land.

Nutrient levels in surface waters declined dramatically after the state implemented regulations mandating advanced wastewater treatment and stormwater treatment, but nutrient levels have crept up again as the state’s population has continued to grow. Limiting the impact of new roads and rooftops will be critical to maintaining water quality in the future, notes Eric Livingston, chief of the DEP’s Bureau of Watershed Regulation.

“We’re not getting the level of treatment we need from current rules,” he said.

A technical advisory committee is expected to start working on details of the new regulations in early 2008, with statewide rule workshops tentatively scheduled for October through February 2009, formal adoption in May and final implementation scheduled for July 1, 2009.

“Treatment Train” Captures Contaminants

Stormwater treatment ponds have become the centerpiece of many new developments, but they aren’t effective at removing some contaminants. They remove about 80% of particulates, but only capture about 30% of nitrogen and 60% of phosphorus in stormwater. Scientists attribute the increase in contaminants to the growth in impermeable surfaces created as new rooftops and roads are built. While excess nitrogen is most damaging in saltwater ecosystems because it fuels run-away growth of algae, the new rulings will limit levels of both nitrogen and phosphorus in stormwater.

While challenging, the ambitious goals for nutrient reduction can be accomplished using low-impact design standards with associated credits and debits and “treatment trains” that include multiple components, Livingston said.

The key difference will be the focus on non-structural elements that capture pollution at the source. Credits will be given for green roofs, cisterns, pervious concrete, berms, swales and rain gardens as well as the preservation of natural vegetation and Florida-friendly landscape maintenance practices.

On the other hand, if a developer chooses to clear all vegetation and bring in low-quality fill dirt, points will be debited because the compacted soil will be almost impermeable. “What we’re trying to do is create a series of incentives and disincentives that encourage the right kind of development,” he said.

Longtime LID advocates like Elie Araj, president of Applied Sciences Consulting Inc. and a member of the U.S. Green Building Council Gulf Coast Chapter, are encouraged by the effort. “We need to promote not penalize innovation and environmentally sustainable development,” he said.

Stormwater treatment ponds will still be necessary to control the volume of runoff, capture sediments and control contaminants. However, the pond size may be reduced as a result of net points accumulated by adding non-structural design elements.

The new regulations also recognize stormwater as a valuable resource – an inexpensive source of water for irrigating landscapes. To minimize potential dangers, wells will collect water that has seeped through four to six feet of soil. “We’ll avoid the issue of toxic algae and other bacteria in the ponds but still capture some nutrients that can be re-applied to landscapes,” Livingston said.

New Land-Use Regulations Necessary

From a developer’s perspective, the new regulations will offer consistent rules across the state instead of different regulations within each water management district. Livingston also expects developers to see some savings from the new land-use regulations that must be written for the new stormwater rules to be effective.

“If local governments don’t change their rules to encourage low-impact development, this rule won’t work,” he notes. One-size-fits-all regulations dictating requirements for wide roads, concrete sidewalks and large parking areas will need to be rewritten to allow more flexibility and focus on more permeable surfaces and clustered developments.

While DEP doesn’t have any control over those land-use decisions, Livingston is confident that the development community will put pressure on local governments. Several local governments, including Sarasota and Marion counties, already have written the rules but are waiting for water management districts to adopt new regulations that give developers credits for low-impact development.
“The state regulations will provide the scientific support local governments need to justify changes to the land development codes,” Araj said. “Local governments have historically followed the state guidelines simply because they do not have funding to support independent scientific research.”

Sarasota County had expected to implement several pilot projects demonstrating the viability of low-impact design in urban redevelopment, but funding cuts are likely to scale the initiative back to government-owned buildings where the cost of land is less an issue than in private redevelopment.

“You can’t have stormwater treatment ponds and low-impact development – it just doesn’t add up,” says County Commissioner Jon Thaxton, a former real estate broker who got involved in government to help protect the environment. “We need the research to document nutrient reduction and available capacity and we have to have an economically viable rule that industry can comply with.”

As the county focuses on redeveloping older shopping centers into modern work/live developments, new stormwater regulations are more important than ever, he said. Other choices – continued pollution, increased sprawl or stalled redevelopment – are not viable. On the other hand, the potential benefits – cleaner water, healthier communities and improved economic development – are “almost immeasurable,” Thaxton said.

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