Stormwater Treatment Train
Historical concepts are driving water-quality benefits.
When Jean Baptiste Point du Sable built his farm as the first white settler of Chicago, IL, he never knew the Des Plaines River was a river. Because, back then, in the 1780s, it really wasn’t. He would have thought of it as a swamp.
|Infiltration and pollutant trapping take place in this sunken parking lot island.
|Infiltration or conveyance zones and relative infiltration capabilities of different landscapes
The conclusion of the study is that natural landscapes managed stormwater through infiltration and evapotranspiration (read: green infrastructure, or Stormwater Treatment Train) far more effectively than today’s urban grey infrastructure. The ultimate ramification is that restoration of green infrastructure systems can be far more cost-effective than grey infrastructure and provide multiple ecological and cultural benefits that would be otherwise forfeited.
Scientific Study: Des Plaines River Watershed
The Des Plaines River was chosen as a study watershed because of available historical data and trackable changes in watershed land uses. The river originates in southeastern Wisconsin and flows south for more than 90 river miles through agricultural, suburban, and urban landscapes through northeastern Illinois—directly through the Chicago metropolitan area. The studied watershed at the gauge station in present-day Riverside, IL, drains 620 square miles, and its eventual outlet is the Illinois River, which flows to the Mississippi River.
Scientific Results: Stormwater Treatment Train
The Des Plaines River study and subsequent on-the-ground demonstrations have led to the proliferation of the Stormwater Treatment Train (STT) concept developed by Apfelbaum and his firm, AES, in the mid-1990s. One of the earliest projects, and perhaps the most acclaimed, where AES used the STT concept was the Prairie Crossing development in Grayslake, IL. Prairie Crossing is a 677-acre mixed-use residential/commercial development in the suburban Chicago area designed with more than 70% open space. Open space was designed as restored prairie and wetland with the intent of providing excellent water quality to downstream receiving waters, including the Liberty Prairie Reserve and the Des Plaines River.
Evolution of the Stormwater Treatment Train
Mike Sands, Ph.D., ecologist and environmental team leader at Prairie Crossing, has conducted dozens of environmental studies documenting the water quality and ecological benefits of the Stormwater Treatment Train in his neighborhood. The endangered species fish restocking program at Lake Aldo Leopold is just one example. But he also initiated a rain garden program to strengthen the “source control” aspect of the STT concept. According to hydrologist Doug Eppich, Ph.D., P.E., of AES, who helped Apfelbaum develop the concept, this is indicative of the evolution of its functionality.
Big Picture STT
Site-specific STT is now proven to benefit water quality in downstream waters, but could there be area-wide benefits for applying the concept to large metropolitan areas—where most of us live?
In fact, yes. And it is coming to fruition in several areas—where mometro areas that are initiating green infrastructure programs with important stormwater management benefits.
|A depressional swale to infiltrate runoff from a roadway
|A wetland, part of the STT at the Metra Wetland Mitigation Bank in Antioch, IL
One early attempt to scale up the concepts and conservation values of the STT was sponsored in the Kansas City metro area by the Mid-America Regional Council (MARC), with funding from USEPA. MARC worked closely with AES to inventory all natural resources in the 3,000-square-mile Kansas City metro area. With GIS modeling and field studies to validate and calibrate the modeling, the natural resources inventory was then used to create an objective method for prioritizing areas for inclusion in a green infrastructure plan.
STTs for CSO Reduction
A major incentive for many metro regions is to use STT concepts to reduce or eliminate the dreaded combined sewer overflows (CSOs) that plague more than 700 communities with combined storm and sanitary sewers. But of course, there are multiple benefits to green infrastructure programs—Leave No Child Inside and others—and significant funding is being directed toward these programs.
Stormwater Parks and Stream Daylighting
As a theme for urban parklands, stormwater is becoming a rock star. Saylor Grove is a 3.25-acre park within Philadelphia’s renowned Fairmount Park system. In 2006, the Philadelphia Water Department constructed a 0.70-acre stormwater treatment wetland in the park to address the impact of urban runoff and bank erosion along the Monoshone Creek, a major tributary to Wissahickon Creek.
Technical Aspects and Ecological Underpinning
AES is currently partnering with TCF to update and add scientific underpinning to the Chicago Wilderness Green Infrastructure Vision (GIV), originally drafted in 2004. One of the goals of the GIV 2.0 project, according to Will Allen, TCF director of strategic conservation, is to establish a network of interconnected “core areas” and “hubs” of well-functioning natural areas that will contribute to ecosystem services such as clean water, flood control, carbon sequestration, and recreational opportunities.
Funding Through Stormwater Utilities
At the Clean Water America Alliance conference, it was noted that the establishment of stormwater utilities has risen by 45% in the past four years, with 36 states and the District of Columbia charging stormwater utility fees to their residents. Some utilities, such as that established by the City of Minneapolis, MN, in 2005, offer credits for management of stormwater quality and quantity.
In 1993, Apfelbaum’s white paper on the Des Plaines River, “The Role of Landscapes in Stormwater Management,” led to the realization of the historic role on how healthy ecological systems managed stormwater. Apfelbaum postulated that through ecological restoration, landscapes can again manage stormwater to add water-quality benefits.
Author's Bio: Jack Broughton is with Applied Ecological Services in Brodhead, WI.