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Rainwater Recycling and Ecology--A Basis for Planning and Design

by Stephen Kelly, regional editor






Approximately 37.5 inches of precipitation falls on every acre of the Midwest. That's equal to nearly one-million gallons of water per acre per year. Of that, almost 90 percent falls in 1/2 inch increments, or less. Photo courtesy of Sarah Griggs, www.hilltop.net/photography


Jay Womack, ASLA, believes rainwater may be the most misunderstood and underestimated design element for landscape architects. In a paper he wrote, "It's All About the Water," he quotes Patchett and Wilhelm in The Ecology and Culture of Water: "When we are unaware of, ignore, or are wasteful in our relationship to the interaction of water with other natural resources, water can become a waste product and potentially a powerful source of destruction."

Jay Womack
Jay Womack, ASLA, born and raised in Illinois, says he has an "affinity for the natural areas of the Midwest." He has worked for large and smaller design firms in Illinois and Georgia, collaborating with design professionals in urban renewal, academic institutions, large-scale community planning and park and recreation development.

In the "second chapter" of his career, his focus has been projects that "integrate environmentally and culturally sustainable land planning techniques." Every design solution, he notes, "requires innovation that can be achieved through the partnership of environmental and economic growth."


The water cycle is well known, of course. Evapotranspiration from the oceans and other large bodies of water creates clouds and precipitation. Rain falls from the sky to support the flora and fauna, permeates the soil to replenish the aquifers, and the ecological cycle begins again. All that is very well, but there is a missing piece to the equation regarding landscape design practices. Womack notes: "Look around, everywhere you go you are surrounded by impermeable paving, endless homes on go-nowhere streets, compacted soils, turf grass, and landscapes that require an inordinate amount of energy and resources to keep them alive."

The EPA ranks urban runoff and storm-sewer discharges as the second most prevalent source of water quality impairment in our nation's estuaries, and the fourth most prevalent source of impairment of our lakes.




















Tellabs Corp. required an integrated site plan and landscape design approach for their new 55-acre corporate headquarters in Naperville, Ill. The plan relies on parking lot bioswales (top), terrace runnels (center) and bioswale overflows (bottom). A bioswale is a shallow depression using aggregates or other filtering material and vegetation to infiltrate stormwater runoff and filter out contaminants. The terrace slopes toward the rock runnel (center), which feeds under the emergency access road into a level spreader. Any overflow seeps into the bioswale (bottom) as natural irrigation for the prairie plants. Jay Womack, ASLA, says these green design tools have saved hundreds of thousands of dollars in construction costs, months of construction time and reduced annual maintenance costs by 48 percent. This project won the Brooks McCormick Environmental Award in 2001.


He is, of course, describing the dominant form of suburban sprawl. "Now, think about the water that falls from the sky within that sprawl landscape," he says. "Where does it go? It falls on the lawn, rolls off the turf grass, across the asphalt, down the concrete pipe, out the flared-end section, and into the brown hole in the ground called a detention basin, along with all of the road oil, grease, pesticides, detergents, and other pollutants that it picks up along the way. Based on the legal release rate of said detention basin into our local streams and rivers along with all the aforementioned stuff, the native flora and fauna that try to live in this riverine system are now accosted with water that is at a temperature, turbidity, and flow rate unlike anything they have evolved with over the last 10,000 years."






The green roof on the restroom absorbs stormwater, of course, but the area in front is a constructed wetlands to handle the effluent. The waste goes into a holding tank where the liquids and solids are separated and the liquids are passed through cells in a rubber liner that includes small river rock and plants. As it migrates through the rocks, the plants absorb certain nutrients and by the time it comes out the other side it is clean water that goes into an infiltration field of prairie plants and absorbs back into the ground water. Because the area was "off grid," a traditional approach (septic tank and lines) would have resulted in a several year's wait (for septic lines to be run to the spot) and would have been enormously expensive.


In the urban environment, very little rain is infiltrating and replenishing the aquifer before it enters the detention basin. Womack asks designers to "imagine a place where rainwater cycling and ecology is the basis for all planning and design; where a project is developed upon a framework of design principles that reintegrate people into the environment, a place that is developed to cherish the environment as an asset, and where open space is based upon a system of living landscapes native to that particular place. When rain falls from the sky, it is treated as a resource, not a waste product."






These are Interlocking permeable pavers at the Morton Arboretum in Lisle, Illinois. Studies on the influence of permeable pavers on runoff pollutant levels and thermal characteristics have been conducted at the University of Guelph in Canada since 1993, led by Professor William James. Studies have found permeable pavers of interlocking concrete blocks demonstrate a 90% reduction in runoff volume and significantly reduce the surface runoff loads of contaminants like nitrate, phosphate, phosphorus, metals, BOD and ammonium. In a lab simulation, permeable pavers also reduced surface runoff temperatures by 2-4 degrees Celsius compared to the runoff from asphalt paving. As the permeable pavers also increase infiltration, the total heat content of runoff is reduced substantially.


Womack's cry is state-of-the-art stormwater treatment systems that bring water resource management into the landscape, allowing water to cleanse and infiltrate as it has historically done.






Coffee Creek Center, a new community in Chesterton, Indiana, is striving to preserve and restore a stable ecology within its 640 acre mixed-use development, including more than 160-acres of prairie, wetland and woodland habitat. The land was formerly a corn field. Level-spreader water filtration is incorporated. The stormwater is taken into a series of 12-in. diameter underground perforated plastic pipes laid level to the ground contour, embedded in clean aggregate to infiltrate into the ground and into Coffee Creek. If the water fills the pipe and cannot infiltrate further into the soil, it percolates up through drain grates to spread out over the ground. To assure the system worked, red dye was put into a stormwater inlet. Six weeks later the dye had made its way to the wetlands via soil migration. The Coffee Creek watershed was awarded the Conservation and Native Landscaping award in 2003 from the U.S. Environmental Protection Agency (EPA) and Chicago Wilderness.







South Detention Section, Typical New Campus Pedestrian Plaza with 100 Year Storm Event

Contained Underground and Above GroundJay Womack, ASLA, was the project manager for a stormwater study at St. Ambrose University. The campus parking lot repeatedly flooded. An eight-foot dia. pipe to carry stormwater to a creek was proposed. The alternative design, shown here, was a civic plaza to infiltrate the water. Overflow rainwater would route through the campus in a series of naturalized water features, ending in a large infiltration field.



Develop Green Building and Site Development Goals

Site Goal

Make places healthy, beautiful and inspiring; avoid harm to precious natural resources, including water and landscapes; use resources efficiently.

Building Goal

Make buildings healthy, pleasant places for people to occupy; minimize energy use; create structures that are durable; use products and techniques that do not deplete natural capital and are non-toxic.

"Imagine a workplace where employees grab their umbrellas and run outside to watch the first rivulet of water begin its journey down from the roof, across the terrace, into the infiltration field and finally through a rain garden where the water intermingles with a series of plants designed to cleanse and absorb the rain," muses Womack. He continues his contemplation: "While following the water through its natural flow pattern, you disturb a green heron that was sitting quietly behind the irises, waiting patiently for a leopard frog to join him for lunch. As the heron takes to the air, you follow its path across the property, into the adjoining site that is the contiguous open space of woodlands, prairies, and wetlands, a place where you bring your family on the weekends. Standing there, you're surrounded by the sounds of nature so deafening that you forget you are at work, quite unlike the cacophony of cars that most people you know are subjected to.













Since Chicago Mayor Richard Daley visited Germany and saw the proliferation of green roofs there, he has pushed for Chicago to be the leader in green roofs. The Chicago Department of Environment initiated the City Hall Rooftop Garden Pilot Project as part of the Urban Heat Island Initiative with the EPA. City Hall, home of the mayor's office, has gone green--well, half green. The half of the roof owned by the county still has an asphalt top (actually seven layers worth, which the green side peeled off before putting down the waterproofing layer). The county side of the roof (think asphalt) has summer air temperatures 50-80 degrees higher that the green side. The City Hall green roof has already saved the city some $14,000 in energy bills.














The plant palette for the City Hall includes over 100 species of plants, including native prairie (e.g., big and little blue stem; dusty miller, sedium, black-eyed susans), woodland grasses and forbs, hardy ornamental perennials and grasses, several species of native and ornamental shrubs. A drip irrigation system supplements the rainfall, which has been essential, as drought-like conditions have occurred. The green roof is designed to hold 50-75 percent of the annual precipitation. The organic life on the roof has greatly increased the presence of avian wildlife. As a side note, Mayor Daley's office has taken to raising bees on the roof and producing honey.


Imagine such a place, where school kids use your workplace as a living laboratory, rain is treated as a resource not a waste product, the open space is really open space, not a leftover triangle of depressed lawn that doubles as a detention basin. Where flora and fauna unlike anything found in suburbia today flourish in a healthy, stable ecosystem--it is a real, vibrant place where you work, in direct contact with nature. Imagine if such a place existed! Well, I can."




















Some interesting examples of urban runnel design in Germany.


Over the last eight years, Mr. Womack has been the project manager on all the projects pictured herein while working for the Conservation Design Forum, and was part of the team for the Chicago City Hall greenroof. He is currently employed by Wight & Co. in Darien, Illinois, integrating natural resource-based site planning and development, incorporating techniques that integrate native landscapes and innovative stormwater management strategies that aim to give a little something back to Mother earth.




















Womack, as project manager for the Landscape Architect site plan for the Wight Office Bldg. in Darien, Ill., incorporated parking lot bioswales (bottom), infiltration trenches (center), rain gardens and native landscape (top) through the site. Rainwater management is key to the overall site development. An example of a Wight Office Bldg. parking lot bioswale before (piping covered by 15 inches of gravel) and one year after (bottom) with native vegetation (sedges). Engineered sand and soil cover the clean aggregate. There are no curbs in the parking lot, to avoid concentrations of water building up.







Roof drainage for the Wight Bldg. goes to the back of the building into a large infiltration bed of three-foot deep aggregate. If there is overflow, it goes into an adjacent swale. In the unlikely event that the swale overflows, water goes into an inlet and drops into a detention basin. There is no water currently in the detention basin.


Create Strategies for Water Use

Strategy

Collect, recycle and reuse water for necessary or desired elements--irrigation, gray water uses, interior climate moderation, ornamental expressions of water.

Strategy

Return surplus water to the environment in a sustainable way that protects downstream resources--evapotranspiration, infiltration, limited surface discharge.

Womack's designs embraces green principles, incorporating ecology directly where people live, play and work. He treats rainwater as a resource. "As designers, we all make decisions that affect rainwater. We need to start making choices that are more positive in nature."

Each spring, enormous quantities of dissolved nutrients (nitrogen) are transported from the upper Midwest into the Gulf of Mexico, resulting in the Gulf of Mexico dead zone. This phenomenon grows to approximately 7,000 square miles each spring. Iowa and Illinois are credited with creating as much as 35 percent of the nitrogen pollution ending up in the dead zone.






Strip malls or other commercial sites can be nearly 100 percent impervious to nature's solution to rainfall--infiltration into the soil for plant growth and to replenish the aquifer! Here, stormwater moves across the asphalt, down concrete pipes and into the brown hole in the ground and the detention basin, along with road oil, grease, detergents and other pollutants collected along the way. Medium-density, single-family home residential areas are better, but have a 25-60 percent range of imperviousness of rain getting into the ground.






Blue Space Tool Box

o Green roofs

o Porous paving systems

o Bioswales, rain gardens and other infiltration techniques

o Naturalized landscape systems



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June 18, 2019, 8:57 pm PDT

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