Remember the song with the line about little green apples and rain in Indianapolis in the summertime? Of course Indianapolis gets rain during the other three seasons, too, for an average annual rainfall of 42.4 inches. That’s a fair amount of stormwater to manage.
Indianapolis also has runoff from melting snow and a combined sewer system (CSS) with its share of overflows to complicate things. Like Atlanta, Cleveland, Portland, and other cities, the city is using both gray and green infrastructure to manage its stormwater.
And like a number of other American cities, Indianapolis is working under a consent decree. The agreement between the city, the Indiana Department of Environmental Management, and the US EPA was signed in 2005. The 20-year plan requires that combined sewer overflows (CSOs) be reduced from 7 billion gallons per year to 414 million gallons per year by 2025. This modified plan, with gray and green infrastructure, will save $740 million and remove stormwater ahead of the original plan’s schedule.
The 6-mile-long Deep Rock -Tunnel Connector, a major piece of gray infrastructure, is part of the plan. Other major pieces of gray infrastructure include the Pleasant Run Tunnel, the Pogues Run Tunnel, and the Fall Creek/White River Tunnel. These tunnels will each hold 250 million gallons of runoff and will be located 250 feet below ground.
On the green infrastructure side, green roofs are becoming popular in Indianapolis. They are found above the Indianapolis Museum of Art, the Capitol Commons, the AUL Courtyard, the Hilton Garden Inn, the Moon Block Building, the HealthNet Clinic SW, the Children’s Museum, Indiana University’s Simon Cancer Center, and the Lilly Corporate Center and Visitors Center.
The orangutans at the Indianapolis Zoo have a new green roof. Radio announcers at WFYI appreciate their building’s green roof because it muffles the sound of rain that their microphones used to pick up. It has deep enough growing medium to produce flowers and vegetables.
Other Indianapolis green roofs include those above Union Station, Schmidt Associates, and the John H. Boner Center. The Nature Conservancy of Indiana’s headquarters has two green roofs.
A 16-foot-high living wall at the Efroymson Conservation Center
A LEED Platinum Conservation Center
An outstanding example of green infrastructure is the headquarters of the Indiana state chapter of The Nature Conservancy. Landscape architecture design for the project was done by Kevin Osburn, RLA, ASLA, principal with Rundell Ernstberger Associates (REA). Axis Architects was the overall designer.
The first LEED Platinum building in the city, The Nature Conservancy’s Efroymson Conservation Center uses 35% less energy and 80% less water than if it had been built conventionally. It has geothermal HVAC and three vertical wind turbines.
Constructed using 8,000 square feet of bricks salvaged from the site’s previous building, Indiana’s beautiful native limestone, and sustainably harvested Indiana native hardwoods, the building is located on Ohio Street in downtown Indianapolis. The $8 million center opened in 2010.
Its 1-acre lot contains more than 14,000 square feet of native plantings, more than 100 different types. Sections of plantings mirror those found at different nature preserves around the state of Indiana and have created a wonderful habitat for wildlife.
“Dozens of goldfinch live in our gardens,” says Mary McConnell, executive director of The Nature Conservancy. “Bees started a hive in one tree. Hummingbirds fly around, and we see baby rabbits.”
One-third of the parking lot has permeable pavers. A bioswale that runs along the parking lot’s length collects runoff from its impervious section. The bioswale contains blueflag iris, tussock sedge, meadowsweet, winterberry, twigged dogwood, and other native plants.
“It’s unbelievable how quickly the water drains,” says McConnell. “Within 15 minutes of the rain stopping, there is no water left in the swale.”
Ten varieties of sedum grow on The Nature Conservancy’s 7,500-square-foot extensive green roof. The building also has a 500-square-foot intensive green roof with 24 inches of growing medium. Both roofs drain to a 2,500-gallon cistern in the basement.
When the cistern or bioswale reaches capacity, runoff goes into an infiltration gallery beneath the bioswale. Outside, facing the basement’s windows, is a living wall 16 feet high. It absorbs some rainfall, but its primary purpose is to allow daylight into the basement, saving on lighting.
The wall features native plants such as wild geranium, wintergreen, columbine, and maidenhair fern. This retaining wall, built of concrete blocks with plants growing within its spaces, is reminiscent of plants growing in the spaces on the sides of cliffs in southern Indiana.
All of the rain that falls on The Nature Conservancy site stays on the site, either captured for use or infiltrated. It eventually filters through to Pogue’s Run, which runs underneath the city to the White River.
“Every drop of water that falls onsite is utilized in some part of the project,” explains Osburn. “There weren’t any sewers on site. We would have had to extend a sewer line a block or half a block, and that would have added a lot to the cost.” That lack of sewer outlets “steered us to a zero-runoff solution.”
This was a real challenge, he adds, “but also caused us to think how we could use stormwater creatively, how we could minimize runoff and use it for irrigation and for a graywater system in the building.”
Rainwater collected in the center’s underground cistern is used to water the native plantings or to flush the building’s toilets. That reduces The Nature Conservancy’s water bill.
Because of its rain capture system, The Nature Conservancy site is not connected to the city’s CSS. The environmental organization doesn’t add to the problem of CSOs. McConnell says that the city will save almost $700,000 over a 30-year period by not having to deal with runoff from the site.
Osburn says that the building was “designed as a showcase not only for The Nature Conservancy’s work, but as an educational tool for school, corporate, and nonprofit groups who are interested in how you achieve a sustainable building on an urban, highly compact site.”
McConnell says that the building attracts many visitors. “Most people are just awed by what we’ve done with our stormwater. We have geothermal, wind turbines, and other features, but stormwater is what we get the most interest in, and it’s what I am most proud of.”
The Wabash River, the largest undammed river east of the Mississippi River, drains two-thirds of Indiana. One of the Wabash’s tributaries is the White River, which flows through Indianapolis. McConnell says that fresh water conservation is very important to The Nature Conservancy. “By protecting groundwater and not adding to the city’s CSOs, we’re protecting Indiana’s river. We’re walking the talk.”
The Cultural Trail includes $2 million worth of outdoor art.
Some areas of the trail are wide enough to allow separate bike and pedestrian lanes.
Indianapolis Cultural Trail
Many cities have difficulty getting suburban residents to come to the urban downtown area. So did Indianapolis, until May 2013. That’s when the final portion of the 8-mile Indianapolis Cultural Trail was dedicated and opened to the public.
“Thousands of people are on the trail every day. People want to be where other people are,” says Lauren Day, program manager for the nonprofit organization that manages the trail.
The Cultural Trail connects six areas in and near downtown Indianapolis. They are Fountain Square, Indiana Avenue, Massachusetts Avenue, The Canal and White River State Park, the Wholesale District, and Broad Ripple (the latter via a link to the Monan Trail).
The project is a remarkable result of citizen initiative and generosity, for the city had no money to fund it. It is a popular destination for both tourists and local residents and a model for connecting various segments of the community and encouraging people to be physically active.
“There’s an equal split between residents and visitors, as more and more people live and work downtown,” says Day. “Indianapolis is a big convention site, and for visitors the trail connects seamlessly to hotels, restaurants, and the convention center.”
Indy’s Cultural Trail is also a fabulous urban green infrastructure stormwater management project. Videos show dedicated bike riders in spandex, casual cyclists on borrowed BikeShare bikes, joggers, walkers, families pushing strollers, and even older citizens holding on to their walkers, all moving along the trail. Whether they are exploring the heart of Indianapolis, heading for a museum or one of the new shops or restaurants the Cultural Trail has spawned, or out for daily exercise, everyone present travels past some of the 25,400 square feet of stormwater planters and rain gardens.
“They’re working incredibly well,” Osburn says of the planters and gardens. “Some have been in place since 2007. We started construction in 2006 and finished in 2012.” He also designed this project.
The stormwater planters nearest the streets range from 8 to 9 feet wide. They vary in length from a minimum of 12 or 15 feet to the longest that run the length of a block. The inner planters or rain gardens also vary in size, from 5 to 8 feet wide.
The stormwater planters are placed so that water drops into them. “We’ve gone as deep as 2 feet. We never wanted them to be deeper than 30 inches so that we had to leave guard rails around the planters,” explains Osburn.
The stormwater planters contain beehive overflow structures to send overflow during heavy rains to the sewer system, but they’re designed to capture 99% of rain events. They do not have underdrains. “The soils and subsoils here are very sandy and gravelly,” says Osburn. “We’re blessed that we have that kind of soil medium to work with.”
He notes, “Collecting runoff from the streets into the public right of way–that whole concept was new to the city. We worked closely with DPW [the Department of Public Works] to get them on board. We used five different planter designs in the first phase. The city was still apprehensive. But they worked well beyond what anyone expected, so we replicated them. The first phase covered only a half mile. We used that method of collecting stormwater for the next seven and a half miles.”
The concept of managing stormwater runoff becomes raindrop clear to the average person who spends even a little time on the Indianapolis Cultural Trail. That management is going on a mere few feet from his bike’s wheels, his child’s stroller, or his own feet.
Osburn says the stormwater planters “were the first visible signs of green infrastructure on the streets of Indianapolis. They’ve helped advertise the idea of sustainable stormwater management. Now we have private developers following the city’s lead.”
On some parts of the Cultural Trail’s 8-mile distance, there was enough room to install separate, parallel paths for pedestrians and bike riders, so the total amount of paving used was 11.25 acres.
Next to the streets are the low planters, curbed all around with cuts for runoff to flow into them. Then come the bike path, the rain gardens, and the sidewalk for pedestrians. All of these elements are laid in parallel linear paths, with some breaks for exiting or entering the trail. These pieces of green infrastructure also serve as visual barriers, separating vehicular traffic from the bicycles and the bike riders from pedestrians.
Some sections of the Cultural Trail were not wide enough for separate paths. Here the combined trail is a minimum of 12 feet wide. Permeable pavers were not used because many sections of the trail go past old buildings whose basements extend forward underneath the sidewalk.
Streets were raised to the level of the trail. A distinctive green thermoplastic logo marks the bike paths, alerting motorists that they are driving across a street section where bike riders are likely to be passing by.
Signage explains how the green infrastructure keeps stormwater out of the city’s overburdened CSS. The planters and rain gardens are filled with beautiful plants native to this area of Indiana.
Osburn says there have been no problems with bicyclists or walkers going into the stormwater planters. “The plantings in the planters are so full, so lush, there’s no place to step into. They have sedges, rushes, and native flowers that are used to having wet feet.”
Five acres of landscaping were installed along the Cultural Trail, and 500 trees were added. The Cultural Trail also includes $2 million worth of outdoor art for visitors to enjoy.
Indy’s Cultural Trail links to another 40 miles of bike paths, the Indianapolis Parks Green Trail System. Mayor Greg Ballard has set a goal to have 200 miles of bike trails open in the city by 2015.
An avid bicyclist, the mayor leads four bike rides for residents and visitors each year, including one in January. From his comments in online videos about the project, it’s clear that he understands how improving conditions for bike riders connects bikers and pedestrians to the city and also becomes a best management practice for dealing with urban stormwater.
Indianapolis officials have worked to make it easy for people not only to get some exercise, but also to commute to their downtown jobs by biking or walking on the trail. The downtown branch of the YMCA offers secure indoor bike storage, lockers, and shower facilities. There’s even a bike repair shop in its building.
And more bike commuters mean fewer cars dripping pollutants on the city streets–one more way the Cultural Trail is helping -Indianapolis manage stormwater.
The Indianapolis Cultural Trail cost $63 million to build, including the green infrastructure and other elements. $27 million was raised through private funds to get the project started. The remaining $36 million came from federal transportation funding, including a $20.5 million TIGER grant. Those funds include $2 million for public art along the trail and $1 million for a BikeShare program, which makes bikes available to anyone for short-term use. A $6 million endowment covers maintenance and operations expenses.
The annual economic impact of the Cultural Trail is an estimated $864.5 million. New restaurants and shops have opened and existing ones have seen their business income increase.
The project has created an estimated 11,372 new jobs.
Day says that to attract more tenants, apartment complexes even advertise that they’re “right on the Trail.”
Besides the challenge of convincing the city such to undertake an unconventional project, Osburn says, “safety was the number one concern. We had to design a project safe for all users.” If the project had been a failure, he notes, “it would have set urban bicycling back.”
Working in the oldest part of urban Indianapolis presented additional challenges. “We could not stick a shovel in the ground without hitting some utility line. There was a huge amount of coordination required to work through those utility conflicts,” recalls Osburn.
He says Indy’s Cultural Trail has sparked much interest from elsewhere. “We’re working with four communities in the state of Indiana. They all want their own version of the Cultural Trail. And we’re getting proposal requests from cities around the country.”
Ten varieties of sedum grow on the 7,500-square-foot extensive green roof.
RebuildIndy
Close to The Nature Conservancy is the Ohio Street pilot project to manage stormwater runoff with green infrastructure. This project was recognized as a valuable case study by the American Society of Landscape Architects’ Committee on Green Infrastructure.
The new installation is in the 600 and 700 blocks, a CSO location with a history of flooding and overflow problems. This area in the Cole Noble neighborhood was much in need of repair. Badly cracked sidewalks, weedy grass, puddles left after storms and other drainage problems, and an air of neglect had existed for years.
The Ohio Street project was the first of many RebuildIndy projects that featured sustainable infrastructure in 2010. It was done as a partnership that included the city of Indianapolis, the Cole Noble District Neighborhood Association, Indianapolis Downtown Inc., The Nature Conservancy, and the Buchanan Group.
The pavement on some sections of Ohio Street was worsened from poor drainage and subsequent freeze-thaw on the surface. Fortunately, the soil types at the project site were ideal for infiltration, creating a situation well suited for the use of porous concrete.
Ohio Street is a gateway into downtown Indianapolis for travelers from I-65. Having a major transportation corridor in such bad shape didn’t make a good first impression on visitors.
Williams Creek Consulting provided engineering and landscape design for the project.
Workers from Smock Fansler Corporation, the general contractor, replaced the old sidewalks with 2,650 square feet of pervious concrete pavement. They installed 900 linear feet of pervious concrete curbs and gutters and 222 square yards of porous concrete street.
An area that had been grass was converted to a rain garden measuring about 750 square feet. United Water gave the city a grant of $5,000 to pay for the rain garden’s installation.
The project manages runoff from 60,000 square feet of impervious surface, keeping an estimated 1.3 million gallons of stormwater from the CSS each year. That amount is 90% of the runoff for Ohio Street.
Although porous concrete often costs more than traditional paving, it was essential for adequate drainage on Ohio Street. Without it the city would have had to install drains, pipes, and other traditional gray infrastructure components. Thus, the porous pavement proved to be cost-effective. With its green infrastructure the Ohio Street project cost $37,500. If regular concrete and gray infrastructure had been installed the project cost would have cost $85,000, and the CSS would have had an increased load to bear.
A Community Nature Park
In another commitment to green infrastructure, the city is partnering with Keep Indianapolis Beautiful to plant thousands of trees. The goal is to have 100,000 trees planted by 2017 to intercept rain before it hits the sidewalks and streets, thus reducing runoff.
In the Washington Township section of Indianapolis a farmer named Peter Daubenspeck owned a lot of land near West 86th Street and Ditch Road. Over the years he sold parts of his land to developers for subdivisions. However, Daubenspeck decided to set aside the plot at 8900 Ditch Road. He gave it to the Metropolitan School District of Washington Township.
The 15-acre field was too small to build a new school, so school district officials eventually decided to sell it. Community residents protested at the loss of vacant land, so the school district reversed its decision.
Members of the Washington Township community formed a nonprofit organization to turn the vacant land into a nature park. The nonprofit group and the school system signed a 30-year renewable contract for the nonprofit to manage Daubenspeck Community Nature Park (DCNP).
In June 2006, the future nature park project was chosen by the national Hands On Network and The Home Depot to be part of their community service projects. More than 130 volunteers from The Home Depot, CitiFinancial, Indiana Native Plant and Wildflower Society, and the community worked together in September 2006 to transform the vacant lot. They created what became the original features of the park and planted more than 400 small trees and 1,000 wetland and prairie plants. Today the DCNP manages stormwater onsite and offers outdoor educational and recreational activities for children and adults.
Work on the separation of nine sewer outlets from the combined sewer system at Fall Creek. The runoff was rerouted to a rain garden.
Protecting Fall Creek
To help reduce raw sewage overflows and improve the water quality in Fall Creek, the Indianapolis DPW completed a $500,000 partial separation project of combined sewers near the College Avenue and Fall Creek Parkway area. Nine existing storm drains were redirected to a new storm sewer pipe.
The drainage area is 2 acres, and 83% of it was impervious. The storm drains and storm sewer pipe now collect stormwater runoff and carry it to a bioretention cell, where it is treated through a natural system of plants, soil, and stone before being released into Fall Creek.
The new storm sewer connects to a series of pipes within a stone filter at the base of the 70-foot by 35-foot bioretention cell. The stone filter temporarily holds stormwater until it rises to the top of the filter. After flowing over the top, stormwater is then absorbed into the bioretention cell. More than 1,300 native plants filter the runoff. They include red maple, river birch, witch hazel, spicebush, buttonbush, tassock sedge, and shenandoah red switch grass.
Porous stone below the soil captures additional pollutants. A perforated drainpipe below the layer of stone allows the treated stormwater to flow into Fall Creek.
The project was designed to handle a 10-year storm event. It treats 390,000 gallons of runoff annually.
Michael Massonne, the storm-water program manager for the DPW, notes that in using green infrastructure “outreach and education are critical. People need to understand how it works and that it has different maintenance requirements than gray infrastructure.”
Counting both education for residents and training for city employees, he adds, “It might be true that we get the biggest bang for our buck with education, covering the what, why, and how.”
Working with local residents DPW has had success with green infrastructure by installing “what we call a “˜hybrid ditch,'” he says. “It’s a shallow swale in the right of way across engineered soil with an underdrain. We use native plants, or turf grass if the homeowner prefers that.”
Massonne concedes that with turf grass, “We get good infiltration, but might not get uptake of nutrients. But citizens will take care of it because it’s easy to mow.”
Another green infrastructure strategy that’s working well is PaveDrain permeable pavers. Massonne says that DPW installs 3-foot-wide strips of the pavers as edging on both sides of streets that have no curbs or gutters. Underneath are engineered soils and an underdrain.
“It looks like a brick walk and fits into almost any neighborhood. We can vacuum them with special equipment fitted to the vacuum truck,” he says.
From small bits of green infrastructure along neighborhood streets to huge projects that change the face of the city, Indianapolis has clearly gone green to manage its stormwater. It will be interesting to see what innovative green infrastructure projects are completed in the future.
