“Let it Rain” — a raingarden project in Central Ohio
(from an engineer’s perspective)
Joseph C. Tribble; PE, CPESC
Stormwater Consultants, LLC
Installing the dry stream
© Joseph C. Tribble
I was fortunate to have had the recent opportunity to work on a raingarden design and installation project with Amy Dutt, of Urban Wild, and members of the First Unitarian Universalist (First UU) Church of Columbus (Ohio). Both Amy and I donated much time and effort on this project, but members of the church donated a good deal of time and effort as well. In addition, they gave us trust and patience — and that was very much appreciated. Without that, the efforts of Amy and myself would have been much more difficult. There were many other contributors on this project and they are mentioned below.
Raingardens – a new stormwater management tool
After over two decades of designing subdivisions, commercial sites and roadways in central Ohio, I thought I had mastered the art of stormwater management design. Paving the landscape and piping the runoff, with a little detention (to slow flowrates down a bit) and some treatment (to remove a few pollutants) had always been a good recipe. It was fast and efficient — and getting stormwater to the rivers as quickly as possible, after all, had always been the main goal. A little erosion, especially where no one would notice, wasn’t going to hurt anything, and, if it did, we could always just add a little more rock channel protection.
It took a while for the raingarden concept to catch on with me. At first, I wasn’t too impressed with the “landscaped holes in the ground” that didn’t drain anywhere. I couldn’t envision how they would be anything more than a mere “drop in the bucket” in the overall stormwater management scheme. But, I humored my raingarden friends and, in the process, began to come around. Maybe draining stormwater into a system of “engineered” filters could remove pollutants as effectively as conventional methods. Maybe giving stormwater an opportunity to recharge the groundwater system (reducing nuisance flooding and hard costs along the way) might be beneficial as well. If we put some thought and effort into this concept, maybe raingardens could become an effective tool to manage runoff, pollution and construction costs. It could be a win-win-win scenario.
When you get down to it, raingardens are nothing more than “sexy” bioretention filters (engineered depressions that treat first-flush runoff and allow managed infiltration) anyway. But, that sexy part of raingardens (ornamental plants, dry streams, etc.) is important. In order for them to catch on as a mainstream stormwater management tool, they have to provide aesthetic appeal. Equally important, however, is the ability to get them designed and constructed efficiently. If the design-build community could find ways to aesthetically, efficiently and cost-effectively incorporate raingardens (in lieu of traditional landscaping) into site-scapes, we might be able to use them to make a positive difference in “stormwater sustainability”.
A Raingarden Opportunity
In March 2009, when Heather Dean of FLOW (Friends of the Lower Olentangy Watershed) and I became aware of grants, from MillerCoors and River Network, to create sustainability demonstration projects, we jumped at the opportunity to create a raingarden project in the Olentangy River watershed — and we knew just the place to do it. Through another endeavor, we had become familiar with the First UU Church in the Clintonville area. They were good neighbors in the community, interested in environmental stewardship and, best of all, had a property that would allow a great demonstration raingarden to be installed. With the help of Amy Dutt, Heather partnered with First UU, prepared a winning proposal (complete with a project budget and concept plan) and received one of the MillerCoors/River Network grants. The concept plan included a stone wall and native plant material, both of which matched the surrounding landscaping, and a decorative “dry stream”. Winning this proposal was exciting for me. I’d be able to work with Amy, participate in the design and construction process — and see this raingarden concept develop first-hand.
Although I was familiar with raingardens, I had never been involved in the design or construction of one before. A successful proposal and a concept plan were a good start, but there was also the issue of making it work — and trying to get it constructed before winter. Those issues made me a little nervous. This project would require retrofitting an existing roof drainage/storm piping system and those types of projects did not always go smoothly. I didn’t know it at the time, but building this raingarden was going to require a monumental effort on the part of the church and the design team — and significant coordination and cooperation with the City of Columbus, Columbia Gas, Igel Construction and others. I didn’t know it at the time, but building this raingarden was going to be an educational experience.
The location of the raingarden was a given. The green space on the north side of the First UU property had been a perfect spot from the beginning. Rainwater from the roof area was convenient, the location was highly visible to surrounding streets and there was plenty of unencumbered area (or so we thought) to work in. Our first assignment, however, was to determine the size of the raingarden. Although there are easy equations to compute raingarden size, this calculation wasn’t that straightforward. The configuration of the existing roof and pipe system(s) created a scenario where, if designed conventionally, we would have had either a very small garden (serving only a small part of the roof area) or a very large and expensive garden (serving the much larger roof area). Neither option was consistent with our project goals and budget.
We settled on a unique design. Our approach was to construct a manageably-sized raingarden and take the entire roof area to it, but incorporate two major deviations from conventional raingarden designs. The first deviation was to inlet stormwater from the roof and pipe system into a sub-surface aggregate trench, immediately below and integral with the dry stream. This gave us some much-needed elevation difference and would allow diffusion of the concentrated pipe system flows, keeping them from eroding the raingarden surface during heavier rains. The second deviation was to provide an overflow device (in an existing upstream manhole) that would allow excess roof runoff to bypass the raingarden when it reached capacity during storms that produced more rain volume than it could handle. This would keep the raingarden from being “flooded out” on a regular basis. Both of these deviations allowed us to treat the larger amount of roof area while protecting the raingarden as well. I hope these concepts can serve as a model for future projects (Raingarden System Schematic).
With our unique design approach in hand, the next task was to get City of Columbus approval of our concept, including the required modification to the existing sewer plan for the property. As many will attest, modifying an existing plan, even without a unique design approach, was normally a time-consuming process. In this case, however, working with the City could not have been easier. With the sustainability effort in mind, they took the time to understand what we were trying to accomplish — and worked with us as we obtained the necessary construction permit. The only major requirement was that we use a licensed contractor to retrofit the existing system. The City’s final and biggest help, however, was waiving the $2000 inspection fee. Without that, starting the project may have not been possible.
Raingarden Retrofitting — expect the unexpected
Gas Line Relocation
Retrofitting anything, especially when it’s old and background information is sketchy, can be a challenge. Our First UU Raingarden project would certainly prove that to be true. Before construction, we were aware that there would be conflicts with an existing irrigation system, but we had no idea that a 20-year-old gas service line would become our main roadblock. One of our project partners, Greenworks Ecological, was scheduled to begin garden excavation, but they had not been on the job thirty minutes before the discovery of the line in our work area brought everything to a complete halt. As it turns out, the gas service line had been constructed improperly, which had made it impossible to locate prior to beginning work. Regardless, a muddy mess had been created in a very visible location and we were stopped dead in our tracks. We knew people at the City who could help us with our plan approval, but finding someone to work with at the gas company was another matter.
I can’t say enough about the effort Amy Dutt put forth in making the First UU Raingarden project a reality. In addition to donating her time for design and installation project management, she worked tirelessly to stay on top of, and resolve, any problems that arose. Amy’s work with gas company representatives paid off almost immediately. Columbia Gas became a willing partner in our project, relocating the gas service in a very timely manner and at no cost to us. Without that, continuing the project may not have been possible.
Pipe system installation
With the gas service relocation completed, we were left with one last hurdle — finding a licensed contractor to retrofit the existing manhole with the bypass device and construct the new pipe system to the garden. Once again, Amy came through. She contacted her friend Joe Igel, who graciously volunteered his company to help us out. Igel Construction completed this last piece of the raingarden infrastructure, along with some of the remaining site grading, and did so in a timely and professional manner as well. As before, this work was done at no cost to the project, allowing us to complete it within our grant budget.
Having completed the raingarden infrastructure, all that remained now was installation of the interior stone wall, dry stream and raingarden plants. For a “normal” raingarden, this step would have been major, but, for us, it was no big deal. We had already overcome several hurdles and were now in the home stretch. The raingarden gods, however, weren’t finished with our project yet — not without sending a little rain our way. Ironic, don’t you think, that, after all that effort, we could not complete the last step because the ground surface was too wet.
A few dry, late October days, however, allowed the wall (with help from Jim Roberts of Watershed Organics), stream and plants to be installed — and the First UU Raingarden became a reality on November 5, 2009. There are still a few minor items on the 2010 spring punch-list, but it looks great. If we can just get past one last irony, it would be awesome. That last irony, of course, is the perfect weather we’ve had since completion. “Let it Rain” — we’d all like to see our new raingarden in action.
Dry Stream Installation
Being a part of the First UU Raingarden project was a great experience — not only from the knowledge I gained, but from the people I had the opportunity to work with. I was surprised at the level of cooperation we received from many parties. Cooperation that, in this economy, was unexpected. Although we were successful, I caution anyone who wants to retrofit a raingarden into any existing system. Expect the unexpected — and allow for time delays and additional costs. “Stuff Happens”!!!
With that said, I’m convinced that raingardens can have a prominent place in existing system and new-build stormwater management. For new-builds, raingarden networks, if properly planned at the beginning of a project, can be a very useful tool. As with conventional designs, however, they must be strategically placed on, and interfaced with other elements of, the site. Raingardens are not appropriate in all soil situations, should be kept away from building foundations, basements and heavily-trafficked or heavily-loaded areas and, as with other stormwater management methods, should be designed to consider and avoid water back-up and freeze-thaw issues. With these precautions in mind, however, raingardens, can, in my opinion, become a viable stormwater management tool.
After over two decades, it is possible to learn something new.
© 2005 – 2014 FLOW all rights reserved.
Volunteers planting wildflowers at project site in May 2007. © C. Gresham
Rush Run is a 1.5 mile long tributary of the Olentangy which drains approximately 2 square miles in Franklin County. Its natural flow has been channelized, and the streamside vegetation has been altered. Invasive plants such as honeysuckle and garlic mustard have crowded out native wildflowers along the stream banks in the residential areas, and turf grasses dominates the industrial areas. The water quality is listed as fair to poor.
In 2006 the National Fish and Wildlife Foundation awarded FLOW a grant to restore a section of the streamside along Rush Run. FLOW selected a 408 foot section in Park Blvd. Park, in Worthington because it was heavily overgrown with invasive honeysuckle and because it was located on park land where it could attract public interest and participation.
In its natural state, the streamside vegetation of Rush Run would consist of a balance of trees, shrubs, grasses and wildflowers. This vegetation would provide erosion control, shade, and a variety of habitats for wildlife. However, the Amur honeysuckle (Lonicera mackii) dominates the banks of Rush Run. Very few native wildflowers and shrubs can survive the crowding and shading. Introduced to the Midwest from Asia in the 1800’s as a garden ornamental, Amur honeysuckle has escaped cultivation. It spreads easily by seed, is fast growing, and is very adaptable. The Ohio Department of Natural Resources has more information on invasive bush honeysuckle.
In the spring of 2007, FLOW and the Worthington Department of Parks and Recreation began to restore native vegetation. Volunteers contributed over 450 hours to clear the banks of honeysuckle and plant 94 native trees and shrubs, 50 ferns and over 900 perennial wildflower plugs. Volunteers also planted a seed mix of native floodplain species and watered and mulched the area throughout the dry summer. FLOW has compiled a list of plants used in this restoration (scroll down) and a gallery of photos showing the work accomplished.
Volunteers monitored water quality before and after the restoration, and FLOW will be continue to monitor Rush Run at Park Blvd. Park in the future.
An educational sign was placed on site in November 2007 describing the work accomplished at Park Blvd. Park. FLOW will participate in the upkeep of this section of Rush Run in the future. Watch for future workdays at Park Blvd. Park in the FLOW Calendar of Events.
An educational sheet for class or scout visits to Park Blvd. Park is available, as well as information on what you can do to improve streamside corridors in your neighborhood.
This project was funded by a generous grant from the National Fish and Wildlife Foundation.
FLOW would like to thank the following organizations and individuals for their participation in making this project successful.
Worthington Parks and Recreation Department
Worthington Public Service Department
Franklin Soil and Water Conservation District
Friends of Rush Run
Boy Scout Troop 365
Thomas Worthington High School Advanced Biology Classes
David White for GIS and Stream Monitoring Support
Ellie Nowels of Centipede Graphics
Friends of the Ravines
Colonial Hills Civic Association
Russell Tree Experts
ODNR Division of Forestry
ODNR Division of Natural Areas and Preserves
Photographers: Cyane Gresham, Marty Kotter, Mike Hock, David White
Plant List for Rush Run Riparian Restoration Project
Planting trees and shrubs at Park Blvd. Park during May 2007 workday. © C. Gresham
Trees and Shrubs (94 planted)
- Bur Oak
- River Birch
- Swamp White Oak
- Paw Paw
- Shadblow Serviceberry
- Highbush Cranberry
- Red Bud
- Flowering Dogwood
Native Herbaceous plugs for Planting (960 planted)
- Great Blue Lobelia Lobelia siphilitica
- Cardinal Flower Lobelia cardinalis
- Hairy Woodmint Blephilia hirsuta
- Virginia Bluebells Mertensia viginica
- Golden Ragwort Senecio aureus
- Wild Bergamot Monarda fistulosa
- Wild Geranium Geranium maculatum
- Wild Blue Phlox Phlox divaricata
- Tall Bellflower Campanula americana
- Obedient Plant Physostegia virginiana
Ferns (50 planted)
- Sensitive Fern Onoclea sensibilis
- Christmas Fern Polystricum acrostchoides
- Lady Fern Athyrium Filix-femina
Seed Mix for well drained floodplain (for ¼ acre)
- Side Flowering Aster Aster lateriflorus
- Panicled Aster Aster simplex
- Sweet Joe-Pye Weed Eupatorium purpureum
- False Sunflower Heliopsis helianthoides
- Smooth Beardtongue Penstemon calycosus
- Cupplant Silphium perfoliatum
- Green-headed coneflower Rudbeckia laciniata
- Wingstem Verbesina alternifolia
- Franks sedge Carex frankii
- Brown Fox Sedge Carex vulpinoidea
- Virginia Wild Rye Elymus virginicus
- Riverbank Wild Rye Elymus riparius
- Beak Grass Diarrhena americana
- Bottlebrush Grass Hystrix patula
The Olentangy River receives high volumes of stormwater at high velocity due to the impervious surfaces, such as parking lots and roofs that do not allow the water to soak into the ground. In addition to the “too much too fast” problem, the water entering the Olentangy River is polluted after travelling over roads and parking lots picking up whatever is in its the path. The lack of infiltration or ability to soak in the ground also causes streets to flood, basement backups and excessive erosion of streamside property.
The solution is to restore the infiltration and the storage capacity with “green infrastructure”. Green infrastructure are structures such as rain gardens, infiltration trenches and rain tanks that allow rain water to soak into the ground, evaporate back into the atmosphere and/or remain stored to be reused later. FLOW created the “Soaking It In” program to engage the local public and city officials concerning the solution to the interrelated problems of a sediment laden Olentangy River, flooded streets, sewer backups and the loss of streamside property.
The Columbus Mennonite Church (CMC) agreed to participate in the program to address sump pump issues and to demonstrate environmental stewardship. After receiving funding from Honda of America Foundation, FLOW and Urban Wild worked with CMC members to create a comprehensive rainwater management solution. With the help of volunteers, a rain garden, an infiltration trench and a rain tank were installed in the fall 2010.
Combined these different structures will harvest or infiltrate approximately100,000 gallons of rain water per year from the 6800 square feet of the church roof. By keeping the water on site, the Olentangy River will not receive as much sediment and other pollutants. The rain garden and other structures are helping to restore the storage capacity that has been lost as a result of tributaries being culverted and wetlands filled along the Olentangy River. We hope that this demonstration project will encourage local officials and the general public to consider installing green infrastructure in public spaces and backyards.
The “Soaking It In” program has been a success in large part because different partnering entities came together to make it work. Columbus Mennonite Church members Al Bauman, Phil Hart, Marlene Suter and Ruth Massey helped plan the project and provided logistical help that enabled the project to run smoothly. Amy Dutt, owner of Urban Wild, planned and coordinated the green infrastructure site design and implementation, as well as donated some of her time to see this project to completion. Other businesses who helped FLOW with discounted services were the Rain Brothers and Scioto Gardens. Volunteers from the local community helped by planting the rain garden and installing the infiltration trench. Ellie Nowels from Centipede Graphics created a beautiful sign that captures the entire project. Of course, this project would not have been possible without funding from the Honda America Foundation. In 2011, FLOW looks forward to completing the project by installing one or two more rain gardens.
Park Blvd. Park in August 2007 after streamside restoration. Photo by M. Kotter
Four blocks west of Colonial Hills Elementary School is a small neighborhood park at Park Blvd. and Granby. It is a 6.1 acre park with a grassy field and picnic tables. A stream called Rush Run divides the park. Forest trees and other dense vegetation border the stream. A bridge crosses the stream in the center of the park and you can follow a walking path beside the stream.
What is new at the Park? In April 2007, FLOW worked with the Worthington Parks and Recreation Department to begin to restore native vegetation to the streamside. Volunteers worked along 400 feet of the streamside, removing an invasive shrub called bush honeysuckle. This shrub has escaped cultivation and shades out native wildflowers as well as native tree saplings. Honeysuckle does not provide the variety of habitat and food that wild animals need. In May, volunteers planted 94 native trees and shrubs, 50 ferns, and over 900 native wildflower plants! A seed mix of floodplain loving plants was spread over the ground. During the hot summer, volunteers and park employees watered the new trees. In November, a new sign explaining the restoration project was put in place by the bridge. The goal of this restoration project is to not only improve the streamside environment, but to improve the aquatic habitat as well. It will also serve as an example what Worthington residents can do to improve their streams.
Come visit the Park!
Bring your class for a nature exploration to Park Blvd. Park. It is a short walk from your school. Take an hour or an afternoon to explore. Please note: FLOW and Worthington Parks and Recreation will not be providing fieldtrip leaders for your visit. You are on your own. Please remember to practice “minimum impact.” Take only pictures and leave only footprints at the park. Thanks!
Winter Exploration Suggestions:
- Look at the colors and shapes in the winter.
- What colors dominate?
- Can you find all the colors of the rainbow in nature during the winter?
- How does snow change the shapes of natural objects—logs, trees, hills, rocks?
- Explore the winter sounds.
- How does snow change outdoor sounds?
- Can you count the number of different sounds from nature you hear in one minute?
- Can you find the mammals or birds making the sounds?
- Explore animal tracks.
- How many different kinds of animal tracks can you find?
- Can you identify some?
- Note that many neighbors walk their dogs through the park so it is important to know what their tracks look like. A good track guide to use is A Field Guide to Animal Tracks by Olaus Murie or visit ODNR’s Species Guide.
- Compare the restored area to the unrestored area along the stream.
- Is there a difference in the activity of birds and animals in the restored area than the unrestored area, by sound, and by number of tracks?
Spring Exploration Suggestions
- Look for the emergence of spring wildflowers.
- Many native species emerge in early April before the tree leaves emerge. Look for these species: Spring Beauty, Dutchman’s Breeches, Wild Geranium, Bloodroot, Virginia Bluebells, Blue Phlox and Golden Ragwort. Please don’t pick the flowers!
- For photos of Ohio Wildflowers visit ODNR.
- Streamside forests are great places to observe birds in the early spring.
- Look for American Robin, Carolina Chickadee, White-breasted Nuthatch, Tufted Titmouse, Downy Woodpecker, and Red-bellied Woodpecker. Use a field guide such as Sibley’s Field Guide to the Birds or visit ODNR’s Bird Species Guide.
Compare the restored area and unrestored area along the stream with bird sitings and wildflowers.
Spring Conservation Projects
Your class may be interested in helping the Park and the Rush Run. In past years, classes have planted a tree for Arbor Day. To arrange a class conservation project, contact Jim Coffield or Shawn Daugherty at Worthington Parks and Recreation 786-7368.