The City of Ann Arbor and Washtenaw County have invested in a unique study along Swift Creek. With the aid of grants from the DEQ and United States' E.P.A. "green infrastructure" will be installed and studied in a target residential neighborhood.
In this week's Issues of the Environment, David Fair discusses the project with the Huron River Watershed Council's Ric Lawson.
* HRWC was awarded a grant from the DEQ and U.S. Environmental Protection Agency to install and study the effects of new “Green Infrastructure” (GI) practices in a target residential neighborhood in Swift Run.
* The City of Ann Arbor and the Washtenaw County Water Resources Commissioner’s office matched those grants by $240,000 for a total of $950,000; the funds will be used to counteract sedimentation, nutrient loading, and bacterial contamination, and return the organic flow of Swift Run.
* Ric Lawson, Watershed Planner for the Huron River Watershed Council, says this “green infrastructure project” is unique in that it uses a targeted geographic approach. Instead of sprinkling practices across a larger region, this project focuses the effort in one neighborhood in one watershed (Swift Run) that is significantly impaired yet has received little previous attention.
* Return Swift Run to a free-flowing stream by reducing runoff volume from storms and increasing groundwater flow;
* Reduce phosphorus and sediments in the stream by providing natural filtration through “Green Infrastructure” throughout an important residential neighborhood; and
* Improve habitat and stream life in Swift Run by improving stream flow dynamics.
Location and Current Land Use
The target tributary watershed of Swift Run drains to the Geddes Pond impoundment of the Huron River in Washtenaw County, upstream of Ypsilanti. The watershed encompasses 5 square miles, most of which are urbanized in older vintage residential and commercial development. The vast majority of the watershed is within City of Ann Arbor. Land uses are as follows based on data from 2000: Agricultural: 27.5% (most of which is a misclassified landfill); Urban: 50.6%; Forest: 3.7%; Water/Wetland: 7.2%; and Open/Public Recreation: 11.0%. Total impervious (paved or otherwise hardened) area in the watershed is estimated at 23.3% based on these land uses. More recent evaluation of aerial data (2008) directly estimates 30% impervious cover for the target neighborhood. National research indicates that streams begin to be impacted at impervious cover over 10%.
Swift Run Need for Improvements
Swift Run has been identified by the Michigan Department of Environmental Quality (DEQ) as “impaired” based on low biological diversity. These biological impairments were found to due to altered stream flow conditions and high amounts of sediment covering stream habitat. The creek is also part of sections of the Huron River watershed that are impaired for: 1) excessive phosphorus, which contributes to algae growth downstream, and 2) high levels of bacteria that could cause human health concerns from recreational contact exposure.
HRWC developed a watershed management plans (WMP) the middle Huron River section as a whole, as well as Swift Run in particular. The top impairments listed in the middle Huron WMP are high sediment and nutrient loadings, altered hydrology, and pathogens. The main causes of these impairments are related to urban development without proper stormwater impact planning.
HRWC was awarded a grant from the DEQ and U.S. Environmental Protection Agency to install and study the effects of new “Green Infrastructure” practices in a target residential neighborhood in Swift Run. The $700,000 grant was one of only seven awards selected by MDEQ in 2014. The grant funding is being matched with $240,000 from project partners at the City of Ann Arbor and the Washtenaw County Water Resources Commissioner’s office for a total project value of almost $950,000.
Overall, the combined Green Infrastructure efforts planned will reduce the effective impervious cover in the neighborhood by a third from 30% to 20%. This will, in turn, annually reduce runoff volume by an estimated 21%, phosphorus loading by 17%, and sediments by 21%. These reductions should return some natural flow to the creek and allow for life to return to the creek as well.
Specific objectives of the project include:
1. Educate and recruit participation of target neighborhood residents. Educational materials will be designed to educate residents about the importance of local stormwater control and GI practices available to them. The materials will also encourage their participation in rain garden and downspout disconnection programs. Materials will also be delivered via a number of neighborhood meetings.
2. Develop design plans and construct three Green Streets. Three residential streets were identified in the target neighborhood to be retrofitted with a series of bioinfiltration “bump-outs” to capture and treat runoff from streets, sidewalks, and driveways. Curb cuts will allow runoff to route to bioinfiltration, with overflow running to existing storm catch basins.
3. Select homeowners for residential GI projects. HRWC will follow-up with interested residents who respond to information in objective 1 by encouraging them to participate in one of two programs below.
3A. Select homeowners for participation in a Downspout Disconnection Program. HRWC will work with residents in the target neighborhood who have roof gutter downspouts that are directly connected to storm drains. HRWC and partner staff and volunteers will visit with each interested homeowner and determine the feasibility of downspout disconnection and work with the homeowner to disconnect. The number of disconnected downspouts will be tracked along with the estimated roof surface area.
3B. Select up to eight homeowners or community properties for small rain garden design and construction. The Washtenaw County Water Resources Commissioner's office runs a successful program to provide homeowners with rain garden designs, technical assistance, plant selection and purchase, and construction oversight. The project will provide resources to select rain garden sites that will provide the greatest reductions in stream impairments and provide technical assistance and support to the homeowner in rain garden site preparation and construction.
4. Develop design plans and construct two public GI projects. Two public projects are planned for construction that will reduce and treat more runoff than smaller rain gardens. The high-visibility projects will illustrate how small public areas can be used to replace impervious grey infrastructure, with GI to infiltrate runoff from the majority of storms. The two projects are described below.
1. Pittsview Park: Pittsview Park is a simple design with connected bioretention cells along Packard Road park border. This bioretention cell includes catch basin diversions to collect road runoff into an area in the sidewalk extension. The main cell in the park is larger and deeper, accepts overflow from the Packard cell and sheet runoff from unpaved Pittsview Road. This project has the greatest visibility of the two.
2. Redwood Park: The Redwood Park project is the smaller of the two, but will capture and treat runoff from the road intersection of Platt and Redwood. It will include curb cuts to divert road runoff into two bioretention cells. The park remains a small public space with good neighborhood visibility.
5. Measure the success of GI implementation and the impact on Swift Run. HRWC will carry out a complete pre and post-project evaluation including social surveys and stream monitoring. Project results will be shared broadly by HRWC and partners. (Source: email for Ric Lawson)
Uniqueness of GI Approach
What makes this suite of GI projects unique is the targeted geographic approach. Instead of sprinkling practices across a larger region, this project focuses the effort in one neighborhood in one watershed (Swift Run) that is significantly impaired yet has received little previous attention. This context provides an opportunity to test targeted implementation of GI practices as a watershed treatment. This same strategy was used successfully by HRWC in Millers Creek, which is impacted by altered stream flow. There, a suite of neighborhood projects were implemented that resulted in runoff flows that were significantly reduced. Applying the neighborhood approach in this case is expected to show similar success, but the proposed project differs in the types of practices deployed. The project launched this fall. It builds on Green Infrastructure planning products developed by HRWC that can be found at www.hrwc.org/green-infrastructure<http://www.hrwc.org/green-infrastructure>. (Source: email for Ric Lawson)
More on the Degradation of Swift Run Creek
Swift Run Creek, an urban freshwater stream located in the greater City of Ann Arbor, Michigan, suffers from the ills that plague similarly encroached upon waterways. State biologists and local volunteer stream monitors recorded problems with Swift Run Creek going back several decades – few fish and aquatic insects; severely eroded and undercut banks; scouring flood waters; baseflows too low to support life; and high levels of pollutants. Among the actions taken to restore some ecological balance to Swift Run Creek, was the state’s decision to employ the tool granted them by the federal Clean Water Act to develop pollution budgets, the Total Maximum Daily Load.
In 2004, the Michigan Department of Environmental Quality developed a Total Maximum Daily Load (TMDL) for Swift Run Creek intended to restore the indigenous aquatic life to the stream – fish and aquatic bugs. The TMDL focuses on the pollutant Total Suspended Solids (TSS) as the main culprit in preventing aquatic life to flourish in Swift Run Creek. The concept is fairly straight‐forward: reduce TSS to levels that allow native fish and insect species to thrive in the creek.
The land managers and water resource managers in this region have demonstrated on‐going
commitment to mitigating impacts to Swift Run Creek and restoring its ecology through several
watershed planning initiatives and project implementation. Swift Run Creek was included in the
Watershed Management Plan for the Ann Arbor‐Ypsilanti Metropolitan Area (1998, updated 2008) and the Phosphorus TMDL Implementation Plan for Ford and Belleville Lakes. Swift Run Creek is located within the section of the Huron River watershed (HUC 04090005) known as the middle Huron River watershed.
The multi‐pronged strategy to meet the biota TMDL involves public education and outreach, policy solutions, and restoration projects within the stream channel and watershed. This Implementation Plan provides a discussion of the Swift Run Creek biota, the progress made towards restoring the creek for fish and insects, and past and proposed restoration activities to meet this goal.
Green vs. Gray Infrastructure
Infrastructure is the stuff of human development. It often conjures images of roads, bridges, buildings, pipes, cables, and parking lots. It is the foundation of modern human society and provides for important human values such as communication, transportation, economic development, safety, and artistic expression.
Yet there is a side to infrastructure that has often been overlooked in human development: green infrastructure (GI). If railroads and buildings can be called gray infrastructure, then open spaces, wetlands, streams and rivers are the often overlooked GI. The ecosystem services they provide have always undergirded our towns and cities, but only recently have we come to appreciate and quantify their value. Through GI, our water is cleaned, our natural settings are preserved, local wildlife find habitat, and our temperatures are moderated . . . all free of charge.
Naturally-occurring GI, such as wetlands and meandering streams, can be mimicked through human-constructed GI for the purpose of managing stormwater. Designers and engineers now construct bioswales, rain gardens, green roofs, pervious pavement, and various site-specific infiltration designs. The point of these projects is to draw stormwater into the groundwater instead of piping it quickly into streams, where it carries pollution raises the water temperature and causes flashy, eroding creeks. Vegetated GI features capture rain water, filter it through the soil, cool it, and slowly deliver it to streams via groundwater.
Green infrastructure is not merely rain gardens and bioswales. Each of these features would be more accurately described as Low Impact Development (LID), or the implementation of best management practices at the site-specific level. GI, like grey infrastructure, expands the same idea to a community-wide scope. Its focus is on the planned, strategic placement of LID features and on the accounting of reduced stormwater volume and pollutant loads those features provide. It requires planning and inter-jurisdictional communication. (Read more about the differences between LID and GI along with case studies<http://www.hrwc.org/our-work/programs/green-infrastructure/lid-vs-gi/>).
Gray infrastructure and GI are similar in some ways, but differ in others:
* Removes stormwater and delivers it to local streams quickly
* Overlays or replaces natural systems with impervious structures
* Requires planning and costly maintenance
* Requires upgrading to accomodate increased stormwater flow that results from development and climate change
* Is limited to stormwater-removal benefits such as flood reduction
* Treats stormwater on-site and delivers it to streams slowly
* Incorporates natural systems
* Requires planning and less-costly maintenance
* Can supplement grey infrastructure to prevent major system upgrades
* Has multiple, quantifiable benefits beyond stormwater-removal
Green Infrastructure and Sustainability
A community that incorporates GI alongside gray infrastructure for stormwater management is concerned about sustainability. The economic benefits of GI have been shown to outweigh those of grey infrastructure, especially at the community-wide scale. In addition, GI helps protect water quality and aquatic ecosystems. It retains a natural landscape aesthetic, which increases property values and quality of life. It provides habitat for local and migrating birds and wildlife. GI is a smart choice for stormwater management because of its many benefits.
Yet many barriers stand in the way of GI implementation. The HRWC spent a year learning about and describing the barriers. They interviewed county, city, and township managers, surveyed the latest literature, and brainstormed options for overcoming the barriers. They also hosted a series of “Growing Green Infrastructure Forums<http://www.hrwc.org/our-work/programs/green-infrastructure/growing-gi/>” with our local partners, [including public and private interests like the Washtenaw County Water Resources Commissioner’s office and neighborhood groups in areas of the county negatively impacted by excessive gray infrastructure.](Source: http://www.hrwc.org/the-watershed/watershed-protection/green-infrastructure/)
Ric Lawson, Watershed Planner for the Huron River Watershed Council, joined HRWC staff in 2006, but has been volunteering for HRWC since 1999. He is primarily responsible for coordinating the development and implementation of several watershed management plans in the upper, middle and lower sections of the watershed. He also runs the Water Quality Monitoring Program across the watershed, and is facilitating Green Infrastructure planning for stormwater. Ric earned joint Masters Degrees in Environmental Management and Public Policy at Duke University. (Source: http://www.hrwc.org/about/staff-of-hrwc/)