A dragonfly finds habitat in a drainage ditch in Dunfermline, Scotland. Stormwater management structures support biodiversity, among other ecosystem services, but so far no one has successfully quantified those benefits.
- By Josh Ellis and MPC Research Assistant Daniel Wolf
- February 3, 2015
Stormwater was once seen as a nuisance to be disposed of as quickly and invisibly as possible. But this past week in Houston, Texas, engineers, planners and elected officials came together to confer on Low Impact Development, the practice of mimicking nature in order to manage stormwater. From the workshops, development projects and research presented, it’s clear that a drastic change of attitude has taken place.
Held by the Environment & Water Resources Institute of the American Society of Civil Engineers, the conference brought together experts from a variety of locations and disciplines. I (MPC Research Assistant Daniel Wolf) attended the conference to present my research on this topic and learn from other experts.
Some of the projects presented at the conference closely resembled the style of drainage systems that Metropolitan Planning Council (MPC) helped implement as part of Chicago’s Milwaukee Avenue Green Development Corridor. But several presenters demonstrated projects using similar technologies adapted for a variety of climates.
Metropolitan Planning Council
As part of Chicago’s Milwaukee Avenue Green Development Corridor, a backyard in Logan Square is equipped with permeable paving and native plants, both of which help stormwater soak into the ground.
Dr. Denver Cheddie of the University of Trinidad and Tobago presented a study on the use of coconut husk fiber, a common waste product found throughout the Caribbean, for filtering stormwater before discharging it into waterways. Dr. Curtis Hinman of Herrera Environmental Consultants investigated how permeable paving can remove contaminants from runoff tainted with even the most “smoking hot” street dirt from Puyallup, Wash. And, most compellingly to me, Kelly Collins of Albuquerque, N.M. explained the role of green infrastructure in the desert climate of the American Southwest.
Unlike the Chicago area, where overabundance of water presents a challenge, New Mexico receives precious little rainfall. When a storm does occur, flash flooding ensues, transforming Albuquerque’s system of arroyos from dry, concrete ditches into gushing torrents. Large flotsam like tree branches and even motor vehicles have been known to wash downstream in such events. Keeping water onsite is the approach Collins recommends for remedying both of New Mexico’s water issues. Slowing the flow of stormwater often requires vegetated landscapes, but in New Mexico’s arid climate, there is not enough water available throughout the year to irrigate plants. Instead Collins, along with Albuquerque Metropolitan Arroyo Flood Control Authority, has implemented mechanical water quality structures that slow the flow of water, allowing debris to settle. The resulting effluent is cleaner and less destructive.
Water Quality Structures installed in Albuquerque’s system of arroyos intercept debris from flood waters. From left to right, view from outside and view from inside. Among the debris are drink containers and a couch.
While the conference also informed my research at MPC, I attended on a generous bursary from the Scottish non-profit Saltire Society to present a study that I began in Spring of 2014 as my master’s dissertation in Ecosystem Services at the University of Edinburgh, Scotland. The study weighs how much it costs to construct and maintain a series of stormwater management features against the quantifiable benefits of those features over time.
On average, the stormwater management features I studied in Scotland deliver benefits worth over three times that of their expenses.
My study site is a mixed-use development consisting of commercial, residential and industrial buildings lying outwith the ancient city of Dunfermline in Eastern Scotland. Having been constructed in the mid 1990’s, the stormwater management features at the site are some of the oldest in the world, making them ideal for studying lifecycle and maintenance costs. I gathered precise costs of construction and maintenance activities from government agencies, developers and landscaping companies who had built and maintained the structures at the site. Then I assessed the costs and benefits of water quality, hazard management and property value increase. No previous studies had carried out cost-benefit analysis of constructed ponds, detention basins or stormwater drainage ditches using robust data. I found that on average, the stormwater management features I studied in Scotland deliver benefits worth over three times that of their expenses.
Much of MPC’s work is similar to the practices advocated for at the conference. We’ve pushed for policy change to allow re-use of stormwater and graywater, we’ve collaborated with municipal and private agencies to inform people about water conservation and we’ve worked with community groups in order to secure public funding for stormwater management retrofits. Many of the projects MPC is working on in 2015 offer opportunities to implement green infrastructure, from river rehabilitation to post-industrial site restoration. As the conference in Houston demonstrates, a plethora of technical knowledge abounds, and peoples’ attitudes about stormwater are changing. What was once seen as a mere waste product is now recognized as a vital resource. Chicagoans can look forward to greener stormwater management projects cropping up in their neighborhoods in the near future.