RCP Rethinks Urban Water Cycle

Students from ARCH 8567 on a site visit to Minnetonka. Photo by Katie Thompson.


For most of us, the urban water cycle is largely invisible, except when it fails. Recently though, I accompanied ARCH 8567: Building and Site Integration in Sustainable Design, on a class field trip to Ridgedale mall in Minnetonka. Don't worry, the class was way more fun than the title suggests. One of almost a dozen University of Minnesota courses participating in the Resilient Communities Project (RCP), in partnership with the city of Minnetonka, ARCH 8567 looks at how building and site design impact the urban water cycle.  The class's primary objective is to come up with design options for Ridgedale mall's redevelopment plan that will make sustainable use of Minnetonka's water resources.

So, why does Minnesota take mall infrastructure so seriously? Peter MacDonagh, Adjunct Professor in Landscape Architecture, put it together for me, “It's the weather.” Evidently, six months of deep freeze across the state is a big incentive to create large, interior public spaces. I never thought of going to the mall as a remedy for cabin fever, but it does situate mall infrastructure within a more logical context.

Sort of.

Though the need for interior public spaces is clear, much of what is familiar about mall infrastructure is anything but logical. MacDonagh explained that many of the characteristics we have come to identify with malls reflect old ideas of “convenience” and how people use public spaces. Specifically, Ridgedale mall is a classic 1970's layout with sprawling parking lots and circuitous pathways between each “village center.” Consumers are forced to drive between storefronts that happen to be on different sides of the mall's widespread complex.

According to Jeff Thomson, Associate Planner for Minnetonka, most of the year, the parking lots are largely empty stretches of pavement that prevent stormwater from seeping into the ground. This increases runoff, which contributes much of the total water volume that must go through water treatment facilities, or lowers water quality in urban lakes and streams. This presents a year-round flooding potential and degrades nearby waterways. Big as they are, the existing parking lots are still not big enough during the holiday shopping season when masses of shoppers frantically descend on the mall. That's a bad tradeoff on all counts. This class field trip was about asking the right questions to help guide Minnetonka's plans towards long-term sustainability and ultimately envision the redevelopment of this area. Parking ramps, and a layout that prioritizes ease of walking instead of storefront prominence, are two ideas that would be a big step in the right direction.

After meeting with Minnetonka officials, the class went to see Bassett Creek, one of Minnetonka's nearby waterways. MacDonagh explained how too much water, moving too quickly, causes stream banks to erode. When land is paved over, the water that used to be retained in soils instead becomes runoff, overloading waterways and creating flood events, or turbid waters. Runoff also carries contaminants from surfaces (think fluids leaking from cars, litter, and road salts) into water bodies.

These impaired watersheds are one of many unintended consequences of our urban development. It is also something we can change. Richard Strong, who co-teaches the class with MacDonagh, explained, “This is not a river problem. It's a watershed problem. Fix the uplands and the water[way] will fix itself automatically.” With more conscientious design in urban areas, excess stormwater runoff could be mitigated with rain gardens, green roofs, and permeable pavements in strategic locations.

It is overwhelming to think about the modifications to our infrastructure that would be necessary to retain 50% of the runoff. Flood events, poor drainage, and degraded water bodies are all indicators that our current infrastructure isn't working. Without investing in the research to develop alternative solutions and forming the partnerships to apply them, we cannot change our current trajectory of unsustainable urban planning. Minnetonka and the University of Minnesota have formed a critical partnership to explore what these solutions might look like. I can't wait to see more from RCP and what promises to be a very productive partnership.

Katie Thompson is the digital content assistant for the Sustainability Education program at the Institute on the Environment.

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