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2020 Green Infrastructure Overpass Contest Winners Announced

02/15/21 07:28:am


(Milwaukee, WI) – Funded by the Tellier Foundation, the Green Infrastructure Overpass Contest awarded three teams for their innovative designs for managing polluted stormwater under freeway overpasses. Polluted stormwater runoff is one of the biggest remaining threats to rivers and lakes across the United States. The area underneath overpasses is often overlooked locations that could help reduce water pollution and, at the same time, provide public recreation space.

The award selection was equally based on innovation, sustainability, and quality of the submittal. The Tellier Foundation and the Milwaukee Metropolitan Sewerage District (MMSD) are proud to announce our three winners below!

1st Place - HNTB

9 members of HNTB contest winners

2nd Place - Hey & Associates

5 members of Hey & Associate contest winners

3rd Place - Lotus Water

6 members of Lotus Water


Each project team developed 2 or 3 alternatives described in a memo, defined a recommended plan, a conceptual design drawing or visual,  an estimate of construction cost, a construction schedule, a description of constructability issues, and a long-term maintenance plan memo. First place won $5,000, second place won $3,000, and third place won $2,000. Join us Wednesday, February 24, 2021, at 12:00 p.m. to learn more about the Green Infrastructure Overpass winning designs.



Team HNTB developed a conceptual design that uses the space beneath an overpass to create stormwater tree farms; a concept that is highly versatile, scalable, and repeatable.  The bigger a tree is, the more it costs, which is why many public sector organizations typically purchase young trees for public projects. Converting underutilized space beneath overpasses into scalable tree farms enables public entities to purchase less costly saplings from local nurseries and grow them to more desirable sizes on their own underutilized property.  The stormwater tree farm concept utilizes the available vertical space while treating and then irrigating with rainfall runoff from the overpass above.  In an accessible urban environment, the trees would occupy about two-thirds of the site and the remaining space could be reserved for public use including a pervious-paver walking path, benches made from recycled materials, and a recycled-material sculpture garden. The tree farm would include educational signage, as it is an ideal site for programming for local schools, and providing an urban arboretum for ecology and water quality lessons.

overpass project rendering

Hey & Associates

Inspired by integrating a variety of natural and urban visuals, textures, and colors, our team presents three innovative conceptual ideas to integrate green infrastructure in overpass areas to provide, volume storage, flow control, energy dissipation, sedimentation, and filtration. Comprised of semi-transparent containers, an interconnected hexagonal planter system, and a suspended waterfall feature, these solutions are built upon a primary strategy to be scalable and adaptable for varying site conditions. Whether these solutions are stand-alone, paired in series with other green infrastructure solutions, or installed in series with traditional conveyance networks, these concepts can either retrofit existing conveyance pathways or be a component of entirely new overpass designs. Social and educational programs were also proposed as part of the recommended plan, including integrating design into parkscapes, developing an outdoor classroom environment, and strengthening existing outreach campaigns.

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Lotus Water

The two design prototypes presented are called the Sculpture Park design and the Waterways Parklet design. Both designs contain water treatment elements that can be separated and combined as needed. The Sculpture Park design deals with the water in a more distributive approach, using modular components that are flexible in their implementation. This design proposes using local artist sculptures to house the baffle box element which settles out sediment and other contaminants. The sculptures can be constructed in a way that invites community members to explore and interact with the park features, while also providing educational information about local flora and fauna. The Waterways Parklet is a more centralized treatment system that uses a vegetated wattle waterway as the initial filtration process and is ideal for size constrained sites. The Waterways Parklet provides air quality benefits, as well as introducing vertical wildlife habitat and vegetation to the site. Both designs finish the water treatment process with a constructed wetland and bio-retention element that provides wildlife habitat, public interaction touchpoints, and community greening.

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Read the original contest announcement:

The Tellier Prize | Greater Milwaukee Green Infrastructure Overpass Challenge

Problem Statement

Changing weather patterns have resulted in a shorter duration, higher intensity storms.  In fact, the Midwest is experiencing the wettest period on record, and Milwaukee data shows the four highest annual rainfall amounts ever recorded occurred in the last twenty years. The 2010s decade was 8 inches of rainfall per year wetter than the 1940s decade. A warmer and wetter future is expected. Coupled with paved landscapes in our urban settings, these storms result in more urban runoff.  In the Milwaukee region, this translates into more unanticipated water entering the Milwaukee Metropolitan Sewerage District’s system


The Tellier Foundation is sponsoring a local competition to identify new, innovative approaches to slow down and retain these peak runoff events. Our current infrastructure, as originally designed, may not be capable of meeting the higher volumes of stormwater. We will need fresh ideas on retrofitting and adapting to meet this increase. The Greater Milwaukee Green Infrastructure Overpass Challenge is focused on reducing and treating runoff from interstate overpasses.  It will be assumed that the roadway drainage area is 50 feet wide by 200 feet long and is 100 feet above the urban landscape. The stormwater management or green infrastructure approaches should capture a two-inch rain event.

Winning proposals will identify innovative ideas to maximize the capture of runoff from the overpass area and strive to attain other triple bottom line benefits. A successful submittal will suggest a resilient solution that can be incorporated into the overlooked green space under freeways. The vertical height of the stormwater system should be treated as an opportunity for both runoff reduction and treatment. The solution should be capable of being replicated throughout the freeway system and should consider stormwater as a resource.

The Challenge is open to any project team with an interest in innovative stormwater management and green infrastructure. Interdisciplinary teams comprised of various focus areas such as water resources, land use planning, ecology, and/or transportation are encouraged. Each project team will develop 2 or 3 alternatives described in a memo, then further define a recommended plan which would include conceptual design drawing or visual, a preliminary estimate of construction cost, a construction schedule, a description of constructability issues, and a long-term maintenance plan memo.  Award selection will be based on innovation, sustainability, and quality of the submittal.