March 11, 2014
In one of Omaha’s historic parks, “green” and “gray” have come together in a project designed to control water during wet weather.
The Elmwood Park Diversion Project, which uses both green and gray infrastructure solutions, is the recipient of Omaha by Design’s 2014 Green Leaf. The award recognizes an individual, organization or business that has worked to preserve and enhance the metropolitan area’s natural setting and public park system. It will be presented to representatives from the city’s parks and public works departments, along with project consultants Veenstra & Kimm and Big Muddy Workshop, at the March 19 meeting of the Omaha by Design Advisory Committee.
A city’s green infrastructure consists of its naturally occurring materials – trees, plants, open spaces, soils and water. A city’s gray infrastructure consists of its manmade materials – roads, sidewalks, buildings and utilities. Green solutions ‘build with nature’ to address the challenges of urban life, such as how to manage stormwater. In contrast, grey solutions build with manmade materials – pipes, culverts, drains – to address the same challenges.
“The Elmwood Park Diversion Project provides a very strong triple bottom line benefit for the citizens of Omaha,” said John Royster, president and CEO of Big Muddy Workshop. “It protects the lower areas in the Aksarben neighborhood from flooding, enhances the environment within Elmwood Park and reduced project costs for the city and taxpayers. By successfully integrating the needs of people, the environment and economics – the three components in a triple bottom line – a truly sustainable solution was achieved.”
The project, completed in 2012, is located just south of Elmwood Park Drive west of 60th Street. The diversion pipe, built on the south side of the park, leads into a series of weirs that allow water to pass after reaching a certain depth. A weir is a concrete wall that’s engineered to slow down large surges of water.
In between the weirs are three bioretention gardens. These gardens contain grasses and plants that naturally clean and absorb excess water. All the plants are deep-rooted, and each year, their roots die. This leaves behind vertical straws of roots that carry water deep into the soil. By absorbing more water into the ground, there is less overflow to manage above ground. As these gardens mature, they will require very little maintenance.
In the case of wet weather, any remaining water heads downstream into a wet detention pond just north of the weirs and bioretention gardens. When the water reaches the Elmwood Park creek, it is clearer, cleaner and cooler – benefitting the creek’s water quality.
To mitigate the number of trees that were removed during the construction process, 50 native trees were added to the park, including Northern Catalpa, Swamp White Oak, Hackberry and Kentucky Coffeetree.
“Big Muddy Workshop is very pleased to have partnered with Veenstra and Kimm Engineering on this project,” Royster said. “Our landscape architects and their civil engineers created an innovative solution that meets engineering requirements, adds biological diversity to Elmwood Park and beautifies an unused ravine in the park.”
In addition to the water quality and aesthetic benefits, this project avoided the neighborhood disruption associated with the removal and replacement of eight additional blocks of streets and resulted in a net savings of $500,000 compared to a traditional gray approach, said Marty Grate, environmental services manager with the City of Omaha Public Works Department. “The project is a great example of the city’s attempts to make wise use of ratepayer dollars and achieve multiple community benefits through smart designs,” he noted.
The Elmwood Park Diversion Project is part of the larger Clean Solutions for Omaha! program’s Aksarben Village Neighborhood Sewer Separation Project.
Past recipients of Omaha by Design’s Green Leaf are:
- City of Omaha Department of Parks, Recreation and Public Property (restoration of Hummel Park)
- Lauritzen Gardens, Union Pacific and the Nebraska Department of Roads
- Stinson Park
- City of Omaha Department of Public Works (The Cole Creek Project)
- Omaha’s right of way gardeners
- Gallup Organization (native meadow project)
- Douglas County Board of Commissioners (inaugural award)
For more information about Omaha by Design’s awards program, visit http://www.omahabydesign.org/about/awards or call 402.554.4010.