As cities expand, an increasing number of hard and impermeable surfaces create new flood hazards. Pavement cannot absorb the rainfall that the natural earth can, and city drainage systems are over capacity. Out of this common problem was born the Historic Fourth Ward Park in Atlanta, Georgia. Dedicated in June of 2011, the 17-acre park contains a 2-acre water detention lake. Unlike other detention lakes, often isolated behind 6-foot fences, this one is open to the public.
There was another solution that would both manage the overflow and provide a public park.
When the city of Atlanta first sought to solve the flooding problem in the Historic Fourth Ward neighborhood, they planned for a tunnel and additional pipes beneath an unused parking lot, a project which would have cost 50 million dollars, according to Robby Bryant, landscape architect at HDR development firm who spoke with ArchiExpo e-Magazine. When community residents got together to ask for a public space, there was another solution that would both manage the overflow and provide a public park.
“The options were to build more pipes or decrease the demand [on the drainage system],” said Bryant. HDR was hired to design and execute the first five acres of a park that would alleviate city drainage system overflow. For a fraction of the cost of new pipes, the Historic Fourth Ward Park can capture 8 million gallons of stormwater.
Construction of the park allowed for cleanup of the formerly industrial site, and restored a natural ecosystem of plants and wildlife. Bryant and his team at HDR designed the area surrounding the water detention lake to keep the public at a safe distance from the water, whose level can rise unpredictably, without making it feel prohibited. Planted shelves and slopes create 22 feet of separation from the water’s edge, while walkways wind above its surface.
You want to think about durability for a park like this just because of the constant inundation. The walkway in particular is a colored concrete with a silt colored aggregate, knowing that there’s going to be water, and not clean water, every once in a while. It has a texture to it so it’s not slippery. Because it was intended to inundate, it looks like it did when it was first built nine years ago.
The Fourth Ward Park is the first to integrate public space that includes an outdoor theater, detention lake and natural ecosystem of native plants. There were, however similar projects that HDR looked to for inspiration including Chesterfield Central Park in Missouri, also designed by HDR, and Tanner Springs Park in Portland, Oregon, which includes flood management features.
Due to the success of the Historic Fourth Ward Park, HDR is in the process of designing two other water detention lake public parks. The concept was recently approved by the Alberta, Canada permitting department for the West District Central Park in Calgary, while construction on another Atlanta park has already begun. The Rodney Cook Sr. Park will be able to capture 10 million gallons of water.