Department of Administrative Services
Press Release
For Immediate Release |
For More Information: |
November 3, 2008 |
Robert Bailey, 515-265-7056 |
Is it a park or parking lot?
State builds parking lot to reduce runoff, promote green
DES MOINES — Instead of paving paradise and putting up parking lots, the State of Iowa is taking a new approach by designing a little of both. Near the corner of East Grand and East 14th, construction is under way on a new parking lot that will feature bio-cells, additional landscaping and pervious paving - a honeycombed type of concrete or asphalt designed to allow runoff to drain while still providing a hard, supportive surface.
“Water runoff is a serious environmental concern,” said Tony Schmitz, project director for the parking lot project. “By mitigating runoff with smaller projects like this, we can hopefully encourage other builders to follow suit.”
As Iowa’s suburbs continue to encroach on rural and natural spaces, the impacts of runoff water from paved surfaces also escalate – preventing the recharging of ground water through natural, trickle-down processes while accelerating the flow of storm water into stressed storm sewer systems. Following a spring and summer of heavy rains and flooding, the issue of overwhelmed storm sewers is a familiar one to most Iowans.
Pervious pavement allows rain water to be absorbed more naturally, recharging ground water while keeping it cleaner through natural filtration processes.
The pervious concrete being poured in the State of Iowa parking lot is also special in its formulation. Unlike traditional concrete that consists of cement, sand, aggregate and water and can range significantly in consistency, pervious concrete eliminates the sand and requires narrower latitudes of cement-to-aggregate-to-water proportions. Essentially, aggregate is ‘coated’ with a pasty mixture of water and cement and, because of a thicker consistency than regular concrete, ‘sticks’ together to create a honey-comb appearance. The porous spaces are referred to as voids and allow water to seep through the surface into the substructure and, eventually, into the ground water. Pervious concrete also requires considerable monitoring and testing as well as a more thorough curing process.
The new parking lot on the Capitol Complex will also feature bio-cells into which draining water will be directed. These cells consist of natural grasses atop a substructure that will facilitate the slow trickle of moisture.
While enhancing paved surfaces with pervious materials is more costly – in some instances 25 percent more – the savings in storm sewer repairs and improved water quality clearly help to counter the added expense.
About the Iowa Department of Administrative Services (DAS)
DAS was created July 1, 2003, as a way to manage and coordinate the major resources of state government; its mission is to provide high quality, affordable infrastructure products and services to Iowa state government customers in a manner that empowers them to provide better service to the citizens of Iowa and support the State of Iowa in achieving economic growth. http://das.iowa.gov/
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