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Cleaning The Kentucky River Begins Up On The Roof
Eastern Kentucky University applied science to the planning and construction of its new, state-of-the-art science building. One of the challenges in constructing it was creating a building on a relatively narrow, steep lot, that wouldn’t add to flooding problems at EKU and in Richmond.
The solution that architects, engineers, EKU professors and building staff came up with involves a carefully engineered system of water handling that takes a very different approach from traditional large-building construction.
Professor Alice Jones explained the principles involved, sketching two curves on a sheet of paper to explain the dynamics of flooding. In both drawings, the same volume of water flows into a creek from a storm. But in one curve, the peak flow comes early and rises high; in the other it’s delayed and smoothed out. Jones said that high, fast curve is dangerous.
“If it all hits the creek at the same time, that’s when you’re going to get flooding, that’s when you’re going to get erosion, that’s when you’re going to actually be carrying a lot more pollutants to the river.”
Jones is a geography professor and director of the Environmental Sustainability and Stewardship at Eastern Kentucky University. She said while floods are called acts of god, the works of man often play a significant role in creating them, too. Rainwater rushes rapidly over hard, impenetrable surfaces like roofs and parking lots. So, as development replaces trees, plants and fields, the peak in that curve Jones described spikes, creating flooding and carrying pollutants into streams and rivers.
Creating structures that can slow that water down could lessen the likelihood of that flooding. So, when EKU began planning for a new science building several years ago, lead architect Eric Zabilka incorporated an innovative system of controlling rainwater runoff.
Zabilka said in traditional buildings, water is something to be moved away rapidly.
“The rain hits the roof, it gets collected by the roof drains, it immediately goes into roof drain piping which is piped down to buried storm water piping and it leaves the building as quickly as possible…..what we’ve done here is slow all that down.”
Each of the seven roofs covering portions of the building is designed like a very, very shallow bathtub that slopes gently toward the center, so the water moves slowly toward an interior drain. Those drains carry the water outside to huge concrete cylinders that bubble up into a channel of carefully-engineered pools lined with rocks and gravel on a sloping hill south of the building.
The system is designed not just to move water, but to hold it. Jones said systems like this one can store water until the ground can absorb it, which helps smooth out that peak and reduce the risk of flooding.
“Already it’s been held a couple of times, it’s been held on the roof, it’s been held in the piping, it’s been held in those upwells.”
The engineered channel outside is no different. There are no smooth surfaces or straight lines to speed the water along.
“It has to kind of make its way around those rocks, the channel itself has curves in it, it’s not straight, so it has to go from side to side or meander.”
An artificial waterfall after the last of the ponds adds oxygen to the water before it travels to a series of wetlands that slow and filter the water even more before it flows into the city’s pipes and ultimately into the Kentucky River. The oxygen is essential to aquatic life – which Jones explains is why home aquariums have bubble systems. Healthy aquatic plants and animals help clean the water in these wetlands. And Zabilka, the architect, said besides reducing flooding and pollution, the system saved money.
“We actually think that we saw a net savings…we believe that this was the least expensive option that we had. With a traditional system, you would be digging trenches in the ground, installing large sections of reinforced concrete pipe and then burying those system…..on this site, because we’re on the side of hill it was going to be very expensive to dig those trenches.”
The first classes were taught in the new building in January 2012 EKU’s science building is just one project on a campus with dozens of buildings and acres of parking lots in a city that struggles with flooding. But Zabilka believes the building can help educate students and future clients about how and why to manage water.
“When it comes to issues of water, we’re all interconnected. My drinking water came from someone else’s property. If each of us takes little steps to try to make the water as clean as possible when it leaves our property, we’re not only helping our neighbors, we’re helping ourselves.”
And in Richmond, there are a lot of neighbors. The water that runs off EKU’s science center ends up in the Kentucky River, which provides the drinking water for about 700,000 Kentuckians.
WEKU received assistance in producing this series of reports from Erica Peterson of Louisville Public Media.