February 24, 2011

UW uses cutting-edge storm water management techniques

Whatever rainwater falls on campus soil is likely to end up in Lake Washington, because of the campus topography. The UW works closely with the city of Seattle, which has been at the forefront in developing cutting-edge ways of managing storm water, says Jim Morin, a facilities project engineer and storm water expert in Facilities Services. The University adheres to city guidelines to mitigate the effects of storm water runoff created by any new campus buildings.

Most of these mitigation measures are invisible to the casual observer because they are below ground.  Water that runs off pavement needs to be filtered before it makes its way into the lake. This obviously requires filters, and the UW utilizes about 20 different kinds of filtering mechanisms to clean the water, ranging from screening devices to natural, grassy areas.

The UW even has a bioretention facility near Conibear Shellhouse. Storm water is collected into the treatment area, which consists of a grass buffer strip, sand bed, ponding area, an organic layer, soil and plants. Water passes slowly through the area and is filtered by gradual contact with vegetation and soil.

The area of chief concern for runoff management is from parking areas, and the challenge is to design mitigation measures that are effective but also minimize maintenance costs to the University. “Were also trying to anticipate future regulatory demands in our current designs,” Morin says.

One way of keeping bad stuff out of runoff water is by limiting the use of pesticides, herbicides and chemical fertilizers. The UW employs a multidisciplinary approach to managing disease and insects, with chemical application far down the list of options, says Howard Nakase, manager of campus grounds operations.

“Healthy grass, for example, does wonders in retarding the proliferation of weeds,” he says. So the grounds crew is using everything in its control — including choice of plants, hand labor, machine removal of weeds, and application of mulch — to avoid excessive use of chemicals. Proper watering also plays a role in preventing disease. Proper choice of plants not only repels bad insects but attracts good ones (think ladybugs vs. aphids).

When chemicals must be used, they are drawn from an approved list and are applied only by individuals who are trained and have a license to use them.