From Ditch to Delight

Aug. 16, 2005

As American cities developed, many streams and rivers flowing through them were buried underground, channeled into huge pipes or relegated to concrete ditches in out-of-sight areas. Today, cities across the country have discovered the economic and ecological value of those streams and have begun to return them to a man-made version of their original, natural state.

The process of restoring streams from underground or back alleys is known as "daylighting." It is slow and arduous work, but a prominent researcher at the University of Arkansas says the effort is worth it.

Marty Matlock, associate professor of biological and agricultural engineering with the Arkansas Division of Agriculture, argues that bringing streams to the front of developments and restoring them to a natural state will yield long-term economic benefits for cities and health benefits for the people who inhabit them.

Communities need the ecological services, such as disinfection and processing of nutrients, that streams provide, Matlock said. Natural streams disinfect water and treat nutrients such as nitrogen and phosphorous. Allowing streams to perform these natural functions will decrease the extent to which cities or other local governments will have to treat water artificially, which is an expensive process.

"We're drinking that stuff or at least someone else is, and if we keep shoving it down a concrete stream, somebody, somewhere has to treat it," Matlock said. "If we can increase the ecological services upstream and preserve them, it will ultimately reduce costs of treatment and increase confidence in our drinking water. So, it's not just aesthetics. This is the direction we've got to go if we want continued fresh water at reasonable costs."

Historically, most stream-restoration projects have been done from the perspective of landscape architecture or restoration ecology. As a licensed engineer and registered ecologist, Matlock is one of the few academic researchers nationwide who is qualified to design stream-restoration projects from an engineering perspective. In applying the science of ecology to engineering practice, he and his research team design natural streams that interact with people and function in an urban environment.

"As ecological engineers, we can predict outcomes with a high level of confidence," Matlock said. "These predictions, which are based on quantifiable data, satisfy the concerns of community leaders, regulatory agencies, property holders and citizens. We're moving this from pure science to an engineering practice that uses and respects science."

Matlock and his research group recently completed the first phase of an innovative greenway development in Rogers, Ark. By returning Blossom Branch Creek to its floodplain and restoring ecological services to the creek, the stream system will control flooding, decrease the need to treat nutrients in the stream and provide a recreation venue for community residents. UA researchers conducted analyses of the ecological services, hydrology and geomorphology of the creek. They then worked with the city of Rogers to design a greenway park, including a recreational trail. The researchers also supervised construction of the project.

Stream restoration activities included decreasing the topographical slope of the stream and creating pools, runs and riffles, or shoals, based on engineers' designs. Part of this involved converting a straight channel into a sinuous stream. The researchers also stabilized stream banks by planting trees and reconnected the stream's channel to the flood plain to give water a place to go during floods. Throughout the construction process, researchers hosted technology-transfer workshops at the site to train developers, city planners and engineers on more sensitive drainage practices.

Source: UA