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UA graduate student leads Sierra Club hike
BY KATE WARD Northwest Arkansas Times

Posted on Sunday, August 13, 2006

The Sierra Club took a group of area residents on a hike Saturday to talk about the condition of the Clear Creek watershed.

"The main point is to discuss streamology and the condition of Clear Creek," said group leader Sarah Lewis." We really want to get people interested so they can learn about urban streams."

Lewis is graduate student at the University of Arkansas and is currently seeking her doctorate in environmental dynamics.

A group of about 12 people met at the Botanical Gardens for a tour of the property, which is still in the works. Group members then headed toward Lake Fayetteville Trail and stopped at an area along Clear Creek.

"There are 90, 000 miles of streams and rivers in Arkansas - that's awesome," Lewis said. "Right now, we're standing on the Great Divide that separates the Illinois and the White River. The native community marched along this area, on what they call Heritage Trail, from Fort Smith to Pea Ridge."

Lewis described Clear Creek as part of the watershed from the Illinois River. A watershed, she said, is the result of drainage from a larger body of water.

"Clear Creek has a riffle pool pattern, but we've lost that riffle, which means there are pools of water rather than a flowing stream," she said. "The river has been channelized to make it stay under this bridge. Rivers are lazy by nature and they will flow where they want, so when you channelize a river, it loses energy."

When a river loses its riffle pattern, certain types of macroinvertebrates, such as snails, crawdads and mayfly larvae, are also lost.

"In urban areas, we usually channel, which is hazardous to the flood plain," Lewis said. "It results in sedimentation - the banks get high and the river bed cuts down to bedrock. This creates high turbidity, which means certain types of critters won't be able to survive since they won't have anything to hold onto."

Group members analyzed the banks of Clear Creek and concluded that sedimentation had not occurred in the area because the stream banks appeared to be slightly sloped.

Members then split off into smaller groups for "bug kicking and macroinvertebrate identification. "As two people lowered a fine net into the creek, another group member gently kicked the bottom of the stream bed. The process disturbs the macroinvertebrates beneath the surface, causing them to move toward the net. After the net was lifted from the stream, group members sifted through sediment to locate various types of macroinvertebrates. Once each type of stream insect was divided into separate ice trays, group members used a sheet to identify each.

After reporting the results of their findings, the group drove to another section of Clear Creek, in Johnson to compare both sections of the watershed. Group members noted more clarity at the second location, but less tree canopy.

"The ensizement bridge at this site is also a part of channeling, " Lewis said. "The riparian zone - which is the area along the sides of the stream - is also narrow."

Lewis said healthy riparian zones are typically the size of the width of stream on both sides.

After a stream analysis of the second watershed site, group members broke into separate groups for more "bug kicking."

"This is something that I hope to do with my kids one day," said Lana Dinan, who attended the group outing with her husband, David." I think it's something they would enjoy and I think it's important for them to learn about. A lot of people who come here just see water - they don't see life."

While bug kicking, Lana and her husband found water pennies, crawdads, damsel flies and a mussel.

Group members noted that the second watershed site they visited was more biodiverse than the first, where they mainly found mayfly larvae and aquatic worms.

"Our actions impact our rivers. From there we can make decisions to change it or not to change it," she said. "In Arkansas, there are hardly any regulations on watersheds. In fact, Arkansas is way behind most of the other states."