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What bugs tell us about a stream’s health

By Dale Booth

Division of Water

Suited up in chest-waders Joanna Ashford stood at the stream edge and frowned at the water. The creek was a little lower than she had hoped, but glancing down the length of the bank she noted several areas of churning water where the stream ran over rocky section of stream bed.

“Who’s ready to catch some bugs?” she said, addressing the group of 5th graders behind her last September.

Ashford, is one of seven Kentucky Division of Water Basin Coordinators who go across the Commonwealth educating school-age children on water quality, pollution, and best management practices.

During Water Week, the Energy and Environment Cabinet is highlighting one of the many functions of a basin coordinator.

“One way to learn about your stream’s health is to look at the critters that live in the water,” Ashford said. “Scientists use surveys of aquatic bugs to give us clues as to what problems might be occurring in a creek. We take kids into the water to capture and identify those animals, so that they can see firsthand how healthy a creek or stream is.”

Aquatic bugs or macroinvertebrates are small animals that live on the bottom of streams, rivers, and lakes. They are large enough to be seen with the naked eye and have no backbone (invertebrate). Many aquatic bugs found in streams are their larval or immature form and may look very different from their adult form.

Dragonflies, for example, lay their eggs in the water and after hatching can spend up to two years as a swimming, larval form called a nymph.

Adult dragonfly and a nymph stage dragonfly. Photo by Chad Von Gruenigen.

Some aquatic bugs are extremely sensitive to their environments. For example, stoneflies and water pennies need water with high oxygen and clear, non-turbid waters to survive. If you find a creek with lots of these sensitive organisms, the stream is likely in pretty good shape. And while there are no “bad” bugs, there are some that are tougher than the others.

Leaches and midges are able to tolerate polluted waters better than the pollution-sensitive species. When you have a polluted stream you are more likely to find these “tough” critters, and very few or none of the sensitive ones.

And with the help of Ashford, these children experience the fun of splashing in the water, outfitted in rain boots and carrying long handled nets. Thus equipped, they perform kick samples, done by holding the net downstream while shuffling their feet on the creek bottom, disturbing rocks and sediment to dislodge any animals hiding there and sending them into their nets.

Basin Coordinator Joanna Ashford and students investigate their catch. Photos by Warren Co. Stormwater Management.

The students then empty the nets into water-filled trays to identify their catches. They typically might find side swimmers called scuds, stoneflies and even small crayfish. The samples can reflect a fairly diverse array of aquatic organisms, which can reflect how ‘good’ or ‘bad’ the water may be in and what steps can be taken to improve it.

Learning about macroinvertebrates with Joanna Ashford. Photo courtesy of Warren County Stormwater Management.

“In addition to looking at the animals in a stream,” said Ashford, “We usually also look at basic water chemistry, like dissolved oxygen, pH and nutrients in order to find out what’s going on in the water. But this type of sampling is great, because anyone can do it and get an idea about how healthy your stream is. All you need is a net and some boots!”

For citizen-scientists interested in learning more about how to sample their creeks and learn about water health, the Kentucky Division of Water and Watershed Watch in KY are organizations that can provide training in water chemistry and aquatic bug sampling, both to individuals and to school groups. For more information, contact your local Basin Coordinator.

 

Photos from top to bottom:

Basin Coordinator Joanna Ashford and students investigate their catch. Photo courtesy of Warren County Stormwater Management.

Adult dragonfly and a nymph stage dragonfly. Photo courtesy of Chad Von Gruenigen.

KDOW Technical Assistant Alyson Jinks and students capturing macroinvertebrates in Drakes Creek.  Photo courtesy of Warren County Stormwater Management.

Learning about macroinvertebrates with Joanna Ashford.  Photo courtesy of Warren County Stormwater Management.

 

 

 

 

 

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