What do mayflies, stoneflies and crayfish have in common? They are all indicators that a stream is healthy. This fact was among the information that children and families learned on Family Fun Day at Rustic Park in Birdsboro during an event presented by the Hay Creek Watershed Association (HCWA), which is a program of Berks Nature.

As part of the program, youngsters and their families were invited to wade into the waters of Hay Creek to search for critters living in the water, which they caught in nets and placed in containers to be identified.

"Macroinvertebrates can tell you a lot about water quality," explained Beckey Seel, volunteer engagement coordinator and educator for Berks Nature. "They are biological indicators of water quality. We are teaching the kids how to identify them, and we can tell if the water quality is good or not."

Healthy water, Seel explained, contains a variety of species. "Good (water) quality would be (finding) mayflies, stoneflies and caddisflies, and we have all of them in Hay Creek. We are happy to say that the stream quality is very good," she said, noting that studying Hay Creek is important since it provides the main water supply for Birdsboro.

She said that pollution is indicated when there is a not a diversity of living creatures in the water. "If only one or two types of critters would have been found, that would indicate a problem," noted Seel. "If there were not different varieties of insects - say there were just leeches or just crayfish and nothing else - that would indicate that there is something wrong with the water quality. You want to have a good ecosystem. You want to have all these different aquatic insects working together. It shows that the stream is very healthy by having these different species."

Stan Kemp, a professor from the University of Baltimore, was also on hand during the event to help youngsters identify macroinvertebrates. "We've got not only crayfish but lots of insects," said Kemp. "We found a lot of great organisms today. It makes me happy to see because these organisms are not very tolerant to pollution."

For example, the youngers found crayfish, which are freshwater crustaceans that look like mini lobsters; mayflies, which have three tails that are often longer than their bodies; and dragonflies, which live most of their lives in the water as nymphs (or larvas) before becoming adults.

After catching the critters, they were identified and then released back into Hay Creek.

Also offered during the Family Fun Day were games and coloring activities.

HCWA presented a similar program at the Hay Creek Fall Festival last year but decided to host its own event this year. However, HCWA volunteers will be on hand for a stream study at the Hay Creek Apple Festival in October at Joanna Furnace.

"Volunteers with the Hay Creek Watershed Association like to do a lot of education and outreach, so this is a family fun program that was planned to educate the public about water quality," said Seel.

The mission of the HCWA is "to protect, preserve, and restore the Hay Creek watershed through active stewardship." The HCWA meets on the third Wednesday of the month at 5:30 p.m. at The Nature Place, 575 St. Bernardine St., Reading. New members are welcome.

For more information, email Seel at Beckey.seel@berksnature.org, visit http://www.berksnature.org/water/hay-creek-watershed-association or search for "Hay Creek Watershed Association" on Facebook.