An event that runs from 1 to 4:30 p.m. Sunday, Sept. 22, will give participants a close look at a stream that runs through Delaware -- one that some people might not even know exists.

Adults and children ages 7 and older are invited to gather at Boardman Arts Park, 154 W. William St., for the second annual Watershed Walk along Delaware Run.

"People are usually amazed and surprised" to find out the stream runs through town, said Roxanne Amidon, president of the Northwest Neighborhood Association and the Boardman Arts Park.

One reason for that is the stream's limited visibility.

It passes beneath the pavement of West William Street, through a tunnel that also takes it under Boardman Arts Park and the UDF gas station at William and Liberty streets.

That tunnel is lined with stone and is more than 100 years old, Amidon said.

Elsewhere in the city, Delaware Run is flanked mostly by trees close to its banks; it also passes under a building along South Sandusky Street.

Another surprise for many is the wildlife the stream attracts, Amidon said.

Caroline Cicerchi, watershed and sustainability coordinator for the city's public utilities department, has been working with the Olentangy River watershed and Delaware Run for two years.

"I've observed snapping turtles, ducks, frogs, water snakes, minnows and a moderately diverse array of macroinvertebrate species, such as crawfish and caddisflies, within the waterway," she said.

Cicerchi, who will be among those leading the hike, said Delaware Run's environmental condition also deserves awareness.

"Waterways can feel the pressures of development similar to people," she said. "Urbanization is a large factor currently impacting the run and other tributaries to the Olentangy River. As more housing, businesses and impervious surfaces are added upstream, less rainwater is being retained and absorbed in natural areas where trees or undisturbed vegetation formerly existed.

"Thus," she said, "when heavy rainfall hits, it makes its way to the run more quickly. When you combine increased development with a stream that has already been channelized, or straightened out through manmade design, it increases chances of erosion on the banks, high flow that can lead to localized flooding, and an overall degradation to the habitat and species that reside within the stream."

Delaware Run's channelized path includes the tunnel under William Street, a concrete-lined trench that takes it from West William to South Washington Street and a stone-lined trench that carries it along the north edge of the Ohio Wesleyan University campus green.

The event is coordinated by Boardman Arts Park, the Delaware General Health District, Sustainable Delaware Ohio and the Central Ohio Communities Project.

Amidon said the idea for the watershed walk was conceived last year after she was approached by the groups for ideas to bring attention to the city's water environment.

Naturalists will lead the hike, she said, which also will focus on geologic features and invasive plants affecting the stream.

Event participants will take either a short walk along and in the stream near Boardman Arts Park, or ride a van to the starting location of a longer walk. Water-quality testing also will be conducted on both walks.

Amidon said the short walk will begin at 2 p.m. Participants are advised to bring a towel and a change of shoes.