Fishways, a sort of stairway that helps river-spawning fish return to better, safer breeding areas once blocked by man-made dams, are coming to two sections of the Falls River.

Alewife and blueback herring (generically called “river herring”) were an integral part of the delicate ecosystem of Falls River. Now, with the help of the Connecticut Chapter of the Nature Conservancy, the Fish and Wildlife Foundation, Tom’s of Maine, and Audubon Connecticut, the Army Corps of Engineering is constructing fishways at the Dolan Pond dam and Mill Pond dam.

According to Sally Harold, director of river restoration and fish passage with the Connecticut Chapter of the Nature Conservancy, the Dolan Pond project should be completed within days. Construction on the project, which required special permits, began in August and included the designs of two engineers.

“There are several species of fish that depend on fresh water access to spawn, two of those species include the alewife herring and the blueback herring, both of which can not jump up stream like salmon can, so they need a little extra help around dams by way of fishways, which are several steps over small rises, with the herrings’ abilities in mind,” said Harold. “The steps are gradually sloped with steep passes inside. The fish are able to enter the fishways at the base of dams and travel up through what is basically a slot in the dam.”

River herring will leave Long Island Sound and find their way to suitable spawning areas in spring time. The juveniles stay until fall. Once the temperatures start to lower and there is a good amount of precipitation, they find their way back out into the ocean, usually in a school, together, at night to avoid predation from hungry birds.

River herring are repeat spawners, so they return again and again for the duration of their lives, which is typically 10 to 12 years, to the same fresh water area in which they were born, so the hope is that next spring there will be a strong return of adults. Because of man-made impediments, such as dams, suitable fresh water habitats for the river herrings in Connecticut have dwindled, hence the fishways.

“These fish are very important fish,” said Harold. “Osprey and other river birds eat them, as do other marine mammals. In addition, these fish are used for bait for eel, conch, and lobster traps.”

The fishway projects are also a good way to monitor the fish activity in the stream, Harold said. She explained that the Mill Pond dam fishway will differ from the Dolan Pond project in that it will have what is essentially a water slide, which will be outfitted with a window for viewing. The hope is that eventually, this project will be a way to integrate hands-on science into the local elementary school, so students will have the opportunity to witness, first hand, the migration of these fish. The Mill Pond project is slated to begin sometime in the next couple of weeks.