Office of Technology Transfer & Commercialization
Fish ladders reconnect stream habitat
Roads and highways connect people to one another, much like rivers and stream connect fish populations. However, the culverts that allow water to flow under roadways can become obstacles for small-bodied fish, like minnows, darters and madtoms.
Associate professor Brian Graeb, right, hands the fish ladder down to graduate student John Lorenzen. Undergraduate David Ahrens, left, and associate professor Katie Bertrand will assist with installation of the ladder on Clip Up Creek northeast of Renner.
“When the water flows through the culvert, it falls off and scours out a pool on the downstream side,” explained associate professor Katie Bertrand of natural resource management. The distance from the lip of the culvert to the pool below can be anywhere from a few inches to several feet.
When water levels drop during the summer months, she pointed out, “They don’t have the strength to jump up that waterfall. You’ve put a wall in their path and fragmented their habitat.”
To reconnect their stream habitat, Bertrand, associate professor Brian Graeb and graduate student John Lorenzen designed their patent-pending fish ladder.