In some streams, sport fish populations are limited by the amount of available cover and shelter (submerged boulders, logs, tree roots, undercut banks, and overhanging vegetation). Fish use these protective areas to rest, hide from predators, and catch food items drifting in the swirling currents that occur around submerged structures, and avoid territorial conflicts. Large sport fish often select a sheltered site as their territory from which they exclude other adult fish. Adding boulders, anchoring logs and trees, and building platforms along the banks can increase Sport fish abundance in streams without sufficient cover.

In-stream structures are built to extend out into the stream channels.They are intended to protect eroding streambanks and create hiding, resting, and feeding places for sport fish.

One example of an in-stream structure is a weir. A weir is basically a “V” shaped line of large rocks that points upstream. The flow of the water over the weir creates a deeper pool immediately downstream.

Weirs can be used in any size stream. Frequently, streambeds need to be narrowed to increase the rate of water flowing over the in-stream structures.

Small, deeper pools are sometimes also built into streams. Whenever fish habitat structures and in-stream work is planned, the streambanks are stabilized as part of the process.

Frequently, LUNKERS are installed when the streambank is being stabilized. (Find out more about LUNKERS here).

This LUNKERS was placed along a streambank.

After the LUNKERS have been installed, they are covered with rock. Soil covers most of the rock, and will be seeded.

In a relatively short time, the grasses planted along the streambank will take hold and help to naturalize the area.

Besides stabilizing streambanks, reducing the sediment entering our fresh water streams, and creating a desirable habitat for fish, streambank stabilization/fish habitat improvement projects become almost invisible once they have aged.