Brice Prairie Conservation Association

Preserving Lake Onalaska and the Black River Bottoms

Fish Habitat: Blackdeer Overwintering Habitat Protection

Flow through an opening "breach" in the Brice Prairie barrier island increased dramatically with recent high-water events, to rates that are ten to 20 times the optimal flow for fish overwintering habitat. The "Blackdeer" area (blue oval) has historically been a very important overwintering area and fishery for perch and bluegill. The increased flow threatens this important fishery and habitat and creates unsafe ice conditions for fishers venturing out onto the ice. BPCA, Wisconsin DNR, and the U.S. Fish and Wildlife Service cooperated to place brush bundles in the opening breach to reduce the flow and width of breach. Boat traffic should still be able to pass through the narrowed gap. The brush bundles are a temporary measure until more permanent rock-based armoring can be installed.

To create the brush bundles, invasive buckthorn saplings were removed from the "Tubes" walkout access area at the end of Northshore Drive

stacking brush bundles on boat

Creating the brush bundles and plugging the hole: Process details and more photos


Fish Habitat: Lake Onalaska Bottom Structures

The BPCA is constructing and placing natural wood "fish cribs" in selected areas of Lake Onalaska. These structures are being placed in 15-20 foot water depths in an area that was previously dredged to form a "sediment trap" at the outlet of Halfway Creek. Woody bottom debris would typically occur in more mature bottom areas of a semi-riverine system like Lake Onalaska, and greatly increases the density and diversity of benthic invertebrates and fish.

Undesirable (not native to the river bottoms) black locust trees were removed from nearby areas to construct the cribs.

stacking logs

More photos of crib-building: photo gallery