Help Add Shelter

Fish need shelter.

From the raptors, runoff flows, and rapacious fly casters. Help give them a break and allow them to grow to enormous size.

South Platte Fish need LUNKERS


L.U.N.K.E.R.S are a stream repair practice used to provide undercut bank habitat and streambank toe protection along meander bends. Originally developed for trout stream enhancement in Wisconsin, the term lunker is an acronym for “little underwater neighborhood keepers for rheotactic salmonids” (Hunter, 1991). (Rheotactic means facing upstream, ed.)  They consist of wooden, crib-like structures that are installed below the water surface along the toe of meander bends (Figure 1). Each lunker is constructed of horizontal wooden planks separated by vertical spacers to form a crib-like box. In recent years, some lunkers have been constructed from recycled plastic materials, which reduce the potential rot/decay issue.

Habitat Features Created – Lunkers have a significant potential to enhance fish habitat and refuge areas by creating overhead cover and undercut streambanks.


Lunkers are located below the low flow water surface on the outside of meander bends so that they will receive enough current to flush out sediment. Lunkers are not suitable for straight reaches or the inside of meander bends because these areas are subject to sediment deposition. Lunkers work best in medium to large urban streams with cobble/gravel substrates and where there is some potential for a recreational fishery. They are not recommended for rapidly incising or degrading streams. Lunkers are often combined with bioengineering or other streambank stabilization practices to protect the upper streambank and have been successfully installed throughout the country. Lunkers are not appropriate for streams that are laterally unstable or have high bedload transport rates. Excavation of the streambank and installation of the lunkers requires access by heavy equipment.


Invented by the Canadians

The Denver Trout  Unlimited Aquatic Habitat committee is working with the restoration groups, municipalities, and agencies to make sure this kind of shelter is part of the effort.