Minnesota Trout Unlimited Coldwater Fish Habitat Enhancement & Restoration

Using FY2014 funding from the Outdoor Heritage Fund (“OHF”), Minnesota Trout Unlimited (MNTU) completed sixteen projects enhancing fish habitat in and along the following public waters (in these counties):

1. Spruce Creek (Cook);
2. Split Rock River (Lake);
3. Miller Creek (St. Louis);
4. Coffee Creek (St. Louis);
5. Garvin Brook (Winona);
6. Trout Brook (Dakota);
7. Blackhoof River (Carlton);
8. Rush Creek (Winona);
9. Mill Creek (Olmsted & Fillmore);
10. Newburg Creek (Fillmore);
11. Willow Creek (Fillmore).;
12. Cedar Valley Creek (Winona);
13. Pickwick Creek (Winona);
14. Trout Run Creek (Winona).

These projects were completed used methods similar to those used on projects completed by MNTU chapters in the past several years and also incorporated new research to improve project designs and fish and wildlife benefits. 
 
The specific methods used on each stream varied depending upon the distinct natural resource characteristics of each watershed and ecological region, the limiting factors identified for each stream, and the variations in the type and magnitude of poor land uses practices within each watershed.  Methods were tailored accordingly, using the best available science, in close consultation with resource professionals within the Minnesota Department of Natural Resources (MNDNR). 

Purposes:  Each project was designed and completed using techniques selected to accomplish one or more of the following purposes:  (a) increase or maintain adult trout abundance; (b) reduce stream bank erosion and associated sedimentation downstream; (c) reconnect streams to their floodplains to reduce negative resource impacts from severe flooding; (d) increase natural reproduction of trout and other aquatic organisms; (e) increase habitat and biodiversity for both invertebrates and other non-game species; (f) be long lasting with minimal maintenance required; (g) improve angler access and participation; and (h) protect productive trout waters from invasive species.

Habitat enhancement methods:  Methods used on each project included one or more of the following techniques: (1) sloping back stream banks to both remove accumulated sediments eroded from uplands areas and better reconnect the stream to its floodplain; (2) removing undesirable woody vegetation (invasive box elder, buckthorn, etc.) from riparian corridors to enable removal of accumulated sediments, reduce competition with desirable plant and grass species, and allow beneficial energy inputs (sunlight) to reach the streams; (3) stabilizing eroding stream banks using vegetation and/or rock; (4) selectively installing overhead and other in-stream cover for trout; (5) installing soil erosion prevention measures; (6) mulching and seeding exposed stream banks (including with native prairie plant species where appropriate and feasible); (7) improving or maintaining stream access roads and stream crossings to reduce erosion; (8) fencing grassy riparian corridors, including in such a way as to facilitate managed grazing, in order to prevent damage from over grazing; (9) placing large logs in northern forested streams to restore cover logs removed a half century or more ago; and (10) in northern forested watersheds with little cold groundwater, planting desirable trees in riparian areas to provide shade for the stream channel, help cool the water, and provide a source of future cover logs.

Agricultural area example:  Many streams in the agricultural areas of southern and central Minnesota have been negatively impacted by many decades of poor land management practices.  The projects in southeast Minnesota used the following approach to address this:

Erosion has led to wider, shallower and warmer streams, as well as excessive stream side sediments which regularly erode, covering food production and trout reproduction areas.  In many cases shallow rooted invasive trees have taken over the riparian corridors, out competing native vegetation which better secures soils, and reducing energy inputs to the stream ecosystem.  To remedy this, a typical enhancement project will involve several steps.  First, invasive trees are removed from the riparian zone and steep, eroding banks are graded by machinery to remove excess sediments deposited here from upland areas.  Importantly, this reconnects the stream to its floodplain.  Since many of these agricultural watersheds still experience periodic severe flooding, select portions of the stream banks are then reinforced with indigenous rock.  In lower gradient watersheds, or watersheds where flows are more stable, little or no rock is used.  After enhancement work is completed the streams flow faster and become deeper, keeping them cooler and providing natural overhead cover through depth and the scouring of sediments deposited by decades of erosion.

Second, overhead cover habitat is created.  Bank degradation and the removal of native prairie or hardwoods have dramatically decreased protective overhead cover in the riparian zone.  Two methods are used to remedy this situation:  increasing the stream’s depth, which alone provides natural cover to trout, and installing overhead cover structures in select stream banks.  Wooden structures or tree trunks are often installed into banks in hydraulically suitable locations and reinforced with rock as a way to restore or recreate the undercut banks which had existed before settlement and agricultural land use altered the more stable flows which had gradually created and maintained them. 
 
Finally, vegetation is reestablished in the re-graded riparian corridor to further stabilize banks and act as buffer strips to improve water quality.  Depending upon the specific site conditions, landowner cooperation, and agricultural use, native grasses and forbes are planted along the stream corridors, although often mixed with fast sprouting annual grains to anchor soils the first year.  Unusual conditions in 2019 caused severe flooding in southeast MN which demonstrated that, due to the unique soils in southeast valley floors, more indigenous rock was needed on the toes of the stream banks on some projects.  These changes were made where needed, while staying within original budget.  
 
Taken together, these actions directly enhance physical habitat, and typically increase overall trout abundance, population structure, the number of larger trout, and levels of successful natural reproduction.  In addition to the benefits to anglers of increased trout habitat and trout abundance, project benefits extending well downstream include reduced erosion and sedimentation, cooler water temperatures, improved water quality and numerous benefits to aquatic and terrestrial wildlife populations.