When most people think of a typical trout habitat project, they think about increasing trout numbers and having an easy place to fish. Another goal of a trout habitat project is to reduce streambank erosion. Historically, agricultural soil erosion from fields led to heavy deposition of fine sediment in streambeds. Excessive bank erosion in wooded and heavily pastured areas continues today. Generally, bank erosion rates are excessive when overhanging vegetation dominates the top of the bank, trees fall into the stream annually, or soil slips and slumps are common. Excessive bank erosion (lateral instability or widening) and downcutting are indicators of unstable streams. Excessive sediment deposition in a stream (formation of central bars or a braided stream) is also an indicator of instability.
Sedimentation of streams results in the loss of deep-water fish habitat and declines in spawning habitat and stream productivity. “Streambank erosion has long been identified as having negative impacts to water quality. The U.S. Environmental Protection Agency lists excessive sediments as a leading problem in our nation’s rivers and streams. Unnatural quantities of sediment entering streams can degrade aquatic habitat and alter physical and chemical characteristics of the water. Nutrients associated with soil particles enter the stream and become available to aquatic plants and algae, ultimately contributing to eutrophication of local and downstream waters.” (Pierce County Land and Water Management Plan. August 2021).
Erosion of streambanks is a naturally occurring process for many waterways, but impacts from humans such as removal of vegetation, foot/vehicle traffic, and channel modifications can exacerbate erosion. Conservation practices such as stream bank restoration, rotational grazing, fencing and buffer strips can be taken to reduce active bank erosion and reduce the impact of fine sediment to streams.
In a recent meeting with Pierce County Land and Water, KiapTUwish and WDNR, Rod Webb shared a formula to calculate how much soil loss is happening each year on local sites.
Eroding Bank Length X Eroding Bank Height X Lateral Recession Rate (FT/YR) X Soil Weight(lbs./ft3)/2000 = Estimated Soil Loss Per Year
Let’s use the latest project on the Trimbelle River-Thom easement using the formula. We did 4,000 feet of integrated bank treatment and the average height of the banks were 7 feet. Lateral Recession Rate for this section of stream is in the severe category with a .4 value due to banks that are bare with rills and contain severe vegetative overhang. Many exposed tree roots and some fallen trees and slumps or slips are present as well. The channel cross section becomes U-shaped as opposed to V-shape. Soil Weight has a 95 value with the Silty Clay Loam texture.
4,000 ft X 7 ft X .4 ft/yr X 95 lbs/ft3 / 2000 = 532 tons per year or 24 quad axle dump trucks of soil are lost each year from streambank erosion within the project site alone!!!
Phosphorus is also reduced by .2 pounds per ton of sediment. With this completed project, we are reducing phosphorus by 106 pounds per year just from within the project area.
Once a project is completed, soil erosion is very limited if not eliminated. Rock protects the bank, the grass covering the rock prevents any future erosion and by sloping the banks to a more gradual slope, lessens the pressure on the banks while allowing the stream to reach its floodplain more easily.
“WDNR records show that Pierce County trout streams have improved substantially during the past 40 years due in part to projects like the Thom easement project and the improved farming practices taking place. In 1980, Pierce County had 17 trout streams for a total of 97 miles. By 2002, there were 47 trout streams for a total of 159 miles and Class I trout streams increased from 11 miles to 47.7 miles and Class II streams increased from 55 miles to 108 miles. The most recent information from Wisconsin DNR, shows 109 miles of Class I trout streams and 95 miles of Class II trout streams in the area.” (Pierce County Land and Water Management Plan. August 2021).
The two photos shown below are the same outside streambank, before the project started and a few months after the project was completed. It not only has habitat for trout and easier to fish, but it’s not allowing any fine sediment to reach the stream, now, and into the future.
Maintaining Habitat Projects For Years Of Enjoyment.
Nate Anderson WDNR
After a trout habitat project is complete, Trout Unlimited and the DNR plant desirable native trees in select spots. Kasey Yallaly’s (WDNR) current plan is to plant larger seedling trees (over 6ft tall and at least 3 years old) along the stream every 50 feet, a distance that will allow continued maintenance after a project is completed. This spacing allows mowers enough room to get around and in between the trees and the stream. Once mature, the trees will provide some necessary shade to help maintain beneficial thermals. Kasey feels that this is a good compromise between (a) reforestation, which could result in a return to unfishable streams or (b) simply planting nothing.
We currently put each new habitat project on a 4-year rotation for mowing to keep out unwanted woody vegetation in an effort to promote native grasses. There are 2 types of mowing that take place on finished trout habitat projects, fishing access paths and mowing maintenance. Fishing access paths allow anglers to access the stream more easily during summer months when streambank vegetation is extremely high. These paths are at least ten feet wide and run along one side of the stream. We have been mowing at Cady Creek, Trimbelle River CTH W project, and Pine Creek annually. The mowing generally occurs through the width of an easement, commonly 66 feet wide and on both sides of the stream. This year’s mowing locations were located at; Gilbert Creek on Thorud’s easement, the fee title property just east of CTH Q, the Trimbelle River Holst easement and the Red Cabin site on the Kinnickinnic River. All mowing takes place in July to reduce chances of disturbing breeding birds but still get to the vegetation before it gets too high.
This year, mowing was done by Extreme Excavating out of Knapp, WI. The total cost came in at $16,800. Cost breakdowns showed that trout stamp monies paid for $8,500, Kiap-TU- wish contributed $1,500 from a past gift to the DNR designated for this type of work and $6,800 was paid by The DNR Parks and Recreation Department.
There are many sites along the Kinnickinnic River that have been brushed within the past several years that cannot be mowed. In order to prolong the effects of the brushing this year, the DNR hired a contractor, to chemically treat by foliar spraying 4 sites in order to control the invasive seedlings that usually sprout after brushing has been completed. The contractor hired for this project was 4-Control out of Menomonie, WI and the total cost was $3,500 paid for with Trout Stamp money.
Kasey Yallaly and I work closely with the Kiap-TU-wish- Maintenance committee each year to discuss what needs to be done. Please reach out to your chapter committee members if you have any ideas, thoughts, or comments regarding maintenance issues in your area or favorite fishing spot.
Our first project of the field season was on Gilbert Creek in Dunn County. The project is located within Gilbert Creek Fisheries Area and on Gene Holte’s easement and is 1,300 feet in length. This project is in cooperation with the Clear Waters Chapter of Trout Unlimited, Dunn County Fish and Game Assn, and Dunn County. This project was a continuation of past 3 years of trout habitat projects along this section of Gilbert Creek. Gilbert creek is a Brook trout reserve stream that has had numerous habitat projects completed on it and this newly acquired easement will allow us to tie in many years of habitat work together. It is a highly visible section, just off HWY 29 which will allow the public to safely park off the busy Hwy in a 75×50 parking lot. Work started on 5/9/22 and project was complete on 5/24/22. We created 1 rock island, 3 spawning riffles, 98 root wads and used 3,025 tons of rock which comes out to 2.3 tons per stream foot.
Our second project of the year was on Sand Creek in northeast Dunn County. This is a highly visible project that enhanced habitat and access to the stream in the park of the town of Sand Creek. It is now a great spot for senior citizens and the youth to fish due to the location and access from a parking area with the potential of catching a trophy brown trout. We partnered with ClearWaters TU, and the Town of Sand Creek. Work started on 5/25/22 and project was complete on 6/15/22. Total distance is 650 feet. We installed 8 LUNKERS, 1 plunge pool, 5 riffles and 1 rock v weir and hauled in 440 tons of black dirt, used 1,325 tons of shot rock and 125 bales of straw. We removed all old, unstable and unsafe trees within the park and will plant more trees in the near future.
Sand Creek City Park
Our next project was on the Trimbelle River-Halvorson easement. This project was partnered with KiapTUwish Trout Unlimited. We completed 3,200 feet with potential for more stream footage downstream on the same landowner’s property/easement. Native species such as Ash, Oak and Maple will be left standing to provide some shade, but this site is a horse pasture with very short turf grass. The project started on 6/20/22 and we finished on 8/16/22. We installed 22 riffles, 41 root wads, created 5 islands, 5 back water refuges, 2 ERO’s, 5 rock v weirs and 1 cross log while also adding too many to count mid-stream boulders and boulder clusters. We used 7,500 tons of shot rock @ $7.98/ton which comes out to 2.34 tons per stream foot and 400 bales of straw @ $8.00/bale and 900 pounds of Orchard grass.
The final project of the field season took place on the headwaters of Gilbert creek, which is owned by the State. We completed 1,550 feet with 1,550 more feet to be finished next field season. We started 8/17/22 and we finished up for the year on 9/15/22. Thirty-six root wads, 3 ERO’s, 16 riffles and 3 backwater refuges were installed. This project site will make for great spawning areas for Brook trout once we are able to flush out the fine sediment and create more spawning riffles.
