The Duchesne River near the town of Hanna is considered a blue-ribbon fishery and has access provided by a fishing easement created during the development of the Central Utah Project. This stretch of river is used frequently by many anglers making use of the fishing access points. Over time, the stretch of river we propose to work on has exhibited changes in the path of the river and has also been affected by various bank reinforcement activities. In the past, landowners located near this stretch of the river installed various structures in an attempt to reduce bank erosion. Additionally, the river has developed a point bar that has pushed the flow of the river to the north bank in the project zone. As this bar developed, stream velocity and depth increased along the north bank creating an unstable bank that has exhibited erosion. Such erosion in this area is an issue as it is currently threatening a landowner's access road that runs through an easement of one of their neighbors. The landowner whose road is being threatened attempted to place gabion baskets and streambank armoring in the form of rectangular formed concreted filled with rock and sandbags. This previous work failed during high flow events such as those back in 2019 and again in 2023. If left in its current state, the bank reinforcement will likely fail further which would lead to loss of access to their property and increase the amount of sediment loading in the Duchesne River. Here, we plan to begin by removing the old bank reinforcements followed by the addition of new structures and armoring that have been shown to work in other locations on the Duchesne River. We plan to implement the addition of rip-rap as the primary armoring along the landowner's bank. We considered the use of a more natural material, such as toe wood, but there is not enough space in order to properly anchor such a structure. In other words, toe wood would likely fail here if implemented. We will also install a j-hook on the upstream end of the rip rap and a cross vane structure at the downstream end of the rip rap. The j-hook will help remove the erosive power of the river along the bank while maintaining the pool located on the outside bend of the pool. The cross vane will be installed to help increase the level of the outside bend pool which will further help reduce stream power along the bank while also helping to direct the flow of the river down the center line of the channel. Implementation of such structures will ensure that erosion will no longer threaten the access road while also helping to maintain or even improve the fish habitat here. Further, this work will improve the aesthetics of this section of the river which will benefit adjacent landowners and anglers who frequent this stretch.

1) Arrest streambank erosion thereby limiting sediment erosion to the Duchesne River. 2) Enhance instream habitat for fish 3) Promote regrowth of willows in interstitial spaces of bank reinforcement

The project will take place across approximately 150 linear feet of the Duchesne River located approximately 1.5 miles northwest of Hanna. This stretch of the river is an important resource for anglers who use the fishing easement in this blue-ribbon section of the Duchesne River. The previous work installed by the landowner had not gone through the permitting process. A report regarding this was made to the Utah Division of Water Rights and the landowner is currently in need to have this stretch reworked. Further, it is important to improve both fish habitat and visual aesthetic because this is such an important stretch of river. If this work is not done now, the bank will continue to degrade threatening landowner access and instream habitat. Similarly, waiting to complete this project may lead to further challenges if the bank continues to erode making the solution more costly and time consuming.

Duchesne River Watershed Restoration Plan - Improve water quality by decreasing TDS and suspended sediment loading to reach TMDL This project will help address TDS and suspended sediment loading through arresting streambank erosion. Arresting the streambank erosion will reduce TDS and suspended sediment loading. Although localized, this work will have downstream benefits. Duchesne County Resource Management Plan Objective: Duchesne County desires to protect and enhance the quality and quantity of usable water by promoting and expanding the efficient management and use of water. - "The management of the watershed should allow for continued multiple use. It should preserve the quality and quantity of water as well as environmental values and allow the watershed to support existing as well as future uses." This project will benefit water quality through the reduction of suspended sediment loading caused by the eroding bank. As such, there will be benefits to water users downstream of the project. Additionally, this project will support multiple use through the enhancement of fish habitat. In its current form, this bank provides limited fish habitat. Utah Wildlife Action Plan: Threats Channelization/Bank Alteration (direct, intentional) - This project will use structures to increase the heterogeneity of instream habitat and limit bank alteration through erosion. Additionally, post-project planting in interstitial spaces will allow for increased willow growth. Sediment Transport Imbalance (sediment rich) - This project will reduce the amount of sediment entering the Duchesne River through arresting bank erosion.

The addition of riprap followed by willow plantings will reduce the population of annual grasses and weeds that currently grow on the disturbed soil. Senescence of these annual plants in the late summer could increase local fire potential. Therefore, the addition of willows and reduction in disturbed ground may have localized reductions in fuel load.

This project will stop streambank erosion along 130 feet of bank. In doing so, this will reduce the amount of total dissolved solids and sediment loading to the Duchesne River. This is of concern in the Duchesne River because there is currently a TMDL in place for the river, with TDS and suspended sediment exceeding daily load allowances.

All permitting and clearances will be in place prior to the reception of funds. There was a previous stream alteration permit in place for this project that has since lapsed.

We will reinforce the eroding bank using rip rap rock. Although this is not the desired choice, land ownership prevents the use of other methods such as toe wood reinforcement. In order to reduce energy while flow hits the rip rap, we will leave the rip rap fairly chunky rather than making it smooth. This should allow for better fish habitat in interstitial spaces while also slowing the water. Additionally, we will install a j-hook structure on the upstream end of the armor. This will help pull energy away from the rip rap armor while also creating additional fish habitat in the form of a small plunge pool. Lastly, we will install a crossvane structure at the downstream end of the armor. In part, we are doing this to further reduce the energy of the water before it continues downstream while also re-centering the main flow of the channel. This will help reduce erosion risk downstream. Further, the crossvane will create more fish habitat in the form of plunge pools. Willow planting will occur during the spring following implementation. We will harvest willows locally from the property to plant in the interstitial spaces of the riprap.

Post implementation monitoring will be conducted for 3 years following installation. Monitoring will include fixed-point photography to assess conditions through time. We will also use drone flights to gather insightful data in regard to the channel morphology such as width and path. Lastly, we will collect cross sectional data including depth and width to assess the degree of erosion following implementation.

Trout Unlimited has been in contact with the landowner and has worked to develop the design in conjunction with the Utah Division of Wildlife Resources. Both UDWR and TU worked together to put together this funding proposal and will work collaboratively to manage this project.

We are anticipating this to be the only time we submit for funding for this project. After construction, monitoring of the site will be conducted for 3 years post-implementation. Monitoring for this site will include fixed point photography and annual cross section measurement to assess erosion.

This project will improve the water quality and improve fish habitat for the Duchesne River. This project is located directly upstream of one of the Duchesne River fisherman's access points. Landowners in this stretch of the river say they frequently see people utilizing this area for fishing but will often pass by this stretch in its current state. I believe that once this work is completed, people will begin utilizing it once again. Additionally, fish habitat enhancements in this project will help quality fish hold in this stretch of the river. Additionally, this project will protect the access road for the landowner maintaining their ability to get to their property while providing an aesthetically pleasing solution for neighboring landowners.