The Colorado River Cutthroat Trout and Bonneville Cutthroat Trout (CRCT and BCT, respectively) are covered under a Conservation Agreement to help protect and expand populations and habitat to prevent them from becoming listed as threatened or endangered species. The UDWR Southern Region identified the Boulder Creek Watershed as important to CRCT and North Creek Watershed as important to BCT for conservation and expansion. Re-establishment of these native fishes has already occurred in approximately 7 miles of the West Fork of Boulder Creek (CRCT), 11 miles in the South Fork of North Creek (BCT), and 6 miles in the North Fork of North Creek (BCT). In order for CRCT and BCT re-introductions to be successful in these streams, non-native fishes (e.g., Rainbow Trout, Brown Trout, and Brook Trout) were removed by chemical treatments and then pure-strain native CRCT and BCT were stocked back into the streams. However, time, cost, habitat variables, and other factors limit the length of stream that can be chemically treated, so fish barriers were constructed to prevent the non-native fishes from moving back upstream into sections already treated for non-native fish removal. Fish migration barriers on the West Fork of Boulder Creek and North Creek tributaries are critically important to maintaining the native populations that currently exist because they only thing preventing non-native trout from moving upstream. In the early summer of 2019, unusually high flood events severely compromised two fish migration barriers on the West Fork of Boulder Creek and three barriers on North Creek tributaries, leaving the sections of stream above the barriers in danger of invasion by non-native trout. Non-native trout would hybridize, compete, and consume the native CRCT and BCT to the point that conservation populations would be lost. Additionally, it would not be possible to chemically treat the West For of Boulder Creek to remove non-native fish again, which means the loss of that CRCT population could be permanent.

Repair and rebuild the compromised fish migration barriers on the West Fork of Boulder Creek and North Creek tributaries before non-native fish species are able to re-establish upstream.

The fish migration barriers could fail and wash out again permitting invasion by non-native trout. It is not possible or practical to build a barrier to withstand the most extreme flooding events that can occur over many years. However, if the fish migration barriers are not repaired and rebuilt, the conservation populations of cutthroat trout in the West Fork of Boulder Creek and North Creek tributaries would almost certainly be lost (likely through cross-breeding and competition), which could ultimately be a factor in listing the species under the Endangered Species Act.

Utah Conservation Agreement and Strategy for Colorado River Cutthroat Trout 4) Selectively control nonnative species (NONNATIVE CONTROL). a) Determine where detrimental interactions, such as hybridization, competition and disease, occur between CRCT and sympatric nonnative species. b) Control or modify stocking, introductions, spread of nonnative aquatic species and spread of disease where appropriate. c) Eradicate or control detrimental nonnative fish where feasible. Targeted species may include brook trout, rainbow trout, brown trout, and some hybrid populations. This action includes construction of fish barriers to prevent nonnative fish movement where presence of nonnative species preclude reestablishment of migratory corridors. Conservation Strategy for Colorado River Cutthroat Trout in the States of Colorado, Utah, and Wyoming 1. "Objective 2: Secure and enhance conservation populations - Secure and if necessary enhance all known and suspected genetically pure CRCT populations. These efforts might include, but are not limited to: -Restricting introduction of non-native fish species -constructing in-channel barriers" 2. "Objective 4: Secure and enhance watershed conditions: Strive to improve watershed conditions for CRCT, including development of protocols and monitoring." 3. "Strategy 2: Secure CRCT conservation populations - Restrict introduction of non-native fish species - Construct in-channel barriers If natural barriers cannot be used, in-channel barriers will be constructed downstream of the populations at risk from invasion by non-native fish species or hybridized cutthroat populations. Maintenance schedules appropriate to each type of barrier will be developed, and maintenance work funded and completed." State of Utah Resource Management Plan Fisheries - Policies and guidelines: - The State will seek to protect, conserve, and improve Utah's fish and aquatic wildlife and the habitats upon which they depend. - The State supports ensuring the persistence of the diversity of native fish and aquatic wildlife in Utah while at the same time providing excellent opportunities for anglers and other recreationists.

Not applicable.

There will be a short term increase in stream sedimentation during construction, which will quickly dissipate and not travel very far downstream. After construction, there will be no change in water quality or quantity.

Dixie and Fishlake National Forests have been been contacted and they consider this project emergency maintenance from a NEPA perspective. A Stream Channel Alteration permit will be secured before repair work begins.

The UDWR Heavy Equipment Crew would be used to repair and rebuild the fish migration barriers with large rock. The will be available onsite at the West Fork of Boulder Creek location and hauled in by truck at the North Creek tributary sites. An excavator will be used to place rock across the stream in a way that will recreate a 5' high barrier with side walls. Rubber pond liner material would be placed on the upstream side of rocks to keep water from leaking through. Regional UDWR personnel would pour a concrete splash pad below the structure to prevent a pool from forming (which makes it easier for fish to navigate the barrier by jumping). A larger excavator would be needed at the West Fork of Boulder Creek sites because of the larger-sized rock. All disturbed areas will smoothed out, blended to contours and reseeded. It should take the DWR Heavy Equipment crew 8 days to complete the work.

Barriers are visually inspected annually to be sure they are functioning properly and are not deteriorating or have problems. Maintenance work on barriers is completed as necessary. Periodically the fishery above barriers will be sampled to be sure non-native fishes do not occur.

Dixie and Fishlake National Forests.

Maintenance work on barriers is completed as necessary. Periodically the fishery above barriers will be sampled to be sure non-native fishes do not occur.

Not applicable. Project will not impact any other uses of resources in the area.

09/03/2019

10/31/2019

2020

A private contractor was hired to repair and rebuild the two fish barriers on West Fork of Boulder Creek. During October 2019 an excavator was walked up stream from the road to the upper barrier. Local area rock was collected and the rock barrier rebuilt such that it is better than previously. A large amount of deposited material below the barrier had to be moved and was used to rebuild and and narrow the stream banks below the barrier. The lower barrier was still mostly intact, but additional rock was added to the barrier to improve and widen it. Berms were constructed above the barrier on both sides of the stream to keep future high flows within the channel and flowing over the barrier. Employees from the DWR poured new concrete splash pads below both barriers. The Utah Division of Wildlife Heavy Equipment Crew hauled large rock to two barrier sites on the South Fork of North Creek and one site on the North Fork of North Creek. Where possible, existing rock was also used. The barriers were rebuilt using an excavator to place rock across the stream in a way that created a 5' high barrier with side walls. Large rocks were also buried immediately below the barrier to prevent pool formation. Often a concrete pad is poured to prevent pool formation, but the high sediment load eroded the original concrete pads quickly and it was believed new pads would not function long before also being eroded. Additionally, a small berm was built above the higher South Fork of North Creek barrier to prevent the barrier being compromised during high flows.

The Colorado River Cutthroat Trout and Bonneville Cutthroat Trout (CRCT and BCT, respectively) are covered under a Conservation Agreement to help protect and expand populations and habitat to prevent them from becoming listed as threatened or endangered species. The UDWR Southern Region identified the Boulder Creek Watershed as important to CRCT and North Creek Watershed as important to BCT for conservation and expansion. Re-establishment of these native fishes has already occurred in approximately 7 miles of the West Fork of Boulder Creek (CRCT), 11 miles in the South Fork of North Creek (BCT), and 6 miles in the North Fork of North Creek (BCT). In order for CRCT and BCT re-introductions to be successful in these streams, non-native fishes (e.g., Rainbow Trout, Brown Trout, and Brook Trout) were removed by chemical treatments and then pure-strain native CRCT and BCT were stocked back into the streams. However, time, cost, habitat variables, and other factors limit the length of stream that can be chemically treated, so fish barriers were constructed to prevent the non-native fishes from moving back upstream into sections already treated for non-native fish removal. Fish migration barriers on the West Fork of Boulder Creek and North Creek tributaries are critically important to maintaining the native populations that currently exist because they only thing preventing non-native trout from moving upstream. In the early summer of 2019, unusually high flood events severely compromised two fish migration barriers on the West Fork of Boulder Creek and three barriers on North Creek tributaries, leaving the sections of stream above the barriers in danger of invasion by non-native trout. Non-native trout would hybridize, compete, and consume the native CRCT and BCT to the point that conservation populations would be lost. Additionally, it would not be possible to chemically treat the West For of Boulder Creek to remove non-native fish again, which means the loss of that CRCT population could be permanent. This project was completed essentially as planned and ensures that invasion by non-native trout will not occur on the West Fork of Boulder Creek and North Creek tributaries.

The barriers will continue to be monitored and repaired as needed. Periodically the fishery above barriers will be sampled to be sure non-native fishes do not occur.