The barrier was constructed in 2009 to serve as the lynchpin to removing red shiner from the Virgin River in Utah. Although built in Arizona, the siting was the only location outside of wilderness where construction was possible.

Remove red shiner from the Virgin River in Utah and prevent their reestablishment -Maintain the ability to keep red shiner from moving upstream -Insure the long term structural integrity of the barrier

The barrier was constructed to allow for the removal of red shiner from Utah, a process begun in 1996, predating the Virgin River Program. In 2021, the last red shiner was captured above the Virgin River Gorge Barrier. This barrier is the key to preventing re-establishment of red shiner which are still present immediately below the barrier. With the rapid development of Washington County, it is unlikely that once re-established, that red shiner could be removed from the Virgin River again, jeopardizing two endangered species populations and three state species of greatest conservation need.

- Virgin River Fishes Recovery plan (USFWS) - Virgin Spinedace Conservation Agreement and Strategy (UDWR) - Virgin River Watershed Plan (WCWCD) - Southwestern Willow Flycatcher Recovery Plan (USFWS) - BLM St. George RMP (BLM) - Zion National Park General Management Plan (NPS) - Utah Wildlife Action Plan

No impact

The barrier was designed to insure that sediment transport along the Virgin River was not impacted by its installation. The fact that the amount of damage was sustained indicates that the barrier is acting properly and not building sediment upstream of the structure.

Since the construction in 2009, the Virgin River Program has obtained and maintained all compliance documents that relate to the fish barrier. These include USACOE 404 permit Consultation with USFWS on Endangered Species BLM management plans AZDOT regulations for construction and maintenance Federal Highways regulations due to proximity to I-15 The Program complies with all applicable laws, including the federal Endangered Species Act, state water laws, river laws and interstate water compacts.

As with previous modifications and repairs, engineers will be consulted to evaluate issues associated with the current existing structure. The engineers in concert with fish biologists will determine what repairs need to occur to hopefully insure the stability of the structure into the future. It is likely that replacement of damaged concrete and removed steel plating will occur. Due to the location of the structure in a narrow section of the river, the river will be dry dammed to allow construction on one side of the river, before shifting to the other. Fish clearances will occur before all work in the active channel.

The Virgin River Program and UDWR have been monitoring both above and below the barrier for over ten years and will continue this monitoring as long as necessary based on agreements with our partners. Monitoring includes both evaluating populations of native fish species as well as monitoring for the presence or absence of all nonnative species.

Program partners include: U.S. Fish and Wildlife Service Washington County Water Conservancy District Utah Department of Natural Resources U.S. Bureau of Land Management U.S. National Park Service The Nature Conservancy Private Landowners U.S. Forest Service Dixie Conservation District Washington County Farm Bureau Additional cooperators include: City of St. George City of Santa Clara La Verkin City, City of Hurricane Springdale Town Washington City Washington County Washington County Flood Control Authority Shivwits Band of the Paiute

It is the sincere hope of the Virgin River Program Partners that ultimately another fish barrier will be installed above Lake Mead and below the Virgin River Gorge Fish barrier and that the states of Arizona and Nevada will eradicate red shiner from the river in their states. However until that occurs the best efforts will be made to insure that Utah remains free of red shiner in the Virgin River.

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07/01/2023

06/30/2024

2024

Activities for this project included hiring an engineer to design repairs to the barrier and acquiring the steel plates that will be necessary for protection. Both of these activities were necessary ahead of construction. The engineer obviously to know how to make repairs that will hopefully better protect the barrier and the steel so that the chosen contractor can insure that it is cut, finished and prepared to be put in place on the barrier. Amount of steel acquired was 60000 lbs of 3/4" steel plate.

The Gorge barrier was constructed in 2009 to prevent the upstream movement of red shiner, an invasive nonnative fish that preys upon and competes with the native fishes of the Virgin River, especially the endangered Woundfin. The barrier enabled the Virgin River Program (VRP) to chemically eradicate Red Shiner from Utah portions of the Virgin River. Once completed, the barrier now serves to keep Red Shiner from recolonizing the Utah reach. Due to the flow conditions in the Virgin River, the barrier, an instream concrete and steel structure is subject to high flows, temperatures and sediment and debris flows. These high flows have previously scoured inches of concrete from the barrier's exposed surfaces. In 2014, following high flows, steel was placed over the splashpad. These plates held until 2023 when high spring runoff broke plates apart and transported them downstream (2000lb plates moved over 250yds). Once the plates were removed, the river again began scouring the concrete faces, exposing the rebar. The overall project will be to repair the concrete and replace steel on the splashpad and this time as well on the vertical faces.

Ongoing maintenance will be required to prevent the barrier from damage that would ultimately allow Red Shiner to move back upstream into Utah. Hopefully the repairs made as part of this project will help that maintenance.