Arches proposes flood mitigation work

The National Park Service has announced that its Environmental Assessment (EA) for the Salt Wash Rehabilitation Project in Arches National Park is now available for public review and comment.

The EA identifies strategies for reducing the frequency of flooding-related closures of the Wolfe Ranch/Delicate Arch Road by improving the flow of water and sediments.

Major components of this project include mechanical excavation and sediment removal from Salt Valley Wash, Salt Wash and Winter Camp Wash, and the mechanical removal of 54 acres of invasive tamarisk.

Park officials say that flooding-induced road closures of the Wolfe Ranch/Delicate Arch Viewpoint road have increased in frequency and duration in recent years. All 15 culverts installed under the road at the three wash crossings have filled in with sediment and are non-functional.

Closing the flooded road, assisting stranded visitors and removing sediment and debris have required more substantial efforts by park staff, and inconvenienced scores of park visitors, officials say. Road closures often last several days, preventing many visitors from accessing Delicate Arch, the most famous natural feature in the park.

Tamarisk is a non-native shrub that is extremely invasive in riparian communities, nearly completely replacing native vegetation with impenetrable thickets in many areas. Increased tamarisk cover in the Wolfe Ranch/Delicate Arch Viewpoint areas has clogged wash channels, exacerbated problems of sediment accumulation and interfered with the natural flow of water.

During this project, sediment removed from the wash channels will be disposed of on-site in large sediment deposit areas selected to avoid impacts to native vegetation. Park staff will monitor these sites and treat any non-native plants that may occur as a result of the wash sediment introduction.

Native seed mixes will be used on the sediment deposit sites to support growth of native plant species. Project activities would take place from November 2017 through March 2018 and from October 2018 through March 2019.

Park officials say that the operation of heavy machinery in the delta and wash channels will have visual and sound impacts during the project. These impacts will mostly be seen and heard by visitors at the Delicate Arch parking area and along the Delicate Arch trail.

No road, parking area or trail closures will occur as a result of this project.

The EA will be available for public review and comment through Thursday, Nov. 16, on the NPS Planning, Environment and Public Comment (PEPC) website at: parkplanning.nps.gov/projectHome.cfm?projectID=70534.

Hard copies of the EA will be available for review at the Southeast Utah Group Headquarters on Resource Blvd., the Arches National Park Visitor Center, and the Grand County Public Library.

Anyone who is unable to submit comments on the PEPC website can send written comments to: National Park Service, Southeast Utah Group, Attn: Planning and Compliance Coordinator, 2282 S. West Resource Blvd., Moab UT 84532.