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Sacramento Wash improvement project one permit away from completion

September 25, 2018

GOLDEN SHORES — The Oatman Bridge to nowhere will continue to be a bridge over troubled water until the berm is removed, officials said.

Mohave County is awaiting a right-of-way permit from the U.S. Fish and Wildlife Service to complete the Sacramento Wash Improvements project.

“This project is so essential, not only for relieving the low water crossing of the issues that it has had, but most importantly in providing for the bridge function,” said Steve Latoski, Mohave County Public Works director.

The first part of the project, the Oatman Highway Bridge, was completed in April. The county placed the bridge at the historic point of discharge of the Sacramento Wash — where water flows out of the wash and into Topock Bay.

The second part of the project needs to be completed in order to alleviate flooding after minor storms, Latoski said.

The approximately 1,331 square miles of watershed of the Sacramento Wash serves drainage basins from Topock, Yucca and Golden Valley, more than 70 miles upstream from its point of discharge into Topock Marsh and Topock Bay.

Sacramento Wash meets Topock Bay a little more than a half-mile from Oatman Highway; at milepost 1.65 the highway sits at the same grade as the wash.

At the root of the highway flooding issues is an earthen dike constructed between 1980 and 1990 south of Sacramento Wash and east of Oatman Highway to capture and direct water flows to the main channel of Sacramento Wash rather than allow water to naturally flow through the forest of tamarisk trees lining the refuge flood plains of the marsh.

The berm created a new low point for water — which takes the path of least resistance — where water crosses the highway. The water flow from the wash meets sediment buildup in the Topock Marsh west of Oatman Highway and backs up over the road.

Sediment suspended in the water from the wash continues to settle from the backup and deposits onto the roadway, making the highway impassible after even minor storms.

The draft Environmental Assessment prepared by the U.S. Department of the Interior, U.S. Fish and Wildlife Service and Havasu National Wildlife Refuge notes that between August 2013 and October 2014, the Oatman Highway crossing was closed 12 times by flooding and sedimentation.

“Ongoing sediment deposit on the roadway is really what has caused those extended closures,” Latoski said.

The permit would allow the county to remove the berm, as well as add channels for the water to flow in the correct direction, to the historic discharge point at the Oatman Highway Bridge, Latoski said.

Oatman Highway is a two-lane highway that generally follows Historic Route 66, serving an average of 1,350 vehicles per day, according to the USFWS. The highway is contained in a 100-foot right of way owned and maintained by Mohave County that predates the establishment of the national wildlife refuge it runs through.

“This is totally a county project and it’s a two-fold project,” said Richard Meyers, Havasu National Wildlife Refuge manager. “They built the bridge in the right of way because they didn’t have to get permission from anybody for that. The bridge is a bridge to nowhere currently unless they do the other part.”

Havasu Wildlife Refuge, established in 1941 by President Franklin Roosevelt, currently encompasses 37,515 acres along the Colorado River within Topock Gorge and 17,801 acres of designated wilderness.

“We work hand in hand with the county,” Meyers said. “We’re trying to get this project completed, but by law we have to go through the process and we’re mandated to do the 106 process and the NEPA process and there’s no way to circumvent them or make them faster.”

On federal land, the National Environmental Policy Act requires some kind of assessment done for any kind of undertaking, Meyers said. For the Sacramento Wash improvement projects, NEPA required an environmental assessment and a Section 106 assessment under the National Historic Preservation Act.

“The 106 process requires us to consult with the tribe on cultural resources and also the State Historical Preservation Office,” Meyers said. “The EA is focused on the impacts and what mitigations that the county would do to implement this project.”

One such mitigation would require the county to restore native habitat that will be destroyed by the project.

“There’s an area that’s been restored in mesquite and this project is going to destroy about an acre of that,” Meyers said. “The refuge spent money to put that area back into natural habitat and (the county’s) mitigation for it is they’re going to restore two acres back into native plants just north of it. It’s compensating for the damage that has to occur. Those are things that are normally required.”

Most of the work for the environmental assessment was done last year, with the refuge focused on the 106 process this year, Meyer said.

“Once those two things are completed and totally signed off by our regional director, who is in Albuquerque, that gives us the ability to issue the special use permit which would allow the county to do their project,” Meyer said.

The county procured a contractor in February and awarded a contract to complete the manmade berm removal work, Latoski said.

“We consider Oatman Highway to be a priority corridor and it’s been something that we’ve always seen as an area of attention,” Latoski said. “It’s probably one of our more significant milestones that we’re looking forward to achieving.”

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