Built by the Civilian Conservation Corps in 1937, the Mathews Drop Structure was constructed for the purpose of preventing severe down cutting action from progressing farther upstream through the Panaca Meadow.
One of several that were built at that time, the Mathews structure is located in a deep cut about a quarter-mile east of U.S. 93 near the 1001 Ranch property.
County Planning and Building Supervisor Cory Lytle said, “The county owns it, and although it’s on private property, the County has an easement to go in and do what is necessary.”
Commission chair Kevin Phillips said the structure, “holds the entire upper end of Meadow Valley in place.”
But over the past 75 years, the structure has suffered the effects of erosion from rain, wind, snow, and heat, and the challenge of concentrated hydraulic energy at the site. In addition, the ground behind the structure has filled up with sediment over the years, so now the structure is little more than a place for a waterfall.
Lytle asked County Commissioners Mar. 2 for up to $25,000 to have a preliminary engineering study done to determine what is the best idea for repairing the structure.
“This is something we have been kicking around for several years,” he said. “It’s a critical structure that needs to be addressed in the County. In 2011, we did some maintenance on the backside and fixed a breach that was in the right wing wall. The temporary repairs are still there, but more needs to be done.”
Maggie Orr of the Soil Conservation District noted the “current best idea” is a roughened chute over the top of the structure, “that accommodates flood waters without accelerating water velocity and hydraulic stress to the channel bottom, and will dissipate throughout the chute rather than at a failing drop structure. The roughened chute will look something like a talus slope of rocks.”
Lytle explained, “Instead of coming straight down, the water cascades over a series of large boulders and different types of rocks and it slows the flow of the water.”
Orr said Dr. Barry Southerland, of the Portland office of the USDA Natural Resources Conservation Service, developed the roughened chute idea after he visited the site in 2007.
The three local landowners affected by the waters and flooding at the drop structure, Robert Mathews, Marla Weaver, and Raymond Thompson, agree the project is needed and are willing to proceed.
Lytle said, “There is a possibility we can get a pre-engineering study done by Sunrise Engineering.” Sunrise serves as the engineering consulting firm for the County.
He said he wanted to do a preliminary study first to determine the right approach for the structure.
The study, he thought, could be done in about five or six weeks. “We would then have something in front of us to look at.”
Following completion of the preliminary study, Orr noted, “Lincoln County can be more casual about asking for the design; the engineers could help formulate the scope of work, and the county can pick the firm they want and work with them to find the most viable solution taking into account the means available in the current economic/grant climate and other considerations the county feels might be important.”
Commissioners approved the request up to $25,000 that will be a sub-grant to reimburse 64 percent of the cost from the Nevada Department of Wildlife Landowner Incentive Program. County Grant Administrator Elaine Zimmerman has commitments for funding until the end of the fiscal year, June 30.
“We’ve doing the project in-house, we’re not taking it out to a state entity,” Lytle said.
Only using up to $25,000 means the County will not have to go out to bid.
A subcontract between Lincoln County and the NDOW program will state the money is for a preliminary engineering study for refurbishing the structure and explains what the county will do to obtain reimbursement. “We basically front the money and it gets reimbursed at 64 percent,” he said.
Paul Mathews stated that CCC crews built quite of few of the flood retention walls and basins for the whole Meadow Valley system in 1936 and 37, some of which the locations are not known anymore, having been covered over by sediment. “But, if we can figure out how to solve one, then some of the smaller ones can be fixed also in the next few years.”