PIERRE, S.D. (KELO) — South Dakota cities and counties looking to understand how much soil is eroding beneath local bridges won’t have to pay for the research — at least not for the eight currently scheduled.
The state Transportation Commission decided Thursday its bridge-improvement grant program would provide 80 percent of the estimated additional costs for the eight studies. Other state funding will cover the remaining 20 percent of the extra research.
What the findings mean for potential costs of new bridges, which already cost in the hundreds of thousands or millions of dollars, isn’t known yet.
State Department of Transportation officials recommended the adjustments as their response to a 21-page tech brief the Federal Highway Administration issued in December.
The brief, titled “Hydraulic Considerations for Shallow Abutment Foundations,” deals with what bridge engineers generally call scour. That’s the soil washed out by water moving past the support structure under a bridge.
Normally, South Dakota’s BIG program requires at least a 20 percent local match. Projects that have higher pledges, such as 50-50, finish higher in the scoring competition for grants.
Counties and cities made those higher-pledged applications before the federal government came out with the new tech brief.
“The criteria changed,” Mike Behm, the department’s director for planning and engineering, told the commission Thursday. “Bridges are the most expensive component you have out there.”
Another department member, Tammy Williams, has been working on what to do now.
“We have had some feedback from counties,” she said.
That drew a few nervous laughs from several commissioners.
“They’re struggling,” she said.
The department will be on the hook for thousands of dollars just for the studies. The total bill isn’t known.
That’s why Williams didn’t want the commission to make any commitments yet regarding 20 other berm-type projects next on the BIG list.
“We’re just trying to get the analysis done to see what kind of increases we’re going to see,” she said.
She added, “We’re going to have to see what the impact is.”