SIOUX CITY | Plans to step up the pace of replacing outdated bridges in Woodbury County will mean fewer headaches for farmers like Darwin Hamann.

Hamann, of rural Correctionville, takes the long way around when transporting loads from his feedlot to avoid bridges with reduced load limits. The extra time on the road cuts into his productivity, he said.

An increase in the county's Rural Basic Fund property tax levy means County Engineer Mark Nahra can add 14 more bridges to his project list over the next five years. The levy, paid only by rural residents, will add $1.3 million each of those years to Nahra's secondary roads budget.

The County Board voted for the $6.5 million increase March 12 after residents in three public meetings expressed support for it.

First up will be four bridges in eastern Woodbury County with an estimated cost of $270,000 to $420,000 each in 2014.

Bumping the number of bridge repairs and replacements from 32 to 46 through 2018 is a help but still won't keep pace with the county's needs, Nahra said.

"We've still got about 20 bridges out there that are not funded," he said. "We are getting there. We are slowly reducing the number."

Woodbury County's 318 bridges are analyzed every two years by Calhoun-Burns & Associates, a structural engineering firm in West Des Moines. The most recent study placed 68 bridges, or 21 percent, on the list with an expected life of five years or less.

Statewide, according to a report delivered at the Iowa Legislature on Wednesday, 22 percent of bridges are structurally deficient, the third highest total in the nation. Most of those bridges are on secondary roads, placing the burden for fixing them overwhelmingly on counties, Nahra said.

Woodbury County experienced a bridge-building boom in the 1950s and 1960s, when "farm-to-market" roads were being developed. That makes the average age of bridges in Woodbury County is 41 years.

The older bridges have an estimated life of 50 years, but the new bridges should have lifespans of 75 years.

"It is because of better, denser concrete," Nahra said, and less use of wood pilings, which can rot.

Most of the 14 bridges Nahra has added to his project list are in the eastern part of the county. Also on the list is a gap in County Road D50 south of Anthon that will be converted from gravel to pavement in 2017 as part of the five-year plan.

Hamann said getting D50 paved will help farmers deliver to the new Platinum Ethanol grain elevator south of Anthon.

The needs of farmers and businesses factor into Nahra's annual prioritization of projects, along with the condition of bridges and traffic count.

As the pace of repairs speeds up starting next year, Nahra, who has been the county engineer since 2009, is thinking of his retirement, some years down the road.

"What I'd like to see before I leave Woodbury County is to have our paved-road system bridges in good condition, where we've eliminated all of the (reduced weight limits) posted and structurally deficient bridges," he said.

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