After two washouts in 18 months on Old Highway 100 outside Washington, Franklin County is taking further steps to prevent it from happening again while meeting federal standards for reimbursements.

On Tuesday, the Franklin County Commission approved spending an additional $5,840 for a hydrologic and hydraulic study of the road west of the St. John’s Road intersection.

The study will include a design for a storm sewer in the area to prevent future heavy rains and flooding from washing out the road again.

County Highway Administrator Ron Williams said the additional costs and studies are necessary to satisfy requirements from the Federal Emergency Management Agency (FEMA), which will eventually reimburse the county for flood damages in that area and others in the county.

“We told them (FEMA) the last time it slid that this was needed,” Williams said. “This will show them what we are doing to alleviate water from coming over the road and washing it out.”

A section of Old Highway 100 was closed in late April when it was undermined by heavy rains and partially collapsed.

Franklin County Highway crews rebuilt the substrate under the roadway and poured a new surface, allowing the road to be open to traffic in June.

In December 2015 the road washed out in the same location and was closed for about a month.

At that time, highway crews added rock to the shoulder area, but it was again washed out just a few months later, even more severely.


Williams assured the commission the additional cost for the study and installation of its proposed drainage system will be eligible for FEMA reimbursement, along with all costs for repair and remediation thus far on the road.

The other trouble spot for the county as a result of the spring flooding was in the St. Clair area where rising waters took out a historic bridge, and washed out a portion of Mill Hill Road about a mile downstream.

Removing the bridge wreckage from the river has cost the county about $20,000, which should be reimbursed by the Federal Emergency Management Agency (FEMA) once all is said and done.

In September, crews spent two weeks using heavy tow trucks to remove the mangled metal bridge from the Meramec River.