Endangered fish helps local bridge project

Springfield Mo - A rare fish in need of better habitat and a Dallas County road in need of a better bridge have become entwined in a unique project that will benefit both.

On Tuesday, July 27, Dallas County officials joined Missouri Department of Conservation and U.S. Fish and Wildlife Service personnel to view the start of a bridge construction project that will improve conditions for local drivers and the federally threatened and state endangered Niangua darter. A low-water bridge will be built where Benton Branch Road crosses the Niangua River, a site known locally as Williams Ford.

This crossing lies squarely in the habitat of the Niangua darter (Etheostoma nianguae). The only place in the world this small fish (between two and four inches long) resides is in south-central Missouri in a few tributaries of the Osage River. One of the places the Niangua darter has been found is in Dallas County in its namesake river. One of the fish’s key habitat needs is relatively unrestricted stream flow.

This is where the new bridge at Williams Ford will provide habitat help. Currently, the Niangua River is spanned at this site with a type of crossing known as a vented ford crossing. This style of crossing forces the stream into narrow vent-like openings and creates a flow pattern that impairs the upstream passage of Niangua darters. The new low-water bridge will resolve these problems.

Besides making things better for Niangua darters, the new bridge will provide a much-needed improvement for humans who drive across the bridge. A problem associated with vented ford crossings is road flooding. Because stream flow under the crossing is limited to what the “vents” can accommodate, fast-rising water can easily over-ride what the vents can handle and flood the road, creating a dangerous driving situation.

The project’s cost is estimated at $249,000. It is being built, in part, with habitat improvement funding provided to the Missouri Department of Conservation from The American Reinvestment and Recovery Act of 2009 through the U.S. Department of Interior. The project started with preliminary work in June and is scheduled for a Dec. 1, 2010 completion date.