Why will building a new Dahly Bridge cost an extra $50,000?

The bridge collapse (decorahnews.com file photo)

Winneshiek County officials have gotten the word that there will be an additional cost to the construction of the new Dahly Bridge to replace the one which collapsed last year.

An environmental study of the Upper Iowa River at the bridge crossing has discovered the presence of a number of mussel varieties--including two that are listed as "threatened."  That means the mussels will have to be moved away from the bridge construction site--an effort that could cost $50,000.

It's "an interesting problem to deal with," says County Engineer Lee Bjerke--not just because of the higher price tag, but because the mussels have to be moved in October.  That could affect the construction timetable of the new bridge, which Bjerke had hoped would begin late this fall, but before the river froze over.

Now divers will enter the river in diving suits and move the mussels away from the bridge to a new location.  Once at the new location, work on the new bridge could begin--if the weather cooperates.

Bjerke says the construction schedule may also be impacted by long-eared bats which are nesting in nearby trees.  The trees will be cut down to provide better access for construction crews, but that has to be done in November, so as not to interfere with the nesting of the bats.