Averting a Crisis

Maquoketa

When in July 2010, Maquoketa residents were sandbagging their water treatment plant, waste water treatment plant, and Municipal Electric Utilities Plant, they already had experience with flooding–the June 4-5, 2002, flood in the Maquoketa River Basin, for example.  That year, 2002, the cubic feet per second (cfs) flowing north of their city in the Maquoketa River was 47,900.  In the North Fork of the Maquoketa, before joining the main channel of the river, that June, the cfs was 22,600, a record up to that year.  The river basin as a whole, in 2002, saw considerable damage; Jackson County mostly counted its blessings, experiencing only damage to three bridges and closings of some county roads. Two-three feet of water did collect in south Main Street in Maquoketa, and a man stranded on a bridge over Prairie Creek had to be rescued by a squad that tied themselves together across the creek.

            But 2010 was different.  Upriver in Delaware County the dam at Delhi had failed.  The year before the dam had passed Iowa Department of Natural Resources inspection with only minor repairs needed.  Nevertheless, in July of 2010 the concrete dam with earthen structures on either side could not hold the major flood waters resulting from heavy rains.  A major breach some 30 feet in width formed on the south side of the dam and the water rushed through cascading down some 40 feet to the Maquoketa River below.  Iowa DNR Environmental Specialist Tom McCarthy said, “Boats and propane tanks were flowing through the dam breach.”

            So Delhi’s watershed neighbors downriver in Maquoketa were preparing for the worst.  Instead, the crest in Maquoketa was expected to be “only” 34.8 feet, about the same as the 2002 flood.  (Flood stage on the river in Maquoketa is 24 feet.). Lyn Medinger, Jackson County Emergency Management Coordinator, explained that debris coming downstream “apparently hit a bridge in the Lake Delhi area which created a lake.  The result meant the high levels of water expected downriver did not happen….I think we have averted a crisis.”

Sources: on-line: David A. Eash, “Flood of June 4-5 2002, in the Maquoketa River Basin, East-Central Iowa,” US Geological Survery, Department of Interior, 2004; Sheri Melvold, “Flooding still high in Maquoketa, but water from dam breached slowed,” Quad City Times, July 24, 2010; co.jackson.ia.us/images/community/MaquoketaMap.pdf.