Report blames combination of wet spring, June deluge for flooding

INDIANAPOLIS – An unusually wet spring that dumped nearly twice as much rainfall as normal in the months before a record June deluge expanded the scope of the flooding that followed, a federal report has concluded.

The report by the U.S. Geological Survey said soils were already rain-sodden and rivers and streams flowing high when a stationary front collided over Indiana with an abnormally large area of Gulf Coast moisture, sparking 16 hours of moderate to heavy rainfall.

Central and southern Indiana’s wet soils worsened the flooding sparked by the June 6-7 deluge. That downpour was so rare, it isn’t expected to be repeated for another 500 years.

The highest rainfall total from the storm was in the small town of Spencer in Owen County, where 10.4 inches fell – an event that isn’t expected to happen again in the next 1,000 years.

“It certainly was a huge event that caused major damage,” said study co-author Scott E. Morlock, chief of the hydrologic network section at the Geological Survey’s Indianapolis office.

The report said precipitation totals in central and southern Indiana from March through May ranged from 123 percent to 180 percent of normal. June’s downpour then dumped more than 8 inches of rain on Martinsville in Morgan County and more than 7 inches on Franklin in Johnson County.

The flooding that followed set peak records at seven of 19 sites along rivers and streams. And 100-year flood events were recorded at five sites.

Morlock said the peaks at many sites exceeded the levels of the 1913 flood, considered by many experts to be the recognized benchmark for flooding in Indiana.
The flooding resulted in 39 Indiana counties being declared federal disaster areas and more than $153 million in federal disaster assistance being distributed in the months that followed.

More than 8,400 evacuations and water rescues were staged, and more than 5,600 homes were damaged, along with more than 650 roads and more than 100 dams and levees.

Hardest hit, according to the report, was Columbus in Bartholomew County, where about 15 percent of the buildings in the city of nearly 40,000 were flooded.

The estimated peak flow on Haw Creek in Columbus was 13,900 cubic feet per second, or 65 percent greater than a 100-year flood event.

That waterway runs next to Columbus Regional Hospital, where flooding caused more than $125 million in damage and led to the evacuation of 157 patients.