Cecil M. Harden Reservoir nears capacity

Published June 13, 2008
Louisville, KY -- The U.S. Army Corps of Engineers Cecil M. Harden Lake Reservoir, Rockville,
Ind. is currently at 687.02 feet or 86 percent full as of Friday, June 13. The lake level has fallen
0.39 foot in the last 24 hours, Corps officials report.

Cecil M. Harden Lake is part of an overall system of reservoirs managed by the U.S. Army
Corps of Engineers. The system is designed to minimize flood damages by storing water
caused by heavy rains until the rivers and streams are at levels that releases from the reservoirs
will not cause additional flooding downstream. At this time Cecil M. Harden Lake is still
providing flood damage reduction benefits.

Currently, rainfall and runoff from the lake’s watershed flow into the lake. Water is released from
the lake under controlled conditions which minimizes impacts to downstream areas. At this time
Cecil Harden Lake is still providing flood damage reduction benefits.

If the lake reaches its highest pool of 690 mean sea level (m.s.l.), the lake will have reached its
maximum storage capacity and it will be “full.” At this maximum storage, any rainfall and runoff
that flow into the lake will pass out of the lake via the stilling basin and the spillway as if the lake
were not there. Conditions being similar to an overflowing bathtub, it is possible that flows out of
the lake will be higher than normally observed.

Reservoirs are designed to hold a large capacity of water in order to limit damage from flooding,
but when rainfall is widespread or localized; engineering solutions can not always completely
manage flooding. Corps flood protection projects seek to minimize potential flood damages.
Should rainfall increase and the reservoir reach 690msl (28 feet above summer pool); the dam’s
spillway will serve as a bypass for flows so the dam isn’t overtopped. The spillway is designed
to provide a safe path for the excess flows. Then, water from the spillway re-enters Big Raccoon
Creek downstream of the dam. Cecil M. Harden Lake provides flood protection benefits for the
downstream areas in Mansfield, Bridgeton, Coxville, Mecca, and Rosedale in Parke County and
to a lesser extent to the cities and areas around Clinton and Terre Haute on the Wabash River.

The dam is continually under surveillance, and it is operational and safe. The lake has provided
more than $107 million in flood damage reduction benefits since it was built in 1960.
For information on conditions in Indiana and the Ohio River Basin, go to the National Weather
Service http://www.erh.noaa.gov/er/ohrfc/.

Release no. 08-004

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