A pumped-storage reservoir in Missouri that collapsed in December 2005 could be back on line by the end of 2009 following selection of a contractor to reconstruct it.

Ozark Constructors LLC, a venture partnership formed by ASI Constructors Inc. and St. Louis-based Fred Weber Inc. has been tapped to reconstruct the Taum Sauk upper reservoir by AmerenUE, St. Louis, the Missouri utility operating company of Ameren Corp., also of St. Louis. ASI, Pueblo West, Colo., is a heavy civil contractor specializing in the construction and rehabilitation of dams, spillways and major water resources. AmerenUE also has named Paul C. Rizzo Associates Inc., Monroeville, Pa., engineer of record and project manager. The 1.5-billion gallon upper reservoir's enclosure will be made of roller-compacted concrete in a design approved by the Federal Energy Regulatory Commission (FERC).

The mountaintop reservoir in Reynolds County, Mo., breached on Dec. 14, 2005, dumping more than 1 billion gallons of water through a 600-ft-wide gap in the 100-ft-high, rock-filled and concrete-lined enclosing wall. No one died in the incident, but three children in a family of five were injured and the family's house was destroyed.

In October 2006, AmerenUE agreed to pay a $10-million civil penalty, fund $5 million in improvements and adopt a comprehensive safety program for its hydroelectric facilities in a settlement with FERC.