GONZALES — The East Ascension Consolidated Gravity Drainage District No. 1 Board of Commissioners unanimously accepted the low bid Monday for a second major capital drainage project being funded with a 2007 bond issue.

Cajun Constructors Inc. beat out 12 other firms to build the Henderson Bayou floodgate, levee and pump at a cost of $15.892 million. Bids on the project ranged from Cajun’s offer to a $27.4 million bid by G.A. West and Co. Inc., a bid letter says.

The planned system in the Galvez area will prevent backwater flooding into the bayou when water is high in the Amite River Basin but allow the bayou to flow freely at others times to sustain swamps behind the structure, parish drainage officials have said. The levee, pump and floodgate will span two relative highpoints on either side of the bayou, plans show.

According to an email from East Ascension Drainage Director Bill Roux, construction is expected within 60 days of the district’s notice to proceed. Completion is expected in late 2012 or early 2013.

Parish President Tommy Martinez told the drainage board Monday the project is expected to cost a total of $21 million when engineering, land and other costs are included.

The project had a budget of $24 million but was brought down through engineering and design refinements, parish officials have said.

With the savings on the Henderson project and on a $17 million expansion of the Marvin Braud Pumping Station, the board also backed Martinez’s recommendation Monday to prioritize other projects under the 40-year, $65 million bond issue from 2007. A $14.35 million low bid was accepted on the pumping station expansion in April.

Under the drainage board’s vote Monday, the next priority is extension of the Laurel Ridge Levee in the southeastern corner of the parish at an estimated cost of $14 million.

Behind that project are improvements in the Spanish Lake area with dredging of Braud Bayou and installing larger locks at Frog Bayou at a combined cost of $6 million.