An Indiana environmental group once again is attempting to stop construction of the Interstate 69 extension between Evansville and Indianapolis by filing suit in federal court.

The Hoosier Environmental Council and Citizens for Appropriate Rural Roads brought their complaint Tuesday in U.S. District Court in Indianapolis seeking to overturn a permit the Army Corps of Engineers issued for the $3 billion project.

The groups say the agency failed to comply with a section of the Clean Water Act because it approved a permit to discharge about 225,000 cubic yards of fill material into wetlands and streams in Greene and Monroe counties without considering less-damaging alternatives.

“In its own rules, the Corps has determined that 'most wetlands constitute a productive and valuable resource, the unnecessary alteration or destruction of which should be discouraged as contrary to the public interest,’” the environmental groups argue in their suit.

A spokeswoman for the Louisville division of the Army Corps of Engineers said the agency is aware of the lawsuit but cannot comment on pending litigation.

The complaint targets what’s known as Section 4 of I-69, which extends 26 miles from the Crane Naval Surface Warfare Center to Bloomington. Construction on the stretch is under way and should be finished by the end of 2014 at an estimated cost of at least $532 million.

The portion of roadway will cross 18 waterways, affecting about 88,000 linear feet of water and filling more than 9 acres of wetlands, the groups argue.

The odds of halting work on the new terrain route appear long, however. Three sections of I-69 extending from Evansville to Crane already are finished.

In addition, the latest lawsuit is the Hoosier Environmental Council's third legal attempt to halt construction on the 142-mile link.

In February 2011,  and again the following October, HEC filed similar suits seeking to halt work on two now-finished sections of the interstate.

Last July, federal Judge Larry J. McKinney denied the first challenge. HEC since has appealed the judge’s decision to the 7th Circuit U.S. Court of Appeals in Chicago.

A decision on the second suit is on hold pending the outcome of the appeal.

Once the section to Bloomington is finished, work is set to begin on the two remaining sections stretching from Bloomington to Interstate 465 on the south side of Indianapolis.   

A lack of funding threatens completion of the remaining sections, though. The southernmost part of the road has been funded in part from proceeds of the $3.8 billion lease of the Indiana Toll Road.

The Indiana Department of Transportation has designated more than one-third of its entire federal highway aid this year toward building the 27 miles between Crane and Bloomington.

A report INDOT filed with the Federal Highway Administration states that 36 percent—or $281.3 million—of the $791 million Indiana will receive this year in federal road funding has been allocated to this stretch of I-69 in 2013.

That’s in addition to the $70 million in state highway funds budgeted in 2013 for Section 4.