The Army Corps of Engineers disregarded parts of environmental law in allowing construction of a $22.5 million St. Peters levee in the Mississippi River flood plain, lawyers for environmental groups told a federal judge on Thursday.

Lawyers for the corps and St. Peters, which holds the levee permit as part of the Lakeside 370 Business Park development, countered that plans for the levee were thoroughly studied and meet all legal requirements.

At issue is the effort by the Great Rivers Habitat Alliance and the Missouri Coalition for the Environment to halt construction of the nearly four-mile levee. Preliminary work on the structure began last week.

After hearing more than six hours of arguments over two days this week, U.S. District Judge E. Richard Webber said he would decide quickly whether to grant the injunction sought by the environmental groups.

Ted Heisel, a lawyer and the coalition's executive director, told Webber that the National Environmental Policy Act and the Clean Water Act require a study of the "cumulative impact" of the Lakeside 370 levee.

Nicholas Pinter, a geology professor at Southern Illinois University Carbondale, testified for the plaintiffs that the corps' study of the Lakeside 370 levee's likely effect on flood levels was simplistic "and not a good representation of reality."

Pinter said a sophisticated hydraulic-model study would show that the levee would cause "a significant increase in flood levels."

In granting the levee permit Sept. 9, the corps said that it had thoroughly studied the plan for a levee to protect Lakeside 370 from a 500-year flood and had concluded that the 22-foot-high dike's effect on flooding would be negligible.

Assistant U.S. Attorney Jane Rund, representing the corps, told Webber that the plaintiffs were unable to show that the levee would cause "irreparable harm." She added that Lakeside 370 plans include development of new wetlands and a recreational lake outside the area protected by the levee.

St. Peters, which envisions thousands of jobs and millions of dollars in taxes from Lakeside 370, has an agreement to sell the nearly 1,600-acre site to developer Leonard Kaplan. He has until Dec. 16 to close on the sale. The deal calls for Kaplan to pay $15.6 million at closing, to reimburse the city for levee construction and to make other payments that would eventually increase the total value of the sale to nearly $50 million.

The city is in a hurry to get the levee built. Last week, aldermen approved adding as much as $500,000 to the city's approximately $15 million contract with Dave Kolb Grading Inc. Jeff Kolb, who heads the company, testified Thursday that he would use the extra money to put more equipment and workers on the job to get the levee built by the middle of November. Any delay caused by an injunction against the project would be costly, he said.

"If we lose 10 days now, we're in trouble," he said.