As the U.S. Army Corps of Engineers’ Chicago District considers possible scenarios for closing Chicago’s locks to keep predatory Asian carp from entering Lake Michigan, the U.S. Supreme Court is set to decide if it will hear a lawsuit that could force the locks’ closure. Lynne Whelan, Corps-Chicago District public affairs officer, says the agency is studying several options, including closing the locks to boat traffic as many as three or four days a week. Michigan Attorney General Mike Cox filed a lawsuit with the high court in December to force closure of the locks. The court is expected to consider the legal merits of the lawsuit on April 16. Two studies released in the last several weeks provide differing conclusions about the economic impact of closing the Chicago Harbor Lock and the O’Brien Lock. A study commissioned by Cox estimated an economic impact to the Chicago region of about $1.4 billion over 20 years if the locks were permanently closed. A study commissioned by the Illinois Chamber of Commerce projected a significantly higher impact of $4.7 billion over 20 years.