In an unusual show of cooperation, U.S. Sens. Mary Landrieu and David Vitter on Wednesday amended a major appropriations bill to require the Army Corps of Engineers to conduct a detailed, 18-month study to determine whether to build permanent, full-time pump stations at the ends of three New Orleans drainage canals and adopt a "pump-to-the-river" option to reroute some rainwater from the 17th Street Canal to the Mississippi River. The amendment to the $34 billion fiscal 2010 energy and water appropriations bill would allow the corps to continue to build its preferred Option 1 plan while the study is under way. That plan calls for pump stations at the Lake Pontchartrain ends of the 17th Street, Orleans Avenue and London Avenue canals to operate only when tropical storms threaten and continues to use interior pump stations to push water to the lake at other times. But the amendment requires the new pump stations to be built so they can be converted into full-time pump stations if the new study determines that the interior stations should be abandoned and deeper canals dug as part of the gravity-fed system.