The floodwalls along the city's major drainage canals were a classic example of the shortcomings. The corps didn't want to build most of them. Initially it planned to block storm surge with giant barriers across the eastern inlets of Lake Pontchartrain, beef up the levees along the southern lakeshore, and erect massive floodgates to keep high water out of the canals. Environmental groups, concerned about impacts on the lake and its wetlands, blocked the plan in court. The corps dropped the barriers and switched to a system that would rely on higher lake levees and floodgates. State and local officials—who were required to pick up nearly a third of the ballooning tab—balked at the cost of the gates. They also feared that closing the gates could actually cause flooding, as rainwater piled up in the canals. City leaders pushed instead for floodwalls along the canals. The groups remained at loggerheads until 1992, when Congress passed a water resources act that forced the corps to do it the city's way.