Even defenders of the U.S. Army Corps of Engineers were shocked and alarmed last week to learn that the corps has built a reservoir in St. Lucie County that is so leaky and erosion-plagued that filling it could endanger nearby homes.

This shoddy workmanship could have serious ramifications for South Florida. If the corps can't build a safe and leak-proof 550-acre reservoir, how can the corps be trusted to fix the Herbert Hoover Dike around Lake Okeechobee? How can the corps be trusted to build the more complex projects that are part of Everglades restoration?

The need for cooperation between the corps and the South Florida Water Management District, partners in Everglades restoration, remains important. First, however, the corps must fix the Ten Mile Creek reservoir near Fort Pierce, where levees are undermined by up to 20 feet of erosion, embankments are crumbly enough to pick apart with a penknife and the cost of repairs is estimated at $13 million. Water district consultants noted many of the problems in a report last November by BCI Engineers & Scientists, the firm that last year said the Hoover dike presents "a grave and imminent danger."

But the corps didn't reply to those concerns until last Wednesday. On Friday, U.S. Rep. Tim Mahoney, D-Palm Beach Gardens, wrote the corps asking for answers. The corps didn't help matters by simply denying that repairs would cost $13 million.

Next, the corps and the water district have to bring the reservoir up to the post-Katrina standards for levees. The reservoir's design and construction began well before Katrina, so both agencies should share responsibility for upgrades.

Some corps-bashers in the water district would like to cut Everglades restoration loose from the corps and let Florida fly solo. But federal involvement is important to ensure that restoration sends clean water to the Everglades first and to new residents second. State-only restoration could be steered to provide water only to Florida's growth machine.

Water district board member Shannon Estenoz, once a corps champion but now skeptical, notes that separating the two agencies could prove difficult. The water district and the corps, she said, "might be Siamese twins sharing a heart." If so, it's clear which one of those twins needs to develop a brain.