Surrounded by two rivers, two canals and 42 miles of levees, the Natomas basin is one of the toughest flood plains to protect in the nation.

Water can find weaknesses at multiple points. If enough water were to find enough weaknesses, it could inundate a part of Sacramento that's home to 70,000 people, an international airport and hundreds of farms and businesses.

Given the lives and money at stake, it's imperative that government flood engineers do the job right in upgrading Natomas' flood defenses. The basin's prime protector – the Sacramento Area Flood Control Agency – now says it will take an extra year, and a lot more money, to do that job. That's not surprising. Nor will it likely be the last surprise.

Ever since Hurricane Katrina swamped New Orleans, federal agencies have endured a torrent of criticism, and they have been steadily tightening their standards for levees and flood protection across the country. Natomas is one area that is bearing the brunt.

Two years ago, federal and state inspectors announced that Natomas' levees no longer met the minimal 100-year standard for flood protection (a 1 percent chance of flooding in any given year). That prompted SAFCA to launch an upgrade of Natomas' levees that, from the start, seemed based on a schedule that was ambitious beyond belief.

Originally, the flood agency assumed it could start work in 2008 and upgrade 26 miles of levee in two years. Such a massive construction project (moving 5 million cubic yards of dirt) would have ended development restrictions in Natomas in less than 24 months. By 2012, the agency hoped to achieve 200-year flood protection for Natomas, providing a margin of safety never before seen in this region.

But all along, SAFCA was candid that contingencies could trip up its schedule. And guess what? They have. The U.S. Army Corps of Engineers has insisted on reviewing all work on Natomas levees from its headquarters in Washington, which has slowed down needed permits. Obtaining right of way for levee work has added to delays and costs.

In addition, engineers have found that the Natomas levee problems go far beyond those that line the Sacramento River and the cross canal to the north. Inspections have shown that, on the east side of Natomas, slurry walls are needed to prevent water from seeping under the levee from ancient stream beds.

These east side streams – Dry Creek, Magpie Creek and Arcade Creek – carry small volumes of water compared with the Sacramento River. But they still could potentially punch a hole in a levee during the biggest of storms.

The combined effect: Some 40 miles of levees will need work. Total costs are projected to increase from $414 million to $618 million. Natomas won't be able to reach 100-year flood protection until late in 2011, with improvements aimed at meeting the 200-year standard coming the following year.

Yet there's still a big "if" hanging over this timeline. The Corps of Engineers must complete a "general re-evaluation report" for Sacramento's levees by 2010, which is essential for Congress to help finance SAFCA's work. Without that help, the flood agency will run out of money, and the project will come to a halt in two years.

Congress and the Corps can't let that happen. Every year of delay means an extra winter where a big storm could be waiting. In the fight against floods, time is not our friend.