Support for water and flood control projects that affect districts throughout the country could trump Republican loyalty to the White House as the House votes Tuesday on what could be the first override of a President Bush veto.

With many Republicans backing the bill, supporters are confident of annulling Bush's veto of a $23.2 billion water resources bill that would approve projects along the hurricane-hit Louisiana coast, the Florida Everglades and hundreds of other water-related enterprises in virtually every state. A two-thirds majority is needed to override a veto.

A Senate vote, expected as early as Wednesday, could complete the first reversal of a Bush veto.

Bush did not veto a single bill during the first five years of his presidency, when Congress was mainly in GOP hands. He has since vetoed a stem cell research bill twice, an Iraq spending bill that set guidelines for troop withdrawal and a children's health insurance bill. He vetoed the Water Resources Development Act, or WRDA, on Nov. 2, saying it was too expensive.

Since Democrats gained control of Congress in January, Bush has issued dozens of veto threats, warning he will veto annual spending bills that go beyond his budget levels. As Congress winds down for the year, veto threats hang over a $288 billion farm bill the Senate is considering and new attempts to come up with a children's health insurance bill.

The WRDA bill, the first water system restoration and flood control authorization passed by Congress since 2000, would cost $11.2 billion over the next four years and $12 billion in the 10 years after that, according to the Congressional Budget Office.

Flood protection projects along the Gulf Coast, including a 100-year levee protection in New Orleans, would cost some $7 billion if fully funded. The bill approves projects, but does not fund them.

It would authorize the construction of navigation improvements for the Upper Mississippi River, at an estimated federal cost of $1.9 billion, and an ecosystem restoration project for the Upper Mississippi costing $1.7 billion.

The Indian River Lagoon project in the Florida Everglades would be funded at about $700 million.