The controversial water projects in a public works bill that President Carter said yesterday he will veto are seen by interested members of the House and the Senate as traditional congressional prerogatives that the White House is seeking to usurp.

"Congress has traditionally set water policy," one experienced Senate aide said yesterday, "and previous presidents have stayed out of it." Not Carter.

The House and Senate committees that approved the water projects Carter now opposes dispute the president's contention that they are inflationary "pork-barrel" undertakings that reflect irresponsibility with the public purse.

The White House argues that the real cost of the projects Congress voted to start in the public works bill will eventually climb toward $2 billion. Congressional sources respond that such long-range projections are meaningless, given the unpredictable future rate of inflation, and that the cost of the water projects in the bill passed by both houses is actually just $25 million to $30 million more during the current fiscal year than the projects the Carter administration supported.

Members and staff officials in both houses have said recently that they believe Carter is most concerned about money in the bill appropriated for six water projects that were on the president's "hit list" last year.

Carter has said he thought Congress agreed last year to kill these six projects, but they were resurrected in the new public works bill. The house and Senate members who voted to resurrect them say they promised only not to fund them last year, and not to kill them.

The new bill appropriates construction money for three of the projects, and "study money" for three others. The White House has called the $300,000 to study three projects a ruse to keep bad proposals alive, but the House and Senate subcommittees that first proposed the studies contend otherwise.

In effect, it is argued in the capitol, the committees agreed that those three projects as now designed do not meet existing criteria for construction and should not be built. But, they add, all three are in areas that need or soon may require new water resources, so that studies of possible alternate projects make sense.

The three projects Congress proposed to study further include two in Colorado - Fruitland Mesa and Savory-POT Hook - located in areas being transformed from agricultural to energy-producing regions, where new water is certain to be needed eventually, according to defenders of the projects.

In arguing against these two projects, the White House has assumed that they will be built according to earlier plans that are no longer valid, the projects' supporters in Congress say.

Similarly, the Lukfata Lake project in Oklaboma that the White House attacks as potentially useful only "to one catfish farm and several potential catfish farms" will not be built as now designed, according to congressional supporters of the public works bill. instead, Congress has voted $150,000 to study the possibility of building a more useful Lukfata Lake project.

Congress did vote construction money for three "hit-list" projects that Carter opposes. They are:

The Yatesville lake project in Kentucky, which the White House calls damaging to the environment, disruptive of life in nearby areas and unnecessary because it duplicates recreational benefits available nearby.

Congressional defenders argue that the project has merit for the economic activity it will bring to a severely depressed area of Appalachia and will help control annual floods along the Kentucky-West Virginia border. It is strongly supported by Kentucky congressmen, though the White House says Gov. Julian Carroll of Kentucky supports Carter's veto.

The Bayou Bodcau project in Louisiana, which the White House says will benefit only 150 landowners at a cost to taxpayers of more than $100,000 for each landowner affected. Congressional supporters respond that the project was cut off last year at a stage of construction that is more hazardous to nearby areas in terms of potential flooding than the pre-project situation was. To restore the conditions that existed before, one Senate staff aide said, Congress would either have to appropriate funds to undo the work done or complete the project. It chose the latter course.

The Narrows project in Colorado, which the White House argues is environmentaliy dangerous (jeopardixing the habitat of the whopping crane, for example) and disruptive to the local community. Supporters respond that it is actively supported by Colorado's governor, senators and representatives, apparently because of preceived economic benefits.

Congressional supporters of the bill also dispute the White House on the issue of "full funding," or appropriating all the money for a water project in the initial appropriation.

Many in Congress see this as a way to dilute congressional control over the pace at which projects that can take several to as many as 20 years to complete are actually constructed. Once the money is appropriated, a staff aide noted, the administration of the day can decide to stretch out the construction process or delay it in many ways, since the executive branch controls the spending of appropriated funds.