The escalating power struggle between the White House and Congress goes public today when the House Appropriations Committee meets to vote on fiscal 1978 funds for water projects President Carter wants eliminated.

Letters and statements have been fired up and down Pennsylvania Avenue as the two sides threaten to hold up programs and possibly veto bills in order to get their way.

On May 11, President Carter sent each member of the Appropriations Committee a letter saying he was "deeply concerned and disappointed" that an Appropriations subcommittee had approved more than $200 million for continued construction of 17 of 18 projects Carter had asked to be halted.

The subcommittee also provided money for 12 new construction starts which Carter also opposed.

In his letter, Carter asked the members to reverse the subcommittee and halt funding for what the termed "needless and counterproductive projects."

Carter also implied that new "necessary programs" would be held up unless "wasteful spending" is curtailed. Yesterday, Cater's press secretary, Jody Powell, linked a prospective national health insurance plan to cutting down spending on programs such as the water projects.

The Carter letter struck some raw nerves on Capitol Hill.

Subcommittee Chairman Tom Bevill (D-Ala) fired off a response to Carter, saying he found himself "in disagreement with the advice you have received."

Carter had written that his decision was based on a "thorough and detailed review by the Corps of Engineers, Secretary of the Interior, Office of Management and Budget, and by me and my staff."

Bevill, in a reference to foreign aid expenditures, added pointely that "we do not require such severe test on any other public works projects that we build in this country or in other parts of the world."

Carter-Bevill exchange was discussed at the President's meeting with congressional leaders last week. At the conclusion of that session, House Majority Leader James C. Wright (D-Tex.) asked if he could have a meeting with the President on the water projects before the full committee meeting.

That session was held Monday afternoon. For 45 minutes, according to Wright, a congressional delegation, which included Bevill, "tried to reason with Carter."

"We said we didn't want to go to a veto, Wright said, "and the President said he didn't want it to come to that."

In a recent television interview, House Speaker Thomas P. (Tip) O'Neill Jr. (Mass.) made the point that there were 35 vetoes during the Democratic administrations of Presidents Kennedy and Johnson. But, he noted, "the leadership never brought a veto of the President to the floor for an override."

On the water projects issue, O'Neill and Wright have made clear, the leadership will want funding continued on those projects that Congress, not the President, approves.

One House leadership aide who has dealt with the water projects issue said recently that the President "doesn't seem to understand he is not playing around with a gadfly like Lester Maddox" in dealing with Congress.

That reference to Carter's record of conflict with the Georgia legislature while he was governor is uppermost in the minds of many congressionaal Democrats these days.