On the surface, it appeared that Rep. Robert E. Wise Jr. (D-W.Va.), a rookie who has hardly been here long enough to be intimidated, had boomed one of those rare first-time-at-bat home runs into the bleachers.

Wise persuaded the House this month to vote against its powerful Appropriations Committee and kill a $26 million appropriation for the Stonewall Jackson flood-control dam in his home district.

The committee is rarely reversed on water projects, but this time a freshman did so--and by a thumping 213 to 161. He did it in part by getting other freshmen, Democrats and Republicans, conservatives and liberals, to go along with him.

No one is ready to say that Congress is breaking its dam habit, but there are signs that the traditional pork barrel is filling less readily than in the past. Environmentalists long critical of costly water-resources projects are finding new, unaccustomed allies among fiscal conservatives.

"Yes, the mood is changing," agreed Rep. Tom Bevill (D-Ala.), chairman of the Appropriations subcommittee that provides the money for locks, dams, lakes, dredging projects and other goodies supposed to warm constituents' hearts.

"With the big budget deficit and the critical economic bind that the country is in, Congress is going to be more cautious--and rightly so," he said.

One of those flashing the caution light is Rep. Gerald B. Solomon (R-N.Y.), a fiscal conservative who last year engineered passage of an amendment requiring reclamation beneficiaries to reimburse Uncle Sam for $650 million worth of dam safety improvements. That was regarded as an audacious move, for it went counter to a pet of retiring Rep. John J. Rhodes (R-Ariz.).

"Six years ago, when I came here," Solomon said, "an amendment like mine would have gone down to a resounding defeat. But everyone is now concerned about budget deficits . . . . I believe the beneficiaries of federal water projects should contribute based on the benefits they receive . . . . We've made significant headway in the last several years in getting that across."

Bevill's and Solomon's views are supported by a series of votes on water issues in recent months confirming that times are changing, perhaps more in the House than the Senate, but changing nonetheless. Some examples:

* The House energy and water appropriations bill left out a $22 million Reagan administration budget request for the large and controversial Garrison irrigation project in North Dakota. And last December, in the continuing resolution, the House denied $4 million for Garrison by 100 votes.

* Similarly, the House bill omitted money for the O'Neill irrigation project in Nebraska. The House in December voted against any more money for O'Neill by a 101-vote margin.

* The House overwhelmingly voted against a bill that would have required the federal government to spend $1.8 million on replacement pump casings for the Southern Nevada Water Project. In effect, the House said make the users pay.

Longtime environmental lobbyists Ed Osann of the National Wildlife Federation and Pete Carlson of the Environmental Policy Center agree there has been a change on the Hill.

"The fiscal arguments now provide an acceptable rationale for a large number of members who would not be with us on environmental grounds," Osann said.

Carlson added, "With the budget clouds looming overhead, many of these members no longer have to go along to get along. They can look at these projects on their merits and vote against them if they don't measure up."

There's another factor at work in the equation: pressure to build projects. Controversy and overreach by the authorizing committees have combined to prevent Congress from passing a major water resources authorization bill since 1976, even though flood-control and navigation needs have continued to mount.

President Carter's attempts in 1977 to stop the porkiest projects and the Reagan administration's insistence that states, local communities and users pay a larger share of project costs have contributed in a major way to the impasse. Congress, complaining about administration inflexibility on cost-sharing, has refused to provide money for 14 new Corps of Engineers projects sought by the White House.

William R. Gianelli, assistant secretary of the Army for civil works, insists that the administration's views on cost-sharing and user fees be adopted before new projects are allowed.

Congressional resistance to the hard line was characterized this way by an aide to Senate Appropriations Chairman Mark O. Hatfield (R-Ore.): "Gianelli hasn't handled it well. He has come forward with a unilateral administration policy, yet he wants new projects on their terms . . . . If they demand huge amounts of money up front from beneficiaries, especially those that are hard-pressed, Congress won't go along."

Feelings thus still run high, and if Congress has changed on the surface, it may not have changed underneath. One sign was the quick reaction that Wise's victory provoked in the Senate.

West Virginia's Democratic senators, Minority Leader Robert C. Byrd and Jennings Randolph, both strong supporters of the $205 million Stonewall Jackson, got on the telephone and began calling House members to ask for their votes if the dam issue surfaced again there.

It is almost certain to surface again, because Byrd got the Senate Appropriations Committee to put the Stonewall money back in the bill, which will make the issue a topic of a House-Senate conference to work out differences.

"I intend to reach everyone in the House that I can," Byrd said. "I know of nothing in the law, no moral reason for me not to make calls. That project was authorized after the due process of hearings and an Army Corps of Engineers recommendation for it. I have worked for it for years, and I'm not going to take this lying down.

"I have no feelings against Mr. Wise, but it's my district, too. I'm doing what I feel I should do for West Virginians. I'll be a conferee. I'm not going to take anything lying down. Any member here, faced with having a project like this knocked out, would say the same thing."

North Dakota Sens. Mark Andrews (R) and Quentin N. Burdick (D) also got the Senate Appropriations Committee to put $22 million back into the bill for the Garrison irrigation project, which has divided farmers in the state and been sharply criticized by Canadians who fear it will endanger the fishing industry in Manitoba. Garrison, too, will be a House-Senate conference item.

But Nebraskans, seeing the handwriting on the fiscal wall, have taken another approach on the O'Neill controversy. Sen. J. James Exon (D-Neb.) has won approval of a study of lower-cost alternatives, hoping somehow to save the project.

The freshman from West Virginia, Wise, has picked up a special taste of congressional reality from his victory in the House. "I'm coming out of this with good and bad impressions," he said. "I feel good because of the win. But this fight seems to have taken on more importance than $26 million and an isolated dam.

"Too many chips are being called in. Anytime a state's senior senator and the Senate minority leader are making phone calls, the stakes are larger than this small dam. It's being fought not on the merits, but on personal and political appeal," Wise added. "The boys are playing hardball. The question now is whether the House will respect my amendment. If a 40-some vote can't send a message to the conferees, we've got some concerns . . . . "