Congress is busily at work on a new generation of public works projects that has this circular characteristic: each is aimed at undoing damage done by some earlier public works project.

A water-resources bill now in preparation in the Senate Environment and Public Works Committee, and another already adopted by its House counterpart, are chock-full of these "second-generation" proposals.

They are a relatively new twist in that age-old game of authorizing water projects -- locks, dams, levees, bridges and other good things that put a twinkle in legislators' eyes.

In its continuing fight with Congress over expensive and sometimes dubious new water projects, the Carter administration is opposing a number of the second-generation schemes in the House and Senate bills.

One such scheme would provide federal assistance to Houston, where traffic along the Houston ship channel is clogged by the slow sinking of a railroad bridge.

Another, in Mississippi, would authorize construction of a pumping system to remove accumulating ground-water from cropland protected by a federal levee system on the Yazoo River.

"There seems to be a superabundance of this type of authorization -- projects that have spawned new projects," said Edward R. Osann, coordinator of the Coalition for Water Project Review, made up of 24 national environmental groups.

"We think the public needs to realize this is a part of the hidden cost of past water-resource blunders," he said.

The Texas problem is created by the withdrawal of underground water reserves to supply the burgeoning industrial and residential demands of Houston and surrounding Harris County.

One of the results is that already low-lying lands lie even lower, making them susceptible to flooding when storm-propelled tides rise on neighboring Galveston Bay.

Another result is that some bridges over water courses, such as the important Houston ship channel, are getting closer to the water, making passage for vessels tougher.

The worst situation is on Greens Bayou, an adjunct to the channel, where the clearance under a railroad bridge has been reduced from 27.6 feet to 19 feet since 1951.

Rep. Bob Eckhardt (D.-Tex.), concerned that industrial shipments from two plants were bottlenecked by the sinking bridge, got the House committee to approve a federal expenditure of $450,000 to rectify the problem.

Sen. Lloyd M. Bentsen (D-Tex.), similarly concerned, is working on the Senate committee to approve the federal expense rather than to force the Houston Port Authority to pay the bill, as current law requires.

Not that President Carter wants to see Houston sink. But his administration is opposing that project, as well as another Eckhardt-Bentsen proposal (also in the House bill) to have Uncle Sam, rather than Houston, pay the cost of digging the ship channel deeper.

Puzzler No. 2 is a different sort of problem, involving a $108 million pumping plant -- the largest ever built in the Western Hemisphere -- in the northwest Mississippi district of Rep. Jamie L. Whitten (D), chairman of the House Appropriations Committee.

The Yazoo River Backwater Pumping Plant has "second generation" written all over it. Its need became apparent when rainwater began gathering behind flood-control levees the Army Corps of Engineers built to protect cotton and soybean cropland.

"This is a glaring example of the pork-barrel politics that have shaped this bill," Osann said. "The Christmas season may be upon us, but this is one political ornament that the taxpayers can ill afford."

But there are other stocking-fillers that Santa's elves on Capitol Hill have conjured up. Another Whitten inspired goody would require the federal government to repay any citizen whose private water supply is disrupted by a Corps of Engineers project.

In its original form, in a water-resources bill that died in the final moments of the last Congress, it applied only to citizens affected by the Tennessee-Tombigbee Waterway, a canal in Whitten's district. This year's bill makes repayment national in scope.

Rep. James Abdnor (R-S.D.) and Sen. Larry Pressler (R-S.D.) have a gift in mind for Springfield, in their home state -- a new $2 million intake system for the little town's water supply from Lewis and Clark Lake on the Missouri River.

The administration opposes the plan (already in the House bill) on the ground that Springfield was warned not to put its present intake where it did because it would silt up. The intake silted up. Springfield says it wasn't warned and shouldn't have to pay for a new intake.

Another case: Alabama legislators are pushing for a $2.5 million program to protect an Indian monument at Moundville, Ala., from bank erosion along the Black Warrior River. The problem is created by an upstream dam. The House and Senate bills have a dozen or more similar erosion-control plans for other areas.

"Theoretically" the congressional Public Works Committee staffer said "almost any flood control project we do can be traced back to something someone did upriver."

Whatever, by the estimate of David Conrad of the American Rivers Conservation Council, these and other damage-repair schemes in the House and Senate bills will cost more than $86 million.