The Alexandria City Council has given preliminary approval to regulations designed to control how the city's two-mile strip of industrial land along the Potomac River will be developed. The vote is considered an important step in the city's efforts to resolve by the end of the year a decade-long dispute with the federal government.

Under the terms of the plan, approved last week, approximately 65 percent of the 40-acre waterfront will be devoted to parks or recreational use, such as boat marinas, outdoor markets and restaurants, with the remaining 35 percent to be used for commercial, residential or office development. The zoning will permit building heights of 30 feet in recreational areas, and 50 to 77 feet elsewhere.

Ownership of the waterfront properties has been in dispute since the early '70s, when the federal government, at the urging of local conservationists, filed suit claiming title to all land east of a disputed 1791 waterline. The suit, intended to prevent high-density development of the waterfront, has not yet gone to court. Instead, the federal government gradually has relinquished its claims to city and privately held land in exchange for development restrictions.

Although the zoning language approved by the council last week cannot formally be voted into law until Nov. 23, city officials saw the action as crucial to the city's effort to settle disputes with the owners of the three largest pieces of land in the affected area.

Owners of those three parcels, known as the Bryant and Robinson Terminals properties, reportedly have reached oral agreements about use of the land with the federal government, and some council members have said that delay or significant change in the zoning proposals would have jeopardized the agreements.

The city's waterfront master plan for the area also provides for five city parks and a 25-foot-wide bike path and promenade to run the length of the waterfront from Daingerfield Island in the north all the way to Jones Point, near the Woodrow Wilson bridge at the waterfront's southern tip.

Last year, Alexandria received title to five parcels the federal government had claimed. That land will be used for public parks. The city also agreed to adopt by the end of this year zoning that conforms to development plans agreed to by the city and the National Park Service.

Two other large private properties, the Vepco and Norton parcels, have reached settlement, leaving six properties still in dispute.

A proposed change to the plan submitted by Republican council member Carlyle C. Ring and Democrat Patsy Ticer, calling for the lowering of height and density limits except with special approval, was voted down on the grounds that deviation from the plan after private landowners had negotiated settlement on the basis of it would throw away five years' worth of work.