Douglas N. King, 33, a Justice Department lawyer who specialized in the law of water rights, died of cancer Wednesday at his home in Alexandria.

Mr. King, who joined the land and natural resources division of Justice in 1970, recently helped try a case involving Pyramid Lake in Nevada, Indians who were represented by the federal government asserted that they had a right to have the water level of the lake raised for the purpose of maintaining trout fisheries. The lake level had been lowered because the Truckee River, which feeds into the lake, had been tapped by the city of Reno and by irrigation projects.

The Indians and the federal government lost in a U.S. District Court and the case is now on appeal.

Mr. King also took part in several cases in which the Justice Department sought to enforce laws that limit the use of water from federal land reclamation projects. The laws state that water from these projects, such as dams, can be used for irrigation only on 160-acre tracts on which the owners live. The thrust of the litigation has been to force large agricultural businesses either to cease using such water, or to divest themselves of much of their land.

Mr. King was born in Morrall, Neb. He earned undergraduate and law degrees at the University of Nebraska. He moved to the Washington area and joined the Justice Department the year he graduated from law school.

In his spare time, he enjoyed trout fishing and back-packing.

Survivors include his wife, Louise Carter King, and two children, Susan Michelle and Benjamin Thomas, all of the home in Alexandria; his parents, James F. and Doris May King, of Morrall; two brothers, William, of Denver, and James, of Houston, and a grandmother, Julia King, of Scottsbluff, Neb.