Walter Hopps, former director of the Washington Gallery of Modern Art and the Corcoran Gallery of Art, and a long-time figure of prominence in art circles in both Washington and Southern California, has taken a job in Texas. Hopps, whose last museum post here was adjunct curator of 20th-century art at the National Collection of Fine Arts (now the National Museum of American Art), has been named director of the yet-to-be-constructed Menil Collection in Houston.

Hopps, 49, who is more widely respected as an art scout than as an administrator, has stretched behind him a record of discoveries few curators can match. While directing the Pasadena Museum of Modern Art, he gave Marcel Duchamp and Joseph Cornell their first museum retrospectives. He was one of the first curators to hang the works of Andy Warhol, Roy Lichtenstein, Barnett Newman and R. Crumb, and in Washington promoted such well-known local artists as Sam Gilliam, Rockne Krebs, Ed McGowin and Anne Truitt.

The Houston Chronicle reported yesterday that Paul Winkler, now associated with the Menil Foundation, will be the new museum's assistant director and the coordinator of its building project. Jacqueline de Menil, whose family's collection the museum will house, will assume no official title but will work closely with the two. Hopps could not be reached for comment.

The collection contains about 10,000 items assembled over the past 30 years by John and Dominique de Menil, and is said to be one of the largest and most diverse personal collections in the United States.

Strong in Surrealism, with important works by Rene Magritte and Max Ernst, the collection also includes ancient art from the Mediterranean area, African art, pre-Columbian pieces, Medieval iron work, American folk art, and choice examples of American and European paintings and sculpture from the last four decades.

The building to house the Menil collection will be designed by architect Renzo Piano, co-designer of the Pompidou Center in Paris. Hopps is on the board of that institution. He has also been involved, of late, with the Museum of Contemporary Art that is now being designed for Los Angeles. That museum is slated to open with an exhibition -- on the car in art -- curated by Hopps.

John and Dominique de Menil, much of whose fortune came from the manufacture of oil-drilling equipment, helped give Houston its Mark Rothko Chapel, and bought the "Broken Obelisk," the monumental sculpture by Barnett Newman that stands just outside. The Menil Collection, which will offer temporary shows drawn from its vast holdings, as well as traveling exhibits, is expected to open in 1984.