Development of a luxury hotel and a small office building has begun on a Georgetown site by JBG Associates. An opening in mid-1979 is projected.

The 73,000-square-foot site at 2800 Pennsylvania Ave. NW, bordering Rock Creek Park on the east and 29th Street on the west, will be developed with a 218-room Four Seasons Hotel, under a management arrangement, and an office building with 74,000 square feet of space, plus 13,000 feet of commercial area.

The development site, purchased from the Washington Gas Light Co. several years ago, covers all of a block except for the eight Diamond Row townhouses that will be preserved on Pennsylvania Avenue. JBG owns two of the houses.

Ben Jacobs of JBG said that a developing partner in the total $15 million project will be DWS Holding Co., Inc., the real estate subsidiary of Louis Dreyfus Holding Co., Inc. of Paris.

Skidmore, Owings / Merrill is the architect for the hotel-office complex that will be connected by an inner court with the entrance from the avenue. A builder will be selected soon.

Zoning, which is a combination of C-3-A and W-2, permits five stories above ground and there will be three levels below grade from Pennsylvania Avenue, with the lower level bordering the C & O Canal on the southern boundary. Other levels below and above grade will overlook the canal.

The hotel will have several restaurants, two of which will overlook the canal. There will be a two-storey ball-room below the hotel, some of it under the inner court providing access to the hotel and the office building.

Jacobs, whose associates in JBG are Donald A. Brown and Joseph Gildenhorn, said that the hotel is envisioned as "being one that will attract high-level business, professional and government people who come to Washington."

He cited adjacency to the Kennedy Center, the State Department and Georgetown, the site is also only a few blocks west of a West End where the Oliver T. Carr firm has started construction on a large development, Westridge, will include both an office building and a condominium apartment. And a Guest Quarters hotel has been started at 25th and Pennsylvania.