Alexandria officials and residents, concerned that a planned $150 million development near the Landmark Shopping Center will cause massive erosion and traffic jams, are expected to ask the City Council tonight to scale down the 10-acre project.

The development, which includes a hotel, three office buildings, 300 apartments and the city's largest parking garage, also has forced officials to reevaluate the zoning laws that permit such dense construction.

"You can't visualize this, it's going to be so big," said Dayton L. Cook, director of transportation and environmental services for the city.

Cook said the biggest problem presented by such a large-scale development at the northeast corner of Duke and Van Dorn streets is the risk that part of Van Dorn Street could collapse if the proposed seven-level garage is built into the steep hill between Van Dorn Street and Ripley Street.

"That site is a difficult one to built on. Why do you think there hasn't been development there before?" Cook said. "Thirty thousand cars a day travel on Van Dorn. If we had to close it even for a day . . . . "

Mayor James P. Moran, displeased with the increased density and traffic congestion the plan could cause, said, "The West End has been miserably zoned. This site was one of the last pieces of wooded land, and we're going to put a massive development on it."

John L. Fagelson, the developer's Alexandria attorney, said yesterday, "I think it's a good plan and done with a lot of concern for the area." To ease the traffic problem, Fagelson said the developer has agreed to purchase a city DASH bus and purchase $10,000 worth of bus tickets for each of the next 10 years for residents and employes of the complex.

The project, which meets Alexandria's zoning requirements, was approved by the city's planning commission in June. Residents have appealed that decision to the City Council, which will review it tonight.

Moran said, however, that while the City Council can pressure the developer, Landmark Century Center Development Corp., to adjust its plans, rejecting the project is nearly impossible at this point.

"Legally, we can't turn it down," Moran said. The development complies with the city's zoning laws, which allow for three square feet of floor space on every square foot of lot space.

The mayor said to avoid future development of this kind, he planned to meet with city officials to amend the 1953 zoning ordinance that allows a 3.0 floor-to-area ratio in commercial and retail districts.

In Fairfax County, Deputy Zoning Director Michael Nolton said the highest floor-to-area ratio permissible in a comparable commercial area is 1.0. Arlington zoning technician Charles Reeves said large development projects are zoned on a case-by-case basis in that county.

"We have an awful lot of high-rises over here," said Robert M. Gardner, a resident in the Landmark area. "The traffic situation is not good and it's only going to get worse."

If the city allows developers to build all the parking spaces they want, Cook said, "We'll need two more Shirley Highways." CAPTION: Picture, Model of $150 million development planned near Landmark Shopping Center. By James Parcell -- The Washington Post