DOWN BY THE river in Georgetown is where rich land and poor planning have gone hand in hand for longer than most residents care to remember. The tract in question, which has everyone gathering around the latest architect's rendering for another outpouring of divergent opinions, is that strip running from Key Bridge to Rock Creek, tucked -- trapped is the word -- between the unsenic Whitehurst Freeway and the Potomac. The object is to find something better-looking and more valuable to the city and its residents than the current eye-catching complex of debris, parking lots and cement plant that grace the area.

The design just unveiled is by Arthur Cotton Moore and was drafted after the Fine Arts Commission wisely said no to another architect's earlier proposal. Mr. Moore's scaled-down design calls for commercial-residential development on 3.4 acres, with two curved buildings that would embrace an elliptical yacht basin.

The view from the water, and Virginia looks fine; the freeway seems fairly well hidden and the boat approach is attractive. But from Georgetown, the design seems more monumental than it need be.To the Fine Arts Commission or the many vocal Georgetown residents who want the land purchased for park-only use, none of it may appeal; and the city government, which last summer was supporting a combination of development and park land, is now siding with the all-park faction.

Fortunately, the National Park Service opposes purchase of the land for park-only use. Though a nice, green strip seems like a quiet, scenic answer for the residents, it would be a waste, both practically as well as financially. An empty tract of this size and in this location would be little more than an unused back yard. Commercial and residential development means important additional revenues for a financially strapped city.The answer should be a compromise, a further scaling-down of the Moore design that still would include commercal and residential facilities and could incorporate the attractive yacht basin idea.

Residents' groups are understandably disturbed at the prosepct of anything that might attract more people to the area, for traffic is a nightmare there. But the traffic dilemma, which goes back to the refusal of residents to consider subway service or pedestrian-only blocks, should be addressed for what it is instead of used as an excuse for prohibiting practical and attractive use of this most valuable property. When the commission considers the design next Tuesday, it would do well to seek modifications of the proposal rather than to toss it out entirely in hopes of holding out for an empty park.