Plans to expand boating and sports facilities at Daingerfield Island, south of National Airport, will be presented at a public hearing July 23.

The hearing, sponsored by the National Park Service, will be at 7:30 p.m. at Jefferson-Houston School, 1501 Cameron St., Alexandria.

The Park Service is expected to present five proposals for the park, including plans that could cost as much as $9.5 million and provide parking for 1,000 additional cars.

Daingerfield Island, just off George Washington Parkway on the northern edge of Alexandria, is a popular sailboat marina created in 1948. The marina restaurant, a surplus World War II building, was moved to the island in the mid-1950s. The island facilities are maintained by the National Park Service and are open to the public.

In proposing the improvements, the park Service has contended that the 226 parking places now at the island are inadequate to handle the thousands of summer visitors and that there also are long waiting lists for the 185 wet slips at the marina's docks and the 364 spaces for trailered sailboats.

The Park Service plans include expanded parking areas, construction of additional soccer and sports fields, construction of additional sailboat launching ramps, dredging of the existing harbor and possibly digging out a new harbor in marshes on the southern end of the 107-acre site.

Although originally an island at the mouth of Four Mile Run, Daingerfield has become part of the mainland because of silt deposits and fill over the last 40 years.

An environmental review report by the Park Service has grouped proposed improvements into five "alternative strategies," with plans ranging from proposals to develop one to five soccer fields and parking for 226 to 1,270 cars. The environmental report is available for review at the marina restaurant, the main library in Alexandria and Park Service headquaters at Hains Point.

The Park Service is expected to make a final decision on development of the island after the public hearing.