ANNAPOLIS -- The Anne Arundel County school board, trying partly to cope with the phenomenal growth in the western part of the county, last week embarked on its first county-wide redistricting of schools.

The number of students enrolled in Anne Arundel public schools has declined from a peak of 84,205 in 1974 to 64,000 in the last school year. But the county has experienced fast growth in Washington-oriented suburbs near the boundaries with Prince George's and Howard counties, as well as in the middle stretch of the county from Crofton through Severna Park to the Broadneck Peninsula on the Chesapeake Bay.

As a result, schools in the county's older, more urban communities such as Annapolis and the Baltimore suburbs of Glen Burnie and Brooklyn Park have schools with empty seats, while schools in the newer suburbs need portable classrooms to cope with the overload.

The process, expected to take until 1995 to complete, involves changing the boundaries of districts from which the county's 13 high schools -- and the elementary and middle schools that feed into them -- draw their students. At the same time, the school board will decide where new schools are needed and where old, underused schools should be closed.

The object, school officials explained, is to avoid crowding and to achieve a better racial balance in each school, while building as few new schools and closing as few existing ones as possible.

In the past, the school board has done only small-scale redistricting in limited areas of the county. Proposals for a county-wide redistricting have been discussed but never have been carried out. Such efforts always prove controversial as parents oppose having their children shifted to new schools or protest the closing of neighborhood schools.

This time, however, school board members say they are determined to act.

"I think the county is really ready for this," school board president Patricia Huecker said. "People are aware that it has to happen. But it's not going to make it any easier."

"It's dealing with people's lives," said Superintendent Robert C. Rice. "I mean that quite literally. You change the whole pattern of what they're thinking, how they think, which way they go. Many of their activities are tied to which way they go to school. It's changing something that they've become established in. It's not so much that people dislike where they might go. It's that they like where they are."

While calculating proper school boundaries is difficult in the best of times, Rice added, Anne Arundel has the added problem of a long, uneven Chesapeake shoreline and lots of rivers. "In some cases, you see an educational facility very nearby but it will take you 20 minutes to get there because of the water," he said. "We have a lot of natural barriers to take into consideration."

Along with the redistricting, school officials want to standardize grade levels at different schools around the county so that all elementary schools have kindergarten through grade 5, all middle schools have grades 6 through 8, and all high schools have grades 9 through 12. By adjusting district size, school officials can make sure these grade changes do not make schools too big or too small.

School officials said they also hope to improve the racial balance in county schools. Minority pupils comprise 17 percent of the county's 64,000 public school students. But most of the minority students attend schools in the Annapolis and Fort Meade areas, where some schools have as much as 75 percent minority enrollment.

School board members said they are unlikely, however, to permit any wide-scale busing of students to adjust the balance.

The school board plans public meetings around the county later this year. In November, Rice is to make recommendations to the school board on which schools he believes need to be closed. The school board is to consider his recommendations in December.

If the board decides to proceed with school closings, public hearings are to be held from January to March next year, with a final decision made by April. Rice said that at the earliest, students would be moved to another school in September 1989.

Although the school board is far from working out details, it agreed last week to tackle first the redistricting in the Arundel High district north of Crofton, and to save debate over closing any schools in Annapolis until later because those decisions are expected to be more complicated. Huecker said Arundel was the logical place to begin because its crowding problems are most severe and because it is a relatively simple, self-contained school district.

A committee of 21 citizens appointed by the school board in January to examine redistricting has predicted that five new schools will be needed to handle future crowding at Arundel and in nearby fast-growing suburbs -- one high school, one middle school and three elementary schools.

A new high school would relieve crowding at Arundel, Meade and South River high schools, and the new middle school would relieve crowding at Arundel, Crofton, MacArthur and Central middle schools. The committee recommended three new elementary schools in the Broadneck, Meade and Arundel areas.

If these new schools are not built, according to the committee's calculations, elementary schools in the Arundel High district would be at 177 percent capacity by 1995, the middle school would be at 136 percent capacity and Arundel High would be at 109 percent capacity.