Four incumbents took commanding leads yesterday in early returns from the Washington school board election.

Barbara Lett Simmons, an at-large member who was the board's most outspoken supporter of ousted Supt. Barbara Sizemore, led the field of candidates for two at-large seats.

However, in ward three, board vice president Carol Schwartz, who stressed that she had helped fire Sizemore, also was far ahead with more than three-quarters of ballots cast for the seat representing her ward.

In other returns based on a count of ballots cast before 2 p.m., two members who had been appointed to fill vacancies, Victoria T. Street (ward four), and Minnie S. Woodson (ward seven), were leading by wide margins in their bids to win two-year terms on their own.

In ward two, where incumbent William Treanor decided not to seek re-election, Alaire Rieffel, a lawyer and president of the Ross Elementary PTA, had a two-to-one lead over rival Alverta Munlyn, an education specialist with an anti-poverty agency.

The results for ward eight, which are being counted by special tabulating machine, were not available shortly after the pools closed last night.

Frank Shaffer-Corona, an activist in several Hispanic organizations, seemed headed toward winning the second at-large seat on the board with a substantial lead over his closest rival, Stuart Rosenblatt, Washington local director of the U.S. Labor Party.

The fourth candidate in the at-large race, Afrodita Constantinidis, a representative of the Socialist Workers Party, was far behind.

Election officials said the turnout in the election was generally light.

With seven of the board's 11 seats up, the results could lead to major changes in policy.

Since the board tired Supt. Barbara Sizemore two years ago, the city school system has been dominated by her successor, Vincent Reed, who has led the city schools through their most stable period in a decade.School board meetings, which had often been long and acrimonious, have become generally calm and relatively brief.

During the eight years before Reed took office, District schools had four superintendents.

Even though most of those running yesterday had warm praise for Reed, several expressed doubts about his competency-based curriculum, now being tested on 23 schools, which is seeking to develop uniform step-by-step teaching methods throughout the school system.

"There will be so many new people after this election that you can't be sure what will happen," one out-going board member remarked. "How will they get along? How will they get along with Vince Reed? Who knows? It's new ball game."

Among those leaving the board are its two-term president, Dr. Therman Evans, who decided not to seek re-election. Julius Hobson Jr. (ward eight) a former-board vice president, also decided to quit, as did William Treanor (ward two).

Hobson said his main reason for not seeking a second term was financial.

"Being on the school board is almost equivalent to a full-time job." said Hobson, who works as an editorial assistant at Howard University. "The $4,000 we get a year just doesn't cover it. I simply can't afford to continue."

Last year another board member, James Featherstone Jr. (ward seven) resigned his seat, after being unable to find a job for 10 months.Featherstone said the only work he could get was with the city government, and under D.C. conflict-of-interest laws he could not serve on the school board as well.

Board members are paid up to $4,000 a year, either as direct reimbursement for expenses, or at a rate of about $19 an hour while they are doing board business. But members say they often put in more than 30 hours a week, so they reach the $4,000 maximum early in the year, and after that set paid no more, no matter how much they do.

Another board member Hilda Mason (ward four) quit in July when she was elected to the D.C. City Council.

Because of the resignations, the seats in wards four and seven are being filled for two-year terms. The other five openings on yesterday's ballot were for regular four-year terms.

Two years ago only 9.8 per cent of the city's registered voters took part in the school board election. In 1973 the turnout was only 11.8 per cent. Even in 1971, when there was a highly publized at-large contest between Marion Barry and Anita Allen, only 16.6 per cent of the registered voters turned out.