You might have expected great things from Laura DeWald.

DeWald recently won the women's marathon in the National Sports Festival, clocking 2 hours 47 minutes 6 seconds. That time and a 2:35:57 performance in the Boston marathon in April has given women's distance running a fresh, top-line competitor.

The past is starting to pay off for DeWald, 24. A few years ago, she organized the University of Virginia's now nationally ranked women's track team but then had to give up her scholarship to concentrate on her engineering studies.

DeWald, who runs 80 miles a week, still doesn't put running first. Now a public works planner for Arlington, she took off only one day of work to attend the sports festival in Syracuse, N.Y.

DeWald finished work Tuesday and headed for Bluemont Park, where she won the annual 10-kilometer Bluemont Cross Country Race, setting a course record for the third year in a row.

Besides her running and a full-time job, she has a serious side interest in dancing ("I just got toe shoes," she said).

"All of this is so new," DeWald said of invitations from race directors that have come her way since Boston, only her third marathon. "It's almost a surprise. I'm just going to enjoy it, see if I can reach some of my goals."

Only in the last year did DeWald surpass Mary Ellen Williams of Rockville, one of her Washington Running Club teammates, as the area's fastest woman.

Her running goals have changed as quickly as her marathon times have dropped. In 1977, she went to the national collegiate cross country championships in Denver, thinking, "This is the biggest running opportunity I'll ever have."

Now, the 1984 Olympics in Los Angeles, in which the women's marathon will be run for the first time, is a natural goal.

"It's a definite possibility," she said. "It's in the picture, certainly. "Probably, by then, the professional running circuit will be in full swing. I know that I might miss a lot, but I'm going to pass on that. The Olympics would mean so much more to me."

DeWald's immediate goal is cracking 2:30 in the marathon, a time once thought unattainable by women.

Her Boston time makes her the sixth-fastest American woman, a newcomer among the likes of Patti Catalano and Joan Benoit, who have dominated the event the past few years.

Two years ago, DeWald, who ran the quarter-mile at Washington-Lee High School, had yet to run her first marathon. Thirty miles a week, if that, was the extent of her training. A 2:59 in the 1979 Marine Corps Marathon convinced her to get serious. She was the leading woman runner through 251/2 miles before letting up and finishing third.

"You learn from finishes like that," she said. "You learn not to let that happen again."

DeWald, who is easily spotted in races because of her waist-length ponytail, caught the attention of Will Albers, a former George Mason University runner. First a boyfriend, now her coach, Albers helps DeWald sort through race invitations.

"It took meeting someone like Will," DeWald said. "He made my running like clockwork. Like today, I've already done eight miles, but he wants me to do another four. He's tough in his workouts, but he's never been wrong."

DeWald's second marathon, also the Marine Corps, came last fall. A 2:44 on the adjusted Washington course qualified her for Boston, where her goal there was only to prove to herself that she could, indeed, run that fast. She did even better, dropping her time by eight minutes in finishing eighth among women.

What made DeWald's 2:35 finish particularly impressive is that she got sick late in the race and slowed to a 10-minute-per-mile pace for the last two miles.

"I think my body still hasn't adjusted to the stress of the Boston race," DeWald said. "I can do 26 miles, but I didn't want to press the pace in Syracuse. I'm getting better, though. I only stopped for the bathroom twice."

DeWald finished the festival marathon 12th overall and broke the course record for women by more than six minutes.

"It was so lonely, running by myself. I just pretended I was out enjoying a training run in the countryside."

DeWald's usual training runs take her through the streets of Arlington, past projects that she helped design.

"There's a sidewalk I like to check the progress on," DeWald said. "And there's also fringe parking lots, trash compactors, stuff like that."

Since her graduation from Virginia in 1979, DeWald has revived a childhood interest in ballet.

"I dance twice a week," she said. "It keeps me limber for running. Plus, it's something other than running. That's a big part of why I like it."

Upcoming races for her include the all-women Avon International Aug. 23 in Ottawa and the Bank One Marathon in Columbus, Ohio, in October.

"By those races, I'll have a solid distance base behind me," DeWald said. "I'm pointing for some hard performances."