The number of juveniles arrested for violent crimes in Maryland dropped by 16 percent in 1998, as the number of youths charged with robbery, aggravated assault and murder fell to levels not seen since the early 1990s, according to Maryland State Police statistics scheduled to be released today.

In addition, fewer juveniles were arrested last year for serious property crimes, including breaking and entering, larceny and motor-vehicle theft, according to state police figures.

Juvenile crime figures were unavailable for Virginia and the District, but the numbers are in keeping with a national trend that has seen a general decline in juvenile crime in recent years.

Lt. Gov. Kathleen Kennedy Townsend (D) attributed the drop in juvenile arrests to an assortment of new programs that have taken root in Maryland. The numbers are to be released today at the state's fourth annual Juvenile Justice Summit in Hunt Valley, a Baltimore suburb.

"These good numbers didn't fall out of thin air," said Townsend, who oversees anti-crime policies for the administration of Gov. Parris N. Glendening (D). "We've been able to do this because we've transformed the juvenile justice system. We've changed the system more in the past four years than it was changed in the previous 40 years."

Experts agreed that new crime-prevention programs and stricter punishment have helped to chip away at the problem. But they said the biggest factor behind the drop in juvenile arrests is that there are simply fewer teenagers around to cause trouble these days.

Rex Smith, a former Maryland secretary of juvenile justice who is now president of the American Justice Institute in Laurel, a private consulting firm, said he expects juvenile arrests to climb again as the children of the baby boom generation grow older.

"You cannot underestimate the size of the population going down," Smith said. "They really need to expand those programs because that population bubble will be coming back at us in the next three years or so."

State police reported that 3,136 youths age 17 or younger were charged last year with violent crimes, a category comprising murder, rape, robbery and aggravated assault. The total represented a 16 percent decline from 1997.

The number of robbery arrests--1,104--was the fewest since 1993, and the number of aggravated assaults dropped to 1,849, the lowest figure since 1991.

After falling for several years, however, arrests on rape charges increased last year by 14 percent, from 98 to 112. Murder arrests remained flat, declining from 72 to 71 between 1997 and 1998. Even so, the number of murder arrests was the fewest since 1990.

State officials used the overall drop in juvenile crime to trumpet a variety of programs designed to prevent teenage delinquents from turning into hardened criminals.

In Howard County, for instance, officials overhauled their community-service program for first-time juvenile offenders two years ago with the help of a $38,000 state grant.

In the past, teenagers who got into trouble were often ordered to perform community service projects, but authorities rarely followed up to make sure the work got done. Now, delinquents are watched more closely and are ordered to make amends in other ways, such as by writing letters of apology to their victims and by writing essays about how they expect to reform their conduct.

"These kids now see they are being held accountable and that there is swift and sure justice," said Neil Dorsey, director of community service for the Howard County sheriff's department. "The earlier you deal with these kids to show them the community is concerned and that there is some sanction for their behavior, the better."