Mayor Marion Barry announced yesterday the start of a series of programs aimed at preventing "at risk" D.C. youths from entering or reentering the juvenile justice system.

The Barry administration packaged the new programs with existing ones to create a juvenile justice initiative made up of a network of services called "Invest in Our Future." The goal is to keep young people from becoming drug abusers, high school dropouts or criminals.

Audrey Rowe, the mayor's special assistant for human resources development, said the combined programs are expected to reach an estimated 3,000 young people and their families in the current fiscal year and will increase the D.C. government budget for youth prevention programs from $4.4 million in fiscal 1987 to $7 million in the current fiscal year.

Rowe said that although the D.C. government previously has launched several programs targeting at-risk youth, those efforts met with limited success because of a lack of coordination among the agencies that operated such programs.

Rowe said a year's worth of planning went into the latest initiative, which she expects to have greater success because it focuses on problems encountered by families as well as children and draws on resources from the community and businesses.

"We're trying to raise the level of attention focused on kids in the city before they get into trouble," Rowe said of the new programs. "If this doesn't work, if we don't make a major impact on our kids, we are all going to be in trouble."

The programs include a scholarship fund to help economically disadvantaged students attend the University of the District of Columbia or technical schools. Also, beginning this year, underprivileged fourth graders will receive special support services and attention from counselors and mentors through a program in which businesses "adopt" classes at a cost of $250,000 per class.

On the community level, a project called "Family-to-Family" will seek companies, churches and groups that are willing to adopt a family for at least a year, in an effort to provide "whatever is necessary to turn that child and family's life around and make them a positive part of the community," the prevention initiative states.

Additional programs have been created to meet the needs of youths involved in different phases of the juvenile justice system. Some who are arrested but not charged will be placed in a diversion program. As an alternative to commitment in an institution, about 200 "serious offenders" will enter an intensive, at-home probation program under which the youths may be visited by probation officers up to seven times a week.

Youths committed to juvenile correctional institutions will become part of the mayor's Executive Mentorship Program. Program volunteers, including members of the mayor's Cabinet, will establish relationships with the youths to help them build self-esteem. Initially, the program will involve 200 young people.