"I'M SENDING ALONG a little press release you may want to look at," said the senior state senator from Northern Virginia with characteristic understatement. The word from Adelard L. Brault--dean of Northern Virginia's legislative delegation to Richmond, former majority leader of the senate and onetime Fairfax County supervisor--was that he is retiring after 17 years in the General Assembly. They have been important years of public service for his constituents, and "Abe" Brault's experience, abilities and rank will be missed as much as they have been appreciated--which is a lot.

Mr. Brault, who is 74, says he thinks it's time for a younger person to run, though anyone who has kept track of the senator's routine in Richmond would not cite fatigue as a factor. On the contrary, Sen. Brault seems to thrive in the around-the-clock legislative world that has exhausted many younger politicians.

Out of these energies have come significant achievements. Mr. Brault says he is proudest of his role in securing legislation to improve education at all levels, special education in particular and other improvements for the mentally and physically handicapped. He also has been--and is still-- pressing for much-needed tightening of the state's conflict-of-interest laws.

It has been Sen. Brault's moderation and influence that have helped get state assistance for Metro-- which, like so many concerns of Northern Virginia, does not easily attract great sympathy from the other lawmakers. Similarly, in the days of governors who seemed to share this lukewarm interest in Northern Virginia, Sen. Brault was able to make the legislature more independent of the governor; he got approval of a constitutional amendment providing for special sessions to consider overriding a governor's vetoes.

We will stop here, since Sen. Brault hasn't yet stopped. The 1983 session is young, and so is the spirit in which the "dean" is attacking a new agenda, with the good wishes of the people of Greater Washington, whose regional interests he has recognized and pursued in the state capital.