Alexandria School Superintendent John C. Bristol last night proposed extensive restructuring of the city's secondary schools as "the only solution" to continually declining enrollment and escalating costs.

"The taxpayers seem to be saying, 'we can't afford to pay more money'... Unless we realistically and effectively reduce the cost of education, those who know less about our programs than we do will do it [for us]," Bristol declared.

In 1969 there were 7,712 students in Alexandria secondary schools, a figure that had declined to 5,144 by this year and is expected to decline to 4,743 in the next five years, Bristol said. He said the need for funds will not be met by the federal government, which is reducing its allocations to the city, nor by the state government, nor the city, which has budgeted only a 5 percent increase in funds even though expenses are increasing by 15 percent annually.

The city now has three middle schools for seventh and eighth graders, two high schools for eighth and ninth graders and one senior high -- T. C. Williams -- for eleventh and twelfth graders.

Bristol proposed three plans at last night's school board meeting, but said he favored the first, under which grades 9 through 12 would be held at both T. C. Williams and Francis Hammond highs, while Minnie Howard and George Washington schools would house seventh and eighth grades and special classes would be held at Parker-Gray school. John Tyler school would be closed.

Under a second plan, grades 10, 11 and 12 would be held at Hammond and T. C. Williams grades 7, 8 and 9 would be held at John Adams, Minnie Howard and George Washington schools, and special education would be held at Parker-Gray. The Secondary School Occupational Center would be closed.

In the third plan, grades 11 and 12 would be held at T. C. Williams as they are now, grades 9 and 10 would be held at Francis Hammond, grades 7 and 8 would be held at Minnie Howard and George Washington schools. Special programs would be held at Parker-Gray and John Tyler and the Occupational Center would be closed.

Each plan is designed to cost about $6 million for physical changes at the schools, but Bristol said the expenditure would be made up through increased efficiency within five years, Bristol said.

Bristol said he will "not stand idly by as our schools continue to approach that time when massive and precipitous surgery must be performed on every aspect of our program and personnel to meet economic constraints. The changes can no longer be held in abeyance."

The citys 11th and 12th grades were consolidated in 1971 at T. C. Williams in order to achieve racial balance. Bristol said last night that two 4-year high schools would benefit students by giving them more time with teachers in one facility.

It was not clear last night what action the school board will take on the superintendant's recommendations.

Board member William D. Euille said he found Bristol's presentation "shocking. I didn't think it would take quite the amount of consolidation (Bristol claims)."

Board member Lou Cook and several other members expressed disappointment that the plans failed to include the idea of closing the school system's central administration building on South Washington Street.

Board Chairman Alison May said a public hearing will be held Feb. 7 and she expects the board to decide on Bristol's recommendations on either Feb. 12 or Feb. 21.