After a period of rapid construction and initiation of new projects in the early 1970s budget years, capital construction by the D.C. government is winding down. The mayor's fiscal 1979 budget places more emphasis on maintenance and improvement than on large new projects.

Among the four major projects outlined by that budget proposal are two high school modernizations and the replacement of an unsafe and outmoded water treatment facility. One large new project - the proposed convention center - faces an uncertain future because of Congressional opposition.

More typical of projects contained in the $129.8 million capital improvements program are projects that correct the defects of age, replace temporary facilities or revamp old structures to meet new needs.

This is a description of what capital improvements the city plans to buy with your tax dollars:

SCHOOL: A total of $4.4 million would modernize the Ellington School for the Arts in Northwest Washington. Modernizing the nearly 80-year-old building means turning standard classrooms into rehearsal halls, dance studios and ceramics and crafts workshops. Modernezation would also include redoing acoustics in the school and building-in special equipment such as dance bars, film processing equipment, drafting tables and kilns.

Modernizing Eastern High School on Eastern Avenue is more costly at $11 million. It involves "almost a complete gutting of the building inside," said the city budget office's director of capital improvements, Terry Peel. Eastern, built in 1923, needs entirely new electrical and heating systems. Some floors and walls willbe replaced and a larger gymnasium will be built. When the work is finished, the school will serve a smaller student body because some former classroom space will be converted to other uses. Enrollment in the District's schools is declining.

In neither case are the operations of the schools expected to be disrupted by the modernization.

Another school project calls for alterations to the M.M. Washington School at 1st and O streets NW to convert this former vocational school into a career development center for health careers with $1.6 million reprogrammed from other areas. The building would include laboratories and equipment designed to train dental, laboratory and other health technicians.

The fiscal 1979 operating budget includes money for staffing and equipment for modernized school facitities at Burrville Elementary School at Division and Hayes Streets NE, and Roosevelt High School at 13 and Upshur Streets NW which are expected to be complete that fiscal year.

LIBRARIES: Public schools may provide the only space for small branch libraries in the future. One branch library request, for a LamondRiggs (or Chillum) Library is pending in the fiscal 1978 budget, but no branches are proposed beyond that. Another branch, Deanewood at Nannie Hellen Burrounghs Avenue between 48 and 49 Streets NE, is expected to open in February 1979. Funding to operate that branch is included in the fiscal 1979 operating budget.

RECREATION: There are no plans at this point to build new facilities that would expand the recreation program, although additions and improvements in facilities are anticipated. In the operating budget for fiscal 1979, the mayor proposed funding and personnel for the National Children's Island, a recreation park with special features for handciapped and mentally retarded children. Funding was also provided for a new recreation center at Fort Lincoln being built with federal funds.

POLICE: The mayor has asked for $3.5 million to build an addition, two floors above an existing parking lot, to the First District Station House at 415 4th Street.

Down the road, there are also plans to replace a temporary facility used as the Seventh District Station House. When the force expanded to seven districts in 1970, there was no district station house in Anacostia. Some "abandoned and dilapidated" buildings owned by the public housing authority were converted temporarily to that use, said Peel.

FIRE: The city is asking for $530,000 as the second phase of a program to replace outmoded equipment.

UNIVERSITY OF THE DISTRICT OF COLUMBIA: The city is asking for $2.5 million for equipment for nes buildings at the Van Ness Campus on Connecticut Avenue. The money would provide fixed equipment such as built in shelves for three buildings and equipment for programs such as engineering. For instance, the money would provide a machine that tests how different materials react to stress.

HUMAN RESOURCES: The mayor is asking for $1 million for D.C. Village, the District's facility for the aged, to replace the electrical system and to make improvements such as replacing rotting llnoleum. For Forest Haven, the city's institution for the mentally retarded, the mayor is asking for $2 million. Among other things, the money would be used to upgrade heating and electrical systems in the cottages where residents live.

The mayor also proposes taking $1.8 million from surplus funds to help build a new receiving home for youths awaiting trial. The home, which would be built at the Blue Plains site in southwest Washington, would provide detention for 125 juveniles. It would be closer to court than Cedar Knoll, the institution in Laurel, Md., where youths awaiting trial are now housed. It would make it easier to keep youths who haven't been convicted separate from adult offenders and juveniles who have been convicted of committing crimes, according to city officials.

Also proposed is $275,000 for improvements to the dog pound on New York Avenue NE. The money would provide space for 30 additional animals and for conversion of a temporary building into a spaying and neutering clinic.

GENERAL SERVICES: The fiscal 1979 budget asks for $770,000 to eliminate fire hazards at the District Building where fire prevention has included aiming small fans at wiring during the summer to keep wiring from overheating and catching on fire. The money would pay for replacing the current electrical system and for fire escapes, which the building does not now have.

TRANSPORTATION: The mayor's proposed budget includes $4.1 million for improvements on Chain Bridge and about $11.2 million for work on the Benning Road Bridge over the Anacostia River.

The mayor also proposes $425,000 for widening and making Southern Avenuecontinuous from South Capitol Street to Eastern Avenue. About $1.9million is requested for local street improvements, $100,000 for traffic operations improvements, $400,000 for resurfacing streets that connect to interstate highways, $200,000 for safety improvements such as installing traffic singals and realigning intersections, and $100,000 to continue creating a bicycle path network.

ENVIRONMENTAL SERVICES: A sum of $12 million has been requested for projects including three imporvements at the Solid Waste Recycling Center (Incinerator Number 1) off of Benning Road NE near PEPCO's generating station. The improvements requested are designed to reduce particles in the air, to recover and recycle water used to cool burned materials and provide for magnetic separation of metals, to reduce the amount of materials to be burned and to make the sale of recyclable metals possible.

WASHINGTON AQUEDUCT: The largest project in the capital budget is $28.1 million to replace the 70-year-old McMillan Reservoir water treatment plant on North Capital Street. The plant now purifies water by filtering it slowly through sand in 29 one-acre sedimentation basins. The plan is to replace the facility with a cheaper fastsand filter process, which requires only two acres for the new plant. The new plant would also remove dangers from sedimentation basins which have settled and represent a potential hazard to the crews who clean them. Freeing the area now used for sedimentation would allow storage capacity for about one day's water supply, Peel said.

McMillan supplies water for all of Anacostia, most of downtown, including the White House, and most of Capitol Hill.