While Arlington voters last week approved $10.9 million in bonds to enlarge the county jail and improve county roads, parks and community conservation programs, it will be next summer at the earliest before county residents see any major work begun on the projects they approved at the polls.

When construction will begin depends on when the county gets the money, which depends on when the bonds are sold -- and that depends on the nation's precarious municipal bond market.

Arlington has yet to sell $10 million in municipal bonds that voters approved in 1979, 1977 and even 1973, primarily because interest rates the county would have to pay have been sky high for the past two years, says Anton Gardner, director of Arlington's office of management, systems and budget. As a result, the highway, sewer and mental health facility projects to be funded by those bond issues were simply postponed, he said.

Arlington expects that this winter, instead of selling $20 million worth of 20-year municipal bonds and paying the prevailing rate of close to 12 percent -- twice the 6 percent rate the county is paying on bonds it sold three years ago -- it may sell two-year bond anticipation notes instead and put off floating any bonds until 1984, Gardner says. Arlington would pay even higher interest on short-term notes, but it would be counting on long-term bonds to be at much lower interest rates by 1984, which would save the county money in the long run, Gardner says.

Arlington has a AAA rating from bond-rating companies, as do Montgomery and Fairfax counties. This means they are considered the best financial risks. Municipalities with lower ratings must pay higher interest rates on their bonds.

But the market for both bonds and short-term notes has been so volatile that the county doesn't really know what it's going to do and will wait and test the financial waters in January before floating anything, Gardner says. By law, no bonds can be sold for at least a month after an election, until the election and referendum votes have been certified by local courts.

Thus major work will not begin on the projects until next summer at the earliest, and then only if county finance officers have taken the plunge into the money market. But plans, at least, are proceeding.

The Arlington bond issue which won the most votes Nov. 3 was the $2.1 million bond to expand the county jail, which has been overcrowded almost since it opened in 1974. County Sheriff James Gondles said this week, "I've been told to proceed almost as if I had the money in hand. We'll soon be going out to bid for an architect, hope to have one in hand by February (if the bonds are sold in January) and from there on, as far as I'm concerned, we're underway," with the summer of 1983 projected as the completion date.

The next step for most of the other Arlington projects approved in the bond issue is to actually select them. The $3 million bond issue for county highway improvements and the $1.8 million bond issue for storm drainage projects do not legally commit the board to any specific projects, according to John Hummel, chief of the county engineering division.

About half of the highway money will be for street paving, he indicated, with much of the rest probably used to fund two major street widenings: South Walter Reed Drive near King Street, and South Eads Street between Fort Scott Drive and Glebe Road.

The $3 million bond issue for parks includes $2.1 million for the Northern Virginia Regional Park Authority and $900,000 for improvements in neighborhood parks. The regional park money, the county's share of contributions for 1977 to l982, will enable the park authority to buy and develop the last two miles of the 44-mile Washington & Old Dominion hiking and biking trail, which are in Arlington.

The park authority has a deadline, since under the option terms with the Virginia Electric Power Co., which bought the old railroad right-of-way when the W&OD went out of business, the park authority must buy the entire right-of-way by December 1982. Werner said it should take about a year to complete the bike trail through Arlington once the park authority gets the bond money.