Roanoke County is expecting recent AA bond ratings -- which its financial adviser categorizes as "extremely strong" -- to help the county quickly sell $62 million in revenue bonds at attractive interest rates of just over 4 percent.

The bonds would finance five capital improvement projects, the bulk of which will be paid off in 30 years.

County staff members updated the Roanoke County Board of Supervisors on the bond sale at their regular meeting Tuesday.

The sale is tentatively scheduled for early March, just after what the staff hopes is the supervisors' final approval of the purchase of property for a new recreation and aquatic center in North County.

That approval was postponed last month on a project that is scheduled to use almost half of the income realized in the bond sale. Final negotiations with two prospects interested in building in the planned upscale office park behind the new rec center are still under way, County Administrator Elmer Hodge said then.

He asked the board to postpone a final vote on buying the land for the rec center until those talks were completed. A vote is scheduled at the Feb. 26 supervisors meeting.

The resolution to purchase the rec center site passed on first reading by a 3-2 vote with new Cave Spring District Supervisor Charlotte Moore, a Democrat, voting against it. She was joined by Republican Windsor Hills Supervisor Joe McNamara, who has philosophical objections to government funding of such projects.

Should one other vote on the project turn into a "no," that would at least delay the project and could affect the bond sale.

"We could do it without it [the recreation center]," the county's chief financial officer, Diane Hyatt, said in a recent interview. But, she added, "I'd be a little concerned about that and we'd probably need to discuss it."

The county already owns the property involved with the other capital improvement projects that will be funded by the bond sale.

Those include a new county garage, new South County library, a new North County fire station, and an upgraded digital radio system for the county's public safety departments.

The county has long held an AA rating on its existing general obligation bond issues. Those are backed by the "full faith and credit" of the county.

The proposed new "lease revenue" bonds for the pending projects would be backed essentially by mortgages on the property and paid for by a combination of taxes and other revenues generated by the projects. Those received AA- rates, one notch below AA.

The highest rating such bonds can receive is AAA, followed by AA+, AA, then AA-. Bond ratings then drop to A ranges, B's and C's.

"AA is an extremely strong county rating," said financial adviser Jim Johnson of the Richmond office of the investment firm Morgan Keegan and Co., who consults with the county.

Even though Virginia localities have a leg up on investment ratings because of the state's AAA rating, Johnson said, Roanoke County's most recent are among the state's best. Only eight of the state's 95 counties have ratings higher than Roanoke County -- most in Northern Virginia -- and only three others match the county's general obligation bond rating, he said.

Being in "one of the higher echelons of credit," helps shield the county from the volatility of the bond market, Johnson said. "People flock to quality credit."

The last revenue bond issue was used to build the new public safety center on Cove Road Northwest. There is $25 million in debt remaining on that project.

The new bond issue would raise the county's total debt to just over $182 million, about two-thirds of which is for the school system.

That amounts to about $2,000 for every resident, Hyatt said. That is below the maximum of $2,500 the county could reach and still maintain its rating. And it is with a debt ratio of 2.2 percent of the assessed value of property in the county, well below the 3 percent maximum the county has set for itself.

Staff members noted that the ratings companies praised the county's strong financial performance, its plan to repay the current bonds, as well as its broad economic base.

Economic development director Doug Chittum said "tying the ... [recreation] center to the business park, and to our sports marketing efforts, made it an economic development driver as well." That impressed the bond companies, he said.

When the bonds are sold, Johnson said he expects the interest to be about 4.25 percent, "not bad for 30-year bonds."

The county has received the AA ratings from both Standard & Poor's and FitchRatings.

A third rating, from Moody's, won't be released until just before the bond sale, Hyatt said.

"This was one of the toughest reviews we've ever been through because of the financial climate. There have been a lot of downgrades going on across the country, so they were very thorough with what they were looking at.

"But even with that and the general economy, we still came out looking good."