Don't mistake the idea of making the new Western Virginia Regional Jail a "green building" with the movie "The Green Mile."

It's not a prison, so there will be no death row there, and what will be green isn't the paint, but the concept -- "green," as in environmentally sensitive.

The designs so far -- final approval is still weeks away -- call for a host of energy-saving and eco-friendly measures, such as natural lighting through skylights and the use of runoff rainwater to wash laundry and cars.

The Roanoke County Board of Supervisors is expected to approve the rezoning of 43 acres for the jail along the Roanoke River near Dixie Caverns during its meeting Tuesday night.

The new 605-bed jail is touted as the solution to overcrowding in the facilities now being used by the four localities that will share it -- Roanoke County, Salem, Franklin County and Montgomery County.

Those three local jails -- Roanoke County and Salem already run a joint lockup in downtown Salem -- will continue to operate, primarily holding inmates awaiting trial. The regional jail will house inmates who have been tried and sentenced -- most to a year or less -- as well as some "special populations," such as those needing medical care or to be separated from others.

Authority members say it became evident early in the planning process for the $71 million facility that it likely could incorporate enough "green" elements to qualify for certification as a so-called "sustainable" building.

Roanoke County Administrator "Elmer [Hodge] was saying this is our chance to be a leader in this. That was nice," said Jennifer Rainey, an architect with Hayes, Seay, Mattern & Mattern, the Roanoke-based architectural and engineering company that is designing the jail.

Rainey is the firm's expert on so-called LEED construction: Leadership in Energy and Environmental Design. She's an officer with the regional chapter of the United States Green Building Council, which issues certifications for buildings that meet criteria for LEED certification.

Those criteria range from things such as water savings and energy efficiency to the promotion of recycling both during construction and operation. Buildings receive points for meeting those, with a minimum of 26 out of a possible 69 points needed for the most basic level of certification for new construction, such as the jail authority is seeking.

From the beginning, "We wanted to be environmentally sensitive," said John Chambliss, Roanoke County assistant administrator and a representative on the jail authority. "We knew we were going to be working ... close to the river, and we don't want any adverse impact -- runoff and so forth," he said. "The city of Salem draws drinking water just downstream" from the site.

The decision to seek LEED certification was made easier by the fact that many of the elements needed for that were either part of the original design requests for the facility or promoted by Roanoke County's existing building and zoning regulations, said John Chaney, the project manager for Hayes, Seay, Mattern & Mattern.

"A lot of Roanoke County's requirements enable us to get LEED points as it is," Chaney said. For example, one of the biggest issues for the certification relates to runoff water, Chaney said, and the county "is already pretty forward-thinking about that ... with stringent requirements in place for quality and quantity."

Chambliss said it's possible that the construction will result in less runoff to the river than from the existing pasture.

Current plans call for collecting all the rainwater from the 225,000-square-foot roof and recycling it. Most of it likely will be used for the jail laundry, he said, and "because it is softer than we typically would use, that also should help reduce the amount of soap we need to buy."

Approaching the building from a "green" perspective meant having to look at some construction elements as having long-term payoffs for an initial investment that may be somewhat higher than conventional building techniques, Chambliss and Chaney said.

"Over the life of a jail" -- which in this case is estimated to be 50 to 100 years -- "90 percent of the costs are operating costs," Chaney said. "When you cut those down, you really help out over the lifetime of the project."

There are sometimes savings during construction, Chambliss said, as with the use of smaller, less expensive pipes for the roof drains in a system that siphons the water off instead of letting it drain by gravity.

And the authority plans limited paved areas -- inmates will not have visitors at the jail, but will communicate with them via videoconferencing from the localities where they were convicted. Those paved areas may end up not having curbing, Chambliss said, to facilitate natural runoff into surrounding grassy areas and the irrigation of the site's landscape.

Some things add costs, however.

The jail authority is considering, for instance, a vacuum-assisted low-flow toilet system of the type that has been used in airplanes and ships for decades. But the technology has not been widely used in this type of construction, and the authority wants to make sure it won't be more trouble than it's worth to maintain.

Should that system be chosen, however, "we can operate with one-third to one-half the water consumption that we'd normally have," Chambliss said.

Although the system would cost $150,000 more than conventional plumbing to install, the reduced water and sewer costs would pay that back in six to eight months, he said.

Chambliss estimated such innovations could account for as much as $1.1 million of the total jail cost, but that it could be recovered in as little as five years through operational savings.

Other LEED-inspired innovations include a white roof that reflects sunlight and helps reduce air conditioning costs; carbon monoxide monitors that will help control the flow of fresh air into the building; sensors to turn off lights in administrative areas when they are unoccupied; and controls on toilets and sinks to regulate water use.