During heavy rains, ground water fills the cave then flows out through a solution channel to the outside of the hillside before running down the hill into the level field on the other side of the road, Douglas said.
The first hole workers found while working on a sanitary sewer line was the end, or the throat, of the solution channel leading to the cave. The first, and most expensive option, costing approximately $110,000, would require running a pipe under the road to allow water to escape from the cave.
"We will leave the room alone because we want the ground water to come up and fill up that room just like it always did, and we don't want to affect how the ground water flows, so we have to provide a new channel, which would be a 175-foot, 36-inch pipe with gravel around it, and a manhole where water can get into this pipe and go out and across the road and daylights back into the low area on the west side of the road in the curve, and go out and become overland flow and we can see it," Douglas said.
The second option, installing a steel grate over the entrance of the cave, which would allow water to continue to flow out of the cave without having to install a drainage pipe, would cost approximately $30,000.
"The other option is to put a grate, steel bars close enough together that nobody can get inside of it, that would cover that front of the cave, leave that exposed so people could walk up and look into it and see this open room. It is on the side of a hill, we don't have to create this channel for the water to flow because when the cave fills up it flows out onto the ground and flows out onto the land. So that would be a much cheaper solution because we are not having to put that pipe in," Douglas said.
The report suggested the best geological solution was to leave the cave open, putting the grate over it and allowing the water to flow out, Douglas said.
The grate covering the cave would be one-inch-by-two-inch steel bars close together, which would be structurally sound enough to drive a truck over, Douglas said. Barnhart said time was of the essence in making a decision on the cave before bats or some other form of wildlife began establishing a habitat inside the cave. The board authorized Barnhart to get a price proposal and contract and bring it before the board for consideration at its April 13 work session.