These conduits in turn help to develop underground basins known as recharge areas.

The primary risk to this resource is human development over the recharge areas.

It is estimated that the metropolitan area grows annually by 200 to 300 hectares on recharge areas.

The area serves as a recharge area for aquifers to the east of the city.

Robert Rubin has proposed to build an 18-hole course and some private houses on his land, which environmentalists said sits over a deep recharge area.

"Suddenly, along come these two wonderful individuals giving us prime woodland and a critical recharge area," he said.

The destruction of playas by farmers and development decreases the available recharge area.

This has mainly taken place in the largest aquifer recharge areas.

The rest of West Tennessee serves as a recharge area for the aquifer.

Situations most likely to qualify, he said, are deep-water recharge areas and the development rights to remaining farmland.