‘Open-space use’ means the current employment of land, the preservation of which use would conserve and enhance natural or scenic resources, protect streams and water supplies, maintain natural features which enhance control of floods or preserve sites designated as historic by the Office of Historic Preservation of the State Department of Conservation and Natural Resources. The use of real property and the improvements on that real property as a golf course shall be deemed to be an open-space use of the land. The use of land to lease surface water rights appurtenant to the property to a political subdivision of this State for a municipal use shall be deemed to be an open-space use of the land, if the land was agricultural real property at the time the lease was granted.