O.C.G.A. § 51-9-7: Diversion, obstruction, or pollution of stream as trespass.

The owner of land through which nonnavigable watercourses flow is entitled to have the water in such streams come to his land in its natural and usual flow, subject only to such detention or diminution as may be caused by a reasonable use of it by other riparian proprietors. The diverting of the stream in whole or in part from its natural and usual flow, or the obstructing thereof so as to impede its course or cause it to overflow or injure the land through which it flows or any right appurtenant thereto, or the polluting thereof so as to lessen its value to the owner of such land shall constitute a trespass upon the property.