7) "Cylinder of Appropriation" means a hypothetical cylinder centered around the location of an existing or proposed well which, for the specific aquifer, contains a volume of water equal to one hundred times the annual appropriation of an existing well or the allowed average annual amount of withdrawal of a proposed well. The radius of the cylinder of appropriation is computed from the following formula: Radius of Cylinder (ft.) = the square root of:
43,560 (ft. sq./acre) × withdrawal (acre ft./yr.) × 100(yr.)
specific yield × saturated aquifer materials (ft.) × 3.141b
where: withdrawal means either the annual appropriation or allowed average annual amount of withdrawal, whichever is appropriate.