Water discharged from karst springs which posses characteristics, primarily that of calcium content, indicating solution during the passage of that water across and through karst limestone. That part of karst spring water which is derived from watercourses sinking into the rock (and therefore originates mainly on impermeable rock) is said to be allogenic; that which derives from precipitation over the karst area alone is said to be autochthonous - the distinction between resurgence and exsurgence waters [19].