Fig. 5. Hydraulic heads and apparent ground water ages in the upper basin transect: (A) hydraulic heads in April 1996; (B) CCl₂F₂ (CFC12) apparent ages in July 1996; (C) CFC12 apparent age gradients in July 1996, with additional data from "other" sites in the upper basin area (not all from the same time period). Heavy dashed lines in (C) indicate approximate limits of apparent age gradients and recharge rates (for porosity of 0.5).