Fig. 4. Draindown as a function of time since the last rinse for higher drainage heaps. Curves are variable, but generally the sharpest decrease in draindown occurs soon after the last rinsing followed by a gradual decrease to steady-state drainage rates between 0 and 2 m³ ha^-1 d^-1. Spikes in curves indicate probable response to climate forcing, particularly in the Wood Gulch curve, which shows spikes in drainage more than 5 yr after the last rinsing. Note that the gradual increases in draindown suggested by parts of the White Pine and Wood Gulch curves represent discontinuities in the data set and should not be considered representative of overall drainage patterns during those time periods.