Fig. 3. Draindown as a function of time since the last rinse for low drainage heaps. Curves are somewhat variable, but generally, heap draindown decreases rapidly just after rinsing stops and drops to <1 m³ ha^-1 d^-1 within a year after the last rinsing. Small spikes in draindown are apparent, particularly in the Preble curve, indicating probable response to climate forcing.