Dr. Ayala's field notes tracked the marsh over four seasons. The water table rose predictably each spring, flooding the basin from the lowest depression upward, one row at a time. By midsummer the whole grid was submerged. Then the August drought — the worst in decades — pulled the water back down. The shallowest layer, the one that had flooded most recently, was the first to go: the topmost row of her grid dried out overnight while the deeper water held. The autumn rains restored the marsh before her next survey.