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Drainage waters leaving the Everglades Agricultural Area (EAA) in south Florida have been implicated as having adverse effects on the adjacent Water Conservation Areas (WCAs) and the Everglades National Park (ENP). As a result, growers are required by law to collectively reduce phosphorus (P) levels leaving farms through the implementation of best management practices (BMPs). Achieving drainage uniformity has been shown to be one of the most effective BMPs. Four rainfall events with accompanying drainage from each of six sites were analyzed to quantify and describe the rainfall and drainage events, characterize their effects on the water table system, and determine any relationships between the open channel drainage system and the field water tables on farms in the EAA.

Water table rise in the soil profile from rainfall averaged a ratio of 10.6:1. Sites normally drained an average of only 48% of the rainfall input into the system, with only two of the 24 cases draining more than the rainfall volume. In 9 of the 24 cases, the net water balance did not correspond to the storage change in the soil profile, which suggests water lost or gained through movement into or out of the limestone aquifer. There was no immediate or consistent behavior observed between field water table response and pump on and off times. Also, traditional expectations of field drainage behavior to channel gradients were not apparent. Drainage rates measured in field observation wells showed no direct relationships to distances across the farm or to the main station pumping rate. Due to the similar field water table responses under varying drainage conditions, the organic soil, open channels, and the underlying geology appear to function as an integrated system with respect to the movement of water.