Shallow groundwater table dynamics of cypress wetland pine upland systems in Florida flatwoods

High groundwater tables are one of the characteristics of the hydrology of Northcentral Florida flatwoods, which represents a coupling of wetland and upland ecosystems. The purpose of this paper is to characterize spatial and temporal water table dynamics, with particular attention to heterogeneity and continuity throughout the entire system. The research site is characterized by poorly-drained Spodosols with pine plantation in uplands and Ultisols with cypress forests in wetlands. The soils are hydrologically isolated by the clayey Hawthorn Formation from the deep karstic Floridan Aquifer. Three small wetlands were instrumented with 20-30 shallow observation wells each for weekly measurements, including 2-3 recording wells, and a central weather station was used to obtain climatic data. The information showed that groundwater tables generally followed topographical gradients. During a dry year, the water levels in the wetlands were below the pond bottom for about 5 months and above the wetland-upland ecotone (i.e. palmetto line) for about 2 months. The water tables in adjacent uplands had higher fluctuation, ranging from a low of 100 cm below soil surface for about 5 months to within the upper 15 cm for about 1 month. Analysis of more than 40 storm events showed that the rate of water table rise is determined by rainfall amount and intensity, and initial water table level, and that the pond margin areas had the highest response in the system. The high spatial and temporal variability of the groundwater water tables determined the complexity of flow pathways in the pine-cypress flatwoods.