Effects of Passive Hydration on Surface Water and Groundwater Storages in Drained Ranchland Wetlands in the Everglades Basin in Florida

Pre-(1 year) and post-(2 years) passive hydration data were used to evaluate the effects on spatiotemporal storages at two pastoral wetlands in the Lake Okeechobee (LO) watershed within the Everglades basin, Florida, United States. To partially restore the predrainage wetland storage and hydroperiod, passive hydration was implemented by raising the discharge elevation using a culvert structure with removable boards at the end of the drainage ditch that drained the wetland/upland system. During the wet season (July-October) groundwater and total storages (surface water plus groundwater; rainfall normalized) in the wetland footprints increased 17 and 12% during the post-hydration periods at wetland 1. At wetland 2, these increases were 39 and 12%, respectively. When analyzed at the subwatershed (wetland plus upland) scale, total storages (rainfall normalized) during wet season increased 12% in both wetlands in the posthydration periods. Annual surface storage (rainfall normalized) increased from 25 to 188 m(3) for wetland 1, whereas at wetland 2, it increased from 0.2 to 6 m(3) during posthydration periods (annual) at subwatershed level. Differences in rainfall, storage areas, topography, and wetland hydrology masked the hydration effects and resulted in inconsistent results across years and wetlands. At the LO watershed-scale, increased storage was only 14% of the desired storage. Long-term data are needed before implementation of passive hydration for achieving storage goals. (C) 2014 American Society of Civil Engineers.