HORIZONTAL GROUNDWATER-FLOW PATTERNS THROUGH A CYPRESS SWAMP-PINE FLATWOODS LANDSCAPE

Groundwater movement in the surficial aquifer of the lower Coastal Pla in cypress swamp-pine flatwoods landscape of the southeastern USA is p oorly documented. This study was conducted to define the patterns of h orizontal groundwater how through a typical landscape with particular attention to water exchange between cypress swamps and the surrounding areas. One hundred and twenty shallow water table wells 1 m deep were installed in a 42-ha study area, one-third of which was covered by po nd cypress (Taxodium ascendens Brongn.) swamps. Water tables were meas ured approximately every 2 wk for 2 yr and the data were used to map w ater table elevation. Directions of horizontal groundwater how were in ferred from the water table topographic maps. Measured hydraulic heads were combined with saturated hydraulic conductivities to estimate gro undwater flux. Most of the groundwater Bowed through the swamps in res ponse to the generalized surface elevation pattern. For selected ponds , the groundwater also flowed from the swamps to the surrounding areas . It was uncommon for groundwater to Bow into the ponds from the entir e surrounding area. The pattern of groundwater exchange between the sw amps and the surrounding area was related to the average water table d epth: the deeper the average water table, the greater chance for groun dwater to how from the swamp into the surrounding area. Waterflow rate s were estimated to be <56 cm d(-1). These groundwater flow patterns a re different from the generally accepted pattern of water Bow and shou ld be useful In defining the hydrologic cycle of these landscapes.