Horizontal Groundwater Flow Patterns Through a Cypress Swamp‐Pine Flatwoods Landscape

Abstract

Groundwater movement in the surficial aquifer of the lower Coastal Plain cypress swamp‐pine flatwoods landscape of the southeastern USA is poorly documented. This study was conducted to define the patterns of horizontal groundwater flow 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 pond cypress (Taxodium ascendens Brongn.) swamps. Water tables were measured approximately every 2 wk for 2 yr and the data were used to map water table elevation. Directions of horizontal groundwater flow were inferred from the water table topographic maps. Measured hydraulic heads were combined with saturated hydraulic conductivities to estimate groundwater flux. Most of the groundwater flowed through the swamps in response to the generalized surface elevation pattern. For selected ponds, the ground‐water also flowed from the swamps to the surrounding areas. It was uncommon for groundwater to flow into the ponds from the entire surrounding area. The pattern of groundwater exchange between the swamps and the surrounding area was related to the average water table depth: the deeper the average water table, the greater chance for groundwater to flow from the swamp into the surrounding area. Waterflow rates were estimated to be <56 cm d−1. These groundwater flow patterns are different from the generally accepted pattern of water flow and should be useful in defining the hydrologic cycle of these landscapes.

A conceptual hydrologic model for a forested Carolina bay depressional wetland on the Coastal Plain of South Carolina, USA

“…Schalles and Shure (1989) deduced that subsurface hydrologic interactions are important influences on the surface water of a Carolina bay on the Upper Coastal Plain of South Carolina (Thunder Bay) based on surface water chemistry findings, whereas Lide et al (1995) suggested that changes in pond stage height within the same Carolina bay could not be purely explained by P and PET fluctuations and that groundwater was entering the bay during certain time periods. Crownover et al (1995) and Sun et al (2000) examined multiple cypress swamps, which are depressional wetlands in the pine flatwoods area of northern Florida. They found that most of the wetlands were of the flowthrough variety, and depressional wetlands that only receive groundwater discharge were less common.…”

“…They found that most of the wetlands were of the flowthrough variety, and depressional wetlands that only receive groundwater discharge were less common. The findings of the Crownover et al (1995) and Sun et al (2000) studies may be applicable to Carolina bays as well; however, additional field data are necessary to assess whether Carolina bays serve as flow-through systems. Because of land ownership constraints within the southern half of Chapel Bay, well and piezometer transects could not be installed in this area and thus hydraulic head data are lacking for this section.…”

“…More recently, Pyzoha (2003) and Sun et al (2006) argued that temporal fluctuations of P and ET can affect surface water-groundwater interactions in these wetlands, and during periods when P exceeds ET, Carolina bays allowed water to flow through the depression, possibly due to the subsurface topography at the site. Hydrologic studies on similar depressional wetlands such as cypress swamps on flatwoods landscapes in northern Florida suggested wetland surface water is tightly coupled with the shallow groundwater system in the watershed (Crownover et al, 1995;Sun et al, 2000;Bliss and Comerford, 2002). However, it is not known if similar hydrologic processes exist in Carolina bays.…”

MODELING THE FOREST HYDROLOGY OF WETLAND‐UPLAND ECOSYSTEMS IN FLORIDA1

“…The Pearson Correlation Coefficient and the objective function (index of disagreement) were used to evaluate the model performance and obtain optimum parameters. Soil parameters such as More than 130 shallow wells were installed at the GNF site and the water table levels in each well were measured bi-weekly from 1992 to 1995 (Crownover et al, 1995). Harvesting treatments were imposed from April 5 to May 31, 1994.…”

Hydrology of a first-order riparian zone and stream, mid-Atlantic coastal plain, Maryland

“…Initial conceptual models for riparian zone hydrology often assumed lateral subsurface flow from an agricultural field (upland site), through a riparian buffer strip, to a stream channel (Jordan et al, 1993;Bosch et al, 1994;Crownover et al, 1995). In such settings, the upland area was considered a recharge zone and the stream (and its immediate border) a discharge point.…”