Analyzing the impacts of a perched layer on wetland hydrology within the Coastal Plain of the Chesapeake Bay watershed

Abstract

Understanding of wetland hydrology is important since wetland ecosystem services are dependent on hydrological interaction with surrounding areas. A perched layer is an impervious zone that limits horizontal water transport below land surface. This perched layer has been known to affect wetland hydrology. For example, the changing pattern of surface water (SW) is distinctive from shallow groundwater (GW) due to a perched layer. In addition, a wetland developed over a perched layer can have a high potential to hold SW than a wetland without a perched layer due to limited water loss by seepage. However, the impacts of a perched layer have not been well documented. This aim of this study is to investigate the impacts of a perched layer on wetland hydrology on the Coastal Plain of the Chesapeake Bay watershed using observed data. A well and piezometer were installed to monitor SW and GW at the two sites with and without a perched layer, respectively. By comparing observations between the two sites, we demonstrate that a wetland with a perched layer indicates inconsistency between SW and GW and less dependence on GW to maintain SW, compared to a wetland without a perched layer. © 2018 American Society of Agricultural and Biological Engineers. All rights reserved.