title: Mapping potential groundwater-dependent ecosystems for sustainable management.
abstract: Ecosystems which rely on either the surface expression or subsurface presence of groundwater are known as groundwater-dependent ecosystems (GDEs). A comprehensive inventory of GDE locations at an appropriate management scale is a necessary first-step for sustainable management of supporting aquifers; however, this information is unavailable for most areas of concern. To address this gap, this study created a two-step algorithm which analyzed existing geospatial and remote sensing data to identify potential GDEs at both state/province and aquifer/basin scales. At the state/province scale, a geospatial information system (GIS) database was constructed for Texas, including climate, topography, hydrology, and ecology data. From these data, a GDE index was calculated, which combined vegetative and hydrological indicators. The results indicated that central Texas, particularly the Edwards Aquifer region, had highest potential to host GDEs. Next, an aquifer/basin scale remote sensing-based algorithm was created to provide more detailed maps of GDEs in the Edwards Aquifer region. This algorithm used Landsat ETM+ and MODIS images to track the changes of NDVI for each vegetation pixel. The NDVI dynamics were used to identify the vegetation with high potential to use groundwater--such plants remain high NDVI during extended dry periods and also exhibit low seasonal and inter-annual NDVI changes between dry and wet seasons/years. The results indicated that 8% of natural vegetation was very likely using groundwater. Of the potential GDEs identified, 75% were located on shallow soil averaging 45 cm in depth. The dominant GDE species were live oak, ashe juniper, and mesquite.
authors.affiliation: Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136.
authors.forename: Si
authors.initials: S
authors.lastname: Gou
authors.forename: Susana
authors.initials: S
authors.lastname: Gonzales
authors.forename: Gretchen R
authors.initials: GR
authors.lastname: Miller
mesh_terms: D000465:Algorithms; D002980:Climate; D003247:Conservation of Natural Resources; D017753:Ecosystem; D040362:Geographic Information Systems; D060587:Groundwater; D062070:Hydrology; D063148:Plant Dispersal; D058998:Remote Sensing Technology; D063809:Satellite Imagery; D012987:Soil; D013781:Texas
chemical_list: D012987:Soil