Developing a Preliminary Classification Schema for Groundwater Dependent Ecosystems

Chad McKenna1, Milczarek, Mike2

1 GeoSystems Analysis, Inc., Albuquerque, New Mexico, USA
2 GeoSystems Analysis, Inc., Tucson, Arizona, USA

Ecosystems that directly or indirectly rely on groundwater for some or all their water requirements are collectively referred to as groundwater dependent ecosystems (GDEs).  Due to a combination of new legislation in California and to aid in the preservation of valuable, highly sensitive habitats in other states and in other countries, there is an increasing need to reliably and consistently identify GDEs. Previous and ongoing efforts in California and elsewhere have utilized a combination of vegetation, surface water, groundwater, soils, and other datasets to aid in GDE evaluation and identification however the approach and results of this work are inconsistent and often lack sufficient detail to aid in conservation decision making, habitat value evaluations, and vulnerability assessments.
During two previous studies in California, GeoSystems Analysis began the development of a GDE classification schema that could serve as an initial framework for GDE evaluations in other basins.  This classification system evaluates and codes specific types of potential GDEs, normalizes, and streamlines their characteristics to support Groundwater Sustainability Plan development as well as and other evaluation purposes. The GDE classification schema currently describes four key attributes for each potential GDE: geomorphic setting, dominant vegetation class, suspected source aquifer, and a man-made modifier, and has proven to be a valuable tool for identifying GDEs, prioritizing conservation, aiding in habitat evaluations, and predicting GDE sensitivity.