The application of ecohydrological groundwater indicators to hydrogeological conceptual models

This article reviews the application of ecohydrological indicators to hydrogeological conceptual models for earth-scientists with little or no botanical training. Ecohydrological indicators are plants whose presence or morphology can provide data about the hydrogeological setting. By examining the literature from the fields of ecohydrology, hydrogeology, geobotany, and ecology, this article summarizes what is known about groundwater indicator plants, their potential for providing information about the aquifer, and how this data can be a cost-effective addition to hydrogeological conceptual models. We conclude that the distribution and morphology of ecohydrological groundwater indicator plants can be useful to hydrogeologists in certain circumstances. They are easiest to evaluate in arid and semiarid climates. Ecohydrological groundwater indicators can provide information about the absolute depth to the water table, patterns of groundwater fluctuation, and the mineralization of the aquifer. It is shown that an understanding of the meteorological conditions of a region is often necessary to accurately interpret groundwater indicator plants and that useful data is usually obtained by observing patterns of vegetation behavior rather than interpreting individual plants. The most serious limitations to applying this source of information to hydrogeological conceptual models are the limited data in the literature and the regional nature of many indicator plants. The physical and physiological indications of the plants exist, but little effort has been made to interpret them. This article concludes by outlining several potential lines of research that could further the usefulness of ecohydrological groundwater indicators to the hydrogeological community.