PUTTING THE LOCAL DETAIL OF A PHREATOPHYTES GROUNDWATER UPTAKE INTO A REGIONAL CONTEXT USING THE ANALYTIC ELEMENT METHOD

Plants that directly tap groundwater sources (phreatophytes) are studied here. While the exact functional form of root water uptake beneath the canopy of a tree is unknown, mathematically tractable equations are developed that simulate uniform uptake or uptake focused about a central taproot. The analytic element method is employed to group fields of plants into a common mathematical representation that ultimately may be modeled by a simple Laurent series expansion at large distances from the field. This leads to models capable of studying the extraction of thousands of plants with the local detail of plant uptake. Applications will be shown for uptake from the High Plains Aquifer in Kansas to illustrate the cumulative impact of fields of phreatophytes on water distribution.