## Analytic Element Modeling

### By Darrel Dunn, Ph.D., PG, Hydrogeologist (Professional Synopsis ðŸ”³)

The technique used in the computer simulations of groundwater systems described in the Water Well Interference and Mine Dewatering pages is called analytic element modeling (AEM). An analytic element model uses relatively simple mathematical equations to compute the effect of elements of a groundwater system on groundwater levels. Elements are such features as water wells and streams. The model adds the effect of each element to produce the final result, which is usually a contour map of water level (technically "hydraulic head"). The model can also produce lines showing the direction of groundwater flow. Aquifer constants such as thickness and permeability must be supplied. Analytic element modeling requires the development of relatively little input data compared to more complex modeling techniques. AEM also requires only one calculation for each element, so it takes relatively little computer time. You can see the answer immediately. AEM is appropriate for illustrating hydrologic concepts. It may also be appropriate for real groundwater projects when the geology and hydrology of the site are simple and little data is available on aquifer permeability and water level monitoring. It is a good tool for quick hydrologic analysis that can precede more detailed modeling requiring large input files and time-consuming iterative computer methods (numerical modeling). A proficient hydrogeologist's software capabilities span applications for specific capacity analysis, step-testing, constant rate aquifer testing (unconfined, leaky, fractured), analytic element modeling, and numerical modeling.

Posted August 6, 2018. Revised November 26, 2018.