HISTORY OF ANALYTIC ELEMENT MODEL DEVELOPMENT AND APPLICATIONS AT THE US ENVIRONMENTAL PROTECTION AGENCY (1994 - PRESENT)

The computational efficiency and conceptual transparency of the analytic element method for regional groundwater flow has been exploited in a number for computer models developed by the U.S. Environmental Protection Agency (US EPA). Initially, a Fortran solver was developed for delineating capture zone envelopes and time-related sub zones for pumping wells in shallow aquifers (USEPA, 1994), and this solver, in combination with a geographical preprocessor (Kelson et al, 1993), was put to service in support of the Wellhead Protection Program (USEPA, 1994). This technology has evolved into the WhAEM2000 framework for the Source Water Protection Program with a modern Windows-based interface and GIS mapping (USEPA, 2007). More recently an open source Python solver was designed using object-oriented principles for modeling groundwater flow in multi-aquifer systems (Bakker, 2010a). The solver has been expanded for transient flow using the Laplace-transform analytic element method (Bakker, 2010b). The solver has been developed to support the Underground Injection Control (UIC) Program, specifically to model and map the area of potential impact of CO₂ injection wells for the purpose of geologic sequestration, and is part of an emerging BAEM (basins analytic element model) framework.

Bakker, M, 2010a. TimML: a multiaquifer analytic element model, version 3.4. (timml.googlecode.com)

Bakker, M, 2010b, TTim: a multi-aquifer transient analytic element model, version 0.01 (ttim.googlecode.com)

Kelson, V.A., H.M. Haitjema, and S.R. Kraemer, 1993. GAEP: a geographic preprocessor for groundwater flow modeling, Hydrological Science and Technology, 8:74-84.

USEPA, 1994. CZAEM User’s Guide: modeling capture zones of Ground-Water Wells using Analytic Elements, EPA/600/R-94/174, contributing authors O.D.L. Strack, E.I. Anderson, M. Bakker, W.C. Olsen, J.C. Panda, R.W. Pennings, and D.R. Steward, University of Minnesota.

USEPA, 1994. WhAEM: program documentation for the wellhead analytic element model, EPA/600/R-94/210, contributing authors H.M. Haitjema, J. Wittman, V. Kelson, and N. Bauch.

USEPA, 2007. Working with WhAEM2000, EPA/600/R-05/151. Contributing authors S. Kraemer, H. Haitjema, and V. Kelson.