FiPy FOR HYDROLOGISTS? A FLEXIBLE TOOL FOR COMPUTER MODELING OF HYDROLOGIC PROCESSES

FiPy is a computer simulations library that solves partial differential equations using the finite volume method. FiPy was developed at the National Institute of Standards and Technology to simulate material science processes, but can by used to simulate a variety of hydrologic processes including surface-water flow, ground-water flow, and solute transport. While most ground-water practitioners interested in computer modeling rely on a small set of software developed specifically for ground-water flow, FiPy represents a flexible alternative to these 'canned' packages that bridges a gap between writing computer code to solve a problem and using one of the common ground-water modeling systems. FiPy has been applied to three different ground-water problems, providing an overview of the utility of FiPy to the hydrologic community. In the first example, a flownet for a simple two-dimensional ground-water flow problem is created to highlight the basic components of a FiPy model. The simulation of a pumping test and calibration to associated field data is used in the second example to estimate hydraulic conductivity in an aquifer. Solute transport and ground-water flow are simulated in the last example to assess results from an ongoing tracer test within a Maine peatland. These examples showcase FiPy's ability to solve a wide variety of hydrologic problems and its capability to link different hydrologic processes within a multiphysics framework.