for Windows

MLU (Multi-Layer Unsteady state) can be used for drawdown calculations and inverse modeling of transient well flow (pumping tests analysis) in layered aquifer systems and stratified aquifers.

With MLU one can estimate selected aquifer parameters based on a best fit analytical solution to measured time-distance-drawdown data. The automatic curve-fitting algorithm computes optimized aquifer parameters and fitted drawdown results that are presented in graphs and ASCII-files.

Unlike other aquifer test analysis software, often supporting a wide variety of different solution types (e.g., Theis, Hantush, Neuman, Boulton, Papadopulos, Moench, Bouwer-Rice) for usually one and sometimes two aquifers, MLU is based on a single analytical solution technique for well flow that handles:

• Layered aquifer systems, i.e. multi-aquifer systems (aquifers and aquitards)
  and single layered (stratified) aquifers,
• Confined, leaky and delayed yield aquifer conditions,
• Effects of aquifer and aquitard storativities,
• One or more pumping or injection wells,
• One or more pumping periods for each well,
• Finite diameter well screens in any selection of aquifer layers,
• Well bore storage and skin effect for each pumping well,
• Delayed observation well response.

Theoretical background information on the developed and applied analytical solution techniques for multiple aquifer systems has been published in: Journal of Hydrology 90, p. 231-249 (1987) and 225: p. 1-18 and p. 19-44 (1999). You may contact the authors (hemker at microfem dot com) for a pdf of these publications. The applied non-linear regression technique is described in Ground Water (1985) 23, no.2, p. 247-253.

The MLU characteristics allow for all sorts of tests, including variable discharge tests, recovery tests, step-drawdown tests, complex tests in well fields and slug tests. It also handles partially-penetrating and large-diameter wells, bounded aquifers and double-porosity systems.

Hydrogeologists have found MLU to be very useful for quickly estimating aquifer properties such as layer-by-layer transmissivity, storativity, and vertical resistance/conductance based on aquifer testing data, and efficiently incorporating these properties into numerical groundwater flow models for advanced subsurface flow evaluations. As far as we know, MLU is the only Windows tool for evaluating aquifer response to pumping in a multi-layer aquifer system.

MLU modeling features Saturated groundwater flow Multiple-aquifer systems and stratified aquifers Confined, leaky and unconfined conditions Multiple wells Multiple finite-diameter screens Well bore storage and skin Variable discharges Delayed observation well response Input & Output Interactive data input ASCII model files Data exchange with spreadsheets Graphs of time-variant drawdown or head Graphs of time-variant aquifer discharge Animated contour plots Clipboard bitmap output Vector-based meta-file output XYZ-file output of contour maps File output of computed heads of displayed time graphs Conversion to MicroFEM finite element model file

Program Capacities 40 aquifers (layers) and 41 aquitards 300 pumping/injection wells 50 pumping periods per well 50 observation wells 100 drawdowns per observation well 16 parameters to be optimized in one run User assigned names for all wells Parameter optimization features Automated curve fitting based on Levenberg-Marquardt algorithm Lineair and log-transformed least squares solutions Individual and grouped parameters to be determined in one run Statistical data output includes standard deviations and correlation matrix Documentation and Support  Fully documented on-line Help Example data files for all kinds of test types MLU Users Guide MLU Tutorial Excellent customer support

The freeware version of MLU is a fully functional, capacity-reduced version of MLU for Windows. It handles up to 2 aquifers and 3 aquitards, 2 pumping wells, 2 observation wells and 6 parameters to be optimized in one run.