MLPU started as a hobby project in 1989, aimed at learning more about 3D groundwater flow and more specifically, analytical multi-aquifer solutions. Another motive was that available analytical multi-aquifer software was outrageously, if not prohibitively, expensive at that time.

Over the years the program grew slowly. When I saw a feasible analytical solution for a specific situation I encountered in my professional occupation, I tried to build it in, yet preserving small size, speed and ease of use.

MLPU exists in its current state already since 1994; it has been used regularly since then. Its predecessor, the simpler and steady state program MLP has been around even longer. Getting the program ready for other users (testing and more testing, remodeling the user interface, writing a manual) went a bit slow due to lack of time. MLPU was first presented to a broader audience in the Analytic Element Conference in Nunspeet in April 1997. The poster description is reproduced on this website (Click here to see it).

Since April 2, 2007 MLPU has been made freeware (but no Open Source!). This has been motivated by the appearance of other analytical multi-aquifer software, like TIM (OSS); MLAEM (proprietary, but freeware for Dutch customers) (Mind you! I don't know if the links on the archived web page still works!); MWELL (proprietary); etc.
I have started programming a Windows version already at the end of 1998 or so, but given the small and highly specialized market (only some tens of customers) the ratio of potential revenues (not just the financial one!) versus time to be invested was simply to small.

You can still obtain MLPU (including a manual in .pdf and a collection of test & validation models) free of charge by sending an e-mail to the author (address see below). But please take notice of the message at the top of this web page.

Year 2000 compatibility

MLPU nowhere uses dates (only numerical quantities expressed in days or years), so it is very unlikely that MLPU by itself would cause problems with the year 2000-bug.
Yet as the program is written in MS-Fortran and Turbo-Assembler, whose inner workings are unknown to me, I cannot guarantee absolute Y2K compatibility.
Another aspect is that MLPU uses files to read from and write to, and these files have date attributes. As the various file manipulation routines are in fact operating system routines, MLPU's Y2K compliance is also dependent on the operating system's Y2K compliance.
Finally, the underlying hardware also determines Y2K compliance of programs running on it.
Tests run by me on my two Y2K compliant computers, and on one old non-compliant notebook fitted with Y2K software, showed no problems.
All in all, Y2K problems cannot be ruled out, but are very unlikely.

I have ran MLPU myself under DOS, Windows 3.1, Windows 95, Windows 98, Windows ME, Windows NT, Windows 2000 Pro & Windows XP, without problems (see below for multicore). I even ran it under OS2 Warp 3, Warp 4, eComStation and various Linux distros, the latter using a DOS emulator.
Given this behaviour, I see no problems in running current MLPU versions in any Microsoft based OS.

However, be warned: MLPU has been found to hang on dual CPU systems, and hang Windows with it; you have been warned...)

Requirements - What is needed to run MLPU?

Requirements | How to obtain MLPU / a demo | How to contact the author | Back to start of home page

Features 

Capacities (many capacities can be increased (somewhat, to some limit) on demand - contact the author)

Requirements | Features  | Back to start of home page

MLPU is freeware as of April 2nd, 2007. 

Support : Only available for customers who have previously paid for the commercial version. That said, I'll do what I can to help people using MLPU, but -be warned- my time is very limited. In principle support is only pertaining to program operation and/or previously unnoted program errors, rather than program applications.

From experience I know there are just a few people on Earth interested in analytical groundwater models, and just a hand full for multi-aquifer analytical models. That is the reason I have no downloads here (yet) - by requesting interested people to ask me I hope to get an idea of what people use this software. You can obtain MLPU (including a .pdf manual and a set of test and validation models) by e-mailing me or writing to:

P.R. Nienhuis
Eerste Oosterparkstraat 183
1091 HA AMSTERDAM
The Netherlands

e-mail: 

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Examples of graphical MLPU output

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Horizontal XY map

This example pertains to a fictitious 4-aquifer system. Three abstraction wells are screened in the second aquifer, three injection wells in the third. For the sake of clarity only the head contours in those aquifers are shown. Some streamlines flowing to the northernmost abstraction well (blue/green) and some streamlines emanating from the southernmost injection well (dark red) are shown. All streamlines show time steps on every 5-year interval. A DXF background (fictitious) map is shown in grey. The map border shows tick marks on rounded intervals.
Horizontal maps can be used to show piezometric head contours (at any model time), groundwater table elevations, head differences across separating layers etc. Other options are: a cross-section trace, lay-out of analytic elements and observation wells. Zooming in and specifying a cross-section trace is done using the mouse. Heads (at any model time), contour map values, discharge components in any aquifer (at any model time), infiltration rates (at any model time), saturated thickness of first aquifer etc. can be requested by moving the mouse cursor in the map and typing a key letter. In addition, in this way time vs. head graphs can be requested for any location under the mouse cursor; info on analytic elements and observation wells (including posting of time/head data) will be echoed on request; streamlines can be started at any location at any depth (at any starting time).

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Vertical cross-section

In this picture five streamlines are shown infiltrating at 10,000, 8,000, 6,000, 4,000 and 2,000 m from an abstraction well in a semiconfined four-aquifer system. The second aquifer comprises two layers, the upper layer has a permeability of 5 times the lower one. Time steps are shown for every 250 year interval. Also shown on top are cross-sections of the piezometric head contours. As you can see, the red head contour shows a deep cone, relating to the large abstraction of the well in the 3rd aquifer.
Zooming in into a part of the cross-section can be done using the mouse.
It may be interesting to note that this model file is one of MLPU's verification files. By computing inflow at the infiltration location of each streamline in all aquifers and comparing that to the depth at which the streamline enters the well screen, a very elegant check can be made regarding continuity of flow. Also the effects of aquifer layering on streamline accuracy can be checked, with the well either in a layered or in a homogeneous aquifer. As you may expect, MLPU's streamline computations comply to this test.

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3-dimensional perspective view

This 3D perspective view is from a real world situation, somewhat simplified for clarity's sake. A water supply well field with deeply screened production wells is threatened by polluted groundwater. A number of less deeply screened interception wells is emplaced to protect the well field. The picture shows some streamlines entering one of the interception well at two levels. All wells are shown in black; the streamlines are color coded after the (model) aquifer they are crossing through.
These 3D perspective pictures can be tilted and rotated; vertical exaggeration and perspective can be increased or decreased, all fully interactively.

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Time vs. head graph

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Last updated 11 April, 2021

BTW this page is deliberately kept simple so that it can be read with any browser

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