AQUASIM - Computer Program for the Identification and Simulation of Aquatic Systems
Short Program Description
In order to support environmental scientists in finding an «adequate» model of the system they are investigating, a computer program is necessary, which allows its users to perform simulations using different models, to assess the identifiability and to estimate the values of model parameters (using measured data), and to estimate prediction uncertainty. The computer program AQUASIM was developed to perform such analyses for technical and natural aquatic systems.
AQUASIM allows its users to define the spatial configuration of the system to be investigated as a set of compartments, which can be connected to each other by links. The available compartment types are mixed reactors, biofilm reactors (consisting of a biofilm and a bulk fluid phase), advective-diffusive reactors (plug flow reactors with or without dispersion), saturated soil columns (with sorption and pore volume exchange), river sections (describing water flow and substance transport and transformation in open channels) and lakes (describing stratification and substance transport and transformation in the water column of the lake and in adjacent sediment layers). Compartments can be connected by two types of links (lakes cannot be linked to other compartments). Advective links represent water flow and advective substance transport between compartments, including bifurcations and junctions. Diffusive links represent boundary layers or membranes, which can be penetrated selectively by certain substances. The user of the program is free in specifying any set of state variables and transformation processes to be active within the compartments. For the model as defined by the user, the program is able to perform simulations, sensitivity analyses and parameter estimations using measured data. These features make the program a very useful research tool. Calculated results can be plotted to the screen (window interface version only), written to a Post-Script file for transfer to a printer, or written to a text file for external post-processing.
Due to the possibility of starting with a simple model and gradually increasing model complexity later on by considering additional variables and processes, AQUASIM is also well suited for application by students in exercises accompanying a lecture on environmental modelling. The possibility of comparing different models and the capability of the program to estimate the uncertainty of calculated results (for a given, certain model) also stimulate discussions on the limits of the reliability of model predictions.
Three versions of the program are available. The window interface version uses the graphical user interface of the Microsoft Windows operating system, the character interface version can be run on a primitive teletype terminal, and the batch version is designed for long calculations to be submitted as batch jobs. The batch and character interface versions can be compiled on any operating system with any C++ compiler.
Please cite the use of the program by referring to one of the following publications. Besides acknowledging our work, this also allows the program users to identify other groups that use AQUASIM.
Survey of program features
Reichert, P., «AQUASIM - A tool for simulation and data analysis of aquatic systems», Water Sci. Tech., 30(2), 21-30, 1994.
Survey of programming techniques
Reichert, P., «Design techniques of a computer program for the identification of processes and the simulation of water quality in aquatic systems», Environmental Software 10(3), 199-210, 1995.
Detailed technical report including manual for version 1.0
Reichert, P., Concepts underlying a computer program for the identification and simulation of aquatic systems, Schriftenreihe der EAWAG Nr. 7, Swiss Federal Institute for Environmental Science and Technology (EAWAG), CH-8600 Dübendorf, Switzerland, 386 p., 1994.
Manual and tutorial for version 2.0/2.1:
Reichert, P., AQUASIM 2.0 - User Manual, Swiss Federal Institute for Environmental Science and Technology (EAWAG), CH-8600 Dübendorf, Switzerland, 214 p., 1998. pdf
Reichert, P., AQUASIM 2.0 - Tutorial, Swiss Federal Institute for Environmental Science and Technology (EAWAG), CH-8600 Dübendorf, Switzerland, 213 p., 1998. pdf
Since 2013 AQUASIM is freely available to interested users.
The following zip file contains the executables for the three program versions and the required initialization file:
The following zip file contains the complete source code of all versions:
AQUASIM users mailing list
We maintain an electronic user group list that facilitates contacts among AQUASIM users. If you send a request to email@example.com it is distributed to all members of the user group. These persons may give answers directly to the sender of the request or let the answer again be distributed to all user group members by sending it to firstname.lastname@example.org . The latter method should be preferred because other readers of the list may also be interested in the answer.
To subscribe to the AQUASIM user group list, send the mail message
subscribe aquasim-users <mail-address> to email@example.com. This message must be contained in the body of the mail (not in the subject) and <mail-address> must be replaced by your mail address.
You can unsubscribe from the list by sending the message
unsubscribe aquasim-users <mail-address> to firstname.lastname@example.org.