Application and Conceptual Development of Genetic Algorithms for Optimization in the Water Industry
Report No. 1388/1/05
March 2005

Executive Summary

Background and motivation

In the previous study, WRC Project K1144 – “POTENTIAL APPLICATION OF GENETIC ALGORITHMS IN THE WATER INDUSTRY”, the application of Genetic Algorithms was reviewed.  Findings from that study indicated that:

Objectives of this study

This study evaluated the application of genetic algorithms in the optimisation of different components of water supply projects and conceptually developed the procedures for the implementation thereof.

Based on the available literature study, as well as the feedback from water supply authorities, the need for the application of GAs as an optimisation technique in the water industry was defined.  The potential applications of GAs in the water industry in South Africa are:
This study objective was to provide the conceptual development of procedures to implement GAs as an optimisation technique for water resources assessment and network optimisation.

Methodology

The focus of this study was to conceptualise the optimisation problems that were identified and to conceptually develop the required procedures for the implementation of GAs in these areas in a follow-up study.

Literature on optimisation techniques was reviewed, problem variables and interdependence were identified and the GA operators for these problems were conceptually described.

In the case of the network optimisation the GA procedures were coded and software was developed and tested for network optimisation. The GA Water Utility programs, GANEO, can be used for the assessment and optimisation networks (Rehabilitation, replacement, placement of parallel pipes or the assessment of new networks).

Results

The use of GA has been conceptually developed for water resources assessment where the WRYM (Water Resources Yield Model) and WRPM (Water Resources Planning Model) are used.  Conceptual models for applying the GA procedure to network optimization and operational optimization problems have also been developed.

A GA front-end interface (see Figure i) for the public domain software, EPANET, has been developed that optimizes water distribution systems.  The results of the developed optimization procedure were tested against benchmark problems that have been reviewed by numerous International Researchers.  The results are extremely promising and the optimization process’s computational time was reduced (Figure ii).

Water distribution network optimization software GANEO
 
Figure i: Water distribution network optimization software (GANEO)


 Results obtained in GANEO

Figure ii: Results obtained in GANEO (various optimized system solutions)

This inclusion of the GA procedure for the network optimisation provides the opportunity for the optimisation of new networks, refurbishment of existing networks or the evaluation of the extension to existing networks.

International benchmark problems were analysed with the utility, in all cases providing the same or an improved optimal solutions in a much shorter computational time.

The GANEO software is capable to solve the following objectives for any complex network:
Recommendation

In this study the conceptual procedures for GAs has been developed for:
These developments created the opportunity of conceptualising the problems and now require the extension of the study to develop the utilities to implement these concepts and create interfaces with existing software.

It is recommended that the following aspects should be attended to:
The software program can be downloaded from either the WRC or the University of Pretoria web sites (links below).

WRC - http://www.wrc.org.za
University of Pretoria - http://www.up.ac.za/academic/civil/divisions/water/ga.html