Development Of A Water Network Modelling System To Evaluate Existing Municipal Water Infrastructure In Developing Countries: Case Study Of Swakopmund, Namibia

Abstract

Geographical Information Systems (GIS) have become more easily accessible with the advent of open-source software such as QGIS. In combination with algorithms, referred to as plugins, written in the Python programming code, the conversion and processing of GIS data sets for use or further processing in other software programs have become less perplexing. The latter can be attributed to the fact that the computing software has become more efficient in processing large data sets with less manual user-input required. The main purpose of this study is to develop a methodological approach based on the integration of open-source software, e.g., QGIS and EPANET, and engineering practices associated with water distribution network design to enable practitioners to create a water distribution network (WDN) model of an existing network. A major contributing reason for the necessity to develop such methodological guidelines, is that of value-added engineering. By reducing the time required to set up a WDN model, time can be more effectively allocated to the actual technical analyses pertained to hydraulics, water loss management, water quality management and evaluation of network-specific challenges. The Swakopmund Municipality in Namibia has been chosen as pilot case study. In other words, the methodology adopted focussed on the compilation of a WDN model for Swakopmund by: (i) compiling methodological procedures for the acquisition and processing of data, (ii) identifying various data sources which can be utilised in the absence of traditional data sets, (iii) conducting a sensitivity analysis to determine the effect of incorrect/inaccurate data on hydraulic results within a WDN model, and (iv) deriving equations from graphical sources to enable the automated implementation thereof in data processing software instead of relying on the manual interpretation and reading thereof from graphs and/or nomograms. The use of QGIS and EPANET, as well as the integration thereof with sound engineering practices and judgement, proved to be both viable and practical. The methodological approach and associated process flow diagrams developed, will not only provide guidance to practitioners, but ultimately, it could also assist municipalities in Southern Africa facing challenges in terms of outdated records and budget constraints. Hence, it is envisaged that the implementation of the methodology and the recommendations for future research will contribute to improved water infrastructure planning, design and management, especially in the Southern African context where water resources are scarce and service delivery remains a pressing issue.