Addressing water incidents by using pipe network models

Abstract

It is now widely accepted that, although infrastructure problems in the electricity sector are currently the demanding crisis in South Africa, another commanding crisis looms on the medium-term horizon: deteriorating water infrastructure, and associated water incidents. A large component of this infrastructure is the water pipe network and associated components. Water service providers often have limited understanding of their pipe networks, and hence cannot address potential adverse incidents. The CSIR has embarked on a program to provide an understanding to a water service provider of its pipe network, so that potential adverse incidents can be addressed. An existing pipe network and associated components can be understood by measuring water quantities like flow rate and pressure with water meters. Such an approach provides a highly exact and realistic understanding, but is potentially very expensive to implement. This is especially so in view of the large number water infrastructure networks in South Africa which need urgent attention. A more cost-effective approach to understanding an existing pipe network, that also provides the ability to explore alternative conditions for the network, is a numerical model of the network. These models are based on physics that is well understood. A pilot analysis is performed for a high impact town/urban area in South Africa with noticeable water problems. Model parameter data are obtained through as-built drawings, and are collected through site visits where the network is mapped from scratch. During site visits as-built drawings are verified, and critical unknown parameters (those whose absence are very detrimental to the model) are measured. The information on the pipe network is then imported into the computer model program EPANET. The model for the town/urban area is presented. The detailed implications of the model for incidents will be presented to the stakeholder in the future, and are not discussed. The time- and cost-efficiency of the entire model construction process is accessed in view of the desire to replicate a similar procedure for the numerous areas in South Africa that demand understanding of potential water incidents.