Oct 10, 2009

Pipe Network Modelling Approach

Development and use of water distribution models comprises of many activities and processes. As with any such complex task, it can be managed more successfully and efficiently if it is broken down into its components or stages. The process is common for almost any such type of project, regardless of the size of the system and it could be divided into eight characteristic stages, namely:

a. Setting up a new modelling project or Re-establishing the existing;
b. Data Collection, Model Build (or Model Update);
c. Data Verification and Model testing;
d. Model Calibration and Validation;
e. Model Use;
f. Results Interpretation;
g. Reports and model documentation;
h. Change monitoring and model management

The following should be noted in the management of the modeling process:

a. The key decision which must be made at the very start of the process is whether or not to use the hydraulic network modelling software as the right tool for providing answers to problems faced in managing water distribution systems;

b. If a hydraulic network model is the right tool, running the water distribution modeling project is an ongoing activity, which needs regular model updating and checking if the existing model is still an adequate tool for providing answers to actual requirements;

c. The process of the management of the modelling process inherently has many loops and feedbacks from previous steps

d. One of the key characteristics of the process is that these feedback make the modelling work an iterative process – not linear as it was traditionally presented;

e. The modelling process should be considered as a process closely linked to other corporate systems, not as an isolated activity. The model’s output provides input and support to many strategic Water Utilities programmes or policies, and the model requires strong linkages with GIS, Telemetry, Water billing and other information management systems;

f. The process requires at various stages, agreements with involved parties, on reached verdicts about the quality of completed work at certain project stages and recommendations prior to commencement of the next stage. Supervision of the project should be continuously run from the beginning of the process by preferably one party based more on a working relationship than on traditional audit control approach;

g. Depending on the size of the distribution systems, models can vary from very simple - with only one water source and a small network, up to very complex systems with multiple sources and sophisticated operating regimes. Although the level of complexity in managing a modelling project varies with the size and complexity of a particular system the principles of the modelling process remain the same.