A research study submitted in partial fulfillment of the requirements for the degree of Master of Engineering (Executive).

The PW A is conducting standard quality water; sufficient delivery pressure and extensive coverage of the supply for maintain customer's satisfaction. The customer's satisfaction study is exploring a wide variety of possible factors. Therefore, the author is developing a water-distribution model using the EP ANET software to assist with assessment in the customer's satisfaction study. The results are showing the percentage of water contributed by specific locations in the Amphur Muang area, Suratthani for 2003 conditions. Initially the model was calibrated using the present-day (2003) data collected during summer-demand conditions of April 2003. The model network consists of 1,567 pipe segments ranging in diameter from 100 millimeters (mm) to 900 mm, and 1,434 junctions (nodes). The absolute difference between measured and simulated hourly average pressures for all measurement locations ranges between 0.2-11.9 mwc. The medium pressure differences support the assertion that the model is well calibrated. Besides, it shows a reliable representation of water-distribution system conditions during 2003. In addition, a simulation of the transpott of residual chlorine was conducted and compared with experimental data gathered at 25 discharge points of the water distribution system for April, 2003. A measured concentration of chlorine range was between 0.3-0.5 milligrams per liter (mg/l). The comparison indicates a difference within the range of 0.01- 0.12 mg/l or a mean relative difference of 15.59% with a range of 2-25%. Basically, the model indicates a slightly under prediction. However a correlation coefficient of 0.56 indicates a medium correlation between measured concentrations and simulated values. Therefore, this water-quality simulation is confirming that the model is reasonably calibrated and an acceptable representation of the present-day water-distribution system characteristics.