Distribution network water quality model.

The implementation and calibration of a distribution network water quality model in a city is presented. For the first time in Mexico, the model includes all network pipes (3 inches in diameter and larger). The model application was carried out in the northern zone of Culiacan, Sin., with a population of 61,500. The network layout and other relevant data were introduced in the SCADRED (R), computer system of the Mexican Institute of Water Technology (IMTA). The flow at the supply sources and the pressure at 18 points in the network were measured during 12 hours. In order to calibrate the water quality model, samples were taken from 64 different network points, obtaining the first-order bulk flow chlorine reaction rate constant k(a) = 0.09881 hours(1). The first-order pipe wall chlorine reaction rate constant k(p) was also determined, resulting in k(p) = 0.4140 m/day for 16-inch-diameter pipes and k(p) = 0.1509 m/day for 10-inch-diameter pipes, This way, for Culiacan, Sin., the total chlorine decay coefficient k value was obtained as 0.2478 to 0.189 hour(1). For 70.83% of the points measured, the difference between the model predictions and the field measurements is less than 25%. In the southern region of the model's application site, this difference is less than 20% for 90% of the points.