Title:Prediction of Roughness Coefficient For Aged Pipes Using Simulation Models Authors: Rasha Yehia ; Ehab Rozaik DOI: Aff: Cairo University. Egypt Author Email: Keywords: C Factor; Leakage; Chlorine Decay; Headloss Gradient and Aged Pipes URLs:ABSTRACT-HTML | FULLTEXT-PDF | Abstract:Many effort is exhausted lately in Egypt for adjusting data used to be introduced in a water distribution modeling software. One of these parameters that were very impressive in changing the results totally is the roughness coefficient (Hazen Williams C). The effect is seen obviously if the flows are increased so leads to higher head losses. These head losses would appear lower due to the fact that we are using uncertain value for roughness especially if we are using the standard roughness for new pipes. The outcome from precise determination of roughness coefficient is adjusting water distribution network models to cope with real field values. The aim of this research is to relate C factor to head loss gradient so engineers can find a way to estimate C factor for aged pipes based in head loss gradient whatever was the network configuration. The relationship of C factor to water quality parameters as chlorine decay is also discussed. Polynomial Equations relating chlorine concentration and Hazen Williams C factor is deduced. A validation of Watergems leakage detection module(Darwin calibrator module) makes up a part of this research. And it is concluded that leak location can be found in a range of circle with a radius of 0.25km around point detected by Darwin Calibrator. Equations of Colebrook and White are inserted in Watergems tables using user data extension tool to enter formulas to be calculated by software engine. This is a way provided to help get a fast estimate for roughness coefficient.