562 APPLICABILITY OF USING THE MULTIPLE LATERAL DEMANDS FOR DESIGNING WATER NETWORKS Mohamed Shamrukh Department of Civil Engineering, Faculty of Engineering, ElMinia University E-mail: mshamrukh@hotmail.com Abstract Many mathematical algorithms have been evolved for solving and analyzing the water distribution system such as Hardy-Cross and linear theory methods. In these traditional design methods, demands (consumption flow) are allocated to the two end nodes of the system pipes. Grouping water usage at the end nodes instead of at the actual locations where water is withdrawn from the system, produces differences between computer-predicted and actual field performance. In real-world water supply pipelines, the demands are withdrawn at different distances not at the ends of the pipeline. A numerical analysis of flow through the main pipes of water networks utilizing a hypothetical assumption of equate distribution of multiple lateral withdrawal lines (demands) along the pipe length has been presented. With the modified approach, head loss calculations in water pipes should be modified in the situations with a limited number of intermediate pipes withdrawing water from the pipe. Equations for friction head loss could be reduced by a coefficient equals to 0.5 for intermediate water laterals less than two points. This coefficient is applied in case of inflow rate which is less than two times the withdrawal rate (Q<2Q c ). The uniform withdraw method could be used in situations when the number of lateral withdrawals more than 10 points. Using this introduced approach (multiple and equate uniform lateral withdrawals) does not need the process of demand allocation used in the traditional methods for design of water pipes. Thus, the actual demand is allocated to the pipe itself instead of its nodes. Therefore, the developed approach is expected to improve the design and simulation processes of water distribution systems to match its reality. Keywords: Water supply, Pipeline network, Demands, Design