The project of balad's major sewerage system is one of the biggest projects who is still in progress in salahulddin province provincial - development plan that was approved in 2013 . This project works in two parts ; the 1st is installing the sewerage networks (both of heavy sewerage & rain sewerage) and the 2nd is installing the life – off units (for heavy sewerage & rain sewerage , as well) . the directorate of salahuiddin is aiming that at end of construction it will be able to provide services for four residential quarters , one of the main challenges that project's management experience is how to achieve these projects in the determined time , added cost and technical specifications although the majority of these projects have been managed with predetermined time and financial resources limits , they still need some improved strategies and more careful calculation in their time and cost management. This project was chosen for the following reasons , The first reason is that the project is currently stopped, because of the security and financial circumstances in salahulddin province in particular .this is a great manage time and cost when the work is resumed , and the second reason is during the progress of the project, the until it was stopped, the completion percentage was behind what it was planned originally . this highlights the need to study how to avoid these delays in future using a scientific and logical method , and the third reason that the project has many variables that affect the progress, which are of great importance for scientific and mathematical methods . To achieve this purpose the project was studied using modern scientific and mathematical methods , which are the curved part method (CPM) for project's real and accelerated timing the Primavera V6 software and the AutoCAD 2015 software . the goal is to benefit from these methods and software to establish a new work schedule for the project . Due to the project's various and clashed (in sometimes) objectives that are have to be accomplished in a limited time , it is very important to be careful and accurate with making the right time . It was highly needed to use an efficient mathematical model that work with all these variables in the limited time allowed and according to their priorities . This mathematical method is called the Goal Programming for multi-objective mathematical models