Urban water supply networks are one of the most expensive infrastructures of urban management. A network that carries with it the task of transporting the most important element and vital human need, which is water, is undoubtedly of great importance. The companies in charge of water supply, such as water and sewage companies, spend a special budget every year for network renovation, while this renovation should be done based on scientific studies. In this thesis, the aim is to separate the concept of failure from the meaning of event and to state that failure has a wide meaning in water supply networks and any factor that causes the water needed by the users to be available in a standard manner. If they are not placed, it will have a part of the concept of failure with it; In the second stage, an attempt was made to present a broad concept called rehabilitation; Rehabilitation means increasing the performance of a water supply network. In the next step, the factors affecting the rehabilitation such as: type, age and diameter of pipes, speed and pressure governing the network, as well as operating factors such as: covered population, working depth, event rate and strategic conditions of each pipe are measured. and the effect of each on the rehabilitation is determined. In the following, an index will be introduced to eva‎luate the performance of pipes called Rehabilitation Pipe Index (RPI), which is an index for prioritizing rehabilitation. This index, which is a number between zero and one, after quantifying each of the factors and then fuzzifying them, is obtained from the algebraic sum of a small amount of 10 factors; The closer the value of this index is to 1, the pipe is a priority for rehabilitation. As a result of this research and investigation, which was carried out within the zone N of Kashan water supply network, it can be seen that 167 network pipes, which have a share of 1.2% of the entire studied area, have an RPI index above 0.5 and a risk above 50%, which They should be prioritized for rehabilitation. Focusing on these pipes shows that among the 10 criteria of rehabilitation, the event rate of pipes with 52% impact, wear and tear of pipes with 19% and network pressure with 10% impact will contribute the most to network rehabilitation. Among the 8 types of pipes in the water supply network, cast iron pipes show the best condition, and asbestos cement and polyethylene pipes have the largest share among the pipes prioritized for restoration. It should be mentioned that steel pipes, despite their length and small share in the network, show a very unfavorable situation in the network with a 42% rehabilitation rate. In a general view, physical factors with 78%, hydraulic factors with 19% and operational factors with 3% impact on rehabilitation show their place in the decision making of the companies in charge of water supply.

هستي هاشمي نژاد , محمدحسين گل محمدي

هستي هاشمي نژاد , رامتين معيني