In the world, improving quality and reliability of water supply systems, improving access to clean drinking water for the populations in conditions of development and intensive growth of urban settlements are considered an important issue. In this research the most important issue is improving the calculation methods of water delivery and distribution systems within urban water supply complexes. In most countries such as the USA, Germany, Russia, Israel, South Korea, China and other economically developed countries, special attention has been paid to provide clean drinking water for their population, improve the quality of design for water supply systems and ensure reliability and design of water distribution system for urban settlements. A water supply network for distributing the water for drinking and other purposes is a component of a city and municipal planning. Therefore, it needs to be planned and designed by city planners and civil engineers with the utmost care. It is also necessary to consider of factors that will have an impact, such as the location of the town or city, its current water demand, the growth in the demand in future, leakage in the systems, the required pressure in the pipes, losses in the pipes, etc. Targeted research aimed to develop scientifically grounded calculation methods for studying and developing theoretical bases for calculation water delivery and distribution system within urban water supply complexes. The study also considered new working conditions and requirements for their modernization, which are especially important worldwide. In this study the most important tasks are to improve calculation methods of water delivery and distribution systems under the condition of multi-mode water flow in pipes and uncertainties of network parameters. Further, Mazar-e-Sharif city has been considered as a case to apply the developed mathematical calculation, describing water delivery and distribution processes, rational development and reconstruction of water delivery and distribution systems. Currently, a wide range of comprehensive studies is being carried out in many countries on the use of modern computer technologies on the implementation of comprehensive measures to improve access to clean drinking water in city, through the construction of new water tanks, an extension of the existing water tanks, sewerage facilities and water supply network. The development strategy of the Islamic Republic of Afghanistan in line with SDG’s is first improving the supply and delivery of clean drinking water in each province of the country. Since many years the local Government of Balkh province and people of Mazar-e-sharif city are wishing to have the new modern water supply system to satisfy all needs but unfortunately, they did not success to get this opportunity. Mazar-e-Sharif is the second largest city in Afghanistan and the population is growing day by day as due to economic reasons people from other provinces immigrate to Mazar. The current water supply system is the individual/local distribution system made by the local community and some NGOs which are not standard, and the quality of the water is not satisfactory.:Table of Content CHAPTER 1 : Introduction 1 1.1 Background 1 1.2 Research Objectives 2 1.3 Structure of the thesis 3 1.4 Study Area 4 1.5 Socioeconomic conditions 5 1.6 Master Plan and Future Development 6 1.7 Physiography 7 1.8 Existing situation 8 1.8.1 Ground water 8 1.8.2 Water Quality 8 1.8.3 Surface Water 9 1.8.4 Actual Production 9 1.8.5 Storage 11 1.8.6 Operation of current Water Supply System 11 CHAPTER 2 : Literature review 13 2.1 Water Supply System 13 2.2 Water supply characteristics 15 2.3 Theory of hydraulic models 17 2.4 Analysis of existing theories and methodologies for modeling a water supply and distribution system in a water supply complex 31 CHAPTER 3 : Research methodology 36 3.1 Overview 36 3.2 Description of the properties and types of sets used in the model 38 3.3 Mathematical model of the water supply system 39 3.4 Mathematical model of the designed water supply network 41 3.5 Water flow continuity equation 43 3.6 Equation of water balance in tanks 44 3.7 Establishment of pressure loss in pipes, under the condition of optimal operation of tanks on the water supply system 44 3.8 The objective function of water supply network optimization 55 3.9 Limitations in optimizing the water supply network 58 3.10 Bringing distributed water consumption to network nodes of a water distribution system 60 3.11 Determination of rational parameters of a water distribution system 61 3.12 Determination of the parameters of water distribution system during the reconstruction of the existing water supply network 62 3.13 Mathematical model for optimizing the reconstruction of a water supply system 63 CHAPTER 4 : Result and Discussion 66 4.1 Assessment reliability of the results 66 4.2 Task 1 (Hydraulic calculation of a single-ring water supply network) 66 4.3 Task 2 (Hydraulic calculation of a multi-ring water supply network in simulation mode) 68 4.4 Task 3 (Test water supply network) 70 4.4.1 Water Demand 71 4.4.2 Parameters for Hydraulic Design 72 4.5 Design procedure 73 4.6 The structure of the software package and the model interface 83 4.6.1 Structure of the water supply optimization system 83 4.6.2 Optimization system control module 84 4.6.3 Graphical editor 84 4.7 Graphical editor input and output files 90 4.7.1 GDX file 90 4.7.2 Text file 90 4.8 EXCEL file 93 4.9 Water supply system indicators (pipe lengths, pipe diameters) 99 4.10 EXCEL file exists 100 CHAPTER 5 : Conclusion 109 CHAPTER 6 : References 112 CHAPTER 7 : Appendix 118 7.1 Diagram of the water supply network of a real settlement 118 7.2 Comparison of water flow rates in a real existing water supply network performed according to existing methods and using an optimization model in simulation mode 119 7.3 Comparison of the values of water consumption in the real existing water supply network performed according to existing methods and using the optimization model in the optimization mode 124 7.4 Compilation of pipe diameter in the real and optimal conditions in meters 129 7.5 Pressure in the nodes of the water supply network before connecting a new user and after connecting and reconstructing the network 135