Analysesand Modelling Of Zonal Management Oriented Water Distribution System

Along with urbanization, water distribution systems have been expanding and becoming increasingly complex, which consequently brings greater challenges to water utilities regarding management and operation control, e.g. nonrevenue water control, optimal control, real-time monitoring etc. Particularly, nonrevenue water control is a topic of the Twenty-First Century, given its importance in water resources conservation and economic benefits of water supply industry. Thus far, zonal management has been proved as an efficient strategy for reducing nonrevenue water. In recent years, the pros and cons of this strategy have been further explored, however, the practical application is still quite limited due to the following constraints. Firstly, in practice, zoning planning, the prerequisite of zonal management, is an empirical work without scientific basis. Secondly, zoning planning is based on―All Pipe‖model, while setting-up and calibrating such a model is an intricate task, in addition to the comparatively low efficiency of hydraulic simulation. Thirdly, no systematic researches are concentrating on the hydraulic behaviors of zonal management system, and therefore how to evaluate a zoning plan comprehensively and eliminate corresponding negative effects is still an open question. To overcome above problems, this study explored the scientific zoning planning method that could be more reliable and efficient than the traditional method. Moreover, several traditional techniques for hydraulic modeling were modified according to the characteristics of zonal management oriented system in order to fulfill various requirements from operation control and management. Finally, hydraulic uncertainties resulting from zoning planning or rehabilitation was evaluated. The outcomes are briefly summarized below.1) Exploration on scientific zoning planning methodology: inspired by decomposition theorems, complex network theories, and related concepts of urban morphology, this study worked out a zoning planning method based on community structure formed in topology evolution. Feasibility of this methodology has been verified through a number of case studies for which zonal management strategy have been already well-planned. Compared with the empirical traditional method, this new approach not only has theoretical basis but also works more reliably and efficiently as district boundaries are generated automatically.2) A calibration method serving for zonal management-oriented water distribution system was designed through modifying traditional method. Except steady state calibration and extended period simulation calibration, this method also calibrates occurrence time of instantaneous states which is so called dynamic scenes calibration. In this way, both accuracy and efficiency of calibration could be dramatically improved, and more importantly model calibration is not just limited to retrieve system states recorded at a series of time stamps anymore, but instead is to correct the complete dynamic process.3) Parallel hydraulic computation based on zonal structure: To improve hydraulic analysis efficiency of zonal management-oriented water distribution system, this study figured out parallel computing schemes for three most commonly-used hydraulic simulation methods respectively inspired by the piecewise solution of large scale systems. Furthermore, those approaches could overcome the common limitations of purely mathematical oriented algorithm design as they integrate professional considerations by providing each subsystem assigned to each processor with physical meaning and ensuring the solution of each subsystem respects to the original schemes of specific hydraulic simulation methods to the largest extent so that the original method's own advantage and convergence are maintained.4) To understand the uncertainty of hydraulic characteristics of zonal management-oriented water distribution system, this study evaluated the possible influences on hydraulic behaviors and lifecycle costs resulting from running a water distribution system that was designed according to a single peaking factor following the traditional standard in zonal management mode. Accordingly, suggestions on design of zonal management-oriented water distribution system and zoning rehabilitation are concluded. For design, different peaking factors should be defined for different districts as long as necessary. For rehabilitation, it is essential to analyze the flow characteristics variation due to rehabilitation and thereby identify corresponding effects on the system's performance through model-based analysis, so that special corrective measures could be determined.