Risk Analysis Of Combined Water Supply Based On Runoff Simulation

The water resources in China are scarce, and the distribution of water tim e-space is uneven. The contradiction between supply and demand of water is b ecoming more serious in some places of China. Thus, water resources have bee ome an important factor restricting economic development. Many areas have suf fered different degrees of the water crisis. Therefore, it can effectively improve the situation of water shortage and realize sustainable utilization of water reso urces by allocating water rationally and using of it efficiently. For multi-reserv oir water system in parallel, the implementation of water supply joint operation for reservoir group, determine optimal water supply reservoirs in decision-maki ng, not only achieving rational allocation of water resources and improve urban water guaranteed rate and reduce the damage caused by the lack of water. Ho wever, due to factors such as uncertainty of water supply systems, leading to r eservoirs in joint operation, there is a certain degree of risk, risk analysis on water supply, identify, assess, and facilitate planning for multi-reservoir water s upply system risk management, is important to ease urban water supply proble ms.Main contents and results in this paper are as follows:(1) In order to accurately estimate the reservoir water supply reliability an d risk, using only existing runoff data was not enough, need to simulate a larg e number of series based on the observed runoff data. According to the basic composition of hydrological time series and statistical characters of the observe d runoff data, choose a reasonable stochastic model, usually Autoregressive mo del for annual runoff simulation, and month runoff simulation using the Season al Autoregressive model and Disaggregating model, and determine the reasonabl eness of simulate results according to the model checking methods(2) The scheduling for multi-reservoir mainly focuses on the following iss ues:first, the establishment of multi-reservoir water supply system joint operati on model; Second, making a reasonable and feasible scheduling rule; Third, det ermining the method for solving scheduling model. The multi-reservoir was equ ivalent to a aggregation reservoir and established optimization criterion about th e maximum amounts of water supply, the minimum amounts water shortage (sur plus water) and the maximum of Water-supply benefits of multi-reservoir water supply system joint operation model. The scheduling rule include the rule of water-supply, which is a piece of combined rule curves and achieve the water-s upply optimal allocation of multi-reservoir; the rule of distribution, which deter mine the water-supply amount of every members of system under different wate r inflows. To analyze on the method for solving scheduling model by simulatin g computation method for reservoirs water supply process.(3) To analyze the definition of risk and the main water supply risk sour ces, the methods of water-supply risk analysis and application conditions, decid e to use Monte Carlo method to analyze the reliability and risk of multi-reserv oir water supply process, and establish the risk evaluation system including wat er-supply reliability, water-supply recovery and vulnerability of water-supply.(4) The multi-reservoir xiaoxiang-xihe-shuicheng in Qujing as an example, analyze the reliability and risk of multi-reservoir water-supply. According to a nalyzing the main features parameter of reservoirs and water supply present sit uation of Qujing and 52 years observed runoff data of reservoirs, used AR(1) model to simulate 300 years annual runoff, SAR (2) model to simulate 300 yea rs monthly runoff, simulation results can keep the statistics characteristics of ob served runoff data, errors is within permission. The maximum amounts of water supply as the optimize target to draw the combined rule curves. According to the rules of water-supply and distribution, using simulating computation metho d for reservoirs water-supply process, analyzing the reliability and risk of multi-reservoir. The results showed that joint scheduling for multi-reservoir water su pply fully meet the domestic water and industrial water demand of Qujing, basi cally meet the agricultural water demand of Qujing, water-supply is reliable. It is prove that the joint operation model for multi-reservoir water supply system is rationality and feasibility.