【正文】 Constraints (8) After solving it by LINGO， the optimal solution has been obtained： Namely the water supply A to B is 108m3 . D to C is 108m3. D to F is to C all is 108 108m3. Sensitivity analysis Obtaining the minimum value of the total cost of the diversion by the lingo software: the data obtained by the sensitivity analysis are as follows: It can be drawn from the above data that the reduction of the third and fourth rows of data would make the total cost reduce more. 100 million m3 water reduction of Zone D and Zone E would make the total cost reduce to 1056 a and 1297a respectively. In addition, 100 million m3 water reduction of zone C would make the increase of 64 a in the total cost. To sum up, just considering the economic cost of water diversion, water diversion can be changed as the follows: minimizing water diversion of D、 E zone or reducing its water transfer distance。 ??4 is maintenance cost。 ??6 is other costs, which can be estimated as 5% of the previous five costs. 2. Analysis of Processing cost Take sewage treatment plant with the handling capacity of 30,000 t / d of North China as an example for analysis. a. Depreciation charges ???? Depreciation is a measure to recover the investment, which means extracting a certain amount of funds as a recovery of investment at the end of the year. According to the calculation method of the annuity, without extra consideration offinancial expense, the depreciation extracted every year is(Jin 2003) ??1 = ?? (1 ? ??)/(12 ??) (15) Where Z is total investment amount( 104 yuan)。P iis the prices of resource (yuan)。??? is the maximum thickness the regulation and storage layer, that is, the water level difference value between the extreme high water level and the planning regulation and storage layer bottom interface()(Zheng et al. 2004). Superiorities： ① Underground reservoir taking natural aquifer as water storage spaces, so it has relatively simple construction conditions and lower construction costs。s more, China has the most water consumption in the world. In 2002, it’s national freshwater usage amount has already reached billion cubic meters, accounting for about 13% of the world39。 （2） In a similar way, the fitted curve of zone GDP and x(x = t ? 2000)、the fitted curve of the water quantity used by agricultural irrigation and x(xt=2000)are respectively shown as Figure 5: Figure 4 GDP and time Figure 5 irrigation and time Its function relationship： M = ? （3） （4） Take（2）（3）（4）into type（1），then it could be gotten that the relational expression about the water demand of zone A and time: A = ?(t ? 2000)3 + 0. (t ? 2000)2 + 2(t ? 2000) + （5） When t=2025，it could be calculated that the water demand of A zone is A=. That is to say, water supply in 2025 is more than water demand, and A zone will have water about = in 2025 for mobilization. In a similar way, using ternary regression analysis, the relationship curve, about annual water consumption of the other zones and time t, can be fitted by Matlab. (x = t ? 2000），and the fitting results are shown as the following table: Table 3: Data collection and statistics Zone Consumption P A A = + + B C D E F G G = + + Zone M N A B C D E F G of freshwater supply： Water supply contains two aspects, one is the natural water supply, and the other is artificial water supply. Natural water supply depends on some uncontrollable natural factors like climate、rainfall and so on, While artificial water supply can provide more freshwater by improving or increasing the watersupply measures. In order to determine water strategy of 2025 in 2013, assume that except the water strategy we developed, there is no additional artificial water supply. So it is necessary to analyze the water supply of 2025 by freshwater supply in 2013. Team 22362 Page 31of 29 Statistical data indicate that the water supplies of each zone in 2013 are respectively shown as the following table: Table 4: the water supplies of each zone in 2013 Zone A B C D E F G Output of supplydemand balances: According to the calculation method of water demand in A zone, water demands of other zones can be calculated, and the results are: Table 5 Analysis of freshwater supply Zone Output Consumption Dvalue A B C D E F G The above table indicates that, among the seven zones, only zone A、 D、and E would have enough water supply in 2025，and their redundant water quantity are respectively 108m3， 108m3，108108m3. While zone B、C、F、G would be in water shortage in 2025, and the quantity of their water shortage are 108m3 ， 108m3， 108m3， 108m3. The water supply indicates that the water shortage situation of some zones is serious. In order to solve the water crisis, national water strategy need to be determined to face the challenge. . Water storage model In the flood season of rainy year, a large quantity of water supply exceeds demand. Excess rainwater would be stored in the intake area, in order to be taken advantage of in the dry season. The excess water is usually stored in two ways: groundwater storage that makes the most of the hydrogeological conditions and the preexisting groundwater extraction wells of the waterstarved city to replenish groundwater。 ④ It provides the basis and conditions for the joint scheduling of surface water and groundwater, and it slows down the flood pressure. Problems：It has relative larger errors to calculate the amount of resources of underground reservoirs。 ??1 is depreciation cos