【文章內容簡介】 e rejected. It indicates that the r2 （Goodnessoffit coefficient）is significant, thus it can be deduced that the established binary linear regression model is effective. II. Single variable inspection（T testing） P: M： N： All the three reject the original assumption. The three regression coefficients are statistically significant. So G = + + fitting of P、M、N To explore the relationship between water demand and time, it is necessary to find the time function of population, GDP, the agricultural irrigation respectively. Now the regional annual data, about population、 GDP and the water quantity used by agricultural irrigation, have been gotten. Then their function relationship about time t can be fitted by Matlab. As zone A，the fitted curve of population and x(x=t2000)can be shown as figure 3: Figure 3 relationship between population and time Its function relationship: 。 （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。 surface water storage that makes full use of the preexisting reservoirs of waterstarved city, the best of which supplements the surface water from the source region of the city39。s water supply (which can take advantage of the preexisting water supply system). The underground reservoir is a special reservoir, built with the natural underground water storage space, playing the roles of impoundment、 regulation and utilizing groundwater flow. As shown in the following figure: Figure 6: underground reservoir According to the thickness of the aquifer, the distribution area and rock storage coefficient, it can be calculated that the maximum regulation and storage capacity of underground reservoir as: ???????? = ??????? (6) Where: ???????? refers to the regulation and storage capacity of underground reservoirs(m3)。 is storage coefficient of the underground waterbearing medium in reservoir storage layer, for the no pressure waterbearing body?? = ?? + ???, for the pressure waterbearing body?? = ???,where is gravity specific yield(dimensionless),??? is elastic storage coefficient(dimensionless)。 is reservoir area (km2)。??? 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。 ② Underground reservoirs has lit