用水特性曲线的线型及其应用研究

Identification of the typical water use curve and its application

建立流域或区域供(用)水总量与降水量的函数关系(用水特性曲线),使年度用水总量控制指标受降水量变化的影响不易进行考核的问题得以有效解决。确定这种函数关系的基本线型不仅为这一方法构筑理论基础,也为其推广应用拓展了空间。本文通过对海河流域规划水平年的供水量、降水量关系分析,建立不同类型函数关系的用水特性曲线,基于选取线型需遵循的变量相关性、函数单调性、极值点特性和方法适用性4项准则,寻找相对合理的分布函数。在详细讨论函数的基本特性和应用范围后,并在海河流域二级区进行了进一步检验,最终确定反正切函数能够正确体现供(用)水总量与降水量的相关关系,可以作为用水特性曲线的基本线型。

Building a curve reflecting the relation between regional water supply/usage （S） of human activi-ties and natural precipitation （P） will help in implementing annual check of the gross water use,as a con-trol indicator in the strict water management,which changes flexibly with precipitation. To find out the fun-damental function for basic theory and wide application of this approach,this paper tried to identify a ratio-nal curve-type of water use curves among several functions through setting up functional relations of S and P in planning years in the Haihe River basin. Four criterions, the variables’ correlation, the functional monotonicity, extreme existence and curve adaptability, were employed in selecting relatively rational func-tion as the curve-type of water use curves. By detailed discussion of the features of selected function and its adaptability conditions, and further testing in four sub-basins in the Haihe River basin, the arc tangent function was finally identified as the curve-type for basic water use curves which better reflects the charac-teristics of S and P relation.