生态技术措施对河流年输沙量的影响遵从统计学原理。本文以无定河年输沙量为因变量,以无定河汛期降雨、暴雨和生态技术措施面积为自变量,采用逐步回归方法,分析研究了1956–2007年时段生态技术措施对无定河年输沙量的影响。结果表明,(1)计算建立了由"无定河7–8月降雨量"、"生态技术措施面积"和"无定河最大一日降雨量"等三个自变量组成的非线性回归方程,相关系数R2=0.857,显著性水平α=0.001。(2)调整R2=0.717,说明回归方程"解释"了52年时段无定河年输沙量71.7%的变化。(3)生态技术措施面积的标准化回归系数在三个自变量中绝对值最大,说明其对年输沙量变化的影响最大。(4)通过实施生态技术措施,到2007年治理水平年,即使是在7–8月降雨量和最大一日降雨量均为研究时段内最大值时,计算年输沙量为1.49亿t,仅为历史最大值的36%。
The influence of ecological technology measures on the annual sediment loads of rivers complies with the principles of statistics. In this paper, the annual sediment load of the Wuding River is taken as the dependent variable and the rainfall, rainstorms during the flood period of the Wuding River and areas of ecological technology measures are taken as the independent variables to analyze the influence of ecological technology measures on the annual sediment load of the Wuding River during the years 1956 to 2007. This research uses a stepwise regression method. The result shows that 1) the non-linear regression equation composed of three independent variables including 7–8 monthly rainfalls along the Wuding River, areas of ecological technology measures and maximum daily rainfall along the Wuding River has been calculated and set up; the correlation coefficient is R2=0.857 and the significance level is α=0.001. 2) R2=0.717 is adjusted and the regression equation reveals a change of annual sediment load exceeding 71.7% over 52 years; 3) The standardized regression coefficient for ecological technology measure area has the maximum absolute value of the three independent variables shows maximum influence on the change of annual sediment load; and 4) Because of implementing the ecological technology measures, until to year of 2007, when the 7–8 monthly rainfall and maximum daily rainfall are the maximum values in the research section, the annual sediment load is calculated as 149 million ton, which is 36% of the maximum value in the history.