【作者】 莫莉；

【导师】 王飞； 穆兴民；

【作者基本信息】 西北农林科技大学 ， 水土保持与荒漠化防治， 2008， 硕士

【摘要】 北洛河流域位于黄河中游地区,为渭河流域的第二大支流,流域内水土流失严重,是黄河泥沙主要来源区之一。本研究采用水文统计分析方法,以流域内水沙监测资料为基础,对流域降水、径流和输沙的年际变化及年内分配特征、水土保持措施减水减沙效益进行了系统的研究,探讨了北洛河流域水土保持措施减沙水代价变化特征及其与各影响因素之间的关系,比较了北洛河流域与我国北方地区部分典型流域的水土保持措施减沙水代价变化特征。取得的主要结果如下:分析了北洛河流域降水、径流和输沙的年际变化特征。其降水量的多年平均值、变差系数和极值比分别为511.4mm、0.19和2.49;径流量为65915.6万m3、0.45和6.79;输沙量为7610.5万t、0.76和90.7。采用滑动平均法、Mann-Kendall和Spearman法分析降水、径流、输沙量年际变化趋势,结果表明:降水、径流和输沙量均呈显著减少的变化趋势。近50多年来单位降水产流量和单位降水产沙量变化可以分为枯水平沙期(1950～1962年)、丰水丰沙期(1963～1969年)、枯水平沙期(1970～1982年)、丰水枯沙期(1983～1991年)、丰水丰沙期(1992～1994年)和枯水枯沙期(1995～2006年)等6个时期。降水量、径流量和输沙量年代变化特征为:降水量随年代的延伸呈减小趋势,径流量随时间的推移呈波动式减小趋势,各年代输沙量呈驼峰型变化特征。采用不均匀系数、集中度和集中期等指标分析了北洛河流域径流量和输沙量年内分配特征,表明:(1)径流量和输沙量年内变化均呈“单峰型”;(2)径流量、输沙量年内不均匀系数随年代呈波动式变化,其中上世纪90年代年内不均匀系数最大,径流量年内不均匀系数以上世纪60年代为最小,输沙量年内不均匀系数在上世纪80年代最小;(3)各年代径流量的集中期均为8月份,上世纪70和90年代径流量的集中程度最大,60年代径流量的集中程度最小;输沙量集中期为7或8月份,集中期输沙量占全年输沙量的90%左右。采用“经验公式法”计算了北洛河流域上世纪70年代大规模水土流失治理以来人类活动减水减沙效益。其结果为:(1)北洛河流域1970～2006年人类活动年均减水量23589.8万m3,减水作用为28.3%;年均减沙量2573.2万t,减沙作用为28.2%;(2)受降水和人类活动的共同影响,1970～2006年年均减水量为27140.6万m3,减沙量为3285.2万t,人类活动对水沙的影响占主导地位。研究了北洛河流域水土保持措施减沙水代价特征。采用上述“经验公式法”的减水减沙量值计算水土保持措施减沙水代价值,该流域1970～2006年水土保持措施减沙水代价平均值为11.76m3/t,小于黄河及渭河下游输沙需水量。水保措施减沙水代价与各影响因素之间的关系分析表明:(1)流域水土保持措施减沙水代价与年降水量以及汛期降水量的关系密切,呈较好的反比关系;(2)水保措施减沙水代价与天然产流产沙量亦呈较好的反比关系;(3)与梯田、坝地、造林相比,该流域种草措施在减少相同泥沙时对径流的影响较小。比较了北洛河流域及我国北方地区其他典型流域水土保持各单项和综合措施的减沙水代价特征。结果表明:(1)不同流域各单项水土保持措施减沙水代价不同;(2)不同流域尺度的水土保持综合措施减沙水代价同样存在明显的区域分异特征。通过不同区域和不同类型水保措施的配置,可以对径流量和输沙量进行调节,当选择减沙水代价小的水保措施配置类型和区域配置时,可以在减少等量泥沙时,相对增加径流量,从而达到减沙增流的调控目的。更多还原

【Abstract】 Beiluo River, one sub-branch of Wei River, is selected as research area to analyze runoff and sediment change and the impact of soil and water conservation practices on them with the observed data of hydrology stations. The runoff cost of sediment control of soil and water conservation practices in Beiluo River basin and other typical basins in northern China are analyzed. The main findings are as follows:The annual variation characteristics of hydrological elements are also analyzed, the results show the means value ,variation, extremes ratio of precipitation, runoff and sediment are 511.4 mm, 0.19 and 2.49, 659.156×104 m3, 0.45 and 6.79, 7610.5×104 t, 0.76 and 90.7, respectively. Analyzing the annual change and trends of precipitation, runoff and sediment by using moving average method, Mann-Kendall and Spearman method, the author obtains that the precipitation, runoff and sediment have been significantly in attenuation trend. By analyzing accumulating curves of runoff and sediment deduced by unit precipitation distance away from averages, I find that the change could be divided into 6 stages: low water but average sediment period (from 1950 to 1962), abundance water and sediment period (from 1963 to 1969), low water but average sediment period (from 1970 to 1982), abundance water but low sediment period (from 1983 to 1991), abundance water and sediment period (from 1992 to 1994), and low water and sediment period (from 1995 to 2006). The characteristics of precipitation, runoff and sediment in each decades are analyzed, the results are: precipitation and runoff have decreasing trends, the change of sediment is a hump-type.The monthly changes of runoff and sediment are analyzed by uneven coefficient methods. The results are: (1) the curve of monthly average runoff and sediment has a peak; (2) the uneven coefficient of the runoff and sediment appeared to vary in a wavy manner during the decades, which in the 1990s are the biggest, but the smallest uneven coefficient of the runoff is in the 1960s and of the sediment is in the 1980s; and (3) the concentrating scheduled time of the runoff is August and of the sediment is July or August; The maximal centralized degree of runoff is 70’s and 90’s of last century, and the centralized degree of sediment is about 90%.Calculating the effect of human activity on runoff and sediment by using“empirical formula method”, the result shows that: (1) from 1970 to 2006, the average reduction of annual runoff induced by anthropoid activities is 23589×104m3 and the effect of reducing runoff is 28.3%; the average annual sediment reduction is 2573.2×104t and the effect of reducing sediment is 28.2%; (2) influenced by precipitation and anthropoid activities, the average annual runoff reduction is 27140×104m3 and the average annual sediment reduction is 3285.2×104t, we can conclude that anthropoid activities cast an importantly effect on the runoff and sediment.The characteristics of runoff cost of control sediment of soil and water conservation in Beiluo River are presented. Based on the result of“empirical formula method”, from 1970 to 2006, the mean of runoff cost of sediment control of soil and water conservation practices in Beiluo River is 11.76m3/t. The relationship between runoff cost of sediment control of measures and the influencing factors are analyzed. The results show that: (1) there are significant negative correlations between the runoff cost of sediment control of measures and precipitation; (2) with the natural runoff and sediment is increasing, the runoff cost of sediment control of measures is decreasing; and (3) in this basin, forestry and grass have less influence on runoff than terrace and dam, while control the same sediment.The runoff cost of sediment control of the different measures, integrated measures on Beiluo River, and different scale basins in the northern area of China are at last discussed. The results show that: (1) the runoff cost of sediment control of individual measures is dissimilar in different basin; (2) the regional differences of the runoff cost of sediment control of integrated measures in different scale basins also are obvious. If the soil and water conservation measures with smaller RRS are selected, it can save more runoff when reducing the same amount of sediment that perhaps improves the water resources condition in arid and semi-arid area.更多还原