水保所知识产出(1956---)知识库

尺度问题在地貌过程及水文模拟研究中具有重要意义，以黄土高原丘陵沟壑区岔巴沟小流域为例，基于毛沟-支
沟-干沟尺度序列典型水文站的实测径流泥沙数据，分析流域系统基于事件的径流侵蚀链内泥沙输移的空间尺度效应。结
果表明：1）基于侵蚀链毛沟-支沟-干沟不同空间尺度的平均输沙模数、平均含沙量、最大含沙量分别依次为3 912、3 285、
3 522 t/km2，497、524、679 kg/m3，639、634、800 kg/m3，且在流域系统中均保持空间上的不变性；2）与单一力学指标相比，引入
洪峰流量项的水流功率、单位面积径流能量及水流能量等复合能量指标能更好地描述侵蚀链不同尺度内及尺度间水沙关
系；3）侵蚀链的输沙量主要取决于径流量，而洪峰流量能更好地解释侵蚀链内不同尺度径流输沙的差异，在侵蚀输沙的预
测变量中引入表征径流变率的指标会提高中小型产沙事件泥沙预报的可靠性；单位洪峰流量（增加1 m3/s）引起的输沙增
量是单位径流量（增加1 m3）增沙作用的875 倍以上，欲消除侵蚀链内上下游径流输沙的空间尺度效应，则需将对应的洪峰
流量比调控至5‰以下，或将对应的径流能量比调控至600 以下；4）侵蚀链内上游含沙水流对下游的泥沙输移影响有限，
随流域面积增大，含沙水流的空间尺度效应降低，输沙模数＞300 t/km2 的大型侵蚀产沙事件尤为明显。分析结果突出了流域
系统径流侵蚀的过程特性和洪水调控可能引起的巨大减沙潜力。因此，针对高含沙水流，侵蚀链内泥沙调控及其水土保持
措施的效益评估和功能评价亦应基于过程。研究结果可为全面揭示径流调控系统的水土保持意义、推动水土保持措施效益
的精细化评估提供理论依据和科学支撑。

Scale issues are of great significance in studies concerning geomorphologic processes and hydrologic modeling,
which have been extensively studied in the domain of soil erosion. Nevertheless, studies are relatively rare on spatial scale
effect on sediment delivery within event-based runoff erosion chains. Based on recorded sediment-runoff yield data from 3
gauging stations including Tuanshangou, Shejiagou, and Caoping station at varying spatial scales in Chabagou river basin,
44 runoff erosion chains across scale sequences of sublateral, branch, and trunk were extracted. Spatial scale effect on
event-based sediment delivery was investigated within runoff erosion chains in a typical agricultural basin system of hilly
loess region on the Chinese Loess Plateau. The results showed that: 1) event-based area-specific sediment yield, sediment
concentration, as well as intra and inter scale flow-sediment relationship remained spatially constant within runoff erosion
chains, and thus almost all the sediment-laden flows could reach erosion thresholds across scales, especially for
hyperconcentrated flows. Average area-specific sediment yield, average sediment concentration, and maximum sediment
concentration at Tuanshangou, Shejiagou, and Caoping station at different spatial scales were 3912, 3285, 3522 t/km2; 497,
524, 679 kg/m3; and 639, 634, 800 kg/m3; respectively; 2) Compared with single indicators including peak discharge and
runoff depth as well as hydrodynamic indicator such as flow shear stress, composite energy parameters such as stream
power, unit runoff energy, and stream energy, all of which incorporated the flood peak discharge term, could better describe
intra- and inter-scale based runoff-sediment relationships within runoff erosion chains; 3) Sediment production was mainly
dependent on total runoff volume, however, flood peak discharge, rather than total discharge could better interpret the
difference in sediment yield across scales within runoff erosion chains. Therefore, the reliability of sediment estimation
would be improved for small and medium sediment-producing events if such variables expressing runoff variability were
introduced into indicators for soil erosion and sediment yield prediction. On the average, the increment in sediment yield
caused by per 1 m3/s increase in flood peak discharge was at least 875 times that caused by per 1 m3 increase in total
discharge in the downstream direction. Statistically, to eliminate inter scale-based scale effect on sediment discharge, the
inter-scale flood peak discharge ratio must decrease to be lower than 5‰ or the inter-scale runoff energy ratio must reduce
to be lower than 600; 4) The influence of upstream sediment-laden flow on downstream sediment output was limited and
spatial scale effect on sediment-laden flow decreased with the increasing drainage area, especially for major sedimentproducing
events with area-specific sediment yield larger than 300 t/km2. The study highlighted the event-based processspecific
characteristics of soil erosion by water flows in basin system, revealing great potentials for sediment reduction
caused by flood regulation and control. Thereby, event-based sediment control should be process-oriented and benefit
evaluation and efficiency assessment of sediment control measures should also be process-based especially for
hyperconcentrated flows. The results may be helpful to fully reveal the significance of runoff regulation systems in soil and
water conservation, and provide supports for evaluation of erosion control strategies within runoff erosion chains across
different spatial scales.