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It has been the conventional assumption that wash load is supply limited and is only indirectly related to the hydraulics of a river. Hydraulic engineers also assumed that bed-material load concentration is independent of wash load concentration. This paper provides a detailed analysis of the Yellow River sediment transport data to determine whether the above assumptions are true and whether wash load concentration can be computed from the original unit stream power formula and the modified unit stream power formula for sediment-laden flows. A systematic and thorough analysis of 1,160 sets of data collected from 9 gauging stations along the Middle and Lower Yellow River confirmed that the method suggested by the conjunctive use of the two formulas can be used to compute wash load, bed-material load, and total load in the Yellow River with accuracy. [ABSTRACT FROM AUTHOR]

An economic valuation of flood reductions arising from land use changes induced by the Conversion of Cropland to Forest and Grassland Program (CCFGP) in China is detailed in this paper. A distributed hydrologic model is used to analyze and predict changes in the probability of flood occurrences in the Yellow River Basin (YRB) due to revegetation activities under the CCFGP. The expected value of flood reductions due to the avoided flood damage potential is then estimated. Losses brought about by each type of flood in the YRB over time and the probability change in flood occurrences are used in the calculation. Results show that the economic benefits from flood reductions will total China Yuan 362 million during 2010–2020. The inclusion of this economic benefit into a benefit-cost analysis of the CCFGP provides a more comprehensive assessment of the program. Implications for prioritizing management options to mitigate flood disasters in the YRB are drawn. [ABSTRACT FROM AUTHOR]

Base-flow separation has long been an important research topic in hydrology. In the Yellow River Basin in China, base flow is of special concern in the headwater catchments because of its importance for integrated water resources management in the basin as a whole. To quantify base flow in the headwater catchments of the Yellow River Basin for 1956–2000, the two-parameter Kalinin method has been proposed with improved implementation procedures and parametrization techniques. Results show that base flow contributes a larger proportion to streamflow in the headwater catchments than that of surface flow, but with a rather low variation. The results are consistent with that of the other two digital filter methods. Sensitivity analysis of parameter performance in the Kalinin method shows, in detail, that the hydrograph of separated base flow is sensitive to a recession constant, and the other parameter (β) is highly related to the base-flow index and the ratio of base flow against surface flow (δ). [ABSTRACT FROM AUTHOR]

The Sanmenxia Dam built in 1960 in the middle reach of the Yellow River has experienced severe sedimentation problems, not only in the reservoir area itself but also extending hundreds of kilometers in the backwater region. Morphological responses in the middle Yellow River and its tributary, the Wei River, upstream of the dam have generally lagged behind the causal changes in upstream and downstream controls. Based on the geometrical characteristics of a wedge-shaped sedimentation body, a method was derived for calculating equilibrium values of the accumulated sedimentation volume in the channel reaches. Combining the method for calculating with rate law models for channel morphological adjustment, a method for calculating the accumulated deposition volumes was derived. The results showed that the proposed method can accurately simulate sedimentation processes in the study reaches during 1960 and 2011, in the response to the integrated impacts of base level fluctuations and changes in incoming water and sediment discharges. The characteristics of the potential adjusted (equilibrium) morphology was analyzed and it is shown that while the nature of the adjusted (or equilibrium state) of the fluvial system varies dynamically with external conditions, it generally acts as the target for the observed channel adjustments, although the actual values of variables defining the fluvial system seldom adjust to their corresponding equilibrium values due to the effects of multiple disruptions, continuously varying water and sediment inputs, and delayed responses in the fluvial system. [ABSTRACT FROM AUTHOR]

The eco-hydrological requirements of a river are related to the health of the river. In recent years, changing climate and intensifying human activities have further aggravated water problems in the Yellow River. Considering hydrological changes, this study addressed the ecological water requirements of the Yellow River basin, wherein the threshold ecological water requirement corresponded to the streamflow with the largest occurrence probability determined by the Pearson Type III distribution. Instream flow ± one standard deviation was adopted as the water resource management target and abrupt changes in streamflow were detected by using the Mann-Whitney test. The results of the analysis indicated that: (1) the annual flow of the Yellow River substantially decreased after abrupt changes and the probability significantly dropped that the amount of annual streamflow satisfied the ecological instream flow requirement; and (2) the water resource management target was satisfied well after th echange point only at the Tangnaihai station, located in the upper Yellow River basin. From the upper to the lower Yellow River basins, the probability has dramatically decreased that the ecological water requirement target is satisfied. Therefore, the Yellow River basin will likely face increasingly serious water problems, particularly in the middle and lower parts. [ABSTRACT FROM AUTHOR]