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421.
Richard M. Vogel Neil M. Fennessey 《Journal of the American Water Resources Association》1995,31(6):1029-1039
ABSTRACT: A streamflow duration curve illustrates the relationship between the frequency and magnitude of streamflow. Flow duration curves have a long history in the field of water-resource engineering and have been used to solve problems in water-quality management, hydropower, instream flow methodologies, water-use planning, flood control, and river and reservoir sedimentation, and for scientific comparisons of streamflow characteristics across watersheds. This paper reviews traditional applications and provides extensions to some new applications, including water allocation, wasteload allocation, river and wetland inundation mapping, and the economic selection of a water-resource project. 相似文献
422.
Bruce Anderson Donald F. Potts 《Journal of the American Water Resources Association》1987,23(4):681-690
ABSTRACT: Forest management activities in a second order drainage basin increased suspended sediment yields 7.7 fold in the first year following road construction, and two-fold following logging in the second year. Sediment supply limitations resulted in poor correlations between sediment concentrations with discharge. Sediment transport was strongly hysteretic, with the highest sediment concentrations occurring on the rising limbs of snowmelt hydrographs and individual peaks. In addition to discharge, hydrograph characteristics such as limb, dQ/dt, and the product of dQ/dt and limb aided in explaining variability of observed sediment concentrations. Sediment-turbidity relationships were strongly discharge dependent, reflecting the changing composition of the suspended load with stream power and sediment supplies. 相似文献
423.
东海特定海区沉积物-水界面附近P释放的实验研究 总被引:1,自引:0,他引:1
以采自长江口外东海表层沉积物为对象,对不同类型的沉积物在模拟海水环境中进行了释P实验。研究表明,在静态条件下,沉积物释P量的高点出现在摇晃后10min左右,大约3h后基本趋于平衡。释P动力学可用Elovich公式与双常数速率公式进行拟合。最大释P量与沉积物的组成密切相关,以粉砂、粘土为主的沉积物释P量高,而砂质为主者释P量低。在释P实验中,铁磷(Fe-P)最为活跃,释放比例最高,其次是吸附态磷(Ad-P)和有机态磷(OP)。它们均属于生物可获得P的范畴。实验结果表明,在合适的水动力条件下,沉积物中的P可以迅速释放到水体.并影响水体的营养状杰和初级生产力。 相似文献
424.
王建富 《石油化工环境保护》2002,25(4):35-40
使用有害烟雾去除中试装置处理腈纶纺丝组件处理过程中产生的硝酸蒸汽和氮氧化物,对中试实验的方法及结果进行了简要介绍。 相似文献
425.
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427.
Brian P. Bledsoe Chester C. Watson David S. Biedenharn 《Journal of the American Water Resources Association》2002,38(3):861-870
ABSTRACT: Incised channels are caused by an imbalance between sediment transport capacity and sediment supply that alters channel morphology through bed and bank erosion. Consistent sequential changes in incised channel morphology may be quantified and used to develop relationships describing quasi‐equilibrium conditions in these channels. We analyzed the hydraulic characteristics of streams in the Yazoo River Basin, Mississippi in various stages of incised channel evolution. The hydraulic characteristics of incising channels were observed to follow the sequence predicted by previous conceptual models of incised channel response. Multiple regression models of stable slopes in quasi‐equilibrium channels that have completed a full evolutionary sequence were developed. These models compare favorably with analytical solutions based on the extremal hypothesis of minimum stream power and empirical relationships from other regions. Appropriate application of these empirical relationships may be useful in preliminary design of stream rehabilitation strategies. 相似文献
428.
James E. Evans Norman S. Levine Sheila J. Roberts Johan F. Gottgens Diane M. Newman 《Journal of the American Water Resources Association》2002,38(6):1549-1565
ABSTRACT: The proposed removal of Ballville Dam was assessed by (1) using a new Geographic Information Systems (GIS) based method for calculating reservoir sediment storage, (2) evaluating sediment properties and contamination from core data, and (3) assessing downstream impacts from sediment routing calculations. A 1903 (pre‐dam) map was manipulated using GIS to recreate the reservoir bathymetry at time of dam construction and used in combination with a detailed 1993 bathymetric survey to calculate sediment volumes and thickness. Reservoir sediment properties and geochemistry were determined from 14 sediment vibracores. Annual sedimentation rates varied from 1.7 to 4.3 g/cm2/yr based on Cesium‐137 (137Cs) and Lead‐210 (210Pb) geochronology and dated flood layers. The pore fluid geochemistry (Ba, Co, Cu, Mn) of four cores showed surficial enrichments in Cu, while Co and Mn show secondary peaks within the sediments. GIS calculations showed that a designed channel through the former reservoir able to accommodate the 10 percent Probable Maximum Flood (PMF) would require removing approximately 0.35 million m3 of sediment (27 percent of the reservoir fill), either by dredging at a cost of up to $6.3 million or by releasing fine grained sediment downstream. A sediment routing model was applied for the critical 6 km downstream using four cross sections. The sediment routing model predicts that, for flows exceeding minimum Mean Daily Flow (1924 to 1998 data), greater than 90 percent of this sediment would be transported through downstream reaches into Lake Erie (Sandusky Bay). 相似文献
429.
430.
地质屏障对有害物质的防护性能取决于地质屏障的岩石性质、水文地质特征以及污染物本身的物理化学性质。为了了解污泥填埋场表层土壤性质、土壤渗透性能及对特征污染物的吸附和截留情况,实验工程以克拉玛依白碱滩六九区及81#污水处理站废水及所产生的污泥为实例,以六九区污水处理站污水贮存塘区为试验场地,实施现场渗水试验,并对该试验场地不同剖面、不同层位的土壤吸附参数进行测定,以评价地质屏障的防护作用,在满足环境保护的前提条件下,尽量减少工程投入,使污泥填埋工程及投资在社会、环境及经济三方面更趋合理、可行。 相似文献