Statistical and geostatistical features of streambed hydraulic conductivities in the Platte River, Nebraska
Statistical and geostatistical features of streambed hydraulic conductivities in the Platte River, Nebraska
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DOI：
10.1007/s00254-005-0007-1
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发表时间：
2005-07
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影响因子：
--
通讯作者：
Xunhong Chen
中科院分区：
文献类型：
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作者：
Xunhong Chen
本文介绍了从内布拉斯加州中南部到东部的普拉特河的河床水力传导率。水力传导率是用渗透试验从河道中确定的。垂直水力传导率（千伏）从七个测试点沿着这条河在内布拉斯加州中南部属于一个统计人口。其平均值为40.2m/d。然而，沿沿着四个样带的阿什兰试验场在内布拉斯加州东部有较低的平均值，是统计学上不同于theKv值在内布拉斯加州中南部，属于两个不同的群体，平均值分别为20.7和9.1 m/d。从卢普河和埃尔克霍恩河流域到普拉特河东部河段的细沉积物降低了河床的垂直水力传导率。水深与Kv值沿试验断面沿着的相关系数表明，正相关，较大的Kv值通常出现在水深较深的部分。实验变异函数来自几个断面的垂直水力传导率跨渠道的普拉特河显示周期性的空间相关性，这可能是由于周期性变化的水深跨渠道。桑迪至砾石河床包含非常局部的粉土和粘土层;在河道中未观察到空间连续的低渗透性河床。同一试验点的水平导水率大于垂直导水率。
This paper presents streambed hydraulic conductivities of the Platte River from south-central to eastern Nebraska. The hydraulic conductivities were determined from river channels using permeameter tests. The vertical hydraulic conductivities (Kv) from seven test sites along this river in south-central Nebraska belong to one statistical population. Its mean value is 40.2 m/d. However, the vertical hydraulic conductivities along four transects of the Ashland test site in eastern Nebraska have lower mean values, are statistically different from theKvvalues in south-central Nebraska, and belong to two different populations with mean values of 20.7 and 9.1 m/d, respectively. Finer sediments carried from the Loup River and Elkhorn River watersheds to the eastern reach of the Platte River lowers the vertical hydraulic conductivity of the streambed. Correlation coefficients between water depth andKvvalues along a test transect indicates a positive correlation – a largerKvusually occurs in the part of channel with deeper water. Experimental variograms derived from the vertical hydraulic conductivities for several transects across the channels of the Platte River show periodicity of spatial correlation, which likely result from periodic variation of water depth across the channels. The sandy to gravelly streambed contains very local silt and clay layers; spatially continuous low-permeability streambed was not observed in the river channels. The horizontal hydraulic conductivities were larger than the vertical hydraulic conductivities for the same test locations.