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Factors affecting the measurement of the vertical hydraulic conductivity of a streambed sediment using standpipe tests
Author(s) -
Huang Yong,
Zhou Zhifang,
Guo Qiaona,
Tang Yuzhou,
Lu Wenlong
Publication year - 2013
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.10003
Subject(s) - hydraulic conductivity , hydraulic head , head (geology) , sediment , hydrology (agriculture) , stage (stratigraphy) , geology , environmental science , geotechnical engineering , soil science , geomorphology , soil water , paleontology
The vertical hydraulic conductivity ( K v ) of a stream or lake sediment is often determined in the field using standpipe tests. Calculation of K v is based on the assumption that the hydraulic head in the pipe is equal to that of the stream or lake stage. In this work, a modified equation for K v is developed for the standpipe test which is applicable when this assumption is not valid. The equation involves not only the hydraulic head at different times but also the difference in the hydraulic head ( a ) between the groundwater level and river stage. The effects of certain factors on K v , such as the ratio of the hydraulic head at different times ( h 1 / h 2 ), the difference a , and the initial water table height ( h 0 ), are also discussed. The results show that when h 1 / h 2 is constant, the relative error ( E r ) in K v increases with the ratio a / h 2 . Furthermore, if a / h 2 < 0.05, then for any value of h 1 / h 2 , E r is less than 5% using the modified equation. Also, if a / h 2 is large, hydraulic head readings with larger h 1 / h 2 ratios must be used to avoid large E r values. The results of a field test also indicate that the error in K v decreases as the value of h 0 increases. Copyright © 2013 John Wiley & Sons, Ltd.