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Basin‐scale geohydrologic drought flow features of riparian aquifers in the Southern Great Plains
Author(s) -
Brutsaert Wilfried,
Lopez James P.
Publication year - 1998
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/97wr03068
Subject(s) - aquifer , structural basin , hydrology (agriculture) , hydrograph , groundwater , hydraulic conductivity , geology , phreatic , environmental science , drainage basin , geomorphology , soil science , geography , geotechnical engineering , soil water , cartography
Low‐streamflow hydrographs from 22 subbasins in the U.S. Department of Agriculture‐Agricultural Research Service (USDA‐ARS) Washita River Experimental Watershed complex in central Oklahoma were subjected to recession slope analysis; this method, after that of Brutsaert and Nieber [1977], was derived from a Dupuit‐Boussinesq formulation for the groundwater outflows from the adjoining phreatic aquifers. The longtime aquifer response characteristics were generally found to be close to linear, and the short‐time response characteristics were consistent with Boltzmann similarity. Representative values of the resulting basin‐scale effective groundwater parameters were (35 days) −1 for the low‐flow extinction coefficient (i.e., a storage half‐life of 25 days); 0.021 m 2 s −1 for the hydraulic diffusivity, D h ; 0.0035 m 2 s −½ for the hydraulic desorptivity, De h ; 8 × 10 −4 ms −1 for the hydraulic conductivity k ; and 0.018 for the drainable porosity (or specific yield), ƒ. The variabilities of D h , De h , and k from basin to basin could be better represented by the log‐normal than by the normal distribution; ƒ could be described nearly equally well by both. The storage half‐life is moderately and positively correlated with basin size; in the case of k the correlation is negative but weaker. Any scale dependence of D h , De h , and ƒ appears to be negligible.