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Estimating groundwater evapotranspiration from streamflow records
Author(s) -
Daniel James F.
Publication year - 1976
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/wr012i003p00360
Subject(s) - groundwater recharge , aquifer , outflow , streamflow , evapotranspiration , hydrology (agriculture) , geology , groundwater , hydrograph , structural basin , drainage basin , environmental science , geomorphology , geography , geotechnical engineering , ecology , oceanography , cartography , biology
Methods for determining groundwater outflow from a drainage basin following sudden or constant recharge were presented by Rorabaugh in 1964. He then developed, but did not publish, a method for computing outflow from an aquifer underlain by a leaky boundary. This method can be extended to determine outflow from an aquifer subjected to constant evapotranspiration (ET). The unaffected aquifer outflow (streamflow) recession following recharge becomes a straight line on a semilogarithmic graph after sufficient time has elapsed. The slope of this recession is, in logarithm to base 10 form, − Tt /0.933 a 2 S , where T and S are the transmissivity and storage coefficient of the aquifer, a is the distance from the stream to the groundwater divide, and t is the time since recharge occurred (sudden case) or began (constant case). A set of dimensionless type curves are developed for the case of constant ET (leakage) which diverge from and lie below the unaffected case. Streamflow records for the basin, Indian Creek near Troy, Alabama, were analyzed by using the method described. A constant ET rate of 0.037 m 3 /s was computed for the 23.00‐km 2 basin during the period April through June 1963.