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| Titel |
Analyzing streamflow changes: irrigation-enhanced interaction between aquifer and streamflow in the Republican River basin |
| VerfasserIn |
R. Zeng, X. Cai |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 2 ; Nr. 18, no. 2 (2014-02-10), S.493-502 |
| Datensatznummer |
250120272
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| Publikation (Nr.) |
 copernicus.org/hess-18-493-2014.pdf |
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| Zusammenfassung |
| Groundwater-fed irrigation has altered surface and groundwater interactions
in the Republic River basin (RRB) in the midwestern United States, where
agriculture heavily depends on irrigation. The decreasing flow trend
recorded at the RRB gauging station since the 1950s reflects the synthetical
effect of dynamic interactions between surface water and groundwater
systems, which has been enhanced by groundwater pumping and irrigation
return flow. This study uses a systematic modeling approach to analyze the
conjunctive effects of pumping and return flow on streamflow. A watershed
management model, the Soil and Water Assessment Tool (SWAT), is modified and
established for the Frenchman Creek basin (FCB), a subbasin of RRB, to
examine the causes of streamflow changes. The baseflow component in SWAT is
linked to aquifer storage so that the model can simulate the combined
effects of groundwater pumping and irrigation return flow on natural
streamflow. Results show that irrigation has not only depleted streamflow
but also changed the flow pattern and seasonal variability. The changes can
be decomposed into decrease in the slow component (baseflow) and increase in
the fast components (surface and subsurface flow). Since the fast components
are subject to higher variability than the slow component, the annual
streamflow variability is amplified. Agricultural water use in this region
also has changed the groundwater storage seasonal regime from the pattern of
"summer recharge and winter discharge" in the past to "summer discharge
and winter recharge" at present. This challenges the existing groundwater
modeling, which usually assumes fixed recharge pattern and rates. |
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