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| Titel |
Uncertainty of natural tracer methods for estimating river-aquifer exchange flux in the Heihe River, northwest China |
| VerfasserIn |
Yueqing Xie, Peter Cook, Margaret Shanafield, Craig Simmons, Chunmiao Zheng |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250122505
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| Publikation (Nr.) |
 EGU/EGU2016-1552.pdf |
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| Zusammenfassung |
| Reliable estimation of river-aquifer exchange flux is critical to the conjunctive management
of surface water and groundwater, especially in the arid and semiarid regions where potential
evapotranspiration is much higher than precipitation. A number of natural tracer methods are
available to estimate river-aquifer exchange flux at different spatial scales. However, these
methods have primarily been applied to rivers with relatively low flow rates (mostly less
than 5 m3 s−1). In this study, several natural tracers including heat, radon-222 and
electrical conductivity were used to quantify river-aquifer exchange flux at both point
and regional scales in the Heihe River, northwest China with a large flow rate (63
m3 s−1). These tracers were measured both on vertical riverbed profiles and on
longitudinal river samples. Results show that the radon-222 profile method can
estimate a narrower range of point-scale river-aquifer flux than the temperature profile
method. However, three vertical radon-222 profiles failed to estimate the upper bounds
of plausible flux ranges. Results also show that when quantifying regional-scale
river-aquifer exchange flux, the river chemistry method constrained the flux (5.20 – 10.39
m2 d−1) better than the river temperature method (-100 – 100 m2 d−1). The river
chemistry method also identified spatial variation in the flux, whereas the river
temperature method did not have sufficient resolution. Overall, for quantifying
river-aquifer exchange flux in a large river such as the Heihe River, both the temperature
profile method and the radon-222 profile method provide useful complementary
information at the point scale to complement each other, whereas the river chemistry
method is recommended over the river temperature method at the regional scale. |
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