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Titel |
Uncertainty of solute flux estimation in ungauged small streams: potential implications for input-output nutrient mass balances at stream reach scale |
VerfasserIn |
A. Butturini |
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 ; 9, no. 6 ; Nr. 9, no. 6 (2005-12-31), S.675-684 |
Datensatznummer |
250007146
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Publikation (Nr.) |
copernicus.org/hess-9-675-2005.pdf |
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Zusammenfassung |
Input-output mass balances within stream reaches provide in situ estimates of
stream nutrient retention/release under a wide spectrum of hydrological
conditions. Providing good estimates of the mass balances for nutrients
depends on precise hydrological monitoring and good chemical characterisation
of stream water at the input and output ends of the stream reach. There is a
need to optimise the hydrological monitoring and the frequencies of water
sampling to yield precise annual mass balances, so as to avoid undue cost -
high resolution monitoring and subsequent chemical analysis can be labour
intensive and costly. In this paper, simulation exercises were performed
using a data set created to represent the instantaneous discharge and solute
dynamics at the input and output ends of a model stream reach during a one
year period. At the output end, stream discharge and water chemistry were
monitored continuously, while the input end was assumed to be ungauged; water
sampling frequency was changed arbitrarily. Instantaneous discharge at the
ungauged sampling point was estimated with an empirical power model linking
the discharge to the catchment area (Hooper, 1986). The model thus
substitutes for the additional gauge station. Simulations showed that 10 days
was the longest chemical sampling interval which could provide reach annual
mass balances of acceptable precision. Presently, the relationship between
discharge and catchment area is usually assumed to be linear but simulations
indicate that small departures from the linearity of this relationship could
cause dramatic changes in the mass balance estimations. |
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