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| Titel |
A Geomorphological Interpretation of the Power Law Relations Connected with Recession Curves |
| VerfasserIn |
Basudev Biswal, Marco Marani |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250051359
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| Zusammenfassung |
| By assuming that in the recession phase the flow rate, q, per unit length of the network and
the rate, c, at which the length of the drainage network decreases because of its progressive
desaturation, are constant in space and time, it has been argued that the exponent α in the
power law -dQ-dt = kQα (where Q is the discharge at the outlet at time t) comes from the
geomorphologic power law relationship N(l) - G(l)α, where N(l) is the number of channel
links located at a distance l from their respective channel heads, G(l) is the total length of the
channel links in the network located at a distance greater than or equal to l from the channel
heads. The parameter k varies from one event to another, implying that there is no unique
relationship between discharge and volume of water stored within the basin. We show here
that k depends on the hydrograph peak discharge (Qp) according to a power law:
k - Qp-γ, and the power law exponent γ is found to be linearly related to α. This
implies that -dQ-dt vs. Q curves of a basin can collapse into a single curve, say
Q*.
Introducing n(l) = N(l)-A and g(l) = G(l)-A, we show that n(l) vs. g(l)
plots for different basins collapse onto a single curve. This finding supports the
hypothesis made earlier by Shreve that link magnitude or number of first order
channels of a basin is linearly related with its area. Also, we find that a similar collapse
can be obtained for recession hydrographs of different basins once the specific
discharge u = Q*-A is defined. Our findings provide a rather general observational and
theoretical framework to interpret recession curves and their relation with basin
morphology. |
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