 |
| Titel |
SCS-CN parameter determination using rainfall-runoff data in heterogeneous watersheds – the two-CN system approach |
| VerfasserIn |
K. X. Soulis, J. D. Valiantzas |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 3 ; Nr. 16, no. 3 (2012-03-28), S.1001-1015 |
| Datensatznummer |
250013224
|
| Publikation (Nr.) |
 copernicus.org/hess-16-1001-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Soil Conservation Service Curve Number (SCS-CN) approach is widely used
as a simple method for predicting direct runoff volume for a given rainfall
event. The CN parameter values corresponding to various soil, land cover,
and land management conditions can be selected from tables, but it is
preferable to estimate the CN value from measured rainfall-runoff data if
available. However, previous researchers indicated that the CN values
calculated from measured rainfall-runoff data vary systematically with the
rainfall depth. Hence, they suggested the determination of a single
asymptotic CN value observed for very high rainfall depths to characterize
the watersheds' runoff response. In this paper, the hypothesis that the
observed correlation between the calculated CN value and the rainfall depth
in a watershed reflects the effect of soils and land cover spatial
variability on its hydrologic response is being tested. Based on this
hypothesis, the simplified concept of a two-CN heterogeneous system is
introduced to model the observed CN-rainfall variation by reducing the CN
spatial variability into two classes. The behaviour of the CN-rainfall
function produced by the simplified two-CN system is approached
theoretically, it is analysed systematically, and it is found to be similar
to the variation observed in natural watersheds. Synthetic data tests,
natural watersheds examples, and detailed study of two natural experimental
watersheds with known spatial heterogeneity characteristics were used to
evaluate the method. The results indicate that the determination of CN
values from rainfall runoff data using the proposed two-CN system approach
provides reasonable accuracy and it over performs the previous methods based
on the determination of a single asymptotic CN value. Although the suggested
method increases the number of unknown parameters to three (instead of one),
a clear physical reasoning for them is presented. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|