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| Titel |
A conceptual model of check dam hydraulics for gully control: efficiency, optimal spacing and relation with step-pools |
| VerfasserIn |
C. Castillo, R. Pérez, J. A. Gómez |
| 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. 5 ; Nr. 18, no. 5 (2014-05-12), S.1705-1721 |
| Datensatznummer |
250120353
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| Publikation (Nr.) |
 copernicus.org/hess-18-1705-2014.pdf |
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| Zusammenfassung |
| There is little information in scientific literature regarding the
modifications induced by check dam systems in flow regimes within restored
gully reaches, despite it being a crucial issue for the design of gully
restoration measures. Here, we develop a conceptual model to classify flow
regimes in straight rectangular channels for initial and dam-filling
conditions as well as a method of estimating efficiency in order to provide
design guidelines. The model integrates several previous mathematical
approaches for assessing the main processes involved (hydraulic jump, impact
flow, gradually varied flows). Ten main classifications of flow regimes were
identified, producing similar results when compared with the IBER model. An
interval for optimal energy dissipation (ODI) was observed when the steepness
factor c was plotted against the design number (DN, ratio between the
height and the product of slope and critical depth). The ODI was
characterized by maximum energy dissipation and total influence conditions.
Our findings support the hypothesis of a maximum flow resistance principle
valid for a range of spacing rather than for a unique configuration. A value
of c = 1 and DN ~ 100 was found to economically meet the ODI
conditions throughout the different sedimentation stages of the structure.
When our model was applied using the same parameters to the range typical of
step-pool systems, the predicted results fell within a similar region to that
observed in field experiments. The conceptual model helps to explain the
spacing frequency distribution as well as the often-cited trend to lower c
for increasing slopes in step-pool systems. This reinforces the hypothesis of
a close link between stable configurations of step-pool units and man-made
interventions through check dams. |
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