Titre :
|
A comparison of steady-state land-drainage equations
|
Auteurs :
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C. Lovell ;
E. Youngs
|
Type de document :
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article/chapitre/communication
|
Année de publication :
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1984
|
Format :
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p. 1-21
|
Langues:
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= Anglais
|
Catégories :
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HYDROLOGIE ET HYDRAULIQUE
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Mots-clés:
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POTENTIEL HYDRIQUE
;
DRAINAGE AGRICOLE
;
EQUATION
;
PRECIPITATION ATMOSPHERIQUE
;
MATHEMATIQUES
;
DRAIN
|
Résumé :
|
The physical assumptions and mathematical approximations leading to ten steady-state drainage equations for installations of parallel cylindrical drains laid above a horizontal impermeable barrier, are critically examined. Water-table heights were calculated from the equations for a range of depths of impermeable barrier and of rainfall rates, using the drain's radius obtained by the hodograph analysis for infinite depth of soil. A consideration of the available solutions show that the water-table height is known with sufficient accuracy for small depths of impermeable barrier and for large depths, but at intermediate depths the solutions lead to an unsatisfactorily large uncertainty in its position. Of the drainage equations Houghoudt's equivalent depth equation, when used with the optimum drain radius given by the hodograph analysis for infinite soil depth, is the only one that gives results contained mainly within the known bounds that result from a consideration of the combination of equations.
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Source :
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Agricultural water management, vol. 9
|