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| Content Provider | Springer Nature Link |
|---|---|
| Author | Walker, Glen R. Zhang, Lu Ellis, Tim W. Hatton, Tom J. Petheram, Cuan |
| Copyright Year | 2002 |
| Abstract | To manage dryland salinity, one needs to know how changed land use affects groundwater recharge. Few techniques are available for comparing 'deep drainage' under different land uses. Soil-tracer methods, although good for replication and remote field sites, are subject to spatial variability. Lysimeters are good for comparisons but are difficult for drier areas and sloping land. Agronomic water-balance studies, where appropriate soil-water measurements exist, may be used with a soil-vegetation model to estimate long-term deep drainage. Complex models are required to analyze specific land-use differences, such as perenniality and root and leaf area dynamics, but models require intensive and extensive data for calibration. This approach is time-consuming, labour-intensive, and difficult in remote locations. Because of the one-dimensionality of most soil-vegetation models and the small fraction of the total water balance that is deep drainage, little success has occurred in extrapolating beyond the research plot, or to spatially heterogeneous systems such as alley farming. Some 'top-down' modelling and landscape disaggregation approaches have been partially successful in making catchment or regional-scale predictions. The direction for further work depends on the level of recharge reduction that is required for most groundwater systems and difficulties that it imposes. Pour contrôler la salinité des terres sèches, on a besoin de connaître comment le changement d'occupation du sol affecte la recharge de la nappe. Peu de techniques permettent de comparer le «drainage profond» sous des occupations des sols différentes. Bien qu'elles soient adaptées pour être reproduites et appliquées à des sites de terrain éloignés, des méthodes basées sur les traceurs des sols sont sujettes à une variabilité spatiale. Les lysimètres conviennent pour faire des comparaisons, mais sont difficiles à utiliser en régions sèches et sur les versants pentus. Les études agronomiques de bilan d'eau, lorsqu'il existe des mesures appropriées d'eau dans le sol, peuvent être utilisées avec un modèle de sol et de végétation pour estimer le drainage profond à long terme. Des modèles complexes sont nécessaires pour analyser les différences spécifiques d'occupation des sols, telles que la pérennité et la dynamique de la zone racinaire et foliaire, mais les modèles ont besoin de données intensives et extensives pour les calibrer. Cette approche prend du temps, demande un travail intensif et est difficile dans les régions éloignées. À cause de la dimension unique prise en compte dans la plupart des modèles de sol et de végétation et de la petite part du bilan hydrique total représenté par le drainage profond, il y a peu de chance d'extrapoler au-delà de ce point d'étude ou pour des systèmes hétérogènes tels que les cultures en alignement. Certaines approches de modélisation du haut vers le bas et de désagrégation de paysage ont donné des résultats en partie intéressants pour faire des prévisions à l'échelle régionale ou du bassin. L'orientation des futurs travaux dépend du niveau de réduction de la recharge qui est recherché pour la plupart des systèmes aquifères et des difficultés que cela impose. Con objeto de gestionar la salinidad en terrenos áridos, se requiere conocer cómo la modificación de los usos del suelo afecta a la recarga de un acuífero, pero existen pocas técnicas que permitan comparar el 'drenaje en profundidad' en función de dichos usos. Los trazadores del suelo sirven para emplazamientos remotos y para reproducir datos, pero están sujetos a la variabilidad espacial. Los lisímetros son útiles para hacer este tipo de comparaciones, pero no se muestran tan eficaces en zonas más secas y agrestes. Los balances agronómicos de agua pueden ser aplicados con un modelo de vegetación del suelo para estimar el drenaje profundo a largo término, siempre y cuando se disponga de las medidas adecuadas de humedad en el suelo. Se necesita modelos complejos para analizar las diferencias específicas en los usos del suelo, tales como el carácter perenne y la dinámica de raíces y hojas, si bien estos requieren datos intensivos y extensivos para poder calibrarlos. Este enfoque exige más tiempo y trabajo, y resulta difícil de usar en zonas alejadas. Debido al comportamiento unidimensional de la mayoría de modelos de vegetación-suelo y a la pequeña fracción del balance de agua que se convierte en recarga, no se ha obtenido resultados satisfactorios a la hora de extrapolar los resultados de una investigación puntual, ni tampoco en sistemas espacialmente heterogéneos, como la plantación en hileras. Se ha logrado resultados aceptables por medio de modelos 'de arriba abajo' y de métodos de desagregación del paisaje a la hora de hacer predicciones a escala de cuenca o regional. Las líneas futuras de trabajo dependerán del nivel de reducción de la recarga que se necesite para la mayoría de los sistemas de aguas subterráneas, así como de las dificultades que esto suponga. |
| Starting Page | 68 |
| Ending Page | 90 |
| Page Count | 23 |
| File Format | |
| ISSN | 14312174 |
| Journal | Hydrogeology Journal |
| Volume Number | 10 |
| Issue Number | 1 |
| e-ISSN | 14350157 |
| Language | English |
| Publisher | Springer-Verlag |
| Publisher Date | 2002-01-18 |
| Publisher Institution | International Association of Hydrogeologists |
| Publisher Place | Berlin, Heidelberg |
| Access Restriction | One Nation One Subscription (ONOS) |
| Subject Keyword | Hydrogeology Hydrology/Water Resources Geology Waste Water Technology Water Pollution Control Water Management Aquatic Pollution |
| Content Type | Text |
| Resource Type | Article |
| Subject | Earth and Planetary Sciences Water Science and Technology |
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