Tesis doctoral de Joaquin Jiménez Martínez
In the past decades a large body of literature has focused on the assessment of the natural recharge and parameters of control (including climate, vegetation, soils, and topography). On the contrary, only few papers focused on aquifer recharge from intensively irrigated farmland. Although findings have improved the understanding of recharge phenomena, they still fail to characterize many features of aquifer recharge from the mentioned land use. In this context, the aims of this thesis are: (i) to improve the understanding of aquifer recharge from intensively irrigated farmland, and (ii) to provide new tools for its characterization. Also, this thesis provides a framework that can be easily used by practitioners to infer quantitative information. field tests, including different crop types and agricultural management, were carried out in the campo de cartagena area of southeast spain, a semi-arid region where intensive irrigated agriculture is prevalent. The development of methodologies, with field observations in both saturated and unsaturated media, along with the application of numerical modelling were used to understand the processes governing the recharge from irrigated farmland. The developed approaches can be summarized as follows: – a field experiment with annual row crops and drip irrigation. Soil moisture dynamics through the root zone and below were simulated from unsaturated flow approach. Soil moisture and pressure head data at different depths were recorded along six hundred days for model calibration and prediction. – a tracer test (tritium) in field along four hundred thirty days. The test was carried out in an experimental plot with drip irrigation and annual row crops. The tracer transport in soil was simulated considering a multiphase approach. Tracer concentration profiles, from a limited and sparse number of destructive samples, were used to calibrate and validate the modelling approach. – a long-term field experiment (based on nine hydrologic years) for different crop types, annual row crops, perennial vegetables and fruit trees. The recharge produced from each crop type was estimated from a water balance approach, including soil, vadose zone and aquifer. Water table fluctuations, recorded along the mentioned period, were used for model calibration and predictions. This long- term approach permits to evaluate recharge estimates reliability of the two previous methodologies (short-term) for the type of crop overlapped (annual row crops). for the three approaches, ground cover and root depth are assumed as upper boundary conditions. Evapotranspiration is allocated to evaporation and transpiration as a function of leaf-area-index and is limited by soil moisture content; transpiration is distributed through the soil profile as a function of soil moisture and root depth. similar recharge values have been obtained from the three techniques, although the unsaturated flow approach slightly overestimates values. Actual evapotranspiration was always lower than potential evapotranspiration, because soil moisture was insufficient to sustain the potential uptake, despite high irrigation frequency. Although the agricultural practices from farmers are sound, high irrigation efficiency, high recharge values are achieved. Rainfall is unevenly distributed into a few intensive events, likewise very common in semi-arid regions, and it meaningfully contributes to deep percolation, due to consistently high soil water content.
Datos académicos de la tesis doctoral «Aquifer recharge from intensively irrigated farmland. several approaches«
- Título de la tesis: Aquifer recharge from intensively irrigated farmland. several approaches
- Autor: Joaquin Jiménez Martínez
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 06/07/2010
Dirección y tribunal
- Director de la tesis
- Lucila Candela Lledó
- Tribunal
- Presidente del tribunal: emilio Custodio gimena
- Rafael Angulo jaramillo (vocal)
- asaf Pekdeger (vocal)
- Jesús Carrera ramírez (vocal)