Tesis doctoral de Lluís Cots Rubio
A simulation model of water resources for irrigation lands has been developed and calibrated. The study area is the river corb basin, in the irrigated area of the urgell canals, with 378 km2, the 43% of the total irrigated area. The developed model can be classified as a quasi distributed deterministic mathematical model, of continuous simulation at daily level with 38 parameters. It is divided in eleven different sub areas according to their hydrologic performance, source of irrigation water, irrigation system or whether they are non irrigated or non-agricultural lands. Daily water balances are applied to the mentioned sub areas. In the phd a methodology for the estimation of the irrigation calendars is proposed for surface irrigation in order to get a time distribution of the duty daily irrigation, as well as a methodology for the effective precipitation estimation. the model has been calibrated according to the corb river registered flows for the period 2000-2002, and allows simulating them at a yearly scale with an average error of only 3.6% from the registered ones, at a monthly level with an acceptable prediction, and at a daily scale with not as good prediction. The yearly global balance closing error is low (-5.8% from the entrances), the average yearly depletion fraction is of 64% and the return fraction of 35%. Without reuse the return fraction would be 42%, showing that the water reuse degree is 7%. for the corb domain irrigated areas, and both yearly level and irrigation period, reuse performs the 18% of the water delivered by canals for farm irrigation, from which 14% comes from drainages and 4% from pumping extractions. At a quantitative level reuse involves a volume of 38.4 hm3 per year for the corb domain and of 69 hm3 per year for the whole irrigated area. at a network transport level and for the irrigation period, the mean conveyance efficiency was of 90.5%, the distribution efficiency of 90% and the system efficiency of 82%. Some of the whole urgell canals mean performance indicators are listed below. The annual irrigation water supply per unit irrigated area is of 8800 m3/ha, the annual relative water supply is of 1.5, the annual relative irrigation supply in canals origin is of 1.7 and of 1.3 in field furnished. The output per unit of irrigated area is about 3000 â,¬/ha, the estimated value of the agricultural production per unit irrigation supplied by canals on field origin is of 0.44 â,¬/m3, of 0.34 â,¬/m3 regarding to the canals origin unit irrigation supply, and of 0.28 â,¬/m3 for the previous volume plus the effective precipitation. the depleted fraction from the balances at a soil level was greater in the sub-areas with pressure irrigation (with values of 0.9) while in the sub-areas with surface irrigation ranged between 0.57 (low water retention capacity soils) and 0.65 (greater water retention capacity soils). The return fraction of the pressure irrigated areas ranged between 0.06 and 0.1, while for the surface irrigated areas was of 0.35 in deep soils and of 0.43 in soils with low capacity of water retention. It is interesting to point out that deficit irrigation was hardly produced in the irrigated areas, taking place only in non irrigated ones. the simulation of the modernization of the urgell canals irrigated area, transforming surface irrigation into pressure irrigation, would involve a decrease of the volume supplied in origin of 89 hm3. This amount must not be wrongly interpreted as saved water due to the modernization. In this way, irrigation modernization would lead to a 10% increase of the depleted fraction and a decrease of the return fraction in the same amount, thus the available downstream would decrease 22 hm3. This highlights the importance of analyzing the available water resources globally and not only the saved water in the supply system origin.
Datos académicos de la tesis doctoral «Desarrollo y calibración de un modelo de simulación de recursos hídricos aplicado a la cuenca del río corb dentro de la zona regable de los canales de urgell (lleida)«
- Título de la tesis: Desarrollo y calibración de un modelo de simulación de recursos hídricos aplicado a la cuenca del río corb dentro de la zona regable de los canales de urgell (lleida)
- Autor: Lluís Cots Rubio
- Universidad: Lleida
- Fecha de lectura de la tesis: 11/07/2011
Dirección y tribunal
- Director de la tesis
- Javier Barragan Fernandez
- Tribunal
- Presidente del tribunal: Alberto Losada villasante
- José Manuel Pascual diaz (vocal)
- Javier Samper calvete (vocal)
- Miguel angel Garcia vera (vocal)