IPAF NOA | Fil: Garcia, Jose Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación y Desarrollo Tecnológico para la Agricultura Familiar Región NOA; Argentina

El control de la calidad de las aguas ha sido objeto de atención reciente por parte de los responsables de la política medioambiental española (Ministerio de Obras Públicas y Urbanismo, 1983). En la actualidad, la calidad de las aguas prepotable es analizada y controlada por la red integral de la calidad de las aguas (red ICA) gestionada por las Confederaciones Hidrográficas. A lo largo de los distintos cauces de los ríos, han sido ubicadas una serie de estaciones de aforo y medición, a fin de realizar análisis periódicos sobre distintos parámetros que determinan la posible potabilidad -y, consecuentemente, la posible contaminación- de sus aguas. El presente trabajo analiza la situación de dos de estas estaciones de medición dependientes de la Confederación Hidrográfica del Júcar, situadas en el canal Júcar-Turia. Controlan la calidad del agua prepotable, que es la destinada al consumo final de la población y que, por lo tanto, exige un seguimiento de los patrones mínimos legalmente establecidos para su uso final. El objetivo pretendido en este trabajo es doble: por una parte, constatar la igualdad -en cuanto a la calidad del agua se refiere- del agua circulante por ambas estaciones; por otra parte, establecer si a lo largo del período estudiado (1994 a 2001) son apreciables las diferencias encontradas en la evolución de los parámetros medidos o si, por el contrario, durante esos años los parámetros medidos pueden considerarse estadísticamente iguales.

The following research presents the development of modern methods of regulating the flow of water adapted to the dynamic characteristics of a canal systems, in order to reduce the water losses caused by operation and make the management of delivery water for irrigation more efficient. This study is based on the case of the main network of La Begona Irrigation District, located in Guanajuato, Mexico. In this research an adaptive control in the regulation of 3 pools of the main canal is stablished, adjusting the setting of the gate in each pool in proportional form to the error existing between the flow or level upstream and its target level and in proportional-integral form to the error existing between the flow or level downstream the reach and its value of reference; in addition, a precompensation is used for the change in the operating conditions. This outline was proven in regulation, varying the outflow on one of the lateral offtakes on each reach; the precompensation working is shown during a change in the demand for irrigation. The results are achieved in simulation with a simple model of adaptive control; becoming thus, a solution to the problem of the regulation of the flow of water in canals for irrigation. | En este trabajo se presenta el desarrollo de metodos modernos de regulacion de flujo del agua adaptados a las caracteristicas dinamicas de un sistema de canales, con el objeto de reducir las perdidas por operacion y hacer mas eficiente el manejo del agua conducida para riego. El estudio se desarrolla tomando como caso la red principal del Distrito de Riego No. 085 La Begona ubicado en el Estado de Guanajuato, Mexico. Se establece, en esta investigacion, un control de tipo adaptable en la regulacion de 3 tramos del canal principal, ajustando la posicion de la compuerta aguas arriba de cada tramo en forma proporcional al error existente entre el caudal o tirante aguas arriba y su nivel de referencia y en forma proporcional e integral al error existente entre el caudal o tirante aguas abajo del tramo y su valor de referencia; adicionalmente, se usa una precompensacijon para el cambio en las condiciones de operacion. El esquema fue probado en regulacion, variando las extracciones sobre una de las tomas laterales en cada tramo; el funcionamiento de la precompensacion se ilustra mostrando su desempeno ante un cambio en la demanda de riego. Los resultados son obtenidos en simulacion con un modelo sencillo de control adaptable, constituyendo este una solucion al problema de la regulacion del flujo de agua en canales para riego.

El control de la calidad de las aguas ha sido objeto de atenci.n reciente por parte de los responsables de la pol.tica medioambiental espa.ola (Ministerio de Obras P.blicas y Urbanismo, 1983). En la actualidad, la calidad de las aguas prepotable es analizada y controlada por la red integral de la calidad de las aguas (red ICA) gestionada por las Confederaciones Hidrogr.ficas. A lo largo de los distintos cauces de los r.os, han sido ubicadas una serie de estaciones de aforo y medici.n, a fin de realizar an.lisis peri.dicos sobre distintos par.metros que determinan la posible potabilidad -y, consecuentemente, la posible contaminaci.n- de sus aguas. El presente trabajo analiza la situaci.n de dos de estas estaciones de medici.n dependientes de la Confederaci.n Hidrogr.fica del J.car, situadas en el canal J.car-Turia. Controlan la calidad del agua prepotable, que es la destinada al consumo final de la poblaci.n y que, por lo tanto, exige un seguimiento de los patrones m.nimos legalmente establecidos para su uso final. El objetivo pretendido en este trabajo es doble: por una parte, constatar la igualdad -en cuanto a la calidad del agua se refiere- del agua circulante por ambas estaciones; por otra parte, establecer si a lo largo del per.odo estudiado (1994 a 2001) son apreciables las diferencias encontradas en la evoluci.n de los par.metros medidos o si, por el contrario, durante esos a.os los par.metros medidos pueden considerarse estad.sticamente iguales.

This Master Thesis is a study of different aspects of water resource management in the project of “Riegos del Alto Aragón”, the largest irrigation project in Spain and even Europe. The main objective is to analyze the basic functioning of irrigation infrastructures and their interactions, and the changes they have experienced as a result of the so-called modernization of irrigation. The study area is located between the Huesca and Zaragoza provinces in Aragon, Spain, with a semiarid climate where rainfed agriculture faces low productivity and a large uncertainty in the crops. So, since the mid nineteenth century there is a growing demand for the use of the discharge of the Pyrenean Rivers (Gállego and Cinca). Finally, the Riegos del Alto Aragón project was approved in 1915 although it has not yet finished actually. Since then, a complex infrastructure has been slowly developed, trying to supply water to 300.000 hectares according to the initial project, although much later revisions have lowered the expectations. In 2012 more than 120,000 irrigated hectares have been transformed, contributing very significantly to the increase in crop productivity and diversity, as well as the landscape and economic diversification affecting to a territory larger than the irrigated area. For this reason several dams have been built, with their smaller ditches, small internal reservoirs and, irrigation reservoirs with their pumping stations, a complex infrastructure network reflecting the purpose of transforming the space and the use of water in the most efficient way. The analysis of the management of water infrastructure (dams and canals), allows us to conclude that in wet years there are no restrictions on irrigation water demand, whereas in dry years, water scarcity at the beginning of the irrigation season (March) forces to establish a quota system limiting the number of cubic meters per hectare available for each farmer. This means that farmers have to adopt critical decisions when choosing crops and surfaces to be irrigated. Also, the study of the typology of the irrigated area in Riegos del Alto Aragón demonstrates the existence of two groups. (i) On one side, the ancient irrigation systems are the first that have been transformed in the 1950’s, 1960’s and 1970’s, dominated by small parcels sometimes bench-terraced, dominated by winter cereals and overflowing irrigation systems. (ii) On the other hand, there are modern or modernized irrigated areas that have been launched in the 1990’s and 2000’s. They are characterized by large parcels (due to land concentration), disappearance of terraces, with a predominance of pressurized irrigation systems and crops with high demand of water and with high yields (corn, alfalfa, rice ...). Therefore, as a result of modernization, water management has resulted in profound changes. For instance, water distribution is handled automatically and from distance through new technologies and softwares (ADOR). Nevertheless, modernization faces to some limitations, among which we must underline the wind in the case of sprinkler irrigation systems, farming part-time, high investment costs for the conversion to pressurized irrigation systems, and rising costs of the energy required for the functioning of the system. An important aspect in which we have placed special emphasis is the need of the construction of irrigation ponds, which are essential in the process of modernization. The ponds are used to store water and to send the pressurized water to the fields, either by gravity or by pumping systems. In addition, the ponds have increased the flexibility in the efficiency of the water use. Among the problems to which the project of the Riegos del Alto Aragón faces, we have to highlight the high costs of modernization, the elevated energy costs and the rising difficulties to regulate the rivers Cinca and Gállego, which calls into question the expansion of irrigation to the southern face of the Sierra de Alcubierre. On the other hand, the system faces several uncertainties regarding the potential effects of climate change. The current and future increases in temperature increases the water needs of crops coinciding with a moment when there is a trend to decreasing water resources, due to the hydrological effect of the expansion of shrubs and forests in mountain areas as a result of depopulation, lower livestock pressure and the abandonment of crops on hillsides