Water Supply Operating Rules In Parallel Dams By Means Of Genetic Algorithms

Cutzamala system is the most important hydraulic work that the Mexico State had provided to Mexico’s center region; its objective is the water supply with at least 16 m3/s to the country’s capital, since 1974. The system consist of Tuxpan and El Bosque dams, both located in Michoacán State, and Ixtapan del Oro, Villa Victoria, Valle de Bravo, Chilesdo and Colorines dams located in Mexico State; each one belong to Cutzamala River Basin. At the Institute of Engineering of the National Autonomous University of Mexico studies have been done since the mid-90s of last century in order to obtain optimal operation rules of several reservoirs. In this study monthly operating policies for three of the most important dams of the system: El Bosque, Valle de Bravo and Villa Victoria, which operate in parallel, were obtained to supply the growing demand of water for various uses. Evolutionary algorithms were used, specifically Genetic Algorithms, to evaluate the objective function which aims to maximize the extraction volume, and minimize, by imposing penalties, the presence of spills and deficits in the dams. The operation of the parallel dams system with the rules defined was done using the historical record entry volumes from 1994 to 2011

Elementos para gestión del agua en la cuenca del lago de Zirahuén

El conocimiento de los fenómenos en el interior de una cuenca permite identificar la relación causa-efecto en tiempo y espacio mediante modelación. Una de las etapas necesarias es conocer los elementos que conforman e influyen en forma directa en los escurrimientos; éstos constituyen la base para plantear y formular estrategias de conservación y manejo del recurso hídrico. El objetivo principal fue conocer la condición actual de la cuenca del lago de Zirahuén estudiando los acervos de información disponibles del lugar de estudio. Se recopiló información fisiográfica, sociodemográfica y geomorfológica, en las bases oficiales de información de acceso público y se ejecutaron procesos geoespaciales en el acondicionamiento y análisis de la información. Se encontró que a pesar de la distribución en cobertura y uso del suelo, las características morfométricas contribuyen a la estabilidad del lago. De continuar las tendencias de la dinámica poblacional y el uso del suelo, la supervivencia de los ecosistemas podría estar amenazada por el aumento de la población y de las actividades productivas que deterioran y alteran el ciclo hidrológico, con disminución de acceso al agua, en cantidad y calidad, para las actividades humanas esenciales

Operación de tres presas hidroeléctricas usando curvas guía y programación dinámica estocástica

La programación dinámica (PD) fue desarrollada por Richard E. Bellman en la década de los cincuenta (Bellman, 1957). Es una herramienta matemática que ha sido utilizada en campos tan diversos como ingeniería, inteligencia artificial, economía, etcétera (Dormido et al., 2002). El campo de la planificación de recursos hidráulicos no ha sido la excepción y se reportan aplicaciones con buenos resultados en diversos países. Tiene como limitante un alto costo computacional; necesita de grandes recursos tanto de tiempo como de memoria y la demanda de ellos crece exponencialmente, al incrementar el número de variables de estado. En este trabajo se presenta la forma en que se organizó un programa de cálculo para contender con este problema y obtener las políticas de operación óptima de un sistema de tres presas que operan en cascada, variando condiciones de penalización por déficit, derrame o por exceder las curvas guía (que son los niveles de almacenamiento que se desea no sean rebasados durante la operación para la seguridad del sistema y que establece la Comisión Nacional del Agua). Las políticas obtenidas se simularon usando tanto el registro histórico como registros sintéticos para probar su bondad en el funcionamiento del sistema

Comparison of Two Convergence Criterion in the Optimization Process Using a Recursive Method in a Multi-Reservoir System

Stochastic dynamic programming (SDP) is an optimization technique used in the operation of reservoirs for many years. However, being an iterative method requiring considerable computational time, it is important to establish adequate convergence criterion for its most effective use. Based on two previous studies for the optimization of operations in one of the most important multi-reservoir systems in Mexico, this work uses SDP, centred on the interest in the convergence criterion used in the optimization process. In the first trial, following the recommendations in the literature consulted, the difference in the absolute value of two consecutive iterations was taken and compared against a set tolerance value and a discount factor. In the second trial, it was decided to take the squared difference of the two consecutive iterations. In each of the trials, the computational time taken to obtain the optimal operating policy was quantified, along with whether the optimal operating policy was obtained by meeting the convergence criterion or by reaching the maximum number of iterations. With each optimization policy, the operation of the system under study was simulated and four variables were taken as evaluators of the system behaviour. The results showed few differences in the two operation policies but notable differences in the computation time used in the optimization process, as well as in the fulfilment of the convergence criterion

Comparison of Two Convergence Criterion in the Optimization Process Using a Recursive Method in a Multi-Reservoir System

Stochastic dynamic programming (SDP) is an optimization technique used in the operation of reservoirs for many years. However, being an iterative method requiring considerable computational time, it is important to establish adequate convergence criterion for its most effective use. Based on two previous studies for the optimization of operations in one of the most important multi-reservoir systems in Mexico, this work uses SDP, centred on the interest in the convergence criterion used in the optimization process. In the first trial, following the recommendations in the literature consulted, the difference in the absolute value of two consecutive iterations was taken and compared against a set tolerance value and a discount factor. In the second trial, it was decided to take the squared difference of the two consecutive iterations. In each of the trials, the computational time taken to obtain the optimal operating policy was quantified, along with whether the optimal operating policy was obtained by meeting the convergence criterion or by reaching the maximum number of iterations. With each optimization policy, the operation of the system under study was simulated and four variables were taken as evaluators of the system behaviour. The results showed few differences in the two operation policies but notable differences in the computation time used in the optimization process, as well as in the fulfilment of the convergence criterion