The water resources planning and management discipline recognizes the importance of a reservoir's carryover storage. However, mathematical models for reservoir operation that include carryover storage are scarce. This paper presents a novel multiobjective optimization modeling framework that uses the constraint-ε method and genetic algorithms as optimization techniques for the operation of multipurpose simple reservoirs, including carryover storage. The carryover storage was conceived by modifying Kritsky and Menkel's method for reservoir design at the operational stage. The main objective function minimizes the cost of the total annual water shortage for irrigation areas connected to a reservoir, while the secondary one maximizes its energy production. The model includes operational constraints for the reservoir, Kritsky and Menkel's method, irrigation areas, and the hydropower plant. The study is applied to Carlos Manuel de Céspedes reservoir, establishing a 12-month planning horizon and an annual reliability of 75%. The results highly demonstrate the applicability of the model, obtaining monthly releases from the reservoir that include the carryover storage, degree of reservoir inflow regulation, water shortages in irrigation areas, and the energy generated by the hydroelectric plant. The main product is an operational graph that includes zones as well as rule and guide curves, which are used as triggers for long-term reservoir operation.
Often in the early stages of planning a major development it is necessary to consider a large number of alternative individual projects and alternative sequences of projects. The main problem at this stage is to screen out the less desirable projects quickly so that only a manageable number of the more promising ones remain for detailed study. A number of simple techniques are presented which can be used to assist the screening process. These include a method for finding the sequence of projects which will meet one or more projected demands at minimum discounted cost, and making a sensitivity test of the results; a method for finding the sequence of projects which would yield the maximum present value of benefits; and a way of finding the optimal planning horizon for facilities where there are economies of scale. A comparison is given between results obtained by the sequencing technique presented and results from a more rigorous but more elaborate and time consuming method for the case of multiple demands.
La investigación se realizó en tres obras hidráulicas: la estación de bombeo de la presa Máximo, la Potabilizadora de Camagüey y la estación de bombeo de la presa Pontezuela. Los resultados obtenidos demostraron que el método propuesto para el diseño de conductoras provocó una disminución de la potencia de las bombas y del costo de operación en 30,2% y 29,2 respectivamente y un tiempo de amortización promedio de 6,51 años. Los valores de velocidades más económicas estuvieron entre 0,52 m s a 0,79 m s con un promedio de 0,655 m s . Los diseños hidráulicos de conductoras con reducción del diámetro para alcanzar la presión requerida en la descarga de la bomba; generan pérdidas superiores en casi dos veces la potencia necesaria en los motores de las electrobombas debido a que constituye un caso de estrangulación de la corriente; por lo que en caso de ser necesario esta variante se debe utilizar una válvula para que las pérdidas sean relativamente más bajas.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.