A Hybrid Water Distribution Networks Design Optimization Method Based on a Search Space Reduction Approach and a Genetic Algorithm

This work presents a new approach to increase the efficiency of the heuristics methods applied to the optimal design of water distribution systems. The approach is based on reducing the search space by bounding the diameters that can be used for every network pipe. To reduce the search space, two opposite extreme flow distribution scenarios are analyzed and velocity restrictions to the pipe flow are then applied. The first scenario produces the most uniform flow distribution in the network. The opposite scenario is represented by the network with the maximum flow accumulation. Both extreme flow distributions are calculated by solving a quadratic programming problem, which is a very robust and efficient procedure. This approach has been coupled to a Genetic Algorithm (GA). The GA has an integer coding scheme and variable number of alleles depending on the number of diameters comprised within the velocity restrictions. The methodology has been applied to several benchmark networks and its performance has been compared to a classic GA formulation with a non-bounded search space. It considerably reduced the search space and provided a much faster and more accurate convergence than the GA formulation. This approach can also be coupled to other metaheuristics

Dispositivo automático de pesada diseñado para medir la evaporación desde el suelo

Número de publicación: ES2299366 A1 (16.05.2008) También publicado como: ES2299366 B1 (16.04.2009) Número de Solicitud: Consulta de Expedientes OEPM (C.E.O.) P200601980 (03.07.2006)Este dispositivo mide la evaporación del suelo humedecido mediante un emisor de riego localizado. Consiste en dos depósitos cilíndricos, concéntricos. El depósito exterior (1) contiene una célula de carga (3) que soporta al depósito interior (2) y permite medir la evaporación mediante diferencias de pesada. El depósito interior contiene el suelo (2a) y un espacio inferior (2b) en el que se recoge el agua de drenaje. El diámetro del depósito interior se diseña con el objetivo de contener toda la superficie humedecida por el emisor y su profundidad no es muy elevada, ya que la evaporación se produce desde la superficie del suelo. La toma de datos se realiza de modo automático mediante un registrador de datos o sistema de adquisición de datos.Universidad de Almerí

Development of a New Control Algorithm for Automatic Irrigation Scheduling in Soilless Culture

In soilless culture, water and nutrients must be frequently and precisely applied due to the reduced volume and low water holding capacity of the substrate. For this reason, irrigation scheduling is an important and difficult task. The use of an irrigation control tray with two electrodes (level sensor) is a simple way for controlling irrigation. Irrigation operation is triggered when the water level in the tray decreases below a preset level. This is a simple on-off control but inflexible because it requires periodic manually calibrations. This work aims at developing a more efficient control system for the irrigation management of soilless culture. The control system is based on a Proportional Integral Derivative (PID) algorithm and it allows for fully automatic operation with a minimum set of variables in order to reduce the cost of the equipment. The results obtained demonstrate that the PID control algorithm can efficiently be used to control irrigation in soilless culture. The calculated average daily leaching fractions fit reasonably well to the target values. Nevertheless, some improvements of the control algorithm are required to reduce the variability of the calculated leaching fractions during the initial stage of crop development

Sustainable Irrigation Management of Ornamental Cordyline Fruticosa “Red Edge” Plants with Saline Water

The aim of this work was to analyze the influence of the salinity of the nutrient solution on the transpiration and growth of Cordyline fruticosa var. “Red Edge” plants. A specific irrigation management model was calibrated with the experimental data. An experiment was performed with four treatments. These treatments consisted of the application of four nutrient solutions with different electrical conductivity (ECw) levels ranging from 1.5 dS m−1 (control treatment) to 4.5 dS m−1. The results showed that day-time transpiration decreases when salt concentration in the nutrient solution increases. The transpiration of the plant in the control treatment was modelled by applying a combination method while the effect of the salinity of the nutrient solution was modelled by deriving a saline stress coefficient from the experimental data. The results showed that significant reductions in plant transpiration were observed for increasing values of ECw. The crop development and yield were also affected by the increasing salinity of the nutrient solution. A relationship between the ECw and the relative crop yield was derived

Análisis descriptivo y documentación de colecciones etnográficas

A documentação de coleções etnográficas em museus requer um processo reflexivo, que tome como ponto de partida uma definição contextual do objeto etnográfico. Apresenta-se aqui um exemplo para a construção de linguagens descritivas estandardizadas e um modelo de registro que surge da análise de um corpus de máscaras. Aprecia-se, assim, a vinculação entre os dados primários (observação direta) e os dados secundários (o texto etnográfico) que permite discriminar os traços de maior significação, e distinguir níveis de informação segundo a profundidade analítica assumida pelo pesquisador.Facultad de Ciencias Naturales y Muse

Multistage Bounded Evolutionary Algorithm to Optimize the Design of Sustainable Photovoltaic (PV) Pumping Irrigation Systems with Storage

Small off-grid photovoltaic (PV) pumping irrigation systems with storage tanks are an environmentally friendly, cost effective and efficient way of taking advantage of solar energy to irrigate crops, and they are increasingly being used today. However, finding the optimal design of this type of system is cumbersome since there are many possible designs. In this work, a new heuristic method based on the hybrid approach, which uses search space reduction, is developed and adapted to the optimal design for this type of PV irrigation system. At different stages, the proposed approach iteratively combines a bounding strategy based on the application of engineering rules with the aim of reducing the search space with a genetic algorithm to find the optimal design within this search space. The proposed methodology was applied to minimize the cost of a benchmark case study consisting of a real farm placed in the province of Almería (Spain). The proposed methodology was able to provide a faster and an accurate convergence due to the reduction of the search space. This fact led to a reduced total cost of the system. This study proved that the most sensitive variables were the number of modules and the type of pump, whereas the diameter of the pipe and volume of the storage tank remained more stable

Irriblend-DSW: A decision support tool for the optimal blending of desalinated and conventional irrigation waters in dry regions

Desalinated sea water (DSW) is increasingly being used as an alternative source of irrigation in dry coastal areas. Owing to its high price and singular composition, it is often blended with other water resources to curb costs. Although this is a common practice, limited resources are available to manage the increased agro-economic complexity required to balance several water sources with heterogeneous quality, price, and availability restrictions. To support the management of fertigation with DSW, in this study, we present an open-source decision support tool (DST), Irriblend-DSW. The DST has been designed to identify potentially profitable fertigation options for different water and fertiliser availability scenarios. To demonstrate the key features of the tool, we applied it to two actual case study scenarios in south-eastern Spain, where severe water scarcity led to massive seawater desalination for agricultural supply. The information provided by the DST enabled the assessment of the viability of different water blending options and the selection of an optimal combination of water and fertilisers. The simulation results showed that the fertigation costs of the studied crops, hydroponic lettuce, and greenhouse tomato substantially increased with the integration of DSW. The DST output showed how water price rises, and how additional types and amounts of fertilisers are required when more DSW is used. However, because the salinity of the blend is also reduced with the use of DSW, the yield outcome improves and, thus, to some extent, compensates for the increased cost. In fact, despite higher costs, the studied crops were found to be very profitable when the optimised solutions computed by the DST were selected. Moreover, the optimum fertigation solutions not only reduced costs but also decreased nutrient leaching in areas of severely polluted aquifers.This study was supported by the Ministerio de Economía, Industria y Competitividad (MINECO, Spain), the Agencia Estatal de Investigación (AEI, Spain), and the Fondo Europeo de Desarrollo Regional (FEDER, Europe), which funded the project RIDESOST (AGL2017-85857-C2-1-R and AGL2017-85857-C2–2-R). Additional support was provided by the European Commission (Europe) (grant LIFE16 ENV/ES/000341, DESEACROP Project). The collaboration of Cátedra Trasvase y Sostenibilidad – Jose Manuel Claver Valderas is also acknowledged. B. Gallego-Elvira acknowledges support from the Ministry of Science, Innovation and University of Spain (“Beatriz Galindo” Fellowship BEAGAL18/00081)

Análisis de la fiabilidad de una red de riego en función de la simultaneidad de la demanda

[ES] Garantizar el suministro es un aspecto de vital importancia en las redes de distribución de agua para cultivos intensivos de invernadero, característicos del sudeste español. Esto es debido a su alto valor económico y a que se desarrollan sobre suelos o substratos con escasa capacidad de retención de agua que exigen riegos frecuentes. En estas condiciones, una interrupción del suministro durante un corto período de tiempo puede suponer un grave perjuicio económico para el agricultor. A pesar de que los tiempos de riego son relativamente cortos y existe un gran número de pequeños usuarios, la demanda de agua no se distribuye de manera uniforme, ya que es frecuente que las operaciones de riego se concentren en pocas horas. Esta simultaneidad del riego aumenta los requerimientos a los que esta sometida la red de distribución. En este trabajo se presenta una metodología útil para analizar la fiabilidad de una red de distribución de agua para riego a presión. Se ha elaborado una herramienta informática que permite estudiar la respuesta de una red determinada para diferentes probabilidades de simultaneidad de la demanda. Este programa realiza la simulación hidráulica del funcionamiento de la red en cada caso y calcula diferentes índices que permiten evaluar la calidad del servicio a los usuarios. Como aplicación del modelo se estudia un caso práctico.Los autores desean agradecer a la FIAPA (Fundación para la Investigación Agraria en la Provincia de Almería) y a la CICYT (Comisión Interministerial para la Ciencia Y la Tecnología) el apoyo financiero que han prestado para la realización de este trabajo, en el marco de los proyectos 97/D/149 y AGL2000-1223 respectivamente.Reca Cardeña, J.; Martínez López, J.; Roldán Cañas, J.; Callejón Baena, JL. (2002). Análisis de la fiabilidad de una red de riego en función de la simultaneidad de la demanda. Ingeniería del Agua. 9(2):157-162. https://doi.org/10.4995/ia.2002.2612SWORD15716292ALIOD, R., EIZAGUERRI, A., ESTRADA; PERNA, E. 1997. Métodos Convencionales y Avanzados para el Diseño y Análisis Hidráulico de Redes de Distribución a Presión en Riego a la Demanda. Riegos y Drenajes Siglo XXI, nº 22, Enero 1997CABRERA, E. y A. VELA (Eds.). 1995. Mejora del Rendimiento y de la Fiabilidad en Sistemas de Distribución de Agua. Grupo Mecánica de Fluidos (U.P.V.). Valencia.CAJA RURAL DE ALMERÍA. 1997. Gestión del regadío en el Campo de Dalías: Las comunidades de regantes Sol y Arena y Sol-Poniente. Caja Rural de Almería.LAMADDALENA, N. y J. A. SAGARDOY. 2000. Performance analysis of on-demand pressurized irrigation systems. FAO Irrigation and Drainage Paper 59. Roma.MARTÍNEZ, J; J. RECA; A. ZAPATA; C. ARRIOLAy J.L. CALLEJÓN. 2000a. Manejo del riego en invernadero. Caracterización experimental en Almería. Riegos y Drenajes XXI, nº 113: 50-55MARTÍNEZ, J; J. RECA; R. LÓPEZ y J.L. CALLEJÓN. 2000b. Desarrollo de equipo automatizado para la toma de datos en redes de riego a presión. Ingeniería Civil, nº 120: 129-134RECA, J.; J. MARTÍNEZ; A. ZAPATA; J.G. LÓPEZ y J.L. CALLEJÓN. 2000. Demanda de caudal en redes de cultivos intensivos. Riegos y Drenajes XXI, nº 110: 40-45ROSSMAN, L.A.. 1997. Manual del Usuario de EPANET Versión 1.1e. Traducción al castellano. Grupo de Mecánica de Fluidos. Universidad Politécnica de Valencia

Valoración energética y diseño óptimo de impulsiones con caudal variable

[ES] En este trabajo se presenta una metodología para la valoración energética de estaciones de bombeo que abastecen caudales variables. El caudal impulsado se caracteriza como variable estocástica mediante su función de densidad. Dada la dificultad de conocer dicha función en la realidad cuando no existen aforadores, se deberá estimar mediante la adopción de hipótesis racionales. Las hipótesis de Clèment se han usado para caracterizar dicha función de densidad asociada al caudal distribuido en zonas regables a la demanda. Caracterizado el caudal, se determina el consumo energético a partir del conocimiento de las curvas características (altura-caudal y potencia-caudal) de cada uno de los impulsores. La metodología presentada permite la evaluación de cualquier sistema de bombeo teniendo en cuenta la variabilidad del caudal.López, R.; Reca Cardeña, J.; Camacho, E.; Roldán Cañas, J.; Alcaide García, M. (1995). Valoración energética y diseño óptimo de impulsiones con caudal variable. Ingeniería del Agua. 2(1):19-24. https://doi.org/10.4995/ia.1995.2653192421Clément, R. y Galand (1979) Irrigation par aspersion et réseaux collectifs de distribution sous pression. Editorial Eyrolles.Granados, A. (1990) Infraestructura de regadíos: redes colectivas de riego a presión (2a edición). E.T.S. de Ingenieros de Caminos, Canales y Puertos, Universidad Politécnica de Madrid.ITUR (1992) Catálogo comercial de bombas.López Luque, R. (1991) Optimización de sistemas de impulsión y distribución de agua para riego, Riegos y Drenajes XXI. 50:29-33.Mataix, C. (1975) Turbomáquinas hidráulicas. ICAI.Meyer, P.L. (1974) Introductory probability and statistical aplications. Addison-Wesley Publishing Company, Reading, Massachussets.Unidad Docente Mecánica de Fluidos (1992) Curso de ingeniería hidráulica aplicada a los sistemas de distribución de agua. Universidad Politécnica de Valencia