Generic typology for irrigation systems operation

Irrigation management / Irrigation systems / Water use efficiency / Canals / Operations / Typology / Water delivery / Water distribution / Water conveyance / Water storage / Irrigation effects / Environmental effects / Gravity flow / Hydraulics / Constraints / Water supply / Networks / Case studies / Sri Lanka

Structural Analysis and Control of a Model of Two-site Electricity and Heat Supply

This paper introduces a control problem of regulation of energy flows in a two-site electricity and heat supply system, where two Combined Heat and Power (CHP) plants are interconnected via electricity and heat flows. The control problem is motivated by recent development of fast operation of CHP plants to provide ancillary services of power system on the order of tens of seconds to minutes. Due to the physical constraint that the responses of the heat subsystem are not necessary as fast as those of the electric subsystem, the target controlled state is not represented by any isolated equilibrium point, implying that stability of the system is lost in the long-term sense on the order of hours. In this paper, we first prove in the context of nonlinear control theory that the state-space model of the two-site system is non-minimum phase due to nonexistence of isolated equilibrium points of the associated zero dynamics.Instead, we locate a one-dimensional invariant manifold that represents the target controlled flows completely. Then, by utilizing a virtual output under which the state-space model becomes minimum phase, we synthesize a controller that achieves not only the regulation of energy flows in the short-term regime but also stabilization of an equilibrium point in the long-term regime. Effectiveness of the synthesized controller is established with numerical simulations with a practical set of model parameters

Vulnerability assessments of pesticide leaching to groundwater

Pesticides may have adverse environmental effects if they are transported to groundwater and surface waters. The vulnerability of water resources to contamination of pesticides must therefore be evaluated. Different stakeholders, with different objectives and requirements, are interested in such vulnerability assessments. Various assessment methods have been developed in the past. For example, the vulnerability of groundwater to pesticide leaching may be evaluated by indices and overlay-based methods, by statistical analyses of monitoring data, or by using process-based models of pesticide fate. No single tool or methodology is likely to be appropriate for all end-users and stakeholders, since their suitability depends on the available data and the specific goals of the assessment. The overall purpose of this thesis was to develop tools, based on different process-based models of pesticide leaching that may be used in groundwater vulnerability assessments. Four different tools have been developed for end-users with varying goals and interests: (i) a tool based on the attenuation factor implemented in a GIS, where vulnerability maps are generated for the islands of Hawaii (U.S.A.), (ii) a simulation tool based on the MACRO model developed to support decision-makers at local authorities to assess potential risks of leaching of pesticides to groundwater following normal usage in drinking water abstraction districts, (iii) linked models of the soil root zone and groundwater to investigate leaching of the pesticide mecoprop to shallow and deep groundwater in fractured till, and (iv) a meta-model of the pesticide fate model MACRO developed for 'worst-case' groundwater vulnerability assessments in southern Sweden. The strengths and weaknesses of the different approaches are discussed

Ecological models at fish community and species level to support effective river restoration

RESUMEN Los peces nativos son indicadores de la salud de los ecosistemas acuáticos, y se han convertido en un elemento de calidad clave para evaluar el estado ecológico de los ríos. La comprensión de los factores que afectan a las especies nativas de peces es importante para la gestión y conservación de los ecosistemas acuáticos. El objetivo general de esta tesis es analizar las relaciones entre variables biológicas y de hábitat (incluyendo la conectividad) a través de una variedad de escalas espaciales en los ríos Mediterráneos, con el desarrollo de herramientas de modelación para apoyar la toma de decisiones en la restauración de ríos. Esta tesis se compone de cuatro artículos. El primero tiene como objetivos modelar la relación entre un conjunto de variables ambientales y la riqueza de especies nativas (NFSR), y evaluar la eficacia de potenciales acciones de restauración para mejorar la NFSR en la cuenca del río Júcar. Para ello se aplicó un enfoque de modelación de red neuronal artificial (ANN), utilizando en la fase de entrenamiento el algoritmo Levenberg-Marquardt. Se aplicó el método de las derivadas parciales para determinar la importancia relativa de las variables ambientales. Según los resultados, el modelo de ANN combina variables que describen la calidad de ribera, la calidad del agua y el hábitat físico, y ayudó a identificar los principales factores que condicionan el patrón de distribución de la NFSR en los ríos Mediterráneos. En la segunda parte del estudio, el modelo fue utilizado para evaluar la eficacia de dos acciones de restauración en el río Júcar: la eliminación de dos azudes abandonados, con el consiguiente incremento de la proporción de corrientes. Estas simulaciones indican que la riqueza aumenta con el incremento de la longitud libre de barreras artificiales y la proporción del mesohabitat de corriente, y demostró la utilidad de las ANN como una poderosa herramienta para apoyar la toma de decisiones en el manejo y restauración ecológica de los ríos Mediterráneos. El segundo artículo tiene como objetivo determinar la importancia relativa de los dos principales factores que controlan la reducción de la riqueza de peces (NFSR), es decir, las interacciones entre las especies acuáticas, variables del hábitat (incluyendo la conectividad fluvial) y biológicas (incluidas las especies invasoras) en los ríos Júcar, Cabriel y Turia. Con este fin, tres modelos de ANN fueron analizados: el primero fue construido solamente con variables biológicas, el segundo se construyó únicamente con variables de hábitat y el tercero con la combinación de estos dos grupos de variables. Los resultados muestran que las variables de hábitat son los ¿drivers¿ más importantes para la distribución de NFSR, y demuestran la importancia ecológica de los modelos desarrollados. Los resultados de este estudio destacan la necesidad de proponer medidas de mitigación relacionadas con la mejora del hábitat (incluyendo la variabilidad de caudales en el río) como medida para conservar y restaurar los ríos Mediterráneos. El tercer artículo busca comparar la fiabilidad y relevancia ecológica de dos modelos predictivos de NFSR, basados en redes neuronales artificiales (ANN) y random forests (RF). La relevancia de las variables seleccionadas por cada modelo se evaluó a partir del conocimiento ecológico y apoyado por otras investigaciones. Los dos modelos fueron desarrollados utilizando validación cruzada k-fold y su desempeño fue evaluado a través de tres índices: el coeficiente de determinación (R2 ), el error cuadrático medio (MSE) y el coeficiente de determinación ajustado (R2 adj). Según los resultados, RF obtuvo el mejor desempeño en entrenamiento. Pero, el procedimiento de validación cruzada reveló que ambas técnicas generaron resultados similares (R2 = 68% para RF y R2 = 66% para ANN). La comparación de diferentes métodos de machine learning es muy útil para el análisis crítico de los resultados obtenidos a través de los modelos. El cuarto artículo tiene como objetivo evaluar la capacidad de las ANN para identificar los factores que afectan a la densidad y la presencia/ausencia de Luciobarbus guiraonis en la demarcación hidrográfica del Júcar. Se utilizó una red neuronal artificial multicapa de tipo feedforward (ANN) para representar relaciones no lineales entre descriptores de L. guiraonis con variables biológicas y de hábitat. El poder predictivo de los modelos se evaluó con base en el índice Kappa (k), la proporción de casos correctamente clasificados (CCI) y el área bajo la curva (AUC) característica operativa del receptor (ROC). La presencia/ausencia de L. guiraonis fue bien predicha por el modelo ANN (CCI = 87%, AUC = 0.85 y k = 0.66). La predicción de la densidad fue moderada (CCI = 62%, AUC = 0.71 y k = 0.43). Las variables más importantes que describen la presencia/ausencia fueron: radiación solar, área de drenaje y la proporción de especies exóticas de peces con un peso relativo del 27.8%, 24.53% y 13.60% respectivamente. En el modelo de densidad, las variables más importantes fueron el coeficiente de variación de los caudales medios anuales con una importancia relativa del 50.5% y la proporción de especies exóticas de peces con el 24.4%. Los modelos proporcionan información importante acerca de la relación de L. guiraonis con variables bióticas y de hábitat, este nuevo conocimiento podría utilizarse para apoyar futuros estudios y para contribuir en la toma de decisiones para la conservación y manejo de especies en los en los ríos Júcar, Cabriel y Turia.Olaya Marín, EJ. (2013). Ecological models at fish community and species level to support effective river restoration [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/28853TESI

Optimal predictive control of water transport systems: Arrêt-Darré/Arros case study

This paper proposes the use of predictive optimal control as a suitable methodology to manage efficiently transport water networks. The predictive optimal controller is implemented using MPC control techniques. The Arrêt-Darré/Arros dam-river system located in the Southwest region of France is proposed as case study. A high-fidelity dynamic simulator based on the full Saint-Venant equations and able to reproduce this system is developed in MATLAB/SIMULINK to validate the performance of the developed predictive optimal control system. The control objective in the Arrêt-Darré/Arros dam-river system is to guarantee an ecological flow rate at a control point downstream of the Arrêt-Darré dam by controlling the outflow of this dam in spite of the unmeasured disturbances introduced by rainfalls incomings and farmer withdrawals

Enhancing Operation of a Sewage Pumping Station for Inter Catchment Wastewater Transfer by Using Deep Learning and Hydraulic Model

This paper presents a novel Inter Catchment Wastewater Transfer (ICWT) method for mitigating sewer overflow. The ICWT aims at balancing the spatial mismatch of sewer flow and treatment capacity of Wastewater Treatment Plant (WWTP), through collaborative operation of sewer system facilities. Using a hydraulic model, the effectiveness of ICWT is investigated in a sewer system in Drammen, Norway. Concerning the whole system performance, we found that the S{\o}ren Lemmich pump station plays a vital role in the ICWT framework. To enhance the operation of this pump station, it is imperative to construct a multi-step ahead water level prediction model. Hence, one of the most promising artificial intelligence techniques, Long Short Term Memory (LSTM), is employed to undertake this task. Experiments demonstrated that LSTM is superior to Gated Recurrent Unit (GRU), Recurrent Neural Network (RNN), Feed-forward Neural Network (FFNN) and Support Vector Regression (SVR)

Adaptive Neural Network Feedforward Control for Dynamically Substructured Systems

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Strategic Group Formation in the Mekong Delta: The Development of a Modern Hydraulic Society

The lower Mekong Delta, one of the largest river deltas in Asia, is a landscape shaped by the waters of the Mekong River that flows, as last part of its long way from the Tibetan Plateau to the South Chinese Sea, through a dense river and canal network in the Southwest of Vietnam. People in this area are, traditionally, exposed to a water-shaped environment and have lived for generations in adaptation to their natural surrounding without much human interference into the complex natural hydraulic system of the delta. However, this has changed dramatically during recent decades when hydraulic management started to become a key issue for the development of the lower Mekong Delta constantly, in particular with respect to the agricultural sector, which is the backbone of the delta’s economy. After the Second Indochinese War ended in 1975 the delta started to shift from human adaption to human control, transforming itself into what Wittfogel has described as a hydraulic society. This was mainly due to the new socialist government’s policy of rapid agricultural extension and growing endeavours in hydraulic management for fostering irrigated rice production. By now, in many places of the delta hydraulic works such as additional canals, dykes and sluices have been set up, constructed for regulating water flows. Technical innovations in hydraulic management and agricultural production have not only had significant impact on the delta’s environment and ecology, but also have triggered social transformation, in particular the appearance of new social groups struggling for access to resources and power. This paper intends to analyzes recent trends of social development and water management in the Mekong Delta from a scientific approach that is based on two social theories, firstly “strategic group analysis”, and secondly selected core aspects of Wittfogel’s social theory of “hydraulic society”. By presenting recently collected data, it is illustrated how the Mekong Delta has been transformed into a modern hydraulic society, in which certain strategic groups emerged as a consequence of growing activities in hydraulic management and agricultural-based economic growth. More specifically, the paper aims to give an overview of strategic group development in the delta by putting a strong focus on the process of forming a state bureaucracy of hydraulic management and the appearance of hydraulic construction companies as its clients. The paper shows how the strategic alliance between both groups has increased the chances for mutually appropriating government funds spent on hydraulic works and how this has caused ecologically and socially far-reaching impacts for the Mekong Delta.Vietnam; Mekong Delta; strategic groups; hydraulic society; social transformation and power; water management; hydraulic bureaucracy; economic development

Strategic Group Formation in the Mekong Delta - The Development of a Modern Hydraulic Society

The lower Mekong Delta, one of the largest river deltas in Asia, is a landscape shaped by the waters of the Mekong River that flows, as last part of its long way from the Tibetan Plateau to the South Chinese Sea, through a dense river and canal network in the Southwest of Vietnam. People in this area are, traditionally, exposed to a water-shaped environment and have lived for generations in adaptation to their natural surrounding without much human interference into the complex natural hydraulic system of the delta. However, this has changed dramatically during recent decades when hydraulic management started to become a key issue for the development of the lower Mekong Delta constantly, in particular with respect to the agricultural sector, which is the backbone of the delta’s economy. After the Second Indochinese War ended in 1975 the delta started to shift from human adaption to human control, transforming itself into what Wittfogel has described as a hydraulic society. This was mainly due to the new socialist government’s policy of rapid agricultural extension and growing endeavours in hydraulic management for fostering irrigated rice production. By now, in many places of the delta hydraulic works such as additional canals, dykes and sluices have been set up, constructed for regulating water flows. Technical innovations in hydraulic management and agricultural production have not only had significant impact on the delta’s environment and ecology, but also have triggered social transformation, in particular the appearance of new social groups struggling for access to resources and power. This paper intends to analyzes recent trends of social development and water management in the Mekong Delta from a scientific approach that is based on two social theories, firstly “strategic group analysis”, and secondly selected core aspects of Wittfogel’s social theory of “hydraulic society”. By presenting recently collected data, it is illustrated how the Mekong Delta has been transformed into a modern hydraulic society, in which certain strategic groups emerged as a consequence of growing activities in hydraulic management and agricultural-based economic growth. More specifically, the paper aims to give an overview of strategic group development in the delta by putting a strong focus on the process of forming a state bureaucracy of hydraulic management and the appearance of hydraulic construction companies as its clients. The paper shows how the strategic alliance between both groups has increased the chances for mutually appropriating government funds spent on hydraulic works and how this has caused ecologically and socially far-reaching impacts for the Mekong Delta.Vietnam; Mekong Delta; strategic groups; hydraulic society; social transformation and power; water management; hydraulic bureaucracy