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Introduction The initial step in a ground water contamination remediation process is to identify the extent of the plume. In normal practice, a number of wells are drilled and ground [...]

The importance of water distribution network rehabilitation, replacement, and expansion is discussed. The problem of choosing the best possible set of network improvements to make with a limited budget is presented as a large optimization problem to which conventional optimization techniques are poorly suited. A multiobjective approach is described, using capital cost and benefit as dual objectives, enabling a range of noninferior solutions of varying cost to be derived. A structured messy genetic algorithm is developed, incorporating some of the principles of the messy genetic algorithm, such as strings that increase in length during the evolution of designs. The algorithm is shown to be an effective tool for the current optimization problem, being particularly suited both to the multiobjective approach and to problems that involve the selection of small sets of variables from large numbers of possibilities. Two examples are included that demonstrate the features of the method and show that the algorithm performs much better than a standard genetic algorithm for a large network.

A computer model for assessing the reliability of water-distribution networks is presented. Both mechanical failure caused by pipe breakages and hydraulic failure caused by insufficient pipe capacity are incorporated into a simple stochastic model. A network solver identifies nodal pressures for individual pipe-failure conditions over a range of network demands, where both pipe failure and network demand are of known probabilities. The probabilities of pressure deficiency at nodes are calculated, from which the availability of supply is determined. Two examples are presented to clarify the principles of the model and to demonstrate the practicality of its applications. The model was developed to enable rapid yet realistic analysis of the reliability of water-distribution networks, and can be used for analyzing either existing systems or proposed designs of new systems.

Introduction Predicting ground-water flow is an exercise that often involves uncertainties. A number of complicated issues, such as geology, hydrology, aquifer boundaries, etc., need to be addressed (Freeze et al., [...]

Climate change has been affecting significantly dams worldwide, particularly by the accentuation of extreme events. The hydraulic insufficiency of spillways is the most hazardous related risk that directly threatens the dams' safety. Thus, the Piano Key Weir (PKW) technology may be a cost-effective solution for adapting the spillways of the existing dams and enhancing their resilience against climate change. This paper aims to provide the state of knowledge regarding the climate change issues related to dams with a focus on Morocco. It aims also to assess the cost-effectiveness of implementing the PKW in 27 large Moroccan dams in order to increase the flood release capacity. This work has determined, first, the climate change impacts on water resources and dams, and has discussed the adaptation measures including the implementation of PKW. Then, a detailed case study has been conducted to evaluate the interest of implementing the PKW in Morocco, at the scale of each hydraulic basin, with a comparison to the international experience. Results have revealed that the PKW allows increasing the global discharge capacity of Moroccan spillways by 70%, at a total cost of about 600 MMAD. Souss Massa Draa basin has accounted more than 40% of the total discharge capacity increase, and the best cost-effectiveness values have been identified in Loukkos, Oum Er Rbiaa and Sebou basins. These results may encourage the PKW integration in order to enhance the Climate adaptation and resilience of dams. [ABSTRACT FROM AUTHOR]

In a water scarcity context, dam reservoirs play a key role in the socio-economic development. Currently, these dams face two major problems: the siltation that reduces their storage capacity, and the risk of submersion during the extreme floods events, which is directly related to the hydraulic insufficiency of spillways. To overcome these potential deficits in terms of storage capacity and flood discharge, at the least cost, the Piano Key Weir "PKW" can constitute an advantageous alternative solution. In this paper, an exhaustive methodology to assess the PKW cost-effectiveness with a Moroccan case study are presented. This study is carried out on 32 large Moroccan dams. Results show that the PKW allows increasing the total capacity of the studied reservoirs by 1150 Mm³ that is about 20% of their current capacity, at a total cost of 930 MMAD. This recovered volume exceeds by far the total volume lost through siltation. The best costeffectiveness is observed in both hydraulic basins of Loukkos and Sebou and particularly within dams of low specific flow rates and moderate hydraulic heads. A PKW cost-effectiveness analysis for increasing the flood discharge capacity and a PKW comparison to other alternative solutions are presented as well. [ABSTRACT FROM AUTHOR]

In this paper, an artificial neural network (ANN) based on hybrid algorithm combining particle swarm optimization (PSO) with back-propagation (BP) is proposed to forecast the daily streamflows in a catchment located in a semi-arid region in Morocco. The PSO algorithm has a rapid convergence during the initial stages of a global search, while the BP algorithm can achieve faster convergent speed around the global optimum. By combining the PSO with the BP, the hybrid algorithm referred to as BP-PSO algorithm is presented in this paper. To evaluate the performance of the hybrid algorithm, BP neural network is also involved for a comparison purposes. The results show that the neural network model evolved by PSO-BP algorithm has a good predictions and better convergence performances [ABSTRACT FROM PUBLISHER]

2D shallow water equations with depth-averaged k−ε model is considered. A meshless method based on multiquadric radial basis functions is described. This methods is based on the collocation formulation and does not require the generation of a grid and any integral evaluation. The application of this method to a flow in horizontal channel, taken as an experimental device, is presented. The results of computations are compared with experimental data and are found to be satisfactory [ABSTRACT FROM PUBLISHER]