Abstract. This paper investigates the hydraulic issues of pumping well optimization in saltwater-intruded coastal aquifers. The well field includes freshwater outflow, pumping wells, and a recharge canal. The objective is to maximize the total pumping rate subject to the constraint of no intrusion of the saltwater front into the wells. Analytical solutions are presented for one-well, two-well, and one-well-with-recharge-canal problems. For problems involving multiple pumping wells, a structured messy genetic algorithm is used to search for the optimal solution.

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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 optimisation problem to which conventional optimisation techniques are poorly suited. A multi-objective approach is described, using capital cost and benefit as dual objectives, enabling a range of non-inferior 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 which increase in length during the evolution of designs. The algorithm is shown to be an effective tool for the current optimisation problem, being particularly suited both to the multi-objective approach and to problems which involve the selection of small sets of variables from large numbers of possibilities. Two examples are included which demonstrate the features of the method and show that the algorithm performs much better than a standard Genetic Algorithm for a large network.

We present GPS observations in Morocco and adjacent areas of Spain from 15 continuous (CGPS) and 31 survey-mode (SGPS) sites extending from the stable part of the Nubian plate to central Spain. We determine a robust velocity field for the W 20Mediterranean that we use to constrain models for the Iberia-Nubia plate boundary.South of the High Atlas mountain system, GPS motions are consistent with Nubia plate motions from prior geodetic studies. We constrain shortening in the Atlas system to <

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