[1] This study examines the effects of a large dam on hydrological droughts in the transboundary Tagus River, central Spain and Portugal. The magnitude and duration of droughts are analyzed by comparing a monthly drought index calculated for the flow series upstream and downstream of the Alcántara reservoir. The dam was built in 1969, and the reservoir is the second largest in Europe (3,162 hm 3 ). Water management in the area is complex because of large seasonal and interannual variability in the flow regime, which is characteristic of Mediterranean environments. This paper demonstrates that, as a result of exploitation of the Alcántara reservoir, (1) during periods of water scarcity, the releases in winter and spring are reduced dramatically and the magnitude and duration of summer low flow show a slight increase and (2) the nature of droughts along the Tagus river basin downstream of the dam has shown severe changes since construction of the dam. In fact, during the predam period , droughts were longer and more intense in the Spanish part of the basin than that in the Portuguese part. Since the construction of the Alcántara dam, however, the Portuguese part of the basin has experienced more severe droughts than did the upstream part in terms of both magnitude and duration.

The current paper focuses on leakage detection in pipe systems by means of the standing wave difference method ͑SWDM͒ used for cable fault location in electrical engineering. This method is based on the generation of a steady-oscillatory flow in a pipe system, by the sinusoidal maneuver of a valve, and the analysis of the frequency response of the system for a certain range of oscillatory frequencies. The SWDM is applied to several configurations of pipe systems with different leak locations and sizes. A leak creates a resonance effect in the pressure signal with a secondary superimposed standing wave. The pressure measurement and the spectral analysis of the maximum pressure amplitude at the excitation site enable the identification of the leak frequencies and, consequently, the estimation of the leak approximate location. Practical difficulties of implementation of this technique in real life systems are discussed.

Is it all about awareness? The normalization of coastal riskCoastal risk is already high in several parts of the world and is expected to be amplified by climate change, which makes it necessary to outline effective risk management strategies. Risk managers assume that increasing awareness of coastal risk is the key to public support and endorsement of risk management strategies -an assumption that underlies a common worldview on the public understanding of science, which has been named the deficit model. We argue that the effects of awareness are not as straightforward. In particular, awareness of coastal hazards might not lead to more technically-accurate risk perceptions.Based on research on risk perception normalization, we explored the hypothesis that coastal risk awareness reduces coastal risk perception -in particular the perceived likelihood of occurrence of coastal hazards-through its effect on reliance on protective measures to prevent risk. Individuals can rely on protective measures, even when those are not effective, as a positive illusion to reduce risk perception. This effect might be stronger for higher-probability hazards and for permanent residents of costal zones. Data from 410 individuals living in coastal zones corroborated most of our expectations. Global results demonstrated a risk normalization effect mediated by reliance on current measures. Additional analyses made clear that this effect occurred in 2 of the 5 high-probability hazards (flood and storm), and not in the low-probability hazard (tsunami).Normalization might be more likely among high-probability hazards which entail catastrophic and immediate impacts. This effect was also found among permanent residents, but not among temporary residents. Results imply that coastal risk management might benefit from a) taking risk perception normalization effects into account, b) tailoring strategies for permanent and temporary residents, and c) promoting a higher public engagement, which would facilitate a more adaptive and effective coping with coastal risk than the use of positive illusions.

This paper describes a two-dimensional numerical model to solve the generalized Serre equations. --i order to solve the system of equations, written in the conservative form, we use an explicit finite-difference method based on the MacCormack time-splitting scheme. The numerical method and the computational model are validated by comparing one-and two-dimensional numerical solutions with theoretical and experimental results. Finally, the two-dimensional model (in a horizontal plane) is tested in a domain with complicated boundary conditions.

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