The wastewater generated in urban areas is one of the main sources of water pollution, particularly in regions characterized with large population density and high urbanization degree. In this paper, we present an optimization model for regional wastewater systems planning. The model is aimed at helping to determine the best possible configuration (layout of sewer networks, location of treatment plants, etc.) for the wastewater system of a region taking economic, environmental, and technical criteria explicitly into account. It can be used separately, or as a building block of a broad decision-support tool designed to cover all (or most of) the issues involved in the implementation of an Integrated Water Resources Management approach. The model is solved through a simulated annealing algorithm. The type of results that can be obtained through the application of the model is illustrated for three case studies.

This paper describes the physical model, experimental setup and tests performed at the Portuguese Civil Engineering Laboratory (LNEC), to study the motions and forces of a moored ship at the Leixões port, for different sea states in irregular waves. The tests were carried out at one of the wave tanks of LNEC, where the Leixões port layout was implemented at scale 1:80 with the detailed model similar to the prototype bathymetry and surrounding structures. The moored ship is a 3.43 m long scale model of the well-known “Esso Osaka” tanker and is moored to the pier A of the oil terminal at 0.135 m draft. Several types of measurements were recorded in this study. The free-surface elevation and wave direction were measured with a set of resistive wave gauges. The wave velocities at the entrance of the harbour were measured with an acoustic Doppler velocimeter. Motions of the moored ship were measured with the OptiTrackTM motion capture system whereas forces on fenders and mooring lines were measured with load cells attached to a complex spring system developed at LNEC. Several tests were carried out for a number of incident sea states characterized by a JONSWAP spectrum, with different significant wave heights and peak periods. The measurement, analysis and results obtained for the incident wave conditions characterized by a significant wave height of 6 m and a peak wave period of 14 s are presented and discussed in this paper.

A set of procedures to evaluate the time series of the diffraction forces on a moored ship inside a harbor basin is presented. Nonlinear wave propagation is obtained using a Boussinesq finite element numerical model, BOUSS-WMH. Determination of hydrodynamic forces acting on the ship is achieved using a modified version of the WAMIT model. Finally, time series of the wave forces on the ship and of the inherent motions of the moored ship are obtained using BAS numerical model. The main focuses of this work are: the coupling of these three models and the modification of the method used in WAMIT to determine diffraction forces. Some simple and practical applications of this procedure are presented as well.

The risks associated with mooring of ships are a major concern for port and maritime authorities. Sea waves and extreme weather conditions can lead to excessive movements of vessels and mooring loads affecting the safety of ships, cargo, passengers, crew or port infrastructures. Normally, port activities such as ships’ approach manoeuvres and loading/unloading operations, are conditioned or suspended based solely on weather or wave forecasts, causing large economic losses. Nevertheless, it has been shown that some of the most hazardous events with moored ships happen on days with mild sea and wind conditions, being the culprit long waves and resonance phenomena. Bad weather conditions can be managed with an appropriate or reinforced mooring arrangement. A correct risk assessment must be based on the movements of the ship and on the mooring loads, taking into account all the moored ship’s system. In this paper, the development of a forecast and warning system based on the assessment of risks associated with moored ships in port areas, SWAMS ALERT, is detailed. This modular system can be scaled and adapted to any port, providing decision-makers with accurate and complete information on the behaviour of moored ships, movements and mooring loads, allowing a better planning and integrated management of port areas.