Operational forecast methodology for submarine outfall management: application to a Portuguese case study

摘要

Coastal waters are an integral part of the natural environment. Careful planning and management is needed to protect andrnconserve them, and to ensure that the water supply is useful for a variety of uses.rnSubmarine outfalls for effluent disposal are used to ensure that the water quality is maintained and that the environmental valuesrnand water uses are protected.rnDecision on treatment and disposal is based on objectives set by national and international legislation and on coastal and maritimernuses identification.rnAn operational forecast methodology is proposed for the management of submarine outfalls providing information to deal with thernmarine environment problems and to satisfy needs at different levels for coastal communities.rnFrom a management perspective the forecast methodology will support decision making by predicting where a discharged plume isrnlikely to be transported over a few days from its last known location.rnShort-term forecasts of maritime climate and hydrological conditions along with foreseen effluent characteristics (depending onrnseasons and population equivalent) of the studied region are used for an accurate estimation of the effluent plume advection andrndiffusion processes near the coastline.rnThe operational forecast methodology, continuously evaluating the plume behavior and its relation with the protection perimeterrn(identified through a coastal usage map), allows the implementation of a precautionary and adjustable management of thernsubmarine outfall. Corrective measures (e.g. increase dilution, increase the number of outlets, increase outflow speed) may avoidrnpossible operational disruptions and minimize potential water quality impacts.rnTo illustrate the application of the procedure, a submarine outfall case study located in the Portuguese coast is analysed.