The Óbidos Lagoon is one of Portugal’s complex coastal lagoonal systems. With a length of about 6 km and 1,5 km in width, this lagoon presents a natural tendency for silting due to the rate of incoming sediments from land (rivers) and sea being superior to the rate of the outgoing sediments.

The objective of the requalification project of the Óbidos Lagoon prepared by Nemus was to counter the progressive silting and to guarantee a permanent connection of the lagoon to the sea, having in mind the sustainable management of the lagoon and the improvement of developing conditions for the various economic and recreational activities. This project also includes the building of a guiding dike and the dredging of a substantial amount of lagoonal sediments.

In addition to the environmental assessment, we aimed to identify the most favorable alternative for the temporary depositing of dredged materials, before they could be used in the environmental recovery of quarries.

This study was comprised of various analysis and field work, such as: hydrodynamic mathematic simulations, the execution of campaigns to collect and analyze sediments and macrobenthic communities present in the deep, noise level measurements and surveying the archeological potential of underwater and bank sediments.

Since 1997, Nemus has worked with the Portuguese Water Institute and other water management entities on circa thirty projects.