Assessment of treatment systems for highway runoff pollution control in Portugal.

Treatment systems for highway runoff pollution control are now common structures for environmental impacts reduction in Portugal. Such systems must be monitored and its performance periodically assessed, in order to understand if they are accomplishing the targets for environmental protection. Wise management decisions must incorporate the soundness of the project, the construction and maintenance costs, and the ability of the system to reduce the pollution to the level required for environmental protection. To gather, organize and analyse all the existing information concerning the constructed treatment systems, their operation, maintenance and efficiency were understood as a priority by the Portuguese Roads' Institute. The authors of this article were responsible for this 3 years study that finished in May 2008. A total of 27 different systems, corresponding to 13 different project types, located in different places in Portugal have been characterized and evaluated. Several conclusions could be drawn from the evaluation and recommendations were produced concerning the project, the construction and operation phases and the monitoring activities. The recommendations concern tasks to be performed and information that should be gathered and presented to the Portuguese Road's Institute. It is expected that these indications will contribute to improve the future practice in Portugal.