Many, including Dr Baretta, believe that the gates are unlikely to cause stagnation anyway.

ECONOMIST: Flood barriers

But Dr Baretta warns that the jetties proposed along with the gates will be a problem reducing flushing of the lagoon, and thus its water quality.

ECONOMIST: Flood barriers

This flushing, says Job Baretta, a consultant on coastal system dynamics, was rapid enough to avoid over-fertilisation of the lagoon until the 1980s, when massive and persistent blooms of algae broke out.

ECONOMIST: Flood barriers