Protecting an Estuary from Floods — A Policy Analysis of the Oosterschelde

An addendum to the third volume in a series of reports describing the methodology and results of a joint research venture between RAND and the Netherlands Rijkswaterstaat. The POLANO project was founded to help the Dutch government analyze the different alternatives (open, closed, and storm-surge barrier cases) for protecting the Oosterschelde region from North Sea floods. The Addendum describes the biological data and methods used to estimate the initial abundances and average live weights of each ecological group of species for the different segments of the Oosterschelde. Since data for the Oosterschelde were incomplete, similar estimates were also made for species in the open and closed Grevelingen, an estuary adjacent to the Oosterschelde that was separated from the North Sea by a barrier dam in May 1971. These abundances and weights were major inputs for the calibration and validation of the general ecomodel described in Vol. III. The Addendum assumes that the reader is acquainted with Vol. III.