For several decades, the Belgian East Coast has posed problems of a sedimentological nature. Off the coast, a gully (called “Appelzak”) has developed to a depth of 8 m below low-water and has shifted dangerously near the existing seadike, causing severe beach erosion. In 1976 the Belgian Government decided to sizeably enlarge the outer harbor of Zeebrugge seaward to a distance of 3.5 km from the coast, and to proceed with a significant beach restoration of about 8.5 million m³ of sand. An extensive observation program is carried out to study beach changes and to indicate unexpected developments, so that counter-measures can be taken in good time. Results of observations over the period June 1979 until February 1981 are examined using survey data from bathymetric soundings, aerial photogrammetry and terrestrial beach measureme