The primary objective of the study was to experimentally explore the protection performance of the emergent vegetation on the morphological changes of a coastal zone. The experiments were conducted under both regular and irregular waves in two different wave flumes. A dimensionless number was derived to characterize the beach profile response under the protection of emergent vegetation. Accordingly, empirical relations were derived that explained the pattern exhibited by the experimental data. The list of wave parameters and beach erosion related functions were incorporated in relation to vegetation intensity in order to define coastal zone response. The relationships of these functions followed good trends with the derived dimensionless number. The findings showed that fall speed parameter is not necessarily involved whereas depth parameter is an important factor while defining the damage. The damage parameter is also considered to formulate the limits of dynamic and static stability of beach profiles under the protection of emergent vegetation. (c) 2005 Elsevier Ltd. All rights reserved.