Gradation from oceanic to estuarine beaches in a ría environment: A case study in the Ría de Vigo

Abstract

Beaches are an important consideration in coastal management. Morphodynamic classification of sandy beaches is used for open-ocean, wave-dominated environments, but fails to describe the shape of natural sandy beaches located in low-energy environments. An important consequence of this is that these environments are excluded from current morphodynamic models, making the design of efficient coastal management plans difficult to achieve.Many of these types of beaches occur in quick succession along the coastline in protected environments such as estuaries, lagoons, fjords and rías, which are favourite sites for human settlements. These particular environments are of enormous economic importance and constitute the zones of greatest human impact on the coast. Correct management requires a good understanding of the physical factors that affect each type of beach and of the interactions between such factors.Fifteen beaches in the Ría de Vigo (NW Spain) were studied in order to determine how the gradational changes from oceanic to estuarine conditions affect the beach morphology and intertidal sediments. The balance between wave action and sedimentary supply was found to be the controlling factor in the ría. The results of this study provide useful information about a coastal ría environment, which will enable better design of a suitable integrated coastal plan for management of rías.