Determination of the beach morphodynamic state using Dean's ? parameter frequently results in wrong classification, mainly for the intermediate stages. This is a consequence of the low correlation between the settling velocity (or grain size) of the beach face sediments and the topographic gradient, when applied to a single beach. For this reason a new approach for the identification of the morphodynamic state is proposed by inferring a new parameter (?) obtained through the comparison of the wave height (H_bs) and mean wave period (T) in the outer breaker zone to the height and duration of wave uprush at the beach face as a surrogate measure of the wave energy dissipation in the surf zone using the equation:

where ? is the beach face gradient, D_up the distance of wave run-up, T_up the mean duration of the significant wave run-up and T the mean wave period.

The method was compared to the visual classification of four beaches, of distinct wave climate, grain size and morphodynamic state, located north and westward from Cabo Frio, using the results of twenty four monthly measurements of beach and surf zone profiles during low spring tide associated to measurements of wave height, period and sediment settling velocity. The result allowed a reasonably good discretization between the different states, with exception of the Rhytmic Bar and Beach State, which was not observed during the fieldwork. The following limits were found:

Beach State	? Parameter
Dissipative	<0.5
Longshore Bar and Trough	0.5-0.8
Transverse Bar and Rip	0.8-1.0
Low Tide Terrace	1.0-2.0
Reflective	>2.0

This result should be considered as a first approach, and only the application and test of the method in different places will give a more reliable answer of the applicability of this procedure.