Caleta Valdés is an area constituted by a set of Holocene and Pleistocene gravel beach ridges, which form part of a barrier spit system. Longshore drift has been predominantly north to south for the last 5700 years. Evolution of the area has been monitored during the last 28 years. In this period, the northern spit has been growing southward, and its rate has increased from 25-meter per annum (1971–87), to 89-meter per annum (1987–96). During the 1996–9 time span, growth has increased up to 167-meter per annum. This growth rate implies an average movement of approximately 1400 metric tons of gravel a day during the last four years. The growth rate during the time span under study can be represented by a polynomial equation of the third order. Spit evolution can be predicted from this equation. It is thus possible to suggest that Caleta Valdés is likely to close by 2002 (±). Such a morphological change will cause drastic changes in hydrodynamics, and environmental conditions due to changes in both water salinity and temperature.