Seasonal morphodynamic classification of beaches in Necochea municipality, Buenos Aires Province, Argentina

Abstract

The seasonal morphodynamic classification of Necochea and Quequén beaches (Buenos Aires Province, Argentina) was determined. Based on 102 seasonal beach profiles and sediment sampling between February 2006 and December 2009, variations in morphology and sediment budgets of five beaches were studied. According to the dimensionless fall parameter and the relative tide range, the beaches were classified depending on their modal morphodynamic state. In Quequén, beaches presented intermediate and reflective states, whereas in Necochea they presented dissipative states. The Iribarren number showed that plunging and spilling breakers predominated in Quequén and Necochea, respectively. In winter, the beaches became more dissipative, while in summer-autumn they were more reflective. This general behavior agrees with the erosion/accretion cycles. Beach profile variability was higher in Quequén. These results have been used to elaborate the coastal management program of the area.

Hazard, vulnerability and coastal erosion risk assessment in Necochea Municipality, Buenos Aires Province, Argentina

“…Wave height presents a seasonal behavior, the highest in winter (1.26 m) and the lowest in summer (0.96 m), with a mean significant wave height of 1.18 m. Wave direction is ESE to SW with a predominance of waves from the SSE in all seasons (Merlotto et al 2013). Mean wind speed is 17.8 km/h and the winds blow predominantly from the N and NW (Merlotto et al 2013).…”

“…According to the predominant morphodynamic state the Quequén beaches are intermediate and the Necochea beaches are dissipative (Merlotto et al 2013). The Necochea beaches are composed of well-sorted fine sands, whereas the Quequén beaches are composed of poorly-or moderately-sorted medium to coarse sands.…”

“…& Storm waves effects: storm waves constitute a significant erosion factor in the study area (Merlotto et al 2013) and their impact could increase in the coming years. Changes in frequency, duration, and wave height during storms were observed in Argentina (D'Onofrio et al 2008;Fiore et al 2009;Dragani et al 2010) as well as in other coastal regions related to the global climate change (Wu et al 2002;Dolan and Walker 2006;Frazier et al 2010).…”

“…Changes in frequency, duration, and wave height during storms were observed in Argentina (D'Onofrio et al 2008;Fiore et al 2009;Dragani et al 2010) as well as in other coastal regions related to the global climate change (Wu et al 2002;Dolan and Walker 2006;Frazier et al 2010). The categories of the indicator (Table 1) were established based on the morphological and volumetric changes registered in the beaches (Merlotto et al 2013). By means of seasonal beach profiles carried out during 2006-2009, positive, stable or negative sedimentary balances of five beaches of the study area were estimated.…”

“…Highest speeds correspond to winds from the SW and S, in concordance with the prevailing largest storm surges and wave storms direction. These storms are considered a main natural cause of morphodynamic changes in the beaches of the study area (Merlotto et al 2013).…”