Coastal erosion in central Chile: A new hazard? Carolina Martínez a, f, * , Manuel Contreras-L  opez b , Patricio Winckler c ,H  ector Hidalgo d , Eduardo Godoy d , Roberto Agredano e, f a Instituto de Geografía, Pontificia Universidad Cat olica de Chile, Avda. Vicu~ na Mackenna 4860, Macul, Santiago, Chile b Facultad de Ingeniería y Centro de Estudios Avanzados, Universidad de Playa Ancha, Chile c Escuela de Ingeniería Civil Oce anica, Universidad de Valparaíso, Chile d INGMAT R&D Center, Jos e Miguel de la Barra 412, 4to piso, Santiago, Chile e Departamento de Ingeniería Hidr aulica y Ambiental, Pontificia Universidad Cat olica de Chile, Santiago, Chile f Centro Nacional de Investigaci on para la Gesti on Integrada de Desastres Naturales- CIGIDEN, FONDAP 15110017, Chile article info Article history: Received 14 February 2017 Received in revised form 4 June 2017 Accepted 12 July 2017 Available online xxx Keywords: Coastal erosion Coastal evolution Storm ENSO Coastal management abstract The coasts of central Chile are increasingly affected by human activity. To date, there are no clear symptoms of shoreline change in the area; however, the incidence of recent extreme storms, in conjunction with an increase in urban area, may have created a new coastal hazard in addition to earthquakes and tsunamis. In this context, coastal erosion on four urban beaches on Valparaíso Bay was analyzed on a decadal scale. Satellite images and topographic surveys were used in order to determine spatio-temporal changes in the shoreline. These changes were linked to the long-term behavior of oceanographic variables such as wave climate and mean sea level. The analysis shows that Re~ naca Beach experienced an accretion of 12.6 m between 1964 and 2006, while Los Marineros and Las Salinas proved to be in stable conditions in the same period. Caleta Portales, in contrast, was significantly affected by a shoreline retreat of 12.6 m between 2004 and 2016. In all cases, erosion rates increased due to i) the sea level rise of up to 30 cm observed during ENSO warm phases and ii) an increase in the frequency of extreme storms, which shifted from nearly 5 events per year in the 1960s to more than 20 in recent years. The erosive trend found in the last decade suggests that this coast could deteriorate if such factors are maintained or intensified. A set of preliminary engineering measures, in conjunction with sediment managing schemes, are proposed for the sustainable development of the coastal zone. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Coastal erosion is responsible for negative impacts on urban coasts, affecting economic activities and sustainable development. Various environmental factors determine the geomorphology of open beaches, among which wind waves, storm surges, crustal changes caused by earthquakes and tsunamis, sea level changes and sediment supply are of major concern. The analysis of these variables is complicated as these phenomena occur at different spatio-temporal scales (Farris and List, 2007; Rodríguez et al., 2012). In recent years, coastal erosion has been exacerbated by the occurrence of extreme events, the frequency and intensity of which have been associated with climate variability and global environmental change (Zhang and Sheng, 2015). Coastal erosion has been much greater in places affected by abnormal storms responsible for a transitory sea level increase and complex re- sponses on the coast (Masselink et al., 2016). The potential for damage due to short-term mean sea level changes is related to atmospheric perturbations at different spatial scales, the nearshore bathymetry and the geomorphological characteristics of the coast (Morton, 2002; Masselink and Hughes, 2003; Stockdon et al., 2007; Del Río et al., 2012; Jim enez et al., 2012). The magnitude of these phenomena can cause violent changes on the coast, affecting lives and coastal infrastructure. The impact of storms on erosion processes may be increased due to the generalized urbanization in the coastal zone (Barrag an and De Andr es, 2015; Gibbs, 2015). The consequences of anthropiza- tion on numerous coasts have been described for several decades and its adverse effects have been associated with unsuitable use of * Corresponding author. Instituto de Geografía, Pontificia Universidad Cat olica de Chile, Avda. Vicu~ na Mackenna 4860, Macul, Santiago, Chile. E-mail addresses: camartinezr@uc.cl (C. Martínez), manuel.contreras@upla.cl (M. Contreras-L opez), patricio.winckler@uv.cl (P. Winckler), hector.hidalgo@ ingmat.com (H. Hidalgo), eduardo.godoy@ingmat.com (E. Godoy). Contents lists available at ScienceDirect Ocean & Coastal Management journal homepage: www.elsevier.com/locate/ocecoaman http://dx.doi.org/10.1016/j.ocecoaman.2017.07.011 0964-5691/© 2017 Elsevier Ltd. All rights reserved. Ocean & Coastal Management xxx (2017) 1e15 Please cite this article in press as: Martínez, C., et al., Coastal erosion in central Chile: A new hazard?, Ocean & Coastal Management (2017), http://dx.doi.org/10.1016/j.ocecoaman.2017.07.011