Beach recovery capabilities after El Niño 2015–2016 at Ensenada Beach, Northern Baja California
This study investigates the recovery capabilities of a single-barred beach in the Pacific Mexican coast before and after the 2015–2016 El Niño winter. Concurrent hydrodynamic and morphological data collected over a 3-year period (August 2014–2017) were analysed to determine the subaerial-subtidal volumetric exchange and cross-shore subtidal sandbar migrations, in relation to the incident wave forcing. The beach presented a seasonal seaward and landward sandbar migration cycle. The sandbar migrated offshore during the energetic waves between November and February, and onshore during the milder wave period in spring, until welding to the subaerial beach around May. The transfer of sediment towards the subaerial section continued over the summer, reaching a complete recovery by September/October. Prior to El Niño, the subaerial beach successfully recovered by the end of summer 2015 through the landward sandbar migration process. The 2015–2016 energetic winter waves caused a subaerial volume loss of ~ 140 m3 m−1 (from October 2015 to March 2016), more than twice the amount eroded in the other winters, and the sandbar moved further offshore and to deeper depths (3–4 m) than the winter before. In addition, the energetic 2015–2016 winter waves lasted for 2 months longer than in other years, making the 2016 spring shorter. Consequently, during the onshore migration, the sandbar was unable of reaching shallow depths, and a large portion of sand remained in the subtidal beach. The subaerial beach recovered 60 and 65% of the loss in the 2016 and 2017 summers, respectively. It is concluded that the landward migration process of the sandbar during the spring is critical to ensure a full subaerial beach recovery over the mild wave period in summer. The recovery capabilities of the subaerial beach will depend on the cross-shore distance and depth where the sandbar is located, and on the duration of mild wave conditions required for the sandbar to migrate onshore.
KeywordsSubtidal sandbars Cross-shore migration Subaerial beach Subtidal beach Sediment transport Climate change
The contribution of all field assistants and the MORDICS research group (www.mordics.org) is acknowledged, especially the technical support provided in the field by Ernesto Carsolio, Julio López and Eduardo Gil. We would like to thank the anonymous reviewers for their constructive comments and suggestions.
The authors are grateful to CONACyT for the funding provided through CB-2014-238765 and INFR-2013-01I005 with the projects 238765 and 205020.
- Allan JC, Komar PD (2002) Extreme storms on the Pacific Northwest coast during the 1997–98 El Niño and 1998–99 La Niña. J Coast Res 18(1):175–193Google Scholar
- Barnard PL, Allan J, Hansen JE, Kaminsky GM, Ruggiero P, Doria A (2011) The impact of the 2009–10 El Niño Modoki on U.S. West Coast beaches. Geophys Res Lett 38(13). https://doi.org/10.1029/2011GL047707
- Barnard PL, Short AD, Harley MD, Splinter KD, Vitousek S, Turner IL, Allan J, Banno M, Bryan KR, Doria A, Hansen JE, Kato S, Kuriyama Y, Randall-Goodwin E, Ruggiero P, Walker IJ, Heathfield D (2015) Coastal vulnerability across the Pacific dominated by El Niño/Southern Oscillation. Nat Geosci 8:801–807CrossRefGoogle Scholar
- Barnard PL, Hoover D, Hubbard DM, Snyder A, Ludka BC, Allan J, Kaminsky GM, Ruggiero P, Gallien TW, Gabel L, McCandless D, Weiner HM, Cohn N, Anderson DL, Serafin KA (2017) Extreme oceanographic forcing and coastal response due to the 2015–2016 El Niño. Nat Commun 8. https://doi.org/10.1038/ncomms14365
- Cai W, Borlace S, Lengaigne M, van Rensch P, Collins M, Vecchi G, Timmermann A, Santoso A, McPhaden MJ, Wu L, England MH, Wang G, Guilyardi E, Jin F-F (2014) Increasing frequency of extreme El Niño events due to greenhouse warming. Nat Climate Change Lett 4:1–6. https://doi.org/10.1038/NCLIMATE2100 Google Scholar
- Cohn N, Ruggiero P, de Vries S, Garcia-Medina G (2017) Beach growth driven by intertidal sandbar welding. Proc Coast Dyn 199:1059–1069Google Scholar
- Komar PD (1999) Beach processes and sedimentation. Prentice-Hall, Upper Saddle River, NJ, p 544Google Scholar
- Lippmann TC, Holman RA, Hathaway KK (1993) Episodic, nonstationary behavior of a double bar system at duck, North Carolina, U.S.A., 1986-1991. J Coast Res SI 15:49–75Google Scholar
- Lizarraga-Arciniega R, Chee-Barragan A, Gil-Silva E, Mendoza-Ponce T, Martínez-Díaz de León A (2003) Effect of El Niño on the subaerial beach Playas de Rosarito, B.C., Mexico. Geofis Int 42(3):419–428Google Scholar
- Revell DL, Komar PD, Sallenger AH (2002) An application of LIDAR to analyses of El Niño erosion in the Netarts littoral cell, Oregon. J Coast Res 18(4):792–801Google Scholar
- Ruessink BG, Kuriyama Y, Reniers AJHM, Roelvink JA, Walstra DJR (2007) Modeling cross-shore sandbar behavior on the timescale of weeks. J Geophys Res 112:F0310Google Scholar
- Ruiz de Alegria-Arzaburu, A., García-Nava, H., Gil-Silva, E., Desplán-Salinas, G. 2015. A morphodynamic comparison of walled and non-walled beach sections, Ensenada beach, Mexico. World Scientific. The Proceedings of the Coastal Sediments ISBN:978-981-4355-52-0Google Scholar
- Senechal N, Pavon J, Asselot R, Castelle B, Taaouati M, Ferreira S, Bujan S (2016) Recovery assessment of two nearby sandy beaches with contrasting anthropogenic and sediment supply settings. In: Vila-Concejo A, Bruce E, Kennedy DM, MacCarroll RJ (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp.462–466. Coconut Creek (Florida), ISSN 0749-0208Google Scholar
- Seymour RJ (1998) Effects of El Niños on the west coast wave climate. Shore Beach 66:3–6Google Scholar
- Shand RD, Bailey DG, Shepherd MJ (1999) An inter-site comparison of net offshore bar migration characteristics and environmental conditions. J Coast Res 15:750–765Google Scholar