Browsing by Author "Esparza Acuña, César Antonio"

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    Extreme sea level projections In Cartagena Bay towards mid and end of the twenty-first century under RCP8.5 scenario
    (2023) Esparza Acuña, César Antonio; Cienfuegos Carrasco, Rodrigo Alberto; Pontificia Universidad Católica de Chile. Escuela de Ingeniería
    Este estudio examina los cambios proyectados en los niveles extremos del mar (ESLs) y sus componentes en la Bahía de Cartagena, Chile, bajo el escenario RCP 8.5 hacia mediados y finales del siglo XXI. Se observan diferencias significativas entre las proyecciones en aguas profundas y aquellas transferidas cerca de la costa en términos de alturas de ola significativas y runup de las olas, atribuidas a la influencia de la batimetría y la línea de costa en la propagación de las olas y las pendientes de las playas en el runup. Además, se prevé una subida gradual del nivel del mar de 19 cm a mediados de siglo y de 75 cm a finales de siglo. Se constata que la contribución asociada a las mareas meteorológicas (storm-surge) es insignificante, siendo los cambios proyectados en esta componente inferiores a 5 cm. También se observa un aumento generalizado de los ESLs hacia mediados y finales de siglo. El factor de amplificación (FA), que indica la frecuencia esperada de eventos de ESLs en el futuro, revela que áreas como Playa Chica, Playa Grande y Playa San Carlos experimentaran eventos que históricamente ocurrían en promedio una vez cada 100 años, con una frecuencia anual hacia fin de siglo. Las posibles consecuencias que pueden tener las tendencias proyectadas de ESL en esta bahía son discutidas en base a la metodología propuesta para transferir climas de oleaje de aguas profundas hacia puntos específicos de la costa para distintos GCMs. En conclusión, este estudio proporciona información valiosa sobre los cambios proyectados en las ESLs en la Bahía de Cartagena, enfatizando la importancia de considerar los factores locales en la dinámica de las olas y las pendientes de las playas para una estimación precisa de la contribución del runup de las olas. Estos resultados constituyen una alerta en relación a los rápidos cambios que las solicitaciones de diseño en ingeniería costera y marítima estarán experimentando en lo que queda del Siglo XXI.
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    Impacts in ports on a tectonically active coast for climate-driven projections under the RCP 8.5 scenario: 7 Chilean ports under scrutiny
    (2022) Winckler, Patricio; Esparza Acuña, César Antonio; Mora, Javiera; Melo Contreras, Óscar; Bambach, Nicolás; Contreras López, Manuel; Sactic, María Isabel
    Economic costs due to operational downtime and wave overtopping under the RCP 8.5 scenario are evaluated at 7 Chilean ports. Wave statistics for a historical period (1985–2004), mid-century (2026–2045), and end-of-century projections (2081–2100) are computed with a Pacific-wide model, forced by wind fields from six General Circulation Models. Offshore waves are then downscaled to each port, where a proxy of downtime is computed by comparing wave heights with vessel berthing criteria. The difference in downtime between the historical and future projections is attributed to climate change. Results show that some ports would reduce and others increase downtime for mid-century projections due to local effects. However, by the end-of-century, all ports would experience a reduction in downtime. Additionally, by mid-century, overtopping would increase in northern ports as a combination of extreme waves and sea-level rise (SLR), while in southern ports, it is expected to be slightly reduced. By the end-of century, overtopping would increase in the whole region, mainly driven by SLR. However, overtopping is significantly altered by coseismic uplift/subsidence that may occur during the design-life of coastal works. Finally, a few practical suggestions aimed atimproving infrastructure management and operational conditions at the analyzed ports are outlined.
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    Projections of Beach Erosion and Associated Costs in Chile
    (2023) Winckler, Patricio; Agredano Martín, Roberto; Esparza Acuña, César Antonio; Melo Contreras, Óscar; Sactic, María Isabel; Martínez, Carolina
    Economic costs associated to coastal erosion are projected in 45 sandy beaches in Chilean coasts. We compare mid-century (2026–2045) and end-of-century projections (2081–2100) of wave climate and sea-level rise (SLR) with a historical period (1985–2004) using several General Circulation Models for the RCP 8.5 scenario. Offshore wave data are then downscaled to each site, where shoreline retreat is assessed with Bruun rule for various berm heights and sediment diameters. Results indicate that mid-century retreat would be moderate (>13 m) while larger end-of-century projections (>53 m) are explained by SLR (0.58 ± 0.25 m). A small counterclockwise rotation of long beaches is also expected. To assess the costs of shoreline retreat, we use the benefit transfer methodology by using adjusted values from a previous study to the sites of interest. Results show that, by mid-century, beach width reduction would be between 2.0% and 68.2%, implying a total annual loss of USD 5.6 [5.1–6.1] million. For end-the-century projections, beach width reduction is more significant (8.4–100%), involving a total annual loss of USD 10.5 [8.1–11.8] million. Additionally, by the end-of-century, 13–25 beaches could disappear. These costs should be reduced with coastal management practices which are nevertheless inexistent in the country.