Abstract

Rip currents are a hazardous phenomenon for beachgoers worldwide. These narrow currents in the surf zone move quickly in an offshore direction and can occur near hard structures such as jetties, piers, breakwaters, and rocks. This study examines the hazard rate (HR) for swimming in different water depths due to rip currents and coastal circulation currents (vortices), as well as the effects of detached breakwater structures on rip and coastal circulation currents (RACC) at the surf zone. The objective is to find a solution to the problem of drowning due to rip currents resulting from the presence of detached breakwaters. Physical and numerical modeling, field measurements, and shore surveying were used to achieve the study's goals. The study was conducted in the wave flume at Abu-Quire Research Station, Alexandria Egypt, for different scenarios. The numerical model (MIKE 21) was applied on the northwestern coast of Egypt about 21 km west of Alexandria. The results showed that the HR for swimming in water depths more than 1.50 m ranges from high to extreme hazard (1.275 m2/s: 2.2 m2/s), and the rip current velocities near the breakwaters are high, ranging from 0.05 m/s up to 1.05 m/s. Their length can extend from 30.0 m up to 200.0 m offshore. It was concluded that the RACC is caused due to the detached breakwaters, as well as the interaction between the boundaries and the beach bed. The proposed solution for RACC formations due to the presence of detached breakwaters is the partial closure of openings between the existing detached breakwaters using submerged breakwaters.

Keyword

Rip and coastal circulation currents, Hazard rate, Drownings, Submerged breakwater, Al nakheel beach.

Cite this article

Hassan RM, Elstohey AS.Effects of detached breakwaters on drowning due to rip and circulation currents. International Journal of Advanced Technology and Engineering Exploration. 2023;10(99):153-172. DOI:10.19101/IJATEE.2022.10100168

Refference

[1]Oliveira MF, Oliveira F, Teixeira A. Modelling the morphodynamics in the vicinity of a submerged detached breakwater. Journal of Integrated Coastal Zone Management. 2020; 20(2):131-43.

[2]Rakha KA, Abul-Azm AG. Nearshore wave modelling for a beach with coral reefs along the Red Sea. In proceedings 9th international coral reef symposium, Bali, Indonesia 2000 (pp. 311-3).

[3]https://www.who.int/news-room/fact-sheets/detail/drowning. Accessed 24 January 2023.

[4]Bowen AJ. Rip currents: 1. theoretical investigations. Journal of Geophysical Research. 1969; 74(23):5467-78.

[5]Drozdzewski D, Shaw W, Dominey-howes D, Brander R, Walton T, Gero A, et al. Surveying rip current survivors: preliminary insights into the experiences of being caught in rip currents. Natural Hazards and Earth System Sciences. 2012; 12(4):1201-11.

[6]Brighton B, Sherker S, Brander R, Thompson M, Bradstreet A. Rip current related drowning deaths and rescues in Australia 2004–2011. Natural Hazards and Earth System Sciences. 2013; 13(4):1069-75.

[7]Arozarena I, Houser C, Echeverria AG, Brannstrom C. The rip current hazard in Costa Rica. Natural Hazards. 2015; 77:753-68.

[8]Brewster BC, Gould RE, Brander RW. Estimations of rip current rescues and drowning in the United States. Natural Hazards and Earth System Sciences. 2019; 19(2):389-97.

[9]Castelle B, Mccarroll RJ, Brander RW, Scott T, Dubarbier B. Modelling the alongshore variability of optimum rip current escape strategies on a multiple rip-channelled beach. Natural Hazards. 2016; 81:663-86.

[10]Austin M, Scott T, Brown J, Brown J, Macmahan J, Masselink G, et al. Temporal observations of rip current circulation on a macro-tidal beach. Continental Shelf Research. 2010; 30(9):1149-65.

[11]Scott TM, Russell P, Masselink G, Austin MJ, Wills S, Wooler A. 14 rip current hazards on large-tidal beaches in the United Kingdom. Rip Currents: Beach Safety, Physical Oceanography, and Wave Modeling, CRC Press, Boca Raton. 2011: 225-43.

[12]Johnson D, Pattiaratchi C. Boussinesq modelling of transient rip currents. Coastal Engineering. 2006; 53(5-6):419-39.

[13]Weir B, Uchiyama Y, Lane EM, Restrepo JM, Mcwilliams JC. A vortex force analysis of the interaction of rip currents and surface gravity waves. Journal of Geophysical Research: Oceans. 2011; 116(C5):1-16.

[14]Long JW, Özkan‐haller HT. Offshore controls on nearshore rip currents. Journal of Geophysical Research: Oceans. 2005; 110(C12):1-21.

[15]Mccarroll RJ, Brander RW, Macmahan JH, Turner IL, Reniers AJ, Brown JA, et al. Evaluation of swimmer-based rip current escape strategies. Natural Hazards. 2014; 71:1821-46.

[16]Haas KA, Svendsen IA, Haller MC, Zhao Q. Quasi‐three‐dimensional modeling of rip current systems. Journal of Geophysical Research: Oceans. 2003; 108(C7):1-21.

[17]Short AD. Australian rip systems–friend or foe? Journal of Coastal Research. 2007: 7-11.

[18]Brander RW, Short AD. Morphodynamics of a large-scale rip current system at Muriwai Beach, New Zealand. Marine Geology. 2000; 165(1-4):27-39.

[19]Gensini VA, Ashley WS. An examination of rip current fatalities in the United States. Natural Hazards. 2010; 54:159-75.

[20]Hassan RM, Hassan SE. Alleviation of deadly hazards of rip and circulation currents using near shore self lighting floating units. Journal of American Science. 2019; 15(12):28-38.

[21]Mccarroll RJ, Castelle B, Brander RW, Scott T. Modelling rip current flow and bather escape strategies across a transverse bar and rip channel morphology. Geomorphology. 2015; 246:502-18.

[22]Short AD, Hogan CL. Rip currents and beach hazards: their impact on public safety and implications for coastal management. Journal of Coastal Research. 1994: 197-209.

[23]Williamson CS. Nutrition in pregnancy. Nutrition Bulletin. 2006; 31(1):28-59.

[24]Reniers AJ, Macmahan JH, Thornton EB, Stanton TP, Henriquez M, Brown JW, et al. Surf zone surface retention on a rip‐channeled beach. Journal of Geophysical Research: Oceans. 2009; 114(C10):1-12.

[25]Dalrymple RA, Macmahan JH, Reniers AJ, Nelko V. Rip currents. Annual Review of Fluid Mechanics. 2011; 43:551-81.

[26]Bruneau N, Castelle B, Bonneton P, Pedreros R, Almar R, Bonneton N, et al. Field observations of an evolving rip current on a meso-macrotidal well-developed inner bar and rip morphology. Continental Shelf Research. 2009; 29(14):1650-62.

[27]Miloshis M, Stephenson WJ. Rip current escape strategies: lessons for swimmers and coastal rescue authorities. Natural Hazards. 2011; 59:823-32.

[28]Macmahan JH, Thornton EB, Reniers AJ. Rip current review. Coastal Engineering. 2006; 53(2-3):191-208.

[29]https://scoopempire.com/death-beach-alexandrias-al-nakheel-beach-drowns-its-latest-victims/. Accessed 24 January 2023.

[30]https://www.egypttoday.com/Article/1/54594/Alexandria.Accessed 24 January 2023.

[31]Rampal N, Shand T, Wooler A, Rautenbach C. Interpretable deep learning applied to rip current detection and localization. Remote Sensing. 2022; 14(23):1-22.

[32]Hassan RM, Abd-elmonem IM, Iskander MM, Almaghraby MM. Control of floating object directions on rip current at beaches by using deflectors. The International Journal of Engineering Trends and Technology. 2023; 71(1): 317-29.

[33]Mcgill SP, Ellis JT. Rip current and channel detection using surfcams and optical flow. Shore & Beach. 2022; 90(1):50-8.

[34]Iskander MM, El-anssary AE, El-mooty MA, Nagy HM. Investigating the value of monitoring the implemented coastal structures along El Agami beach, Alexandria, Egypt: case study. Journal of coastal Research. 2007; 23(6):1483-90.

[35]https://assets.publishing.service.gov.uk/media/602bbb768fa8f50386a7f8aa/Flood_risks_to_people_-_Phase_2_Project_Record.pdf. Accessed 24 January 2023.

[36]Pranzini E, Rossi L, Lami G, Jackson NL, Nordstrom KF. Reshaping beach morphology by modifying offshore breakwaters. Ocean & Coastal Management. 2018; 154:168-77.

[37]Sulaiman D, Hidayat H. The role of geotextile tube as low-crested breakwaters in restoring severe beach erosion problem at Pebuahan beach in Bali Island. Coastal Engineering Proceedings. 2020; (36v):1-6.

[38]Zahra KA. Assessment of implementation stages of submerged breakwater on the bay and shoreline at Al-ahlam sea resort, northwest coast, Egypt. Ocean & Coastal Management. 2018; 165:15-32.

[39]Vu MT, Nguyen VT, Luong PH, Nguyen TH, Nguyen TV. Preliminary study on coastal protections for Balang beach, Nha Trang city, Vietnam. In international conference on substainability in civil engineering, Hanoi, the transport journal 2018 (pp. 609–16).

[40]Burt J, Bartholomew A, Bauman A, Saif A, Sale PF. Coral recruitment and early benthic community development on several materials used in the construction of artificial reefs and breakwaters. Journal of Experimental Marine Biology and Ecology. 2009; 373(1):72-8.

[41]Saengsupavanich C, Ariffin EH, Yun LS, Pereira DA. Environmental impact of submerged and emerged breakwaters. Heliyon. 2022; 8(12):1-9.