Ocean Engineering 190 (2019) 106421 Available online 18 September 2019 0029-8018/© 2019 Elsevier Ltd. All rights reserved. The extreme waves in Kuwaiti territorial waters using measured data N. Al-Mashan a, * , A. Jradi a , Hasan Aldasthi b , S. Neelamani c a Department of Civil Engineering, College of Engineering and Petroleum, Kuwait University, Kuwait b Directorate General of Civil Aviation, Kuwait c Kuwait Institute for Scientifc Research, Coastal Management Program, Kuwait A R T I C L E INFO Keywords: Extreme waves Kuwaiti territorial waters Gumbel distribution Weibull distribution Signifcant wave height Measured wave data ABSTRACT The extreme signifcant sea wave height, swell wave height and total wave height were determined for return periods of 10, 25, 50, and 100 years for seven stations in Kuwaiti territorial waters based on measured data. The measured wave data was obtained from Kuwait Meteorological Department of the Directorate General of Civil Aviation (DGCA). The extreme wave analysis was carried out using Gumbel and Weibull distribution methods. It was noticed that the Weibull distribution is a better ft to the measured wave heights in Kuwaiti territorial waters. The result of the extreme signifcant sea wave height for 100-year return period ranges between 3.24 and 3.99 m, while there is a large variation in the extreme signifcant swell wave height, which ranges between 2.31 and 4.55 m. Furthermore, the extreme signifcant total wave height varies from 3.37 to 4.25 m among these seven stations in Kuwaiti waters. The comparison between the present study and the prediction of the extreme wave heights based on hindcasted data by Neelamani et al. (2007) shows closer correlation of the results, except for the North West part, where there are some noticeable differences in the results. The present study is important for optimal design of marine structures and coastal infrastructure development of Kuwaiti islands. 1. Introduction Nowadays, there is an increase in marine and off shore structures all over the world. Thus, the estimation of extreme wave condition is an important step to ensure optimal design and safety of such marine structures. The extreme wave condition is expressed in terms of wave characteristics such as signifcant wave height, which is the most important parameter in coastal structures design. The aim of this paper is to avoid under either estimation of extreme wave height that leads to unsafe structures or over estimation of extreme wave height that leads to uneconomical structures. This study is important for oil companies for the installation of offshore drilling platforms in Kuwaiti territorial wa- ters to explore and exploit crude oil well below the seabed. The signif- icant wave height is also an important parameter for sediment transport and coastal erosion. It can be used to calculate the shoreline erosion (Ekphisutsuntorn et al., 2010), which is present in Kuwait, for example, the island Qaruh is suffering from erosion in the east to the south part of its shoreline. In Kuwait, most of the marine structures are over-designed because there is not an actual application of an extreme wave height prediction in Kuwaiti territorial waters in coastal structures design process. Unfortunately, only a few researchers have studied the extreme wave heights in the Arabian Gulf especially in Kuwait territorial waters. Kuwait is an arid country located in the northeastern corner of the Arabian Peninsula and at the northwestern corner of the Arabian Gulf as shown in Fig. 1. It has boundaries with Iraq from the north and west and southern boundaries with Saudi Arabia. The geographic coordinate system of Kuwait is between longitudes of 46.30 � and 48.30 � east of the Greenwich Prime Meridian and latitudes of 28.45 � and 30.05 � north of the equator. Kuwait has a total area of 17,818 square kilometers and a total area of territorial water about 7611 km 2 , as stated by the Amiri Decree on December 17, 1967. Kuwait has nine islands: Failaka, Boub- yan, Maskan, Warba, Ouha, Um AIMaradem, Um AI-Naml, Kubbar, and Qaruh. Kuwait coastal zone is a vital location because of its importance for residential, commercial, oil industry, water resource and electrical generation purposes. Development projects in fve of Kuwait islands: Boubyan, Warba, Failaka, Maskan and Aouha have been planned for tourism and marina construction purposes. Thus, the estimation of the design wave height for different return periods is essential for optimal marine structure and coastal design in these locations. Until now, most of the extreme wave height prediction for different return periods has been conducted based on hindcasted wave height data due to the diffculties of obtaining long-term wave measurements * Corresponding author. E-mail address: nourah.almashan@ku.edu.kw (N. Al-Mashan). Contents lists available at ScienceDirect Ocean Engineering journal homepage: www.elsevier.com/locate/oceaneng https://doi.org/10.1016/j.oceaneng.2019.106421 Received 3 July 2019; Received in revised form 5 September 2019; Accepted 6 September 2019