The US state of Hawaii consists of 8 volcanic islands: Hawaii, Maui, Oahu, Kahoolawe, Lanai, Molokai, Kauai and Niihau. According to 2012 Census data, the total population of Hawaii was 1,426,393 (World Population Review, 2018). Kauai's population of 66,921 makes up 4.69% of Hawaii's total population, and Oahu's population of 953,207 makes up 66.83% (World Population Review, 2018). Ontop of experiencing growing populations and urbanization, Oahu and Kauai also experience millions of tourists per year (Hawai'i Tourism Authority, 2016). With such human activity and development occurring around Hawaii's coastal areas, it would be beneficial for decision makers to gain more knowledge regarding the effects of humans on coastal erosion (Hawai’i Tourism Authority, 2016).

The islands of Oahu and Kauai are chosen for this study to gain insight as to where and why coastal erosion due to human activity was happening more specifically. As seen in Figure 1, Oahu consists of a significant amount of urban built-up areas, while Kauai has much less development (Figure 2). By comparing these two islands, a baseline can be set for what is considered ‘a lot’ of human activity in Hawaii. This may give decision makers a better understanding of which areas of human activity to focus on among the multiple islands of Hawaii. The Hawaii Coastal Erosion (2016) website provides data displaying historical records of shoreline changes all along the coasts of Oahu and Kauai. The historical records show it is evident that erosion is occuring along the entirety of Oahu’s and Kauai’s coasts, therefore, a more detailed analysis of these coasts will provide some insight as to where and why coastal erosion is happening more specifically.

Figure 1. State land use districts of Oahu, Hawaii.

Figure 2. State land use districts of Kauai, Hawaii.