Kim, I.H., Lee, H.S. and Song, D.S., 2013. Time series analysis of shoreline changes in Gonghyunjin and Songjiho Beaches, South Korea using aerial photographs and remotely sensed imagery

Given the speed and pervasiveness of anthropogenic landcover changes, especially in coastal areas, monitoring shoreline alterations and their impacts is critical for intelligent coastal development and beach use management. In this study, we describe a monitoring and analysis framework that uses aerial photography, remotely sensed imagery, and field surveys to detect changes in beach width and area along Gonghyunjin and Songjiho Beaches in South Korea. We used IKONOS imagery acquired in 2004; aerial photographs captured in 1991, 2005, 2009 and 2010; and field surveys conducted in 2010 and 2011. Based on comparisons of these data sources, we detected widespread erosion on both beaches starting in 2004, resulting in 12% reduction in the plane area of these beaches between 2004 and 2010. Most dramatically, we noted that beach width eroded by 28.5 m at the point 700 m south of Gonghyunjin Harbor, and similar declines occurred at several other locations. Erosion occurred at these locations because extended breakwaters in the Gonghyunjin Harbor either blocked or interrupted drift sand transport processes, causing sand to be carried away from some locations without accretion to replenish it. In addition, according to field surveys, we determined that erosion and accretion processes continued to vary seasonally in 2010 and 2011, resulting in smaller overall changes than those in the study years prior to 2010. However, we suggest that severe erosion may occur in the future at some locations if sand continues to be transported north onto Songjiho Beach without replenishment. Thus, we demonstrated that the construction of artificial structures around the harbor caused changes along the shoreline. Our monitoring framework has important applications for future observation of anthropogenically driven changes to this coastal area and serves as an applicable tool in other coastal regions worldwide.