Abstract
Ibusuki coast has been the most popular spot for the sand steamed hot spring. In addition, its sandy beach has important functions in the environment and disaster prevention. However, the loss of its functions has been threatened by the recent coastal erosion. Integrated shore protection system composed of beach nourishment, groin and distorted ripple mat (DRIM) has been applied to prevent the nourished sand from being washed away. The beach nourishment was constructed in 2009 and 2011 with topographic monitoring surveys. The present study discusses the effects of the countermeasure work comprised of DRIM and groin based on the survey results from 2010 to 2015. Evaluation of the beach deformation was carried out through topographic change, deformation trend and empirical eigenfunction analysis. From the results of the evaluation, it was confirmed that the countermeasure work is effective in retaining the nourishied sand.
