Granulometric Extraction Value to Determine Waves, Currents, and Tides Characteristic of Tangsi Beach (Pink Beach) East Lombok Regency, Indonesia

The coastal area is the most dynamic place on earth. Deposition of coastal material is one of the natural agents to determine the occurrence of the coastal dynamic. Characteristics of the coastal material reflect the characteristics of waves, currents, and tides. This research was conducted at Tangsi Beach or Pink Beach, East Lombok Regency, Lombok Island. Lombok Island is one of the islands in the province of West Nusa Tenggara, considered as the world's third best island in 2018 for tourism. The main objective of this study was to extract granulometric values as estimators of the characteristics of waves, currents, and tides of Tangsi Beach, East Lombok Regency. Sorting and roundness as part of granulometry information were used as the main parameters of the granulometric approach. The method to granulometry assessment by the Gradistat program that was taken from the results of the coastal material screening. The results show that the characteristics of Tangsi Beach material are classified as Rounded poorly sorted. The classification results illustrate that wave and current conditions tend to be less stable with a distance of high highest water level (HHWL) and low lowest water level (LLWL) tend to be medium.