Pengaruh Kemiringan Seawall Terhadap Run Up Gelombang di Pantai Indah Selatbaru Kecamatan Bantan

Abstract

Selatbaru Indah Beach is one of the tourist beaches in Bengkalis Regency, located in Bantan District, 22 km from Bengkalis City. This beach has sheet pile construction using geobag materials and Armor rock. Currently experiencing changes in the plaster structure with the slope of the previous structure was 1:3 changed to 1:5. This research is to find out which slope of the structure is more efficient in reducing run up and overtopping in the Selatbaru tourist beach area. This research method uses field observation methods with surveys of building conditions and wave and tidal data from other sources. Wave height data is 0.5 m with HWL 2.45 m, LWL 0.03 m, wave period is 2.7 seconds, freeboard height is 0.45 m now and 0.25 m after a sea level rise of 0.2 m from present condiition. The results of the analysis for the slope of 1:3 sheet plaster, the value of Irribaren is 1.58 and Ru/H is 1.7, so the run up value is 0.85 m and overtopping occurs, for the slope of sheet pile 1:5 the value of Irribaren is 1.58 and Ru/H is 0.95, so the run up value is 0.2 m and there is no overtopping. The slope of 1:5 is able to reduce run up from 0.85 m to 0.2 m by 76%. This is because the sloping side of the sheet pile towards the sea will reduce wave run up.

Keywords: Seawall, run up, slope structure, overtopping