Comparative analysis of singlebeam and multibeam echosounder bathymetric data

Abstract

Gresik Port, East Java, is a port that has a very strategic location because there are several large industries such as the PT. Petrokimia Gresik, PT. Semen Gresik, PT. Maspion, PT. Wilmar, PT. Pelindo III, and other factories. This condition makes the need to obtain accurate necessary water information such as bathymetry. Bathymetry is an essential parameter of port management. There are currently two types of equipment used frequently to measure bathymetry, namely Singlebeam and Multibeam Echosounder (SBES and MBES). However, these two bathymetric survey instrument tools may not provide the same depth. This study compared the bathymetry data derived from MBES and SBES, collected at the same time and place. The depth comparison test between the SBES and MBES shows the Z 0 of the statistical Z test is 0.018 m. This Z 0 value is smaller than the Z table for the 95% confidence level, which ranges -1.96 < Z 0 < 1.96. This result means that the data has a good quality within the standard 1a of the IHO SP-44 5 th edition in 2008.[1] The comparison between the SBES and MBES surfaces reveals that the cut volume is greater than the fill volume, which is 21078.81 m 3 . This result means the SBES data has shallower average depths than the MBES data. The dredge volume difference of the SBES and the MBES data with 15 m depth as a reference is 23617 m 3 inside the area 22.1 Ha. It means the dredge volume difference of 0.11 m 3 per m 2 or 11 cm difference depth in m 2 .