The Comparation of Low Water Level Based on Observation Time Variations in Jakarta

Abstract

The implementation of the sea toll program positively encourages the development of new marine infrastructure along the area it passes. One of the problems that arise in the development of new marine infrastructure is the unavailability of chart datum values. Therefore, there is a need for tidal observations to determine the value of the chart datum in the area. This study contains a comparison of the value of the chart datum from data of 15 days, 30 days, three months, six months, and one year in the Jakarta waters. This study is using data from Jakarta tidal station of BIG. The results of this study can be used to consider the efficiency of tidal observations, especially in determining the duration of observation. The value of the chart datum (LWL) is calculated from the tidal component generated from the harmonic analysis using MATLAB. Significance test for chart datum resulted from MATLAB carried out in Excel. The average value of LWL in Jakarta waters from 15 days data is 0.104 meter, 30 days is 0.192 meter, three months is 0.216 meter, six months is 0.221 meter, and one year is 0.222 meter. The most significant difference from the LWL result is 0.118 meter from 15 days and one year’s data, and the smallest difference is 0.001 meters from six months and one-year data. The significance test determined that observation time variations didn’t have a significant influence on chart datum (LWL) values that resulted. So, this study determines that we can only choose 15 days, or 30 days tidal observation despite three months, six months, or one year’s tidal observations to result in Low Water Level value for a place.