Simple Analysis of Determination of Tidal Types of Sea Water: A Case Study in Lamong Bay Waters, East Java

The development of Integrated Coastal Zone Management (ICZM) on aspects of shoreline change, is always related to the character and dynamics of seawater in the coastal area. Changes in the forward (sedimentation) and retreat (erosion) of the coastline depending on the dynamics of seawater. These dynamics include ocean currents and ocean waves. In general, people often see tidal conditions of seawater. This paper aims to show the results of a tidal survey and a simple analysis to determine the type of tide. Tidal surveys have been carried out in Lamong Bay, East Java. The calculation and analysis of tidal parameters were have been conducted as well. The calculation results have been obtained in the form of a datum chart, namely HAT (Highest Astronomical Tide), MHHWS (Mean Highest High Water Spring), MHHWN (Mean Highest High Water Neap), MSL (Mean Sea Level), MLLWN (Mean lowest low Water Neap), MLLWS (Mean Lowest Low Water Spring), and LAT (Lowest Astronomical Tide). This simple analysis is intended to determine the type of tides just by looking at the footage of how many waves a day are there. If there is one wave a day then the tidal type is Diurnal, while if there are two waves in a day then the Semi-Diurnal type. The type of mixture will be displayed in the curve, if there are more than 1.5 waves a day then the type of mixture tends to be diurnal. On the other hand, if it is less than 1.5 waves it tends to be semi-diurnal. Two samples of recordings from Indonesia at the western end and Indonesia at the eastern end are also given.