The Hydrodynamic Modeling in Kawal Estuary Area: A Study of Current Patterns
Reni Wijayanti (a*), Dewi Surinati (a), Risandi Dwi Putra (b), Asep Mulyono (c), Ida Narulita (d), M Rahman Djuwansah (c)

a) Research Center for Oceanography, National Research and Innovation Agency, Jakarta 14430, Indonesia
*reni.wijayanti[at]brin.go.id
b) Naval Architecture Department, Faculty of Engineering, Raja Ali Haji Maritime
University, Tanjungpinang 29411, Indonesia
c) Research Center for Environmental and Clean Technology, National Research and Innovation Agency, Bandung 40135, Indonesia
d) Research Center for Climate and Atmosphere, National Research and Innovation Agency, Bandung 40135, Indonesia

Abstract

Kawal Estuary is a river mouth region located in the east of Bintan Island that facing the Natuna sea which affected by monsoon wind conditions predominantly. This area localized for tourism, settlement, seagrass conservation, and fisherman harbour affecting the sustainability of coastal activities and conditions such as abrasion, sedimentation and coastline changes. Therefore, this area becomes an unique region with its geographical, hydro-oceanographic and social conditions. Hydrodynamic modeling was conducted to study the characteristics of the current pattern conditions around the Kawal river in every season for 1 year. Modeling is conducted using MIKE 21/3 integrated flow model software. The result of modeling also had a good validation value of 81.69% against naotide tidal data and 85.04% against field data measurements using the Recording Current Meter tool in March 2021. The magnitude and direction of the surface current are observed at four extraction points that are representing northern, southern, and middle areas. At the RCM measurement point, North and South points indicate that the dominant surface current moves uniformly in the direction between north-east. Only at the midpoint of the surface current detected moving varies along all season. From tidal conditions (towards tide, tide, towards ebb and ebb), surface currents are observed have 2 patterns, flowing to southwest-south and to northeast (reverse counterclockwise) at different hours both during spring and neap conditions. The value of the surface current will be at peak level when heading to the towards tide condition.

Keywords: Hydrodinamic Modeling- Current Patterns- Mike21/3- Flow Model- Kawal Estuary

Topic: Oceanography