2021-12-02T04:50:23Zhttps://repository.dl.itc.u-tokyo.ac.jp/oaioai:repository.dl.itc.u-tokyo.ac.jp:000407162021-03-01T13:22:43ZTide and Tidal Current in the Mahakam Estuary, East Kalimantan, IndonesiaMANDANG, Idris139288YANAGI, Tetsuo139289452numerical modeltidetidal currentEstuary of Mahakam Deltariver dischargeapplication/pdfTwo-dimensional barotropic hydrodynamical model ECOMSED (Estuarine Coastal and Ocean Modeling System with Sediment) developed by HydroQual, Inc., (2002) has been applied to the Estuary of Mahakam Delta, East Kalimantan, Indonesia, to study the dynamics of tide and tidal current in this region. The model was run for 15 days (27 June.12 July 2003) using river discharge and tides as generating forces. The calculated elevation and current velocity agree well with the observed elevation (maximum amplitude of about 0.6 m) and currents velocity (maximum amplitude of about 0.15ms1) in the Mahakam Estuary. The root mean squared error in the model elevation and current velocity are 0.15 m and 0.05ms1, respectively. Wave form is changed from the mouth of the estuary to upstream. The natural oscillation period of the Mahakam Delta Tn is 19 hrs. Tn is near the period of diurnal tide and far from that of semi-diurnal tide. The decrease of semi-diurnal M2, and S2 amplitudes in the estuary is larger than that of diurnal (K1, O1) ones. The M4 tidal current amplitude follows the M2 tidal amplitude distribution, peaking at mid estuary, whereas M4 tidal elevation amplitude is greatest farther to upstream. In the Mahakam estuary, tidal elevation amplitude distortion (M4/M2) is less than 0.3. For current amplitude, M4/M2 reaches a maximum of 1.85 about 40km from the head of the estuary. The simulation results of the hydrodynamical model show that at flood condition and highest water, the waters flow into the delta, while at ebb condition and lowest water, it flows toward the Makassar Strait.departmental bulletin paperInternational Coastal Research Center, Ocean Research Institute, the University of Tokyo2008-08-20application/pdfCoastal marine science13218AA1195789913493000https://repository.dl.itc.u-tokyo.ac.jp/record/40716/files/CMS320101.pdfeng