Application numerical model to study on morphological change in redriver coasltal area

Abstract

     This paper presents some results application of the integrated model (hydrodynamics-wavesediment transport) basedd on Delft3d system model to study on morphological change in Red river delta (RRD) coastal area. The numerical model was validation/calibration by measured data and set up with differences scenarios to assess characteristics of morphological change as well as estimate role of wind, wave and tide on morphological change. The results showed that sediment source decided maximum deposition rate, it was more than in the rainy season (average of 2.215cm/month) compared with 0.03cm/month in the dry season. Wind-wave directions have different effect on sediment transport as well as morphological change in RRD coastal area. Windwave make and increase erosion trend in the dry season. In the rainy season, NE wind-wave is factor which cause decreased deposition in outer of Day mouth, coastal Hai Hau and make increase deposition rate in outer of Van Uc mouth. On other hand, wind-wave SE causes increase deposition in outer Day mouth, coastal Hai Hau and make a strong decrease deposition rate in outer of Van Uc mouth. Win-wave in all direction causes decrease deposition in Ba Lat and increase deposition rate in Tra Ly mouth. In the dry season, tidal oscillation makes decrease deposition rate, increase erosion rate in Ba Lat and Van Uc mouth. It also causes increase deposition rate in near coast of Ba Lat and Van Uc mouth. In coastal Hai Hau, tide (combined with wave) causes increase erosion in near coast.