Water Resources Management

, Volume 28, Issue 12, pp 3937–3955

A Comprehensive Approach for Estimating Hydraulic Quantities in a Multi-branched Estuarine System

  • Motohiko Umeyama
  • Duc Hoang Nguyen
  • Cat Vu Minh
  • Xuan Roanh Le
  • Satoshi Motani
Article

DOI: 10.1007/s11269-014-0719-7

Cite this article as:
Umeyama, M., Nguyen, D.H., Vu Minh, C. et al. Water Resour Manage (2014) 28: 3937. doi:10.1007/s11269-014-0719-7

Abstract

Despite many previous investigations, there is no theoretically justifiable equation to determine the freshwater discharge, tidal velocity, and salinity in a complex estuary that contains several branches. In this study, the longitudinal distributions of freshwater and salinity concentration in multi-branched estuaries are investigated using a mathematical model, considering the energy balance by frictional head loss and the salt balance by diffusion and advection in a one-dimensional steady-state condition. We attempt to obtain the time-mean freshwater discharge rate quantitatively at a junction where the main flow separates into two branches. The salinity distribution along each branch is calculated by following the dispersion coefficient equation previously proposed for a single estuary. The salinity field is divided into the near-coast region and the upstream region, because in each segment the inland velocity varies according to the tidal flux. For computing the tidal velocity, we propose the Burgers equation and the Hoph-Cole transformation. The theoretical results obtained by these equations were found to be in good agreement with a set of observed data in the Red River estuary system.

Keywords

Salt intrusionGeometric characteristicsMulti-branched estuaryRed River

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Motohiko Umeyama
    • 1
  • Duc Hoang Nguyen
    • 2
  • Cat Vu Minh
    • 3
  • Xuan Roanh Le
    • 3
  • Satoshi Motani
    • 1
  1. 1.Department of Civil and Environmental EngineeringTokyo Metropolitan UniversityHachiojiJapan
  2. 2.Department of Hydrology and EnvironmentsWater Resources UniversityHanoiVietnam
  3. 3.Department of Marine and Coastal EngineeringWater Resources UniversityHanoiVietnam