The construction of river training works for Jamuna Multipurpose Bridge, the biggest project in Bangladesh, started in 1995. DHI in association with SWMC was involved in mathematical modelling study for the bridge site since August 1995.

The approach for the modelling activities was based on combined use of one and two dimensional hydrodynamic and morphological models to determine the bed level changes and associated bank erosion rates. The 2D model covered 36km reach of the river and used a curvilinear grid which has the advantage of providing accurate resolution of the curved boundaries.

Both 1D braided model (which provided boundary conditions for the 2D model) and 2D model have been calibrated for the 1995 monsoon when the discharges were high. Water levels, discharges, sediment transport and morphological changes were reproduced with good accuracy, especially at the bridge site.

The results show that confluence and constriction scour will take place between the guide embankments, bank erosion will be enhanced along the left bank at the downstream of the bridge site and a new channel at the downstream of the western guide embankment will develop.

Recently SWMC entered into a 3-year contract with JMBA for maintenance of the morphological model upto 2001. The activities include detail bathymetric survey and post-monsoon scenario for 1998 devastating flood in Bangladesh.