Impact of Internal Road Network on Water-Logging Inside Polders

Water logging is the most acute problem inside the polders of the south-west coastal region of Bangladesh. Though polders were constructed in order to protect the region from tidal inundation, these polders are now believed to be responsible for creating water-logging issues. It is generally believed that polders cause skewed sedimentation in the rivers, which then results in rise in bed levels of the peripheral rivers when compared to land elevation inside the polders. This phenomenon slowed down the natural gravity drainage and as a result extensive water-logging was initiated. While trying to find the causes of water-logging inside polders, impacts of the internal drainage system was largely ignored. Unplanned road construction inside polders hindered the natural drainage route which resulted in delayed and obstructed drainage. This research aims to study the impacts of road network and the dredging of peripheral river on water-logging. It is found that the appropriate drainage route along with river excavation can reduce the extent of water-logging in the area. The strategic placement of culverts plays an important role in determining maximum drainage rate. River dredging is only effective if the internal drainage system is improved.