Morphological Changes and Siltation Rate Analysis of the Gaglajor-Mohonganj Navigation Route in Bhogai-Kangsha River

Abstract

Gaglajor-Mohonganj navigation route is located at Bhogai-Kangsha river which is one of the major routes of that area. The route is used for several purposes but mainly cargo and passenger vessels use the route. The motives of this study are to maintain the navigability of Gaglajor-Mohanganj route and to get an idea about the siltation and scouring rate of that route and to predict the maintenance dredging. At first, morphological analysis was conducted as well as long and cross profiles were taken at certain intervals to examine the condition of the route. Then dredging was implemented and sounding lead and GPS surveys were conducted along the navigation route. Total nine monitoring sections at various locations had been taken to assess the siltation and scouring rate. From the assessment, at monitoring section 1 and 9 the siltation rate was higher as compared to other sections. On the other hand, the scouring rate was maximum at section 2 and 4. Then the whole area was divided into three reaches based on chainage. At reach 1 (Gaglajor to Jainpur), almost 35%-45% siltation was calculated within 3-5 years. As the rate of siltation is low, dredging is needed within 4-5 years. At reach 2 (Jainpur to Dharmapasha), the siltation rate was 20%- 30% within 4-4.5 years. As the amount of siltation is very low, dredging isn’t required here. Finally, the siltation rate is 45%-55% within 2-3.5 years at reach 3 (Dharmapasha to Mohonganj), which is maximum as compared to two other reaches. So, dredging is needed readily at that location.