Patna: Work on the proposed six-lane mega bridge over the Kosi river under the Patna-Purnea Greenfield Expressway has entered a key planning stage, with the process of preparing the detailed project report (DPR) gaining pace.
The private limited consultant company for the project, has sought a no-objection certificate (NOC) from the Inland Waterways Authority of India (IWAI) to conduct a mathematical model survey of the river.
Officials said the survey will be carried out between Simri Bakhtiyarpur and Kusheshwar Asthan after approval, under the supervision of IWAI’s Bhagalpur office.
Scientific survey to assess river behaviour
The mathematical model survey will examine the Kosi’s water level, flood pressure, erosion patterns, silt deposition and possible shifts in the river’s course using modern technology.
Given the Kosi’s history of changing channels and strong currents, officials said the study is essential to assess long-term structural safety before bridge construction begins.
The findings are expected to guide the technical planning and help reduce risks from future floods and erosion.
DPR to finalise bridge design and alignment
Once the survey is completed, the consultant will prepare the DPR, including the bridge design, pillar depth, road alignment, drainage system and safety measures.
The technical report will be reviewed before the project moves to the final approval stage.
Officials said the DPR will be a crucial step in determining construction timelines and cost estimates.
Key component of Bharatmala Phase II
The Patna-Purnia Greenfield Expressway is being developed under Bharatmala Pariyojana Phase II.
The proposed expressway will span 281.95km, starting from Dighwara in Patna and passing through Vaishali, Samastipur, Darbhanga, Saharsa and Madhepura, before ending at Dagarua in Purnia.
The corridor is planned to include 21 major bridges and 11 railway overbridges.
Bridge expected to improve regional connectivity
Among the proposed structures, the approximately 7km-long Kosi bridge is considered one of the most significant.
Once completed, the expressway is expected to improve road connectivity between Patna and the Kosi-Seemanchal region, reducing travel time and supporting trade and transport in eastern Bihar.
