E-Paper
Expert panel flags construction issues in Polavaram project
Experts monitoring the Polavaram project in Andhra Pradesh raised concerns over dam construction integrity, urging improved design and safety measures.
An independent panel of foreign experts and Central Water Commission (CWC) engineers monitoring the progress of construction of Polavaram major irrigation project being built on Godavari River in Andhra Pradesh, have raised a series of concerns in the construction of earth-cum-rock-fill (ECRF) dam, the most crucial component of the entire project, people familiar with the development said.
The experts’ team comprising David B Paul and Gias Franco de Cisco (both from USA) and Seas Hinsberger (from Canada), along with officials from various wings of the CWC, inspected the project works for the second successive day on Tuesday.
An irrigation department official said on condition of anonymity that the panel of experts raised technical red flags concerning the alignment between the CWC observations and the ECRF dam design proposed by consultant AFRY.
“This scrutiny focuses on ensuring the structural integrity of the dam, which is tasked with withstanding extreme flood pressure, as was witnessed in August 2020,” the official said.
The experts expressed directed concern over “bleeding issues” observed in the wall, prompting a call for stringent remedial implementation. They also instructed contractor – Megha Engineering & Infrastructures Limited (MEIL) and the state irrigation department to present comprehensive data from sample ECRF sections, as they flagged a deficiency in compaction methodology.
The CWC authorities asked the authorities to ensure that the core, filter, shell, and foundation of the ECRF dam are fully protected against internal erosion and piping, even if there are extremely heavy floods. “This step will ensure that internal erosion cannot emerge as a potential failure mechanism for the dam,” the panel said in its report.
Experts have recommended a fresh derivation of the diaphragm wall’s top elevation using rigorous seepage and piping. If required, the thickness of the clay cap above the wall must be increased. “This will prevent under-seepage of water and sinkholes or blowouts at the core–foundation,” the report said.
The experts panel also called for a stringent seismic analysis study, followed by rechecking dam stability and deformations under Maximum Credible Earthquake (MCE) conditions. “This will confirm that the dam can safely withstand strong earthquakes without relying on non-conservative or insufficiently explained assumptions,” the panel said.
