Author(s): Romeji Ngangbam; Jitender Kushwaha; Victoria Ningthoujam; Mukesh Kumar Yadav; Jayalaxmi Ngasepam; Sandy Thingujam; Sapam Ksheroda

Linked Author(s): Ngangbam Romeji Singh

Keywords: domain; non-homogeneous; finite element method; steady; transient; exit gradient

Abstract: Embankment dams are vulnerable to internal and slope erosion and more significantly piping due to seepage flows that compromises the dam safety. In this study, the seepage through Singda dam, an earth-fill embankment dam located about 20 km from Imphal, the capital of Manipur in India, has been investigated using numerical model SEEP/W. The dam has been constructed to impound flows of three minor streams – Singda, Kharam and Ireng lok and commissioned in 1973, mainly to supply 16 to 19 MLD potable water to Imphal urban and its peri-urban areas. Seepage analysis of the dam has not been entirely conducted as practical problems are not easily convertible into an equivalent numerical domain due to the heterogeneity of the earth material and the varying boundary conditions (Athani et al. 2015). Singda embankment dam with gross storage capacity of 9.72 MCM, is of length 490m with a vertical sand chimney at the downstream side of the core, and 60m height from deepest foundation bed level. The present study encompasses a multiple scenario study of both homogeneous and non-homogeneous Singda dam sections under steady and transient flow states with slow as well as instantaneous (rapid) drawdown conditions. The exit gradient of the embankment dam section was found to be less than unity (<1.0) for the various scenarios investigated with observed reservoir water levels, which conforms the safety criteria of the dam.

DOI: https://doi.org/10.3929/ethz-b-000675921

Year: 2024