Mohammad Gharehzadeh Shirazi, PhD Ahmad Safuan Bin A Rashid, PhD Abideen Adekunle Ganiyu, PhD



This paper concerns the adequacy of utilising a chimney drain, horizontal filter and cutoff wall in reducing seepage through an earthen dam. To this end, anti-seepage systems comprising a chimney drain, a horizontal filter and a cutoff wall were investigated.

Variations of lengths, angles and locations of these features were studied. The amount of seepage was determined using SEEP/W software.

The results indicated that by expanding the vertical chimney drain and the horizontal filter from the embankment toe to half or three-quarters of the downstream slope, the seepage flow from the dam body and its foundation will decrease.

On the contrary, when the horizontal filter’s length is extended to more than three-quarters of the dam’s downstream slope, the amount of seepage flow that may pass through the dam’s cross-section rapidly increases.Additionally, it was observed that seepage from the earthen dam and its foundation reduced by increasing the cutoff depth.

Finally, with respect to the minimum factor of safety for the downstream slope, obtained using SLOPE/W software, a suitable model for seepage control within the body and foundation of the dam was found to be the hybrid model introduced at the end of this study.



dams, barrages & reservoirs design methods & aids water supply