THIS is with reference to the report ‘Sukkur barrage on the verge of collapse due to rising level of sedimentation in Indus, warns minister’ (Jan 1). The minister added that the construction of dams and new canals over the Indus in upper riparian portions were major causes of the rapid sedimentation in the lower reaches of the river.

The chief engineer of irrigation added that 30 million tonnes of sedimentation occurred per barrage during the 2010 flood.

The width of river upstream the barrage expanded to over 40km during the 2010 floods, whereas the barrage is 1km wide. Due to the reduction of width, the velocity of water will be the highest at the barrage entrance and the chances of sedimentation will be low.

The sedimentation occurs where velocity is quite low or nearly zero. It is evident on the Sukkur side, because the three canals are partially open. Of the 66 gates, 11 are totally blocked by silt on this side and three islands are visible.

No water flows through the 11 gates even in peak floods, overloading the remaining 55 gates. Ensuring that all the gates remain functional should be the top priority. It will also prevent stressing the barrage, and the chances of the barrage collapsing will be eliminated.

Till the early 1980s, there used to be a dredger operating upstream of Sukkur barrage which would constantly remove the silt. We can rent out or buy a dredger to help unblock the 11 non-functional gates.

S. Nayyar Iqbal Raza
Karachi

Published in Dawn, January 25th, 2022