IIT-Roorkee suggests Piano Key Weir tech for in-stream storage in Brahmani

The Indian Institute of Technology (IIT), Roorkee has suggested the Orissa government to adopt the new Piano Key Weir Technology for in-stream storage of water in the river Brahmani.

As per the proposal, 5 Piano Key Weir type barrages can be set up over about 100 km stretch of Brahmani between Kharagprasad in Dhenkanal district and Jenapur in Jajpur district.

The barrages can be 25 kms apart from each other and the volume of the in-steam storage in low flow condition from one barrage is estimated to be about 10.15 million cubic metres.

Accordingly, the in-steam storage from 5 barrages is expected to be 50.75 million cubic metres. The cost of the project will range from Rs 40 crore to Rs 80 crore each, depending on the site conditions. Since 50 percent of the Brahmani water remains untapped, this can be a viable proposition, sources said.

Basing on a preliminary study done at Kharagprasad, Professor Narayan Sharma of IIT Roorkee made a presentation before the chief secretary, Ajit Kumar Tripathy on Saturday. During his discussion with the senior state government officials, Sharma stated that Piano Key Weir technology provides an increase in the stability of the dam structure as it can be placed on the top of most existing or new dam spillways.

This also provides smooth passage of the incoming sediments along its ramps with minimum river channels. This new Piano Key Weir Technology has already been used by the Himachal Pradesh Power Corporation Ltd. (HPPCL) on Sawra Kuddu Barrage. The new technology is reported to have a number of hydraulic advantages.

While the discharging capacity of a Piano Key spillway is much higher than that of a conventional Ogee spillway, for a given maximum reservoir level, the live storage can be more in case of the former compared to gated spillway.

This technology helps to reduce the reservoir sedimentation. It will also help in minimising the sub-mergence effect. About 52cm of submergence depth reduction can be achieved if Piano Key Weir is adopted instead of conventional barrage.

In-steam water storage will be created without submergence in the river channel cross section to meet low flow demands of the industry, drinking water and navigation. Besides, the system will not have any operation and maintenance costs.

Water resources secretary Suresh Chandra Mohapatra, energy secretary Pradeep Kumar Jena and industry secretary Sourav Garg were present in the meeting.