KATHMANDU, Aug 23: A four to five kilometer stretch of the Sikta Irrigation Project main canal is largely weak and vulnerable to further damage. The parts of the canal constructed with soil refill are more seriously vulnerable than the parts that have been cut into the ground.
Special soil treatment or strengthening work is needed before bringing this stretch of canal into use, according to officials of a government investigation team. This is confirmation of a series of reports carried by Republica following the breakdown of the tunnel a month ago.
Over 100 weak points along the 45 km canal were identified during a field observation then.
Team leader Sushil Chandra Tiwari, joint secretary at the Ministry of Energy, Water Resources and Irrigation, said that the weakened stretch was mostly built by refilling the soil. “The high level of sodium in the soil has resulted in severe depression and the effect is acute in the soil-refill stretch which could not bear the weight of the concrete lining and the water,” said Tiwari.
There are also some minor problems in the cutting work but the soil refilling has posed the most problem as the soil has dispersed with the water.
The investigation team, which returned to Kathmandu from Banke on Tuesday, collected samples of the soil from the field for lab testing. The team included a soil expert this time unlike in an investigation carried out two years ago when there was a similar breakdown of the main canal. The team has also asked the project office in Banke to submit all the project design and contract documents.
Tiwari, however, said that details of the canal strengthening will be presented in the report on which the team is now working.
The cost of this additional work is still unknown but estimates are it may be in the millions at least.
Tiwari said soils at the project site were obviously tested during the project design but it seems there were no tests on how a particular soil reacted to water.
He also claimed that the government may compel the contractor to do the remaining work as the project completion certificate has not yet been issued.
The canal saw severe breakdown when it was tested a month ago with the releasing of five cumecs of water flow. The design capacity is for 50 cumecs water flow. The canal testing was done after the termination of the defect liability period for the project, allowing the contractor, Kalika Construction Pvt Ltd, to go scot free.
The investigation team comprised soil expert Prakashman Shrestha, senior divisional engineers Yogendra Mishra and Krishna Belbase and divisional engineer Dinesh Rajauriya.
Tiwari, who was also a member in the previous investigation team, disclosed that their previous report was not acted upon.
“We had suggested adopting measures for strengthening the soil ago but we found that our advice was not followed,” Tiwari said.