This monsoon once again reminded farmers in the Terai of the cost of waiting. As rains arrived late, paddy planting was delayed - and thousands of farmers, who rely on timely irrigation, watched their fields dry.

For years, the government has promised to end this recurring hardship through the Sunkoshi–Marin Diversion Project (SMDP), a multipurpose scheme designed to channel Himalayan river water to the nation’s food bowl. The project pledges a lifeline: irrigation for over 125,000 hectares of farmland across six Terai districts.

The tunnel - the engineering centerpiece of the project - is already complete. But the dam that will feed water into it is moving at a crawl, raising doubts about whether the long-awaited promise will arrive in time for farmers who have waited too long already.

Tunnel ahead of time, dam far behind

A 13.3-kilometer tunnel from Sunkoshi to the Marin River was completed this April - ahead of schedule - using a Tunnel Boring Machine, the same technology used in the Bheri-Babai Diversion Project. It will eventually divert 67 cubic meters of water per second to the Terai.

Yet the Sunkoshi dam - the key to channeling water into that tunnel - is nowhere near the pace required.

Project Chief Ganesh Marasini said dam work should already have crossed 60 percent, but only about 10 percent has been completed. “Only 10–11% of the dam work has been completed,” he said. “This delay is directly affecting the overall project timeline.”

The dam, planned at Kanadhungri in Sunkoshi Rural Municipality-7, will stand about 30 meters high and 158 meters long. From there, water will flow into the tunnel and eventually irrigate farmland in Bara, Parsa, Rautahat, Sarlahi, Mahottari, and Dhanusha districts.

Contractor under scrutiny

Patel–Raman JV was awarded the contract worth Rs 14.759 billion, but only Raman Construction is currently active onsite. With construction lagging far behind expectations, the government is now considering terminating the contract.

“Progress is far below target,” Marasini said. “We are monitoring the company’s work for another two to three months before deciding whether to continue or cancel the contract.”

Floods last year and heavy rainfall this year further hampered work, said Raman Construction chief Raman Mahato, who added that mobilization challenges and flood damage slowed progress.

The overall project - estimated at Rs 50 billion - was expected to be completed within four years and seven months. The dam contract was signed in 2079 BS with a deadline of 2084 BS. Now, with only 22 months left, officials fear time is slipping away.

Energy and irrigation promise

Beyond irrigation, the project also plans to generate 31.7 MW of electricity by using the diverted water’s 66.29-meter head. Power generation structures and grid connection - via Sarlahi’s Nawalpur - are part of later phases.

But until the dam rises, neither irrigation nor hydropower can begin. Farmers, meanwhile, continue to depend on the weather instead of reliable irrigation - hoping the national dream of water security does not turn into yet another delayed promise.

By Dilip Paudel