Connectivity: Except for the Thimphu to Wangdue tunnel road, for which a feasibility report is being finalised, no progress has been made on the remaining nine tunnel roads of the road master plan 2007-2027.
The road master plan is a 20-year programme to expand the road network in the country through realignments, tunnelling and new constructions. Ten tunnel roads were proposed in the road master plan with objectives to shorten travel distance and travel time, bring down road maintenance costs and minimise vehicle operating and transportation costs.
Tunnel roads like the Ganglakha-Gedu tunnel were planned as a solution to bypass landslide prone areas while the Geyzamchhu-Sengor tunnel was designed to circumvent snow blockades in winters.
Although the Thimphu-Paro tunnel was initially the top priority, the Thimphu-Wangdue tunnel road was prioritised later. This was done to decongest traffic in the capital and to shorten travel distance from Thimphu to the rest of the country since it will reduce travel time to 15 dzongkhags across the country.
Tunnel roads were also found more environmental friendly compared to building roads which required cutting into mountains and forests.
Accordingly, in 2011 the Department of Roads conducted a pre-feasibility study on the proposed Gedu-Ganglakha tunnel and on highways like Thimphu-Phuentsholing, Thimphu-Paro and Thimphu-Wangdue, and Geyzamchhu-Sengor.
As per the department’s pre-feasibility study all tunnel roads were found viable for construction.
However, only one of the tunnels, which is the Thimphu-Wangdue tunnel road, has entered the feasibility study stage. But little has happened even for the Thimphu-Wangdue tunnel road since SkyTEM, the Danish geophysics consultancy firm began the survey in December 2013.
The roads department and the Norwegian Geotechnical Institute conducted pre-feasibility study on the Thimphu-Wangdue tunnel road as early as 2005 with another in 2010.
Department of Geology and Mines seismology and geophysics division head, Dowchu Drukpa said though the feasibility study is complete, reports are still being compiled. “Only the final compilation of the report is left,” he said.
It has also been found that from the two proposed portals from Thimphu; Yusipang-Nabasa (Nahi) and Semtokha-Nabasa, the latter despite being longer in length (15km) proved more stable and viable.
The Yusipang-Nabesa tunnel, though shorter (10km) proved risky because of steeper gradient. “Coming back from Wangdue to Thimphu could be difficult because of steeper gradient,” Dowchu Drukpa said.
But no budget has been mobilised yet for construction of the Thimphu-Wangdue tunnel. Similarly, the other tunnels also have no specific budget for their survey or for the construction.
“None of the 10 tunnel roads have been constructed yet because of lack of budget,” DoR design division chief engineer, Lungten Jamtsho said.
As per estimates from DoR, a kilometre of tunnel road will cost over Nu 600 million (M) against Nu 31M for a double-lane road.
The 10.5km Thimphu-Wangdue tunnel road is estimated to cost Nu 4.7 billion (B) based on the costs of the 1.5km Tsirang-Wangdue tunnel road. Rurichu tunnel road cost Nu 720M.
The cost of the Thimphu-Wangdue tunnel could however be much higher if it’s to be constructed through Semtokha since its length increases to 15km.
“Geological factors could also lead to further spike in the cost,” DoR geo-technical engineer, Tempa Thinley said.
Dowchu Drukpa said while cost might increase because of length no major geological problems are expected in on the Semtokha-Nabesa portal. “The rock were found competent without weak zones along the way, which is important in tunnels since the cost depends on the geology,” he said.
Though construction of tunnel roads will prove costly initially the cost of its construction could be recovered in the long-run through saving on fuel, transportation costs, and environmental damages.