Watershed management plans to protect Pasakha industrial area and landslide stabilisation measures at Phuentsholing have proven helpful, Phuentsholing thromde officials said.
These are part of the various project activities under the National Adaptation Programme of Action (NAPA) II project that started in 2014. The activities at Phuentsholing worth USD 4.388M will end this October.
With three rivers in its vicinity, Pasakha industrial area was identified as one of critical areas under the risk of flooding.
Phuentsholing thromde’s project engineer, Lhendup Dorji, said that of the three rivers passing through the area, Barsa river poses the maximum threat of flood and landslide. “There are three clusters at the industrial area and this river passes through two of the clusters adjacent to each other.”
According to a study conducted at the area, the monsoon river level and the intensity of extreme rainfall events are increasing at Pasakha industrial area. These have contributed to increased erosion along the river banks and chances of flooding.
Lhendup Dorji said that Phuentsholing thromde would have prevention, prevision, protection, and crisis management measures in case of a flood. A flood risk prevention plan, watershed management, and sensitisation are among the prevention measures.
The thromde would install a water weather station and an automatic station to measure water level. “The protection measures include flood protection structures and conservation of the watershed.”
The thromde has constructed two flood mitigation structures along the Barsa river today. Lhendup Dorji said that following the completion of one of the structures in 2017, the performance of the structure was monitored during monsoon. “We recorded videos and it showed that the structure was keeping the overflowing Barsa river from reaching the houses near the river.”
To further manage the watershed area, 17 hectares of land have been identified for enrichment plantation at Pasakha. Plantation at Samphelling and Ganglakha will begin this month.
Measures to stabilise landslide areas are also underway at Rinchending. The Rinchending check post, Reldri Higher Secondary School, Rinchending Goenpa, and the old hospital colony were identified as landslide prone areas in Phuentsholing.
Phuentsholing thromde’s former project manager, Gautam Thapa, said that to stabilise the slopes that lead to landslides, a soil nailing procedure is being used at Rinchending Goenpa area in Phuentsholing. “Soil nailing is a procedure to reinforce and strengthen the ground adjacent to an excavation by instilling closely spaced steel bars called nails as construction proceeds from top down.”
Soil nailing procedure was adopted for the first time in Bhutan at Rinchending Goenpa area.
Lhendup Dorji said that a survey has shown that land movement at the check-post and goenpa has decreased following the interventions. “The movement has not completely stopped but has decreased up to 80 percent.”
Also under the NAPA II project, Department of Geology and Mines identified four critical landslide and flood prone areas – Phuentsholing watershed, Wamrong or Moshi in Trashigang, Lamsorong in Samdrupjongkhar and Box cutting at the Gelephu-Zhemgang highway.
Economic affairs ministry’s project manager, Tashi Tenzin, said that a report of the four critical landslide and flood prone areas would be published.
The report will include information on geology, landslide characteristics, hazards, vulnerability, and the risks associated, map on proposed mitigation measures, and recommendations on both long and short-term mitigation measures.
He said that stabilisation measures would include construction of walls, drainage, road realignment, sealing of tension cracks and non-structural measures such as bioengineering. “The reports and maps will be published soon and will be shared to relevant stakeholders.”
Funded by Least Developed Countries Fund, NAPA II project has a budget of USD 11.49 million.