7240. Flood Protection alongside Maokhola - Bhutan - D2B17BH01

The Mow river is predominantly a natural river. Its source is in the Bhutan Himalaya and it flows into the Ganges. Gelephu, the third largest town in Bhutan is vulnerable to flooding and the agricultural lands are lost due to erosion. An ESIA is supporting a project that aims to decrease the risk of flooding and erosion whilst the natural character of the river will be maintained as much as possible.

Advisory reports and other documents

Significant details

The project aims (i) to protect some essential public services against flooding and (ii) decrease the risk of flooding and loss of agricultural land at both sides of the Mow river at a stretch of 10 km north of Gelephu. The proposed interventions can be categorised in two types:

• riverbank and flood protection by using gabion-based revetments stacked (steel wires container filled with rock), where required placed on new dike sections (for simplicity sake, the gabion protections placed on new dikes are further in this report also denoted ‘revetments’);
• protection against further erosion and flooding by closing of less active channels using cross dams. 

• The NCEA made some recommendations for some of the proposed interventions.
• Uncontrolled sediment mining is ongoing in the riverbed of the mow river and that might have considerable impact on the effectiveness of the proposed interventions and needs therefore be addressed in the ESIA.
• To ensure that the proposed interventions will contribute to the proposed project objectives, a monitoring and training programme needs to be developed for a period of five years. Especially, because the concept of adaptive management will be applied and that requires yearly evaluation and planning of activities influencing the river morphology.

Parties involved

Members of the working group

Chair: Tanya van Gool
Technical secretary: Arend Kolhoff

Further details

Country: Bhutan

Last modified: 19 Dec 2023