Objective and Purpose of the Assignment
 | The objective of the consultancy assignment is to provide support for the preparation of the proposed project in Bhutan, titled ‘Climate-Resilient Omchhu River Basin Project (the project)’. The proposed project will focus on the Omchhu River in Phuentsholing and its upstream river basin. Building upon the ADB-financed Phuentsholing Township Development Project (PTDP) and its Additional Financing (approved in 2018, ongoing) and the SASEC Road Connectivity Project (approved 2014; closed Dec. 2022), the project will tackle one of the critical economic development inhibitors of Phuentsholing: annual flood risk from the Omchhu River, exacerbated by unpredictable erosion of its riverbanks and landslides from its upstream hilly slopes and worsening climate impacts. The proposed project will focus on climate and disaster resilience through an integrated river basin approach to flood and erosion risk management and combine a full range of structural and nonstructural measures. The project will (i) design and build riverbank, flood embankment, and landslide protection works along four priority river reaches; (ii) develop holistic measures to reduce landslide and sediment-related risks; (iii) strengthen institutional capacity to assess, map, and disseminate multi-hazard risks, including from GESI perspective, enabling better land-use planning and management on risk-sensitive land; investigating geological and geotechnical conditions; monitoring and mitigating risks; and enhancing the forecasting and early warning systems and disaster preparedness; and (iv) enable subsequent riverfront development in appropriate locations. Phuentsholing area has historically been exposed to flood risk from two river systems: Amochhu River located to the west, and Omchhu River which runs through the city. The two rivers have posed significant threats to lives and properties when the rivers swell under the influence of tropical monsoon. Direct flooding from the Amochhu River is now mitigated up to the 1% annual exceedance probability event through the PTDP. Flood risk, significantly exacerbated by debris flows, from the Omchhu River remains. Omchhu River has a relatively small, steep, catchment (22 km2), high riverbed gradient passing through Phuentsholing, and receives high monsoon rainfall (~5000-6500 mm) with intense storms, which result in relatively large and high-velocity floods. In addition, the catchment is underlain by weak geology, with degraded vegetative cover in places, and has been subject in places to urbanization and inappropriate development control. As a result, landslides and large sediment inflows contribute significantly to the flash floods which frequently damage the existing flood protection system and leave large deposits of sediments/boulders in the lower reaches near the confluence of Omchhu River with Amochhu River. The project is aligned with the impact: increase the Phuentsholing Thromde’s resilience to disasters triggered by natural hazards in the Omchhu River basin. Its outcome will be climate-resilient flood and landslide risk management systems in the Omchhu River basin enhanced. The two main outputs will be: (i) Output 1: climate-resilient flood and landslide risk mitigation measures in the Omchhu River basin implemented and maintained, and (ii) Output 2: flood and landslide risk management institutional capacity strengthened. Phuentsholing Thromde (PT) will be the executing and implementing agency of the project and responsible for all procurement and implementation activities, contract administration, monitoring, and reporting aspects through a project management unit (PMU) . The project is anticipated to be implemented over a 6-year period from late 2025 and is currently estimated to cost about $56 million out of which ADB financing is anticipated to be through a concessional loan of about $35 million and an ADF grant of about $10 million. Key features of the project include: (i) Project will focus on four priority river reaches of Omchhu River basin and encompass structural and nonstructural measures in each reach. (ii) Riverbank protection. The project will predominantly utilize reinforced concrete retaining walls. Large rocks will be utilized at the toe of the structures. (iii) Flood embankment protection. Existing embankments will be protected and strengthened as necessary. The project will be designed to accommodate the currently estimated 1 in 100 annual exceedance probability event including allowance for climate change and freeboard allowance. (iv) Access is required to the riverbed at a few locations for maintenance purposes. A demountable flood barrier will be installed in downstream reach to provide access for excavators and trucks for sediment removal after a heavy rainfall/flood event. (v) Riverbed protection. To mitigate scour and downcutting risks along the river, transverse grade control structures will be proposed in selected locations. (vi) Ancillary structures. Culverts for road crossings across tributaries. Existing local drainage to the river will require energy dissipation structures and scour protection measures. Check dams are proposed to reduce the gradient and trap sediment. (vii) Worsening landslides occur in the upstream rural parts of the basin (ie: generally within the administrative boundary of the DA). Landslides risk assessment will cover the river basin. Mitigation measures to reduce risk are not yet defined. Due to the scale of the slope stability and sediment debris issues, it is envisaged that mitigation measures would be implemented on a pilot basis under the project. The quantum of physical works will be determined under the preparatory technical assistance (TA) and then added to the existing 2022 Detailed Project Report (DPR) prepared by PT and already been endorsed by the Ministry of Infrastructure and Transport (MoIT). (viii) Anti-erosion nature-based solutions will be implemented as appropriate. (ix) The final design with: (i) increase the use of large rocks in the flood protection works, for durability, sustainability and visual reasons; (ii) use a riverine terrace and other strategic locations, for storage of equipment and supplies for emergency purposes during monsoons to enhance disaster preparedness; and (iii) establish precedent in the region for successful use of bioengineering measures for slope stabilization (e.g. wire mesh/jute with vetiver plantation as appropriate). (x) Flood forecasting and warning (generally implemented through the National Centre for Hydrology and Meteorology) requires close coordination between a range of institutions involved at different levels and informing different departments. Activities of the PT and DA need to be integrated with activities from the project and PTDP with the foreseeable aim of integration into one system. (xi) Other nonstructural measures will include: flood risk mapping and raising awareness of riparian population, surveys and river monitoring, asset management system, design guideline, quality control of the construction, riverfront beautification measures (if funds permit) as well as capacity building through trainings to ensure relevant government organizations remain up to speed with modern developments. The purpose of this intermittent assignment includes supporting the ADB Project team to: (i) finalize project preparation closely with PT and DA teams, (ii) provide training, (iii) complete due diligence for loan and grant processing, and (iv) contribute to the Report and Recommendation of the President to the Board of Directors (RRP) and its Appendices (including linked documents (LDs)) until the approval of the project by ADB Board. The Consultant will be part of the team of individual international consultants engaged by ADB (Landslide Hazard Expert, Procurement Expert, Economist). The Consultant will lead the team of the individual consultants. The Consultant will work closely with the PMU as a team member of the ADB Project team, but independently undertake the tasks. The Consultant will report to ADB. |
Scope of Work
| Working closely with PT and DA teams, the individual consultants, and the ADB Project team, the Consultant will (i) contribute to the finalization of the project design, (ii) provide training to the PMU staff on flood and erosion risk management, (iii) complete the technical due diligence for loan and grant processing, and (iv) contribute to the RRP and its Appendices and LDs until the approval of the project by ADB Board. |
Detailed Tasks and/or Expected Output
| The Consultant will perform and deliver, but not limited to, the following tasks and outputs: (i) review relevant technical documents and in particular the 2022 DPR; (ii) undertake site visits to refine extents and alignment of the proposed riverbank and riverbed protection works, including to increase the use of large rocks; (iii) guide the PMU to update and finalize the DPR, including its cost estimate (estimate in the 2022 DPR uses 2022 Bhutan standard rates, hence estimate needs to be revised with the latest schedule of rates). Also, landslide risk mitigation measures (when defined by the Landslide Hazard Expert) will need to be added to DPR. Then, the final DPR will be re-submitted by PT to MoIT for re-endorsement. (iv) review the ToR and cost estimate of the project implementation support consultant (PISC) package; the PISC will support the PMU to implement the ensuing project. The draft ToR and cost estimate will be prepared by the PMU. The Consultant will guide the PMU for the finalization of the ToR and cost estimate. (v) Inputs to the draft RRP and its Appendices and LDs (accordingly to the ADB latest templates); (vi) contribute to addressing comments to be received during the ADB interdepartmental review process of the RRP and its Appendices and LDs; (vii) contribute to the finalization of the draft final RRP and its Appendices and LDs; (viii) support ADB missions and provide inputs to Aide-memoire of the missions; and (ix) perform other tasks as may be requested by the ADB Mission Leader from time to time. |
Minimum Qualification Requirements
| • Bachelor’s degree in civil engineering with a specialty in river or water resources engineering from a recognized institution. Master’s degree is preferable. • Minimum of 15 years of relevant professional experience in flood and river(bank) erosion risk management of rivers, including planning, design, construction, and monitoring of riverbank and riverbed protection works and ancillary structures, as well as nonstructural flood risk mitigation measures including flood modelling, forecasting and warning, and community-based flood risk management in developing countries in South Asia. • Minimum specific experience of 7 years in designing, preparing, implementing ADB-/World Bank-financed flood and river/coastal erosion mitigation projects, including river engineering/modelling aspects in river systems, and 5 years as team leader. • Experience in preparing Reports and Recommendation of the President to the Board of Directors of ADB (RPPs) and its Appendices and linked documents is highly desirable. • Experience in the mountainous river basins is desirable. |
