Tonga: Integrated Urban Resilience Sector Project

Sovereign Project | 49455-002

The project is aligned with the following impacts: (i) living standards in Nuku'alofa improved , and (ii) resilience to existing extreme natural events and to the threat of climate change increased. The project will have the following outcome: Nuku'alofa residents have access to improved, effective and climate resilient urban services and infrastructure.


Project Details

  • Project Officer
    Katich, Kristina N.
    Pacific Department
    Request for information
  • Country/Economy
  • Sector
    • Water and other urban infrastructure and services
Project Name Integrated Urban Resilience Sector Project
Project Number 49455-002
Country / Economy Tonga
Project Status Active
Project Type / Modality of Assistance Grant
Source of Funding / Amount
Grant 0651-TON: Integrated Urban Resilience Sector Project
Asian Development Fund US$ 18.27 million
Strategic Agendas Environmentally sustainable growth
Inclusive economic growth
Drivers of Change Gender Equity and Mainstreaming
Governance and capacity development
Sector / Subsector

Water and other urban infrastructure and services / Urban flood protection - Urban policy, institutional and capacity development - Urban sanitation - Urban water supply

Gender Equity and Mainstreaming Effective gender mainstreaming

The project is aligned with the following impacts: (i) living standards in Nuku'alofa improved , and (ii) resilience to existing extreme natural events and to the threat of climate change increased. The project will have the following outcome: Nuku'alofa residents have access to improved, effective and climate resilient urban services and infrastructure.


Output 1: Effective flood risk management infrastructure implemented. To reduce flood risk, the project will rehabilitate and provide new flood management and drainage infrastructure at seven flood prone locations throughout Nuku'alofa, including the central business district, Vuna road, Salote road, Fanga, Haveluloto, Tofoa and Sopu. The project will also assist the Ministry of Infrastructure (MOI) to review the current Land transport Division (LTD) funding arrangements and to prepare and implement a review of tariff structures and charges to achieve and maintain full recovery of operations and maintenance costs for public flood management and drainage infrastructure. The project will also assist the LTD to prepare a 10-year asset management plan and will provide capacity building support to operate, repair and maintain the new drainage network, strengthen revenue collection and asset management.

Output 2: Water supply service in Nuku'alofa improved. The project will reduce NRW through the rehabilitation and upgrading of Nuku'aola piped water distribution network and by improving TWB leak detection, monitoring, repair and maintenance capabilities. The project will also improve TWB service capacities by providing new field-testing equipment and vehicles, assisting the utilities board's integration of financial systems and providing capacity building to use numeric water supply models and field data to guide the planning and implementation of pipe distribution network upgrades. The project will also carry out a gender sensitive review the current TWB tariff structures and charges to achieve and maintain full recovery of operations and maintenance costs while ensuring that water supply is affordable and accessible to the poorest members of the community, and will assist TWB to a prepare a 10-year asset management plan and to develop policies and processes to support women in the workplace.

Output 3: Public and environmental health enhanced. The project will enhance septage and solid waste management and collection in Tongatapu by upgrading the Tapuhia septage and leachate wastewater treatment plant, constructing a new sanitary landfill cell, providing a new office and a mechanical servicing facility at Tapuhia sanitary landfill, and by procuring essential plant and equipment for waste operations, including waste collection trucks that will allow women to work as female waste collectors for the first time ever. The project will assist WAL to improve its financial management capacity and will review the current WAL tariff structures and charges to achieve and maintain full recovery of operations and maintenance costs while ensuring that waste services are affordable and accessible to the poorest members of the community. Considering WAL mandate to expand its operations to the outer islands, the project will assist WAL to explore possible economically and environmentally sustainable solutions for waste management in the outer islands, including the shipping of waste to Tapuhia. The project will also assist WAL to a prepare a 10-year asset management plan and to develop policies and processes to support women in the workplace. Additionally, the project will support the government in the delivery of a water, sanitation and hygiene (WASH) and menstrual hygiene public awareness program in schools, health centers and public buildings.

Output 4: Urban resilience strengthened. In order to address long term resilience and sea level rise, the project will prepare a gender sensitive Climate and Disaster Resilient Urban Development Strategy and Investment Plan for Greater Nuku'alofa area to guide further government urban planning and investments. At the community level, the project will implement a pilot gender sensitive community-based disaster risk management (CBDRM) program which will involve Nuku'alofa communities, including women and girls, in the preparation of disaster risk management plans.

Project Rationale and Linkage to Country/Regional Strategy

Urban growth and development pressure. Tonga's total population is estimated at 100,745._Nearly three quarters of Tonga's population resides on the main island of Tongatapu, and 80% of the island's population and infrastructure are located in low-lying coastal areas. This includes the capital, Nuku'alofa. The greater Nuku'alofa area comprises 6,134 households---a total population of 35,184---and is forecast to grow to 45,000 (or about 40% of Tonga's population) by 2030._Migration to Nuku'alofa from Tonga's outer islands is significant._Urban growth in Tonga is a relatively recent phenomenon and has not been matched by the provision of, or improvement in the delivery of, adequate urban services. Living conditions for many of Nuku'alofa residents are deteriorating and demand for improved urban infrastructure is increasing. Sustained urban growth has put pressure on the availability of urban land and infrastructure. Expansion in the capital is limited to peripheral agricultural and ecologically-sensitive areas, placing development pressure on existing marginal areas. Some of these areas are below high tide levels and therefore experience frequent coastal inundation.

Climate change and natural hazards. Natural hazards and climate change pose a significant threat to Tonga. The country's archipelago is located in the Pacific cyclone belt and within 200 kilometers of the subduction zone of the Indo-Australian and Pacific tectonic plates, where intense seismic activities occur. In addition, most of its atoll islands, including the main island and Nuku'alofa, are very flat with an average altitude of 2 to 5 meters. As a result, Tonga -and Nuku'alofa- are highly exposed to sea level rise, storm surge, and tsunami inundation. Nuku'alofa is home to critical infrastructure and services, such as government agencies, the country's main port, hospital, commercial buildings, schools, and water and power supply. In all, more than 10,000 buildings are located in low-lying Nuku'alofa. Consequently, the entire country's economic and operational vulnerability to natural hazards, such as tsunami, floods and cyclones, is extreme. The World Risk Report_points out that despite Tonga's comparatively high income and high developmental level (compared to many other countries in the Pacific), the country has not decreased its vulnerability to natural hazards. In fact, according to their measurements, all vulnerability components experienced an increase between 2012 and 2016. Susceptibility rose by 0.75%, lack of coping capacities by 0.49% and lack of adapting capacities by 2.65%.

Flooding. Rain-fed floods have affected Nuku'alofa's urban population more than any other type of natural hazard in terms of frequency and number of people impacted, and tropical cyclones and storm surges suppose a major threat for the population, as hundreds of households experience flood waters inside their houses and families need to be relocated to community evacuation centers. There is high confidence that the frequency and intensity of extreme rainfall events will increase with climate change, so Nuku'alofa's rain-fed flooding problems will likely worsen if significant measures are not taken._The impacts of flooding are exacerbated by poverty, as the poorer communities are mostly concentrated in the lowest-lying areas. Ponding of water leads to increased health risks, which are exacerbated by poor sanitation. This can cause increased incidence of typhoid, diarrhea, and skin diseases. The stagnant water also increases mosquito breeding habitat, thus increasing the risks of vector-borne diseases. There are also gendered impacts of flooding as women have additional caring responsibilities (as a result of health risks) and are primarily responsible for household maintenance.

The greatest long-term threat to Nuku'alofa is sea level rise due to climate change, which will lead to permanent inundation of low-lying areas. Although sea level rise is a long-term process, the initial impacts are already observable. In the low-lying districts of Popua and Sopu, rising sea levels have led to inundation during spring tides and storm surges. By 2100, mean sea level is projected to be approximately 1 meter higher than present under a RCP8.5 scenario._Most of current Nuku'alofa will lie below sea level by 2100. However, by 2050, sea level rise will already start having negative impacts, including the permanent inundation of some areas and decreased effectiveness of drainage infrastructure. The very flat terrain of Nuku'alofa limits engineering options to convey rainfall runoff and mitigate flooding, and in areas where wider trunk channels might be effective in the short-term, mitigating flooding beyond the once-in-two-year rainfall event would require significantly widening these channels (to 200 meters in some cases to handle the one-in-50-year event). To accommodate this infrastructure entire lots would be required. The need for significant land acquisition for these systems raises additional obstacles.

Because of these challenges, a city-wide flood management system is not viable in Nuku'alofa. However, to alleviate the current situation, some infrastructure solutions need to be implemented in the short to medium term to ease flooding in parts of the city. These solutions need to focus on improving roadside drainage in economically relevant roads and areas and particularly the central business district and lower-lying areas, building on existing infrastructure. Areas for potential investment have been selected considering: (i) number of properties and catchment area benefiting, (ii) flood level reduction associated with the proposed works, and (iii) limited requirement for use of privately leased or owned land.

Sanitation. Most households' septic tanks are undersized and serviced only when full or overflowing. Septic tanks are likely to be the main source of contaminants in aquifers within the Nuku'alofa area. The improved availability of septic tank pump-out trucks, together with greater public awareness of environmental issues, is having a positive impact and creating a significant upsurge in septage collection and transport of septage to Tapuhia. However, not all households' septic tanks are yet serviced and septage sludge treatment facilities in Tapuhia do not have sufficient capacity to treat all the liquid waste generated in Nuku'alofa and need to be augmented.

Solid waste management. Waste Authority Limited (WAL) operational responsibilities are being expanded by government to include not only the original Tongatapu waste management area (WMA) but to progressively roll out to all of the outer islands over the next few years. This expansion has the potential to place greater pressure on the safe disposal facilities provided at the Tapuhia Waste Management Facility (TWMF) until other safe disposal facilities can be constructed in the outer island WMAs. Additionally, over the recent years, greater pressure has been placed on the TWMF through the greatly increased public awareness of waste management and a clean-living environment within communities across the urban and semi-rural communities of Tongatapu Island. Based on current projections, it is expected that Tapuhia's landfill cell number two will reach its full capacity around early 2023, hence, Tapuhia's capacity to accept and manage waste needs to be augmented.

Water supply. Non-revenue water (NRW) is estimated to be in the range of 45% in Nuku'alofa. Additionally, 41% of households are having problems with water pressure, and 19% experience problems with service interruptions. The zoning of the system, which has been implemented under the Nuku'alofa Urban Development Sector Project (IUDSP) will allow the possibility to isolate zones and introduce monitoring points throughout the system, assisting the identification of problem areas and allowing shut-off of individual zones for repairs or re-direction to other zones for emergencies, naturals disasters etc. Upon commissioning of the new zoned network, a monitoring program needs to be put in place and a rolling year to year network upgrade plan is necessary to identify the rehabilitation priority areas and then proceed to undertake the planned works to upgrade the sizes of service pipes, valves and fittings where this is currently inadequate, repair leaking pipes, valves, and disconnect illegal connections, where detected.

Asset management. Management of existing and new urban infrastructure is a high priority. Government policy is that the cost of operations and maintenance of economic infrastructure should be funded from user charges. The government intends to work closely with public enterprises, the private sector, and development partners to lift the overall performance of the economic infrastructure sector and to achieve self-funding of sustainable operations and maintenance by the government and public enterprises. However, all public enterprises have yet to develop and implement asset management frameworks and asset management plans.

Value added by ADB assistance. Until recently, assistance from international, agencies to Tonga's urban sector has been limited. Historically, external assistance has focused on rural areas and the outer island. In Nuku'alofa, previous projects have been mostly ad hoc and limited in scope, with a number of exceptions. ADB has been one of the main development institutions supporting the development of urban infrastructure and improvement of urban services in Nuku'alofa, and posedes relevant experience and knowledge of the sector. The challenges identified during the preparation of the Integrated Urban Resilience Sector Project require not only addressing short-term urban development priorities, but to look forward and start preparing for long term climate change impacts that will have a huge effect in Nuku'alofa. A strategic plan is required for a long-term urban development phased approach to dealing with flooding and sea level rise while allowing urban growth. This approach needs to consider the possibility of a progressive relocation to higher ground for communities in the lowest areas as well as the possibility of filling and raising of land. These longer-term options must be subjected to a detailed economic assessment to provide appropriate information to policy-makers in the context of the long-term development and urban planning of Tonga's capital city. ADB's experience and planed investments in Tonga will play a crutial role in supporting a coordinated approach and being part of an integrated adaptation solution that could leverage substantial climate change cofinancing from other development institutions.

Sector Financing. The project meets the criteria for sector financing as (i) the government has prepared a costed urban sector development plan for Tonga, the TNIIP; (ii) Tonga is implementing the NUDSP, which has a sector loan modality, and has the capacity to implement the TNIIP; and (iii) the policies for development of Tonga's urban sector as provided in the NUDSP are appropriate, are supported by infrastructure development polices articulated in the TNIIP and the Tonga Strategic Development Framework (TSDF) and will undergo further improvement. The National Spatial Planning and Management Act prepared under the NUDSP and approved by the government will provide the framework for planning and coordinating urban development. Lessons from previous relevant ADB and development partner operations in Tonga have been incorporated in the project design.


Living standards in Nuku'alofa improved

Resilience to existing extreme natural events and to the threat of climate change increased

Project Outcome
Description of Outcome

Nuku'alofa residents have access to improved, effective, and climate-resilient urban services and infrastructure

Progress Toward Outcome
Implementation Progress
Description of Project Outputs

Effective flood risk management infrastructure implemented

Water supply service in Nuku'alofa improved

Public and environmental health enhanced

Urban resilience strengthened

Status of Implementation Progress (Outputs, Activities, and Issues)

In preparation

In preparation

In preparation

In preparation

In preparation

In preparation

In preparation

In preparation

In preparation

In preparation

In preparation

In preparation

Geographical Location Nuku'alofa
Safeguard Categories
Environment B
Involuntary Resettlement B
Indigenous Peoples C
Summary of Environmental and Social Aspects
Environmental Aspects
Involuntary Resettlement
Indigenous Peoples
Stakeholder Communication, Participation, and Consultation
During Project Design
During Project Implementation
Responsible ADB Officer Katich, Kristina N.
Responsible ADB Department Pacific Department
Responsible ADB Division PAUW
Executing Agencies
Ministry of Finance
Concept Clearance 06 Jun 2017
Fact Finding 27 Mar 2019 to 05 Apr 2019
MRM 11 Jun 2019
Approval 28 Aug 2019
Last Review Mission -
Last PDS Update 01 Sep 2022

Grant 0651-TON

Approval Signing Date Effectivity Date Closing
Original Revised Actual
28 Aug 2019 13 Sep 2019 16 Oct 2019 31 Mar 2026 - -
Financing Plan Grant Utilization
Total (Amount in US$ million) Date ADB Others Net Percentage
Project Cost 21.32 Cumulative Contract Awards
ADB 18.27 12 Oct 2022 5.18 0.00 28%
Counterpart 3.04 Cumulative Disbursements
Cofinancing 0.00 12 Oct 2022 1.44 0.00 8%
Status of Covenants
Category Sector Safeguards Social Financial Economic Others
Rating Satisfactory Satisfactory Satisfactory Satisfactory Satisfactory Satisfactory

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Evaluation Documents See also: Independent Evaluation

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Related Publications

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Tender Title Type Status Posting Date Deadline
Integrated Urban Resilience Sector Project Individual - Consulting Closed 12 Mar 2022 18 Mar 2022
TON 0651: Integrated Urban Resilience Sector Project (G-01) Invitation for Bids Closed 09 Dec 2021 25 Feb 2022
TON 0651: Integrated Urban Resilience Sector Project (IURSP-G-06) Invitation for Bids Closed 08 Dec 2021 25 Feb 2022
Integrated Urban Resilience Sector Project Firm - Consulting Closed 02 Sep 2021 27 Oct 2021
Project Implementation Assistance Consultants Firm - Consulting Closed 08 Jun 2019 10 Jul 2019

Contracts Awarded

Contract Title Approval Number Contract Date Contractor | Address Executing Agency Total Contract Amount (US$) Contract Amount Financed by ADB (US$)
Project Accountant Grant 0651 12 Sep 2022 Lisipesi Henwood | Bybass Road Pahu Pahu, Kolofo'ou, Tonga Ministry of Finance 120,340.00

Procurement Plan