Solomon Islands: Honiara Flood Risk Study and Management Plan


Flooding damage, Honiara, April 2014. Source: IFRC

Context and Objectives
As a small Pacific island state, Solomon Islands is particularly vulnerable to natural disasters. Catastrophic risk modelling by the World Bank suggests that Solomon Islands is expected to incur, on average, US$20.5 million per year in losses due to earthquakes and tropical cyclones.  Honiara is the capital city of the Solomon Islands and serves as its main transport hub and economic, political and educational centre. It is the most densely populated area of the country.  Some 52,000 people are estimated to have been affected by the April 2014 flooding, equivalent to around 10 percent of the population of the country. Up to 80% of the capital’s population were affected.  This includes those who had their properties destroyed or severely damaged, as well as those who lost their livelihoods (for example, through damage to their food gardens).  There was also significant disruption to transport, with key bridges around Honiara being washed away.  Furthermore, some 35% of residents live in informal settlements, which are now spreading beyond the City boundary, often in houses susceptible to cyclones and floods.  This has the potential to increase the risks to the population from flooding, as more people move into flood prone land.

The project objective is to investigate urban flood risk and provide quality information to better manage and reduce flood risks in the greater Honiara area, thereby building and strengthening the city’s disaster preparedness and resilience to weather extremes.

Main Activities
Component 1: Preparation of Flood Risk Study. This component will include the preparation of a detailed flood risk study report, which will provide: 

  • A description of the hydrologic and hydraulic analyses that has been undertaken; 
  • A presentation of results showing extents, depths, levels and hazard of design flood events; 
  • A detailed assessment of flood risk in the study area; 
  • A description of the impacts of climate change on flood behavior and risk;  
  • The identification and assessment of flood risk management options.

Component 2:  Planning for future flood risk. This component will include two sub-components: 

  • Investigation of Flood Risk Management Options.  Having assessed the flood risk for Honiara under Component 1, options to manage the identified risks – particularly the risk to life – shall be identified and evaluated, beginning with options to modify the way floods behave.  Options to modify property will also be considered, as will options for modifying/improving flood response mechanisms. 
  • Development of Flood Risk Management Plan.  This activity will build on the study prepared under component 1, and the options identified under Component 2 to develop an integrated Honiara Flood Risk Management Plan which can be used to inform future investments, including priorities for investment, timeframe and estimated costs.

The terms of reference for the Honiara Flood Risk Study that were prepared following the Honiara Flooding in April 2014 have been finalized, and the contract was signed in early 2018. Work has now started on the preparation of the flood risk study.

Partnerships and Coordination
Stakeholders have been consulted widely in the finalization of the terms of reference. Valuable feedback was received by a range of stakeholders, including government agencies and local government.

  • Pacific
Priority area
  • Risk identification and assessment
Window of Action
  • Window 2
Amount approved
  • $500,000
  • $0
  • 06/2017 - 04/2019