[Indonesia] Extreme rainfall and its effects on flood risk in Indonesia

Indonesia suffers from severe flood risk due to a combination of its climate (intense monsoon rainfalls), geography (steep mountains and rivers) and the mega-cities built at the outlet of rivers. This risk is already severe and it is feared it will become worse as climate change takes affect and the population of the cities grows even larger with uncontrolled development.
When floods strike, they are often the combination of several sources: high river flows, intense rainfall on impermeable ground in cities and storm surges from the sea. Even worse, they often affect several cities and towns at once - stretching emergency responses and disaster recovery even further.
The project aims to understand how these flood events happen so that planning and mitigation strategies can be developed. This understanding includes:
- when floods occur, and what warning can be given
- what controls the spatial extent (how many cities may be damaged at once)
- how large the river flows can be and how often they happen
- what effect land use (deforestation, urbanisation) has on the size and speed of floods
- how the flood size and frequency of occurrence may change in the future
- how much damage is caused in cities by the floods
Strategies to manage the flood risk will be informed by better understanding, and may take the form of:
- better insurance cover
- better warning systems for areas likely to be flooded
- changing and controlling land use
- building flood diversions, defences, or detention reservoirs
The approach being taken for the research is to use computer models of rainfall, climate, river flows and cities, so that the effects of different floods and management strategies can be simulated safely. The project team is therefore made up of experts in meteorology, climate change, hydrology and computer modelling.

The Government of Indonesia (GoI) has climate change mitigation and adaptation as a national priority agenda and will be a major beneficiary. This proposal is aligned with this GoI agenda in strengthening flood resilience and will involve local authorities and national policymakers as well as business communities. Project outputs are expected to become new national and local policies and will engage with a range of project partners and end users.

Key end users have been invited to join the project and will be involved in designing the research and maximising the benefits: These include:

Jasa Tirta 1 public corporation who manage some river basins as well as water infrastructure. By implementing project findings in their managed basins, they will benefit from the project and develop long-term sustainable economic growth in Indonesia.

The Agency for Assessment and Application of Technology (BPPT), will inform the implementation of project findings in the National Planning Policy Framework.

Focus group discussion and a series of workshops will be conducted with other key end-users, such as the Hydrology and Water System, Ministry of Public Works, the National Agency for Disaster Management (BNPB) and the Agency for Meteorology, Climatology, and Geophysics (BMKG).

We expect our recommendations will be adopted as flood mitigation strategies for national and local policymakers and water managers.

The project will also benefit the insurance and re-insurance industry. Flood risk models are in particular demand for Indonesia (and elsewhere in SE Asia) due to a gap in insurance caused by severe risk as well as low penetration of insurance products. This development is severely restricted by lack of both data on hazards and understand of the hydrosystems and exposure of city populations. Newcastle University as members of the Willis Research Network are in a uniquely advantageous position to disseminate research findings efficiently into the CAT modelling and insurance industries to effect a step change in capability, with major benefit then accruing to the population and economy of Indonesia as effective and affordable insurance becomes available.