WATER. DIGITAL. RESILIENCE

How can we build flood resilience in Indonesia?

Written by Ismail Weiliang and Ainul Firdatun Nisaa, Water Resources Lecturer and Researcher in Indonesia. MSc in Water Resources Engineering and Management from University of Stuttgart, Germany.

07 MAR 2022

3 MINS READ

ISMAIL WEILIANG

The Climatebender

AINUL FIRDATUN NISAA

Co-author

Water Resource Lecturer and Researcher

Views are entirely ours

and not connected to any company

"Enabling digital is key for building flood resilience through engaging communities for early flood warnings and response in Indonesia."

Flooding in Indonesia

Indonesia had a total of 1080 flood events in all provinces last year. West Java and Central Java are the most flood-prone provinces among all, according to the 2021 report, with reported cases of 160 and 150, respectively. The third province with the most flood events with 117 reported cases is East Java, the most populous island in Indonesia. Just last month, more than 30,000 were displaced by floods in Sumatra, Indonesia. (al-Jazera, 2022).

Sinking Lands. Rising Seas.

Jakarta, the capital of Indonesia, has long been known as a city with a high risk of flood hazards. Jakarta is one of the Asian megacities with a total population of 10.5mio, as per the 2020 census. The city is sinking 1–15cm a year on average, making almost half of the city lie below sea level (BBC, 2018). The coastal areas in the north are the most prone to coastal flooding. The rise in the sea level exacerbates the land subsidence rate in northern Jakarta. If the city fails to stop the sinking within two decades, about 80% of northern Jakarta will get below sea level (C40, 2019).

Red colours indicate subsidence and blue colours as uplift. Averaged 2006–2009 LOS velocity map of Sumatra, Java, and Bali, Indonesia, from ALOS InSAR time-series analysis (Chaussard et al., 2013)

By 2050, up to 1,500 Indonesian islands will be wiped off the map. Sea level rise in Indonesia estimated to be 4.3±0.4 mm/year (NOAA, 2022)

Heavier Rainfall. Lesser Infiltration.

With climate change, we can expect rainfall events with increasing frequency and intensity. Statistics Indonesia's data showed that Indonesia's rainfall increased from 2317 mm per year in 2011 to 2748 mm per year in 2020 on average. In the Special Capital Region (DKI) of Jakarta, the rainfall intensity reached 2832 mm in 2020. The increase is also followed by the increased number of rainy days in a year.

Urbanization and land-use changes have long been named as some of the most contributing factors in the hydrological alteration of watersheds. Increasing economic and populations contribute to the increasing land pressure in the urban areas in Indonesia. Deforestation was reported in many parts of Indonesia contributing both land degradation and biodiversity losses. There is less permeable ground and more rainfall runoff. With the larger runoff, the existing drainage system has insufficient capacity and the water inundates, resulting in flooding.

Rainfall data between 2011-2020 is processed from Statistics Indonesia

Adaptation + Mitigation for Resilience

Tackling flood resilience requires two fronts: Adaptation and Mitigation. Adaptation involves taking action to adjust to and prepare for effects of climate change, such as more frequent floods and rising sea levels.​ It can apply to human systems or natural systems. Mitigation involves taking action to mitigate—or reduce—the emission of greenhouse gases to limit global warming.​

Current Measures

The government carried out some adaptation measures, including sediment dredging from floodways and canals, increasing the capacity of the retention basins, repairing the existing river banks, and improving institutional capacity and policy framework. Other adaptation efforts have been done by the local communities such as building small dikes to prevent water from entering the house or raising the level of the house.


The aim is to reduce the number of inundated areas and the duration of the flood. Many cities in Indonesia possess coastal flood hazards. Therefore, coastal floods and other weather events have to be accounted for when planning and designing a project in coastal areas. City governments have started to incorporate disaster resilience in their city’s mid-and long-term development planning even though it focuses more on mitigation efforts. 


Early warning system for flood is currently available in major cities, e.g., Jakarta and Semarang. (World Meteorological Organisation, 2019) Before flood events occur, the responsible agency would issue a notification from their social media. The inundated area in Jakarta can be monitored via a website (Flood Monitoring Jakarta, 2022). However, this is not always the case since notifications often came rather late with the lack of awareness from communities. (MDPI, 2020)

Recommendations

Residents are aware of the flood risks, but they believe that it is the government’s job to take care of the flood events (Kefi et al., 2020). The government should provide solutions that involve public participation and build awareness to ensure the smooth running of the flood prevention program. Communities must be aware that the area where they work or live might be affected once there is flooding.

Decision support system with early warnings and response: Indonesia’s authorities can develop smart flood management through decision support systems like the one delivered in Thailand. Based on rainfall nowcast, flood forecasting is done with hydraulic models and early warnings are communicated to the local authorities. This is all delivered within a digital twin which centralises all available real time data and predictions, providing a single source of truth to the authorities. This allows the local authorities to predict, prepare and protect their local communities from flooding. (Global Future Cities, 2022)

Flood alerts channel: Indonesia’s authorities may also consider establishing various communication platforms such as the telegram channel for flood alerts that Singapore has delivered. This will assist in communicating flood alerts to local communities. (Straits times, 2022)

"Enabling digital is key for building flood resilience through engaging communities for early flood warnings and response in Indonesia."

Authors:

Ainul Firdatun Nisaa is a lecturer and researcher at the Department of Environmental Engineering – Institut

Teknologi Sepuluh Nopember (ITS) in Surabaya. She holds an MSc in Water Resources Engineering and Management from the University of Stuttgart and a BEng in Environmental Engineering from ITS. Her research works are related to environmental quality, urban water management, and resource recovery.


Ismail Weiliang is a climate resilience consultant with over half a decade of experience and specialises in flood risk advisory for Asia. His work involves advising governments and development banks on strategies to transform climate risks into resilience. He also founded “The Climatebender” a non-profit organisation that provides humanitarian relief to communities vulnerable to the climate crisis.

Source:

  • al-Jazera, 2020. More than 30,000 displaced by floods in Indonesia Sumatra. https://www.aljazeera.com/news/2022/1/6/more-than-20000-displaced-by-floods-in-indonesias-sumatra
  • BBC, 2018. Jakarta, the fastest-sinking city in the world. https://www.bbc.com/news/world-asia-44636934
  • C40, 2019. Jakarta: On the front line of the climate crisis <https://www.c40.org/news/jakarta-on-front-line-climate-crisis/
  • Chaussard, E. et al, 2013. Sinking cities in Indonesia: ALOS PALSAR detects rapid subsidence due to groundwater and gas extraction. Rem. Sens. Environ. 128, 150–161. https://doi.org/10.1016/j.rse.2012.10.015
  • Flood Monitoring Jakarta, 2022. https://pantaubanjir.jakarta.go.id/peta-informasi-banjir
  • Global Future Cities, 2022. Successful Onboarding Session New Digital Platform Flood Management. https://www.globalfuturecities.org/story/successful-onboarding-session-new-digital-platform-flood-management
  • Kefi, M., Mishra, B.K., Masago, Y. et al, 2020. Analysis of flood damage and influencing factors in urban catchments: case studies in Manila, Philippines, and Jakarta, Indonesia. Nat Hazards 104, 2461–2487. https://doi.org/10.1007/s11069-020-04281-5
  • Statistics Indonesia, 2017. Total Rainfall and Number of Rainy Days at the BMKG Observation Station.
  • MDPI, 2020. The Level of Public Acceptance to the Development of a Coastal Flooding Early Warning System in Jakarta.https://www.mdpi.com/2071-1050/13/2/566/htm
  • NOAA,2022. National Oceanic and Atmospheric Administration, 2022. Laboratory for satellite altimetry/sea level rise. Silver Spring: National Oceanic and Atmospheric Administration; https://www.star.nesdis.noaa.gov/socd/lsa/SeaLevelRise
  • Statistics Indonesia, 2017. Total Rainfall and Number of Rainy Days at the BMKG Observation Station.https://www.bps.go.id/statictable/2017/02/08/1959/jumlah-curah-hujan-dan-jumlah-hari-hujan-di-stasiun-pengamatan-bmkg-2011-2015.html
  • Straits Times, 2022. PUB launches Telegram channel to provide weather and flood alerts. https://www.straitstimes.com/singapore/environment/pub-launches-telegram-channel-to-provide-timely-alerts-warnings-amid-wet
  • World Meteorological Organisation, 2019. Coastal Flooding Forecast Strengthened in Indonesia. https://public.wmo.int/en/media/news/coastal-flooding-forecast-strengthened-indonesia

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