Muh Aris Marfai

Governance of flood risk management in a time of climate change: The cases of Jakarta and Rotterdam

More than half the worlds population lives in cities, and over two-thirds of the worlds cities will be exposed to flooding within the next 30 years due to factors including climate change, land subsidence, sea level rise, and socio-economic development. Traditionally, flood management has concentrated on providing protection against floods using technical measures, but there is currently an international shift towards more integrated flood risk management, whereby flood risk is defined as the probability of flooding multiplied by the potential consequences. Governance plays a key role in this transition. However, relatively little has been written on how climate governance lessons are implemented on a city-scale. Several characteristics of recent climate change adaptation governance, relating to its structure, orientation, content, and timeframe, are gleaned from the research literature. Flood risk management of two cities – Jakarta and Rotterdam – is examined.

Flood risk assessment for delta mega-cities: a case study of Jakarta

Jakarta has suffered major floods in 2002, 2007, and 2013. To cope with and adapt to both the current and future flood problem, the city requires quantitative assessments of flood risk. In this study, we develop a flood risk assessment model for Jakarta. The model is based on the Damagescanner model, adapted for Jakarta using local information on hazard, exposure, and vulnerability. The model was first set up using existing estimates of economic exposure of different land use classes to represent exposure and depth-damage functions (vulnerability curves) from several existing studies in south-east Asia to represent vulnerability. Using these data to simulate damage led to an overestimation by several orders of magnitude. Hence, we held a series of expert meetings and workshops with local stakeholders to develop specific estimates of economic exposure per land use class and to derive vulnerability curves specific for Jakarta. We compare the resulting simulated damages to reported damages and found them to be in good agreement, giving confidence in the use of the model for flood risk assessment. Under current conditions, we found the annual expected damage due to river flooding in Jakarta to be approximately USD 321 million per year. We also examined the sensitivity of flood risk assessments to the use of different vulnerability curves. The sensitivity is high: using the six curves described in this study to simulate risk led to a factor eight difference between the lowest and highest values. Our findings demonstrate that flood risk assessments need to pay close attention to the selection, development, and testing of vulnerability curves.

Community responses and adaptation strategies toward flood hazard in Jakarta, Indonesia

Jakarta, as the capital of the Republic of Indonesia, has long been known to be at risk from flood hazard. It is increasingly recognized that community responses and adaptation strategies are essential for planning future mitigation action. In order to investigate the community responses and adaptation strategies employed in Jakarta, in-depth interviews were performed in the flood-prone areas. The results reveal that vulnerability to flooding is increasing, and it is linked to several factors: (1) stakeholders, (2) environment, (3) communities, and (4) infrastructure and its maintenance. Various physical adaptation strategies have been adopted by the local communities, which include raising the housing level, building terraced housing, and building small dikes to prevent water entering the settlements. Several non-physical adaptations were also identified from the fieldwork. These adaptations tend to be conducted through communal work and the reuse of resources and materials left undamaged by flooding. However, uncoordinated responses during flood events produce greater exposure to the hazard, and it can be inferred that community responses remain below the ideal. This study highlights the need for urgent attention to be given to improving the institutional links between stakeholders, especially at the municipal level, which could provide more efficient disaster response.

Impact of coastal inundation on ecology and agricultural land use case study in central Java, Indonesia

Impact of coastal inundation on ecology and agricultural land use case study in central Java, Indonesia Focusing on the regional scale, this study provides information concerning the existing ecological problems associated with coastal inundation in the northern part of coastal area in Central Java Province, Indonesia. The objectives of this paper are to map the coastal inundation, to investigate the impact of coastal inundation on coastal environment and ecology, and to assess the impact of inundation on agricultural land use. An integration of techniques, namely neighborhood analysis, iteration operation, and superimposed analysis method has been applied to generate the digital map and to analyze the impact of inundation. Fieldwork measurement has been done using cross-profiling in order to observe the impact of inundation on the coastal ecosystem. Based on the scenario of 100 cm and 150 cm of inundation, the affected area is about 15 207.6 Ha and 16 687.31 Ha, respectively. Fishpond, dry farming and paddy field are the most affected agricultural areas due to coastal inundation.

Preliminary assessment of coastal erosion and local community adaptation in Sayung coastal area, central java – Indonesia

Abstract . Dynamic environment in coastal area, especially due to coastal erosion process, has negative impact on human environment. Sayung coastal area, located in Central Java-Indonesia, has experienced severe impact of coastal erosion. As the result of the coastal erosion, hundreds of settlement located in coastal area has been destructed. Moreover, fishponds as the land use dominated in the coastal area also has been severely destroyed. Besides the coastal erosion, increasing of inundated area due to sea level rise also threaten the local community. Although devastating impact suffering the coastal area, the people of Tambaksari, as the part of Sayung area, decided to live and adapt with the coastal erosion. This paper aims to identify the coastal erosion and understand adaptation strategies held by the local community related to reduce the impact of the coastal erosion. Based on this research, various adaptation strategies has been identified, namely (1) Planting mangrove alongside the shoreline, (2) elevating the ground level, (3) building staged house, (4) utilizing deep well for freshwater supply, (5), maintaining social interaction with mainland community, (6) Collecting fish from the mangrove as the food, and (7) changing work into the tourism sector.

Impact of sea level rise to coastal ecology: a case study on the northern part of Java Island, Indonesia

Abstract The coastline of Indonesia, which borders almost 17,500 islands and the sea and extends for more than 80,000 km, is vulnerable to sea level rise. This paper aims to investigate the impact of sea level rise on coastal ecology in Indonesia focusing on coastal area of Jakarta, Pekalongan, Semarang and Demak in the northern part of Java Island. Geo-spatial data, i.e. satellite images and maps were used to monitor the environmental changes and primary data were obtained through field survey and observation on the specified area. In Jakarta, sea level rise has been predicted to bring great damages to infrastructure in coastal area. Multiple impacts of sea level rise towards mangrove, agriculture, and aquaculture ecosystem occurs in Pekalongan. Semarang coastal area also suffers from the widening spread of health problems as the coastal inundation increases. At the same time, Demak experiences major losses on mangrove and aquaculture ecosystem due to sea level rise.

Flood Risk in Polder Systems in Jakarta: Present and Future Analyses

Polder systems in Jakarta have been implemented since 1965, but their development has been hindered by social and political issues. Currently, the government of Jakarta has started to consider polder system as seen in the Spatial Plan 2030. This chapter assesses the benefits/costs of the polder system in Jakarta under current conditions and under future scenario of climate change, land use change, and subsidence.

Ecosystem Services of Coastal Dune Systems for Hazard Mitigation: Case Studies from Vietnam, Indonesia, and Chile

In many developing and emerging tropical and subtropical countries, coastal dune systems (CDS) are under high pressure, which leads to progressive degradation and loss of dune areas. This in turn weakens the protection function against coastal hazards. In this chapter we discuss CDS in three case studies: Thua Thien-Hue province (Central Vietnam), Parangtritis (Java Island, Indonesia), and Ritoque (Central Chile). For these CDS, we assess relevant ecosystem services (ES) with particular regard to protection services as well as the current degradation status through a rapid assessment approach. Moreover, we analyse the legal frameworks for coastal dune management and protection in the case study countries. Main results include indicator sets for assessing ES and the degradation status of CDS, which are transferable to other coastal dune areas. Based on these sets we evaluate and compare the three dune systems and provide policy recommendations for a more efficient regulation and management of CDS.

Profiles of marine notches in the Baron coastal area—Indonesia

Coastal wave erosion along the arid karst region of southern Java, Indonesia has produced residual landforms such as cliffs and marine notches. The aims of our study were (1) to create profiles of marine notches in the Baron coastal area, Yogyakarta Province and (2) to explain the evolution process of marine notches in the research area. Field measurements using a laser distance meter produced profiles of three marine notches; one profile of a double notch formation was identified at a location farthest from the shoreline and two profiles of a single notch formation were identified closer to the shoreline. The vertical positions of the two single-notch formations are at the same elevation, while the double-notch formation is at a lower elevation. Several joints and displacements in the limestone material generated by an uplifting process are believed to be the main cause of this unconformity.

Comparsion of TRMM Precipitation Satellite Data over Central Java Region – Indonesia

Abstract This research aims to compare precipitation data derived from satellite observation and ground measurements through a dense station network over Central Java, Indonesia. A precipitation estimate from the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B42 Version 7 are compared with precipitation data from interpolated rain gauge stations. Correlation analysis, mean bias error (MBE), and root mean square error (RMSE) were utilized in the analysis for each thee-monthly seasonal statistics. The result shows that the 3B42 products often estimate lower rainfall than observed from weather stations in the peak of the rainy season (DJF). Further, it is revealed that the 3B42 product are less robust in estimating rainfall at high elevation, especially when humid environment, which is typical during the rainy season peak, are involved.