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Transport sector climate proofing in Timor-Leste

July 2017

In recognition that an efficient and safe transport system is vital to secure economic and social development, ADB provides support for infrastructure upgrade and maintenance in Timor-Leste.


This is done through the Road Network Development Sector Project, targeting general improvement of routine maintenance practices on existing national roads, and in particular focussing on the trans-island road from Manatuto to Natarbora in order to help improve national connectivity and support the government’s petroleum and gas developments on the south coast. 

The ADB project fits well into the ADB Long-Term Strategic Framework 2020, in which the bank explicitly commits to continue to integrate environment and climate change considerations into regional, national, and local development plans and actions. As Timor-Leste remains fragile due to years of conflicts, one of the initiatives identified in the operational plan is the development of a customized risk management framework to better address or mitigate four major risks: economic, political, state building and governance, as well as natural hazard. 

Development and maintenance of infrastructure is very complex and expensive not at least in Timor-Leste, where inland roads are highly exposed to changed intensities and patterns of rainfall affecting landslides, floods, debris, scouring and rapid droughts after flooding. Therefore, developing and maintaining a complex infrastructure project is a challenge that has to be done in parallel with detailed hydrological analyses. The understanding of watersheds and its characteristics and the identification of climate risks will assure the sustainability of infrastructure projects and preservation of natural hydraulic conditions from surrounding catchments during the monsoon period. 

ADB’s project will upgrade the existing National road A9 between Manatuto and Natarbora, including the 10 km long spur extending to Laclubar. In order to make sure that the upgrading works comply with the ADB strategy on climate proofing of their projects, ADB would like to assess the current and future flood and drought risks associated with the road corridor. This is done mainly through the analysis of the expected change in precipitation, and associated overland flow, as this is the main source of risk for inland roads. 

The EO support project helped to better quantify climate risks, especially from floods and droughts, and in particular on the road network in Timor-Leste. It also supported capacity building activities to raise awareness of the impact of climate and environmental changes. Focus was put on natural capital and road infrastructure, and the role of EO to support climate proofing and better watershed management. 

The EO support project demonstrated how many relevant EO-based datasets can replace traditional data sources and how these data can be applied for relevant analysis.

The following products and derived services were provided as part of the project:

  • Reliable and up-to-date climate data (based on the TRMM satellite, 3 h/ daily rainfall), 

  • SPI (drought index) and rainfall statistics (IDF curves) based on the climate data,  

  • Digital Elevation Model (30 m resolution), hydrological catchments and rivers, 

  • Current land cover (2014) and recent land cover change (between 2007 and 2014), 

  • Hydrological modelling to support drainage design, 2D HD and 1D Design discharge,  

  • Risk screening maps for floods and drought. 

Most of the above products as well as analysis of these were provided for browsing and further analysis in a web viewer specifically developed for the project available at

During the inception phase ADB representatives expressed special interest in 1) accessing and applying (in the hydrodynamic modelling) as detailed climate change scenario data as possible and 2) slope stability, as an essential part of a road engineering project. Both issues were investigated and implemented, noting that slope stability could only be considered on the coarse scale, as detailed studies of this would require much more detailed data than available. 

The project clearly demonstrated the added value of providing access to longterm consistent data on local climate, allowing for derivation of IDF (Intensity- Duration-Frequency) curves describing the rainfall patterns in the area. IDF curves are essential (and used directly) for the correct dimensioning of roadstructures like culverts and bridges. The original design of road structures were based on rainfall statistics from Darwin, Australia due to lack of reliable local data. Data from the TRMM and GPM satellites allowed for derivation of IDF curves at the scale of TRMM resolution (approximately 25×25 kilometres) and 3 hours temporal resolution which was further extrapolated down to 1 hour. Comparison between the IDF curves from Darwin and the EO-based, also considering climate change scenarios from IPCC showed that road structures have generally been over-dimensioned. Even for the RCP 8.5 scenario for 2090, the chosen design dimensioning should be sufficient. This is of course positive in that the road structures are likely to accommodate the expected rainfall for a long time, but over-dimensioning is likely to incur increased construction costs and maintenance. The main issue remains for similar projects– the lack of sufficient/reliable local data can lead to incorrect dimensioning. 

The project has also demonstrated how to apply the supplied EO information in hydrodynamic modelling with direct benefits for the road engineers in terms of the expected effects of climate change on runoff along the road corridor. This kind of analysis requires not only high quality data on topography, but also information on land cover as this influences the runoff. The mapping of land cover and land cover change has shown a decline in forest cover during the period between 2007 and 2014. As the progression of forest into less vegetated land cover types is likely to increase the overland flow in case of heavy rains, the observed (and any similar future land use change) will increase the risk of flood damages to the road. 

As part of the project, a two-day workshop/capacity building event was carried out at the ADB Resident Mission in Timor-Leste. The workshop had over 15 participants from government agencies (Ministry of Public Works, National Directorate for Water Resource Management, Institute of Petroleum and Geology), international organisations (ADB and various UNDP offices), NGOs and road engineers working on the road project. The project EO data and services were showcased by presenting how the data can be applied to a range of topics within climate change, infrastructure design and monitoring of land use and climate. All of the training sessions included local examples of the relevant data products, as well as demonstration on how and where these products were available in the project web viewer. Material was prepared for the course through the framework of The Academy by DHI, including and course presentations and project data distributed through the web viewer (requires login). In order to increase the uptake of the information locally in Timor-Leste and make the deliverables more accessible, ADB requested a number of “info sheets” explaining the value of delivered products for road projects and broader initiatives. As internet access is not widely available in rural areas in Timor-Leste and generally has very limited bandwidth, the info sheets were distributed also as paper versions. 

The service utility assessment showed that there is great interest and potential for applying EO data and services within ADB projects, but currently significant, mainly institutional, constraints need to be overcome. In general, for road infrastructure projects, ADB presently only specifies the required outputs of feasibility and design studies and leaves it to the contractors to carry out the work as desired. This effectively means that the methods and data sources are chosen not by ADB, but solely by the consultants, making the uptake of EO data and services quite arbitrary and not an integral part of the current practices. Furthermore, the lack of knowledge and training on EO capabilities, as well as potentially the cost of this training and required software is seen as factor currently limiting the uptake of EO data and services. 

Overall the project concluded that there is great potential for application of EO data and services within ADB on projects with similar scope. The data and services delivered were found to be of better quality, better value and easier to obtain than traditional data sources. They also provide information that is not otherwise available. The main obstacles for further update of EO-based information is the current practices on the Terms-of-Reference for new projects and the lack of knowledge and training on EO capabilities.

The project helped ADB in better quantifying climate risks (in particular flood risks) to inform and validate the climate-proofing and watershed management activities. It also helped ADB to raise awareness about the impact of climate change and land-use changes in Timor-Leste, with focus on ecosystem services and road infrastructure. [...] Feasibility studies for larger projects could be facilitated using EO. Detailed drainage design, environmental mitigation, preliminary design could cut the time currently needed for ground based topographical survey – especially at the feasibility stage where the order of accuracy (particularly vertical) would be sufficient.

Richard S. Phelps 
ADB Principal Infrastructure Specialist

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