Building Climate Resilience into Timor Leste’s Roads


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The only thing worse than taking 5 hours to drive 106 km along winding and often damaged mountainous roads, is the realization that having reached your destination you have to turn around and repeat the trip to get home. That was in the forefront of my mind as I sat in the very quiet town of Ainaro, south of the capital in Dili. The second thing I thought about was that we had to do a lot of work to help Timor Leste make their roads more resilient to the effects of climate: or more particular, water.

Timor‐Leste is a small and mountainous island country surrounded by Indonesia, with a population of about 1 million. It has a dramatic topography dominated by the Ramelau Mountains stretching across the middle of the island from the east to the west. About 44% of the Timor‐Leste's total land area lies between 100 and 500 meters in elevation, and 35% above 1,000 meters. My trip took me across this mountainous spine towards the south of the country.

An assessment of the likely impact of climate change on Timor Leste done in 2009 by the consultant Cardno Acil forecasted that rainfall would increase in the future. This may bring fewer extreme rainfall events but their intensity would be more important.


Water and roads do not mix, particularly in mountainous areas such as in Timor Leste. This was obvious during my field trip where there was ample evidence of erosion, slope failures, and pavement damage from water. The photos give an idea of the types of issues encountered. With the likelihood of more rain, with higher intensity, it is necessary to take steps to build some resilience into Timor Leste’s roads.

Traditionally, the responses to hazards such as flooding and landslides were to desig and provide additional or reinforced engineering structures such as more/better drainage, culverts, higher bridges and re-aligned road sections. However,  it is now recognized that re-vegetation and bioengineering measures for water courses and road slopes are key to implementing a lasting solution.

Bio-engineering improves slope stability, controls storm water and sediments, and helps absorb pollutants through natural processes. There are a variety of measures that can be taken including tree and shrub planting on unstable slopes, and the use of vegetated erosion control blankets which are natural fibres able to retain soil and sediments while providing a medium for planting shrubs. The goal is to increase water retention capacity and slow infiltration through natural or bioengineered systems.

There is still a place for civil engineering measures—such as providing sufficient capacity longitudinal and transverse drainage, as well as improved retaining walls, gabions (i.e. stone filled nettings)—but without bio-engineering they are only partial solutions.

The Timor Leste government is already taking steps to address the issues, and there were quite a few locations where civil engineering works were going on. There were many good examples of well constructed gabions, as well as other examples where they had not been so effective.

There were workers constructing excellent quality retaining walls from local stone, of which there is abundance. It was impressive to see a crew quarrying stone from the side of a mountain, attacking large rocks with sledge hammers and then moving the stone around as if it weighed very little.

A major benefit from constructing stone retaining walls, gabions and stone drainage is that it creates work for local communities. This can provide much needed stimulus and support to the local economy. The team building the gabion below were all recruited from the local village. They estimated that it would take them a month to gather the necessary stone and construct the gabion, and said they were very grateful to have the opportunity to work. The ILO has been working on labor based methods for road construction in Timor Leste, and it is clear that there are a number of areas of success.

We plan on exploring how we can assist the government of Timor Leste with building resilience into their road network to better cope with rainfall and the potential future climate changes. Relatively modest investments will yield major benefits not only in keeping roads open, but in saving on potentially large future maintenance or rehabilitation investments.



Chris Bennett

Lead Transport Specialist

Join the Conversation

Rob Wesley-Smith
November 19, 2010

Congratulations on this paper, Chris, it is spot on, imho You don't say how to convince the East Timor government to take it on board. The need for environment rehabilitation and careful planting of trees in association with road works has been clear for a long time. Also, it is clear that people can use the water that soaks into the landscape and comes out slowly in springs , rather than seeing it all rush off in dirty rivers into the sea.
Terrific to see a roads report (building roads resilience into East Timor roads) highlighting the need for planting trees to reduce erosion above the roads. In an unusually Wet year in East Timor, all the north-south roads have had major problems.

The biggest problem is: how to get government to understand these issues, and build environment protection and repair into road works!!
Incorporating forestry practices into road building and maintenance is also a great way to involve local rural communities and allow them to earn a few dollars too.

In East Timor to my observation the roadside drains are not quite big enough, especially with global warming factored in, plus there are not enough cross road drains to take the water away.

East Timor is getting short of drinking water, partly because so much rushes off into rivers which flow fast and dirty into the sea, instead of soaking in and emerging as springs, like it used to!!
Rob Wesley-Smith

Ishwar Sunwar
September 18, 2012

Please accept my apology for late response and I hope my comments are still helpful even if the project is being implemented!

The project is very interesting to me. At last, a good justice has been given to Bio-engineering. I come from Nepal where I started Bio-engineering in my early career in 1986 by implementing of UK based TRL (former TRRL) designed experimental plots on the Dharan - Dhankuta Road, east Nepal. Later, we expanded works with the guidance of three other expatriates and since then I have been practicing it on roadside slopes and watershed management.

The ongoing project in Timor-Leste looks like the right approach to make roads and other rural infrastructures more resilient to climate change. Extensive use of Bio-engineering in all infrastructures developmental projects and watershed management is probably the most efficient tool for present context of CC impact where both the drought and excess water can make great impacts to slopes. Bio-engineering can help to stand the infrastructures in such events. However, to achieve best results from Bio-engineering, it will depends on how well the design is made. Like most people viewed, we (in Nepal) also conventionally thought the use of vegetation, tree or shrub planting, making surface cover with vegetation and also to promote aesthetic view along the road would still regards as Bio-engineering. But later we knew that it rather requires accurate identification of problems on sites associated with water, materials properties and alteration of physical features of such locations where infrastructures are being built. In other words, correct site assessment is required with appropriate designs. This would be site specific since we have not yet got numerical methods of testing the success other than qualitative means. Lesson learning from Nepal further revealed that just replication of those successful techniques in the US, Canada, Europe and Japan do not necessarily applicable or successful the Nepalese condition for various reasons. So, selection of techniques should be open to problems associated onsite. For example, Gabion is standard practice in Nepal for any slope related failure mitigation and roads retaining purpose due to its flexibility in nature in the most dynamic terrain like Nepal. But they do not necessarily stand everywhere unless they are well integrated with vegetation which we know as Bio-engineering. The definition for Bio-engineering in Nepal is "Use of vegetation either alone or in conjunction with civil engineering structures and non-living plant materials to control shallow slope instability and erosion on slopes" DoR 1995. This definition was just appropriate to convince conventional engineers in Nepal who have trust only on civil engineering structures but not with the vegetation. Since then, it is the application of vegetation + civil engineering structures but needs will be identified as per the requirement of site conditions as assessed by an experienced person. I have not been to Timor-Leste but as I can make out of the relevant literature and reports such as IEE and RSP of said road, the material types are similar to Siwalik range of Nepal where additional load for any betterment will often have adverse impact to slope stability. For example, photos 11 (counting from 1st before the Precipitation graph) above may have nature of materials that cannot accept gabion load despite it is very flexible. Similarly, if the subsidence (photo 8) goes, adding gabion wall alone may not be right solution where Bio-engineering would assess the appropriate site requirements more systematically (though I am not blaming previous designer not being very systematic).

So, Nepal's lesson learning from 1986 till now further reveals that: a) success of Bio-engineering design is dependable on quality of site assessment; b) if the design being the most appropriate, then success of it will depend on quality of implementation which can be achieve only from critical monitoring and regular coaching. Only Inspector's job will not be sufficient but regular mentoring and coaching to implementer (actual person involved in carrying out of activities on site) is paramount needs. For quality checking of fills in the road construction, there will be various methods of testing thus one can immediately predict the success and failure of fills but for plants, it takes several weeks to show any sign of up-taking or survival after planting. If quality work is missed at this stage there will be only no chance of success and only failure. Therefore mentoring and regular coaching is vital at the time of implementation. Finally, to make sustainable Bio-engineering system, due consideration should be made to social, cultural and economical aspects of plants that are going to be used together with their engineering properties well at the time of selection. Not all green cover will be effective Bio-engineering!

Wish this project goes well and becomes resilient to CC impact. Wish you and People of the Timor-Leste have very good luck.


November 15, 2012

I guess all the common road quality issues and simple pathways to build climate resilience of the kind of road network are well addressed in the World Bank Environmental Safeguard Policy (OP 4.01) or Safeguard Procedures, 2009 and 2011.

What I need to learn more about is how are building climate resilience and implementing environmental safeguards (for better road quality) different or complementary for the development context in general and in the above specific context of road infrastructure development? Grateful to hear your insights.


John Bartlett
May 04, 2013

Congratulations Chris on this excellent paper. Since travelling the remote roads of Timorlese on foot cycle and 4wd I have concluded that the most important component of the road system is ongoing maintainence.there needs to be a small crew of local people trained and paid to clear the gutters and drains during and after storms,often all it takes is an hour or two of person with a shovel to protect a major road or bridge.This doesn't seem to be happening?