• The Code - developed by stakeholders including the NBRO, the UDA and the CIDA - will set min. standards for structural and geotechnical safety 
• Builders will be regulated by setting qualifications and performance standards
• Buildings in flood-prone areas will require raised foundations, those in high-wind zones will need stronger roofing, and structures in tremor-prone areas must follow specific designs while fire safety and water mgt. will also be covered
• NBRO DG Dr. Asiri Karunawardena further explained that even though Local Authorities must approve constructions only after receiving NBRO clearance – must send building applications received for constructions in landslide-prone areas for recomms. - implementation varies, with not all LG Bodies being compliant with this process 

The increasing change in climatic conditions being experienced globally in recent years has called on all related institutions to help reduce the wrath of Mother Nature. This fury, now quite regularly manifested in the form of earthquakes, tornadoes and cyclones, leaves in its wake destruction, debris and shattered human lives, as seen during last year’s Cyclone Ditwah.

When Ditwah made landfall, it brought heavy rain, strong winds and damage across several parts of Sri Lanka. Prolonged rainfall caused flooding in low-lying areas and triggered many landslides, mainly in the Hill Country and nearby Districts. Homes were damaged, roads were cut off, and daily life came to a standstill for many vulnerable communities.

As the situation worsened, attention turned to institutions responsible for disaster monitoring and risk reduction. One such agency was the National Building Research Organisation (NBRO), the country’s main technical body for landslide risk management and geotechnical assessments. With climate-related disasters becoming more frequent, the role of such institutions has become increasingly important.

This interview with the NBRO Director General (DG), Dr. Asiri Karunawardena, explores the organisation’s role during Ditwah and the lessons learned and future preparedness.

Following are excerpts of the interview: 

Can you give us the definition of the technical terms the NBRO use when defining vulnerable and hazardous areas? 

We have done the hazard zonation map which helps us identify potential landslide areas where with the sufficiency of rain, there can be a landslide occurrence. A potential area where a landslide could occur is identified as a vulnerable area. Also, if people are living in a particular area, there can be a landslide hazard. 

What is an unauthorised construction?

When you do whatever the construction, you have to get the proper approval from the relevant Government institutions. For instance, if you construct a house, you have to get the approval of the relevant Local Authority. Depending on where you live, it can be the approval of the Urban Development Authority (UDA), or the Local Authority like the Municipal Council, Urban Council or Pradeshiya Sabha, or the Provincial Council. You have to get their approval. If you have not got their approval – in simple terms, it can be categorised as an unauthorised constriction. 

Is there relativity with the geographical situation of some of the areas which led to the disaster such as the landslides?  

From 2011, a circular issued by the Disaster Management Ministry required construction in landslide-prone areas to be carried out with recommendations from the NBRO. This was introduced to reduce landslides caused by human activities. NBRO officers assess whether a proposed construction could create a landslide risk.

In some cases, land is identified as highly prone to landslides due to geotechnical or geographical instability. In such situations, approval is refused, and construction is discouraged as the land is not suitable for building.

In other cases, the land may not be naturally prone to landslides, but, the construction could increase the risk. If the risk can be controlled through proper construction methods, the NBRO provides recommendations. For example, on sloping land, builders are advised not to cut or disturb slopes and to design buildings according to the natural angle of the land. Drainage improvements are also recommended.

The NBRO provides guidelines based on detailed land investigations to help reduce the landslide risk. When a Local Authority receives a building application in a landslide-prone area, it must send the application to the NBRO for recommendation. Local authorities should approve construction only after receiving NBRO clearance.

However, implementation varies, with some Local Authorities following this process and others not. The NBRO is therefore engaging with the Local Authorities to streamline and strengthen the system.

District offices have been set up where ever the NBRO has identified landslide zones through its mapping. So, these District offices work with the Local Authorities and their Divisional Secretariats (DSs) in those particular Districts. 

Sri Lanka has the vaastu/waastu and baas-based building systems and then the more sophisticated architectural designs. How does the Organisation view this and what advice can you give them?

In the Sri Lankan culture, importance is given to auspicious times and vaastu/waastu principles. However, the NBRO focuses mainly on resilience and sustainability. Its goal is to promote houses that can withstand strong winds, minor tremors, floods and landslide risks.

As building a house is usually a once-in-a-lifetime investment, any damage can cause serious hardship. The NBRO therefore advises people to select land with the lowest possible disaster risk. While risks cannot be fully avoided, careful site selection can greatly reduce vulnerability.

The Organisation also stresses the use of appropriate construction technology. This includes soil testing to determine the correct foundation and the proper design of the structure. Although builders may carry out constructions, professional advice is strongly recommended. Simple houses may require a technical officer or an engineer, while multi-storey buildings must be designed by qualified engineers and architects.

Professional guidance helps reduce costs while ensuring safety, durability and sustainability. This has led to efforts to introduce a Sri Lankan Building Code, which has already received Government approval. At present, standards exist as guidelines, but, once enacted, compliance will be mandatory.

The Building Code is being developed with the NBRO, the UDA, the Construction Industry Development Authority (CIDA) and other stakeholders. It will set minimum standards for structural and geotechnical safety, in line with international practice.

For instance, buildings in flood-prone areas will require raised foundations, those in high-wind zones will need stronger roofing, and structures in tremor-prone areas must follow specific designs. Fire safety and water management will also be covered.

The Code will also regulate builders by setting qualifications and performance standards. While this is a long-term process, the draft Code is expected within a year, with training for Local Authorities planned over the next two years.

What sort of safety measures can be adopted to prevent natural disasters in the future? 

Natural disasters are becoming more frequent due to climate change. Changing weather patterns and heavier rainfall highlight the need to protect nature and build resilient infrastructure. This requires proper land-use planning and well-organised settlements to reduce disaster risk.

In countries like Japan, settlements are carefully planned in safe areas. In Sri Lanka however, people are scattered and live on mountain tops and slopes, making the provision of their safety harder to ensure. Planned settlement clusters would make protecting communities during disasters easier and less costly.

Identifying safe areas for housing, cultivation and industry while protecting vulnerable zones is therefore essential. The Government is working on this. A recently issued Gazette notification declared central fragile areas in sensitive high-mountain catchments. Discussions are also underway with the National Physical Planning Department (NPPD), the UDA and the Central Environmental Authority (CEA) to develop a coordinated approach.

Disaster management systems, including early warning mechanisms, also need strengthening. Current systems must be assessed to ensure that warnings reach communities at the grassroots level. Remote sensing and other technologies (e.g. drone) will be improved based on lessons from recent disasters, with Government support, to enhance preparedness and response.

The NBRO, following the disaster, said that 60 per cent of the land in the Badulla District was uninhabitable. How will these people be relocated? 

We have identified the potential by landslide potential mapping. One of the factors is the slope angle or the gradient. If the gradient is higher than 10 or 11 degrees, there can be a landslide. That does not mean that there will be one. It means that it is vulnerable. Now, we have identified high hazard areas in Badulla, Nuwara Eliya and all these mountainous areas. We have identified that about 15,000 families were in high risk areas. That was before this landslide. The Government has initiated a programme now where 5,000 families were resettled in safe areas. The balance is 10,000. However, following Ditwah, we identified an additional 7,000 families who would again be in high risk areas. They were identified by the field investigations that were carried out. And, they too would be resettled. 

How would you prepare the social groundwork when resettling these people? 

While safe land can be provided, the impact of relocation on livelihoods must also be considered. Therefore, efforts are made to identify suitable land as close as possible to the original location. Where possible, families are allowed to continue using their former land for cultivation and income, although it is no longer permitted for housing.

The challenges of resettlement are well recognised. Discussions are held with the affected communities and the DSs to reduce disruption. Relocation sites are selected where basic services such as water and electricity are available, and where livelihoods, including farming, can be maintained.

Wherever possible, the NBRO aims to keep communities in their existing locations by reducing disaster risks. Of the 7,000 people identified in high-risk areas, over 20,000 live in moderate-risk zones. In these areas, the focus is on mitigation measures to improve safety, and this work is ongoing.

Resettlement is considered only when mitigation is neither technically nor economically feasible, taking into account the country’s financial and technical limitations.

How far are you concentrating on resilience for future constructions?

During reconstruction, the principle of “Build Back Better” is followed. This approach improves buildings by considering future disaster risks. The aim is not only to withstand disasters, but to ensure that structures don’t collapse even if some damage occurs. Many lives have been lost due to building failures, and these lessons are now reflected in construction practices.

For example, daily rainfall can now reach 300–400 millimetres (mm), compared to about 150 mm in the past. Design standards have therefore been revised to reflect this increase, including a higher drainage capacity.

Resilient infrastructure can be restored within a few days, allowing transport, businesses and daily life to resume quickly. Although some damage may occur, the recovery period is significantly reduced.

How do you view the criticism that the relevant authorities and the Government had not paid attention to the warnings that had been given? 

Rainfall thresholds are used to issue alerts. When rainfall exceeds 75 mm, an alert is issued. At more than 100 mm per day, a warning is given advising people to be ready for evacuation, and when rainfall exceeds 150 mm per day, an evacuation order is issued. Based on the actual rainfall received during this event, the necessary warnings were issued in a timely manner.

Many people were evacuated, although this has received little attention. Thousands stayed in relief camps, while others moved to safer locations on their own. The damage occurred because this was an extreme event, unprecedented in recent times.

Rainfall of more than 300–400 mm was recorded over three consecutive days, and over 1,000 mm was received within five days. This amounts to nearly one-fifth of Sri Lanka’s average annual rainfall, causing widespread instability across many areas.

This was also the first time a cyclone struck the Central Highlands. In the past, cyclones typically passed through coastal areas such as Batticaloa, as seen in 1977. This time, the cyclone affected mountainous regions that had already experienced continuous rainfall for several days, significantly worsening the impact.

In some areas, debris from landslides travelled up to five kilometres, destroying villages where residents had no prior indication of nearby slope failures. These areas are now being studied to assess the likelihood of similar incidents occurring in the future.

Has any of the research that has been done been incorporated into the work that has been going on?

The hazard zonation maps are prepared through research carried out by the National Building Research Institute (NBRI - the current name of the NBRO). About 80% of the landslides occurred in areas identified as high risk on these maps.

The Institute also conducts research on early warning systems and other aspects of landslide and disaster management. However, we understand that more research is needed to cope with these changing conditions.

Research is also carried out on building and structural stability and geotechnical engineering. The NBRI has six technical divisions: the Landslide Risk Management Division, the Geotechnical Engineering Division, the Environmental Engineering Division, the Human Settlement and Planning Division, the Building Materials Division, and the Project Management and Structural Research Division. All Divisions conduct research in line with the Institute’s master plan to ensure a safe environment.

In addition, the NBRI has three advanced laboratories — the Geotechnical Engineering Laboratory, the Environmental Engineering Laboratory, and the Building Materials Laboratory. These Laboratories are equipped with modern technology and skilled personnel. Also, some research is carried out in collaboration with universities.

When people are asked to evacuate, what should they take with them to overcome future difficulties? 

During landslide awareness and evacuation programmes, people are advised to prepare in advance. They should take important documents such as birth certificates, educational certificates, national identity cards (NICs) and marriage certificates. Valuables should be placed in boxes and kept in safe, protected places.

The actions to be taken depend on the type of disaster. During floods, people should move to higher ground, while in the case of landslides, they should go to a safe area. In short, people should protect items that they will need to restart their lives after a disaster.

What was the impression you got of the public response when people were asked to be alert and to evacuate? 

Most people took the early warnings issued by the NBRO seriously. Public participation and awareness are vital during disasters. In Sri Lanka, some people may not receive these messages due to infrastructure limits, but, those living in hilly areas must learn how to stay safe in landslide-prone zones.

Before the monsoon, drains must be cleared. Landslides are mainly caused by heavy rainfall, but, the proper diversion of water from upper to lower slopes along natural paths can greatly reduce risk. Many landslides happen due to poor drainage, often caused by the people themselves. Diverting water away from one plot can destabilise the land below, so, drains must not be blocked and deforestation should be avoided. Following these guidelines can prevent most landslides.

The NBRO urges people to heed warnings and take action. Awareness programmes are ongoing, and educating children has proven most effective. A child-centred programme, supported by the Education Ministry, now targets schools in landslide-prone areas, as lessons learned early in life tend to last.

The views and opinions expressed in this column are those of the interviewee, and do not necessarily reflect those of this publication

Precautionary measures

• On sloping lands, builders are advised not to cut or disturb the slopes and to design buildings according to the land’s natural angle with a higher drainage capacity 
• Apt. construction technology includes soil testing to determine the correct foundation and the proper structural design 
• Design standards have been revised to reflect the increase in Ditwah-period daily rainfall (300-400 mm)
• Before the monsoon, drains must be cleared, and water must be properly diverted from upper to lower slopes along natural paths 

PHOTOS VENURA CHANDRAMALITHA