By Asmita Tiwari, Suranga Kahandawa, Masatsugu Takamatsu and Keiko Sakoda
Our hearts sank as we looked at the Hurricane Katrina-affected house, now the Flooded House Museum in the City of New Orleans, United States. Our team from the World Bank was accompanying Sri Lankan officers visiting New Orleans in October 2019, to learn from the city’s post-Hurricane Katrina flood risk-management efforts.
We could see what the family must have seen after the flood waters receded—broken furniture, a piano, paintings, and toys including a stuffed teddy bear. We could almost feel the chaos and grief that must have followed after the floodwalls failed, releasing thousands of cubic yards of sand and millions of gallons of water at the breach site of London Avenue Canal Floodwall.
On 29 August 2005, three major levees broke, flooding 80% of the city. Hurricane Katrina caused 1,500 deaths, damaged 135,000 houses, and brought $150 billion in financial impacts. The city’s population fell by half in the immediate aftermath of the storm.
Lessons for Sri Lanka?
Half of New Orleans lies below sea level and the City of New Orleans is continuing to sink, making it more vulnerable to storms. What lessons can this highly flood prone city offer to Sri Lanka?
Sri Lanka, with its large coastline, is one of the world’s most vulnerable countries to climate change impacts. Under a worst case scenario, GDP could decline by 7.7%, and 90% of the country’s population could be at medium to high risk of climate impacts by 2050.
The Sri Lankan Government is rightly giving a very high priority to improvements in climate and disaster resilience. The country has initiated many innovative projects. The recently approved Climate Resilience Multi-Phase Programmatic Approach Project aims at improving flood warning and response, and risk reduction measures in key river basins of Sri Lanka. The new project successfully builds on the Climate Resilience Improvement Project and many past initiatives.
With heavy ongoing investments in climate resilience and flood risk management, now is the critical time for Sri Lanka to build an effective flood- and climate-resilience system, benefitting from global experiences.
The study tour highlighted three key lessons for Sri Lanka.
1. Assess the risk of failure of planned flood mitigation measures and minimise any negative impacts
Critical floodwalls failed during Hurricane Katrina due to several unexpected consequences of a flood protection strategy that relied heavily on floodwalls and pumps. The approach provided a false sense of security to citizens, who stopped individual risk mitigation measures (such as raising houses on stilts), thereby aggravating flood impacts in 2005.
Post Hurricane Katrina New Orleans has focused on reducing flood risk rather than providing absolute flood protection. This includes rebuilding levees and major flood gates to withstand extreme events with improved engineering designs (extended foundation and proper anchorage in ground) to minimise potential damages in case of failure or overtopping.
2. Develop an inclusive and effective flood preparedness system, keeping citizens in charge
During Hurricane Katrina, many citizens living in flood-affected areas of New Orleans could not be evacuated on time. Understanding the critical importance of flood preparedness, the city of New Orleans has developed a timeline-based disaster response and evacuation plan that includes improved planning and evacuation of high-risk citizens during emergency.
This includes improving capacity to evacuate the city’s high-risk population on short notice, massive community awareness campaigns—such as NOLA Ready – and training of volunteers. Innovative programs are in place for special needs citizens to ensure that they are alerted and evacuated in times of emergency.
A major focus is on communicating flood risk to individual homeowners so that they can make more informed decisions about retrofitting their homes. NOLA Ready’s website has a dedicated webpage which provides homeowners with details of flood risk in their property, suggestions to improve flood resilience, and available resources.
3. Consider green infrastructure
Post Hurricane Katrina New Orleans is gradually starting to invest in the development of green areas that can absorb excess storm water to reduce flood impacts and help recharge ground water. Green infrastructure or Nature Based Systems not only support drainage (gray) infrastructure but can also potentially reduce flood risk in a cost effective way. Research is currently ongoing in New Orleans on measures to reduce impacts from mosquitoes and other water borne diseases in planned green areas.
No time left for poor decisions
As we left New Orleans, we couldn’t help thinking about the Flooded House Museum, which has been preserved to remind people about the fatal impacts from Hurricane Katrina. The city seemed to have learned many lessons from the bitter experience, and has improved planning, engineering design, coordination, and public awareness on flood risk management.
The study tour to New Orleans offered a great opportunity for the Sri Lankan delegation to learn from post Hurricane Katrina efforts. Eng. Sudharma Elakanda, the Project Director of Sri Lanka’s Climate Resilience Improvement Project, summarised the visit: “We are planning for large flood protection infrastructure in Kelani river basin, but we lack experience with large flood protection works. This visit gave us the exposure and confidence that we can carefully build and effectively maintain the embankments and pumping stations, learning from New Orleans’ experience.”
As climate change impacts worsen, there is no time for Sri Lanka to make poor decisions. It will be important to carefully design and implement flood mitigation measures and build inclusive and functioning flood warning and response systems.