FEATURE: Da Nang – A rising star, menaced by extreme rainfall
Miren Gutierrez uncovers the measures taken by a CDKN project to protect residents in the Vietnamese city of Da Nang from worsening rainfall in a changing climate.
Da Nang is one of the major port cities in Vietnam, and a commercial and transportation hub on the Central Vietnam. With its easily accessible port, at the opening end of the Han River, Da Nang is the leading industrial heart of central Vietnam, and according to Vietnam News, it has set raising targets of its industrial production value. This city is also an international tourist attraction. As a result, its GDP per capita is one of the highest in Vietnam.
Da Nang is also very vulnerable to climate change and extreme weather events, such as typhoons and flooding.
According to 100 Resilient Cities, “for years, the city has been developing innovative models to enhance resilience to climate change… And despite the challenges, Da Nang has become an attractive destination in Vietnam for foreign investment. By late November 2013, Da Nang had attracted 279 foreign projects, totalling over US$3.31 billion.”
However, the tourism and service industries are likely to suffer “significant losses” when extreme weather events, such as typhoons and floods, strike the city, “if preventive measures are not carefully considered and incorporated,” says Phong Tran, the Vietnam Technical Lead of the Institute for Social and Environmental Transition (ISET).
Phong, a technical lead of ISET-Vietnam, has more than 15 years working on climate change resilience and disaster risk reduction in developing countries in the Asia and Pacific, particularly in Vietnam. ISET collaborates with local partners to build resilience and catalise adaptation to social and environmental change.
Rapid development in Da Nang is increasing flood frequency and severity in the city during extreme rain events. “Climate change will increase the intensity of extreme rainfall events in and around Da Nang,” says a report published by the Climate Development Knowledge Network (CDKN) in 2014. In 2007, for example, “a moderate rainfall event caused significant flooding in the city; flooding was clearly exacerbated by rapid development and urbanisation occurring in the floodplain.”
By the end of the 2020s, the CDKN report says, climate change could increase the rainfall intensity of such events by 3 to 24%.
In 2012 ISET, with funding from (CDKN), undertook a 2-year long analysis research project to evaluate the economic costs averted from building to storm resistant standards in Vietnam. The Sheltering From a Gathering Storm research programme, also implemented in India and Pakistan, targeted peri-urban areas in Vietnam to identify solutions for resilient shelters and the long-term economic returns of investing in such shelter structures.
The problem was that construction standards based on historical experience would not prepare houses and infrastructure for future events, which are to be more frequent and intense. “If the city continues to expand into low-lying areas without taking a multi-activity flood risk reduction approach and multi-hazard resilient construction, damage and possible loss of life may be severe even in areas of new construction,” concludes the CDKN report.
Da Nang sits on a long piece of lowland coastline, with the city centre resting along the Han river. Flooding occurs frequently and typhoons are yearly occurrences. The poor households of the city face insufficient access to housing and other services, such as health care, transport and education. This project helped “build and retrofit” –that is, adapt— hundreds of houses for the poor, says Phong.
But what is a storm-resilient house, exactly? Storm-resilient construction methods include “closed concrete frames” –single-piece concrete frames that are easy to assemble and are very resistant—; “ring beams at foundation and roof levels” –supports connecting walls and increasing the load capacity of the walls—; “detached veranda, strong connections between roof parts, and tightened windows and doors,” says Phong.
There are also mitigation co-benefits in resilient building. Features included in resilient houses are “openings on both sides,” for example, which “enable natural cross ventilation and natural lighting inside the house and, thus, reduce energy consumption for artificial cooling and lighting equipment (fans, lightbulbs),” he adds.
The expectations from this project include –according to Phong— “wide replication of safe housing construction practices”, as well as “increased public awareness on safe housing”, the engagement of “a wide range of stakeholders in building a resilient housing system” with the support of the city; and “the mainstreaming of risk reduction measures” in granting building permits in vulnerable areas, he says.
On October 15, 2013 typhoon Nari landed in Da Nang city. Storm winds and heavy rainfall led to flooding, thousands of homes were damaged and many people were injured. According to the report of Da Nang City People´s Committee, the damage amounted to up to $40 million.
“No damages were incurred, however, in the homes built as part of the Storm Resistant Housing for a Resilient Da Nang City project,” says a report published by ISET in the aftermath of the typhoon.
The Storm Resistant Housing for a Resilient Da Nang City project has been funded by Rockefeller Foundation and administered by ISET, in partnership with the Da Nang Women’s Union, and it linked with the learning derived from the Sheltering From a Gathering Storm research programme, co-funded by CDKN.
“The retrofits were a great success and showed great added value,” says Kenneth A. MacClune, President and CEO of ISET.
“Beneficiary households strengthened their houses and prepared carefully to cope with the typhoon, therefore their houses were all safe. Meanwhile, many houses and public structures in their area, even right next to them had their roofs blown away and they suffered heavy damages,” says the ISET report on the consequences of Nari.