Floods and Vulnerability

The late geographer Neil Smith wrote that there is no such thing as a natural disaster. Denying the naturalness of a disaster is definitely not a denial of natural processes. Instead, this perspective widens the possibilities, and responsibilities, of coping and living with hazards. By recognizing that vulnerability to hazards is often human-induced, primarily through economic and spatial injustice, management policies can no longer focus solely on 'minimizing' the physical effects of a hazard by structural or technological means. Underlying issues of socio-economic inequalities, ethnic discrimination, gender biases and other community-specific forms of exclusion need to be addressed and incorporated into hazard management programs.   

Our ongoing work in northern Thailand covers both the physical and human-induce aspects of flood vulnerability in Thailand. We are looking into the less-studied area of the latter, of how various belief systems and local histories shape different understandings and knowledge of floods in northern Thailand. For example, how does the Buddhist philosophy of impermanence feature in relation to floods and natural hazards in general? Or, how do folklores and customs of spirit worship affect the way Thai people understand floods? Such cultural understandings can inform hazard responses, and may also underpin certain community-specific exclusions in the region. Ultimately, we want to explore the possibility of a broadbased, community-driven flood management program which considers, or even utilizes, cultural beliefs. 

For news on the politics of floods in Thailand see:

http://www.guardian.co.uk/commentisfree/2011/oct/21/thailand-floods-bangkok

http://www.bbc.co.uk/news/world-asia-pacific-16713875

http://www.iied.org/thailand-s-floods-complex-political-geographical-factors-behind-crisis

An interesting video on water resources and its relationship with the human environment:

Upstream Downstream - ADB Water Voices Series

http://www.youtube.com/watch?v=qSV6EdreqR8&list=PLFFB081288A7EC0C3

Ancient floods, modern hazards: the Ping River, paleofloods and the ’lost city’ of Wiang Kum Kam 

This paper demonstrates that the importance of rivers in northern Thailand was anchored upon society’s dependence on them for sustenance and defense. Concurrently, rivers were also of deep religious and cultural significance. Hence, many northern Thai settlements were located near rivers. This resulted in their susceptibility to flood hazards. Our study investigates the interactions between the Ping River and the population of Wiang Kum Kam. Wiang Kum Kam was one of the former capitals of the Lanna Kingdom, a thirteenth- to sixteenth-century polity in northern thailand. Described as the ‘Atlantis’ of the Lanna kingdom, the city was buried under flood sediments several centuries ago. Based on the floodplain sediments excavated, we argue that the city was abandoned after a large flood. Radiocarbon dating of charcoal found in the coarse sand layer deposited by the flood suggests that the deposition occurred sometime after ca. 1477 AD–1512 AD. Prior to this large flood, persisting floods in the city were noted in the Chiang Mai Chronicle and were also recorded in the floodplain stratigraphy. We show that an elongated mound on the floodplain in Wiang Kum Kam was a dyke constructed after ca. 1411 AD to alleviate the

effects of persisting floods. From this story of paleofloods and Wiang Kum Kam, we conclude with two lessons for the management of modern floods in urban Thailand. 

Ng, XQS, SH Wood, AD Ziegler. 2014. Ancient floods, modern hazards: the Ping River, paleofloods and the ’lost city’ of Wiang Kum Kam. Natural Hazards. 10.1007/s11069-014-1426-7.

Modifiers and Amplifiers of High and low Flows on the Ping River in Northern Thailand (1921–2009): The Roles of Climatic Events and Anthropogenic Activity

In this study, we analyse an 89-year streamflow record (1921–2009) from the Upper Ping River in northern Thailand to determine if anomalous flows have increased over time (Trenberth, Clim Res 47:123–138, 1999; Trenberth, Clim Chang 42:327–339, 2011). We also relate the temporal behavior of high and low flows to climatic phenomena and anthropogenic activities. Peak flows have not increased significantly since 1921. However, minimum flows showed a very significant downward trend over the study period (α00.01). Annual and wet season discharge show significant downward trends (α00.05). All flow variables appear to be more variable now than 90 years ago especially annual peak flows. Both annual peak and minimum flows are correlated with annual and wet season rainfall totals. Minimum flow is also sensitive to the length of the monsoon season and number of rainy days in the previous monsoon season. Peak flow activity is driven predominantly by climate phenomena, such as tropical storm activity and monsoon anomalies, but the relationship between peak flows and ENSO phenomena is unclear. In general, annual discharge variables did not correspond unequivocally with El Ninõ or La Ninã events. Minimum flows show a major decline from the mid-1950s in line with major anthropogenic changes in the catchment. The plausible intensification of the hydrological cycle that may accompany global warming is of concern because of the potential to affect tropical storm activity and monsoon anomalies, phenomena that are linked with very high flows in this river system. The obvious effect of human activities such as reservoir management on low flows calls for careful management to prevent droughts in the future.

Lim HS, K Boochaphun, Ziegler, AD. 2012. Modifiers and Amplifiers of High and low Flows on the Ping River in Northern Thailand (1921-2009): The Roles of Climatic Events and Anthropogenic Activity. Water Resources Management 26 (14): 4203-4224.

Reducing Urban Flood Vulnerability: The 2011 Thailand Flood

The 2011 flooding of the Chao Phraya River in Thailand highlights the difficulty of managing surface water in tropical monsoon areas where several months of ample rainfall are followed by long dry periods.  Dual-purpose reservoirs provide two competing functions: (1) maximizing water storage for irrigation and commercial use in the dry season; and (2) minimizing flood risk late in the wet season.  In 2011 uncharacteristically high rainfall and questionable reservoir management decisions are mentioned as factors exacerbating the estimated US$45 billion in flood damages in Bangkok and surrounding areas.  We however believe the fundamental cause of the catastrophe was failure to prepare for a recurrent hazard—major floods have occurred on the Chao Phraya River in each of the last four decades.  This is not an isolated issue. Thailand is simply an unfortunate example.  Each year an increasing number of people worldwide live in areas vulnerable to flooding. Continued development of large population and manufacturing centers in flood-prone areas means that catastrophic flood damage will certainly reoccur.  Anticipated acceleration of the hydrological cycle and sea-level rise resulting from climate change could worsen the problem.  

       Drastic measures to reduce vulnerability are urgently needed. Proposed engineering approaches such as building cascades of dual-purpose dams or constructing higher dikes are short-term water management solutions that are potentially dangerous because as people grow complacent when small disasters are avoided, they become more vulnerable to truly catastrophic events.  Long-term development solutions are needed.  Fundamentally, we must address the social, economic, and political issues that force some people, and allow others, to inhabit areas of high environmental risk.  Concurrently, vulnerable cities could be redesigned by linking metropolitan areas located on higher grounds via appropriate transportation systems engineered through potential inundation zones.  This development approach would also serve a secondary purpose of helping coastal cities combat sea-level rise.

Support

DL Higgitt (PI, NUS), M Chui (NUS), AD Ziegler (NUS), Lim HS (NUS), R Wasson (Charles Darwin, Australia), G Brierly (U Auckland). 2011-2013. River Rehabilitation: An integrated approach to flood hazard management in Asian cities. NUS Global Asia Institute ($178,862): Singapore, China, India, Thailand.