Risk factors in relation to human deaths and other tsunami (2004) impacts in Sri Lanka: the fishers'‐eye view

Abstract

ABSTRACT1. This study examines the perceptions of 500 Sri Lankan fishers about influences on the outcome of the 2004 Asian tsunami. It is based upon analysis of questionnaire data on 13 natural environmental and development risk factors, in relation to human deaths and house damage (impact indicators).2. Mangroves, coral reefs and sand dunes afforded protection against tsunami damage (67-94% of fisher responses), as did housing and roads.3. Fishers overall believed rivers/estuaries, concave coastlines and hotels exacerbated impacts. However, a significantly greater proportion of fishers living within 100 m of the coast reported that rivers/estuaries had a protective role than those living further inland. Rivers seemingly diverted 'tsunami water' far inland, where it overflowed and caused damage.4. Risk and damage are multi-faceted concepts and measurable in different ways. Findings are considered in the light of ecological studies and modelling, with special reference to mangroves, whose alleged protective role has become equivocal during post-tsunami research.5. Insights of fishers and other communities with intuitive knowledge add a valuable perspective to the understanding of natural disasters and environmental change. This approach is seen as complementary rather than an alternative approach to purely 'scientific' research.

Modelling ecological and other risk factors influencing the outcome of the 2004 tsunami in Sri Lanka

“…Compared to a straight coastline, convex coastlines were protective, perhaps by deflecting tsunami waters to adjacent areas, thereby preventing inundation. This is consistent with fisher views that concave coastlines exacerbated tsunami damage (Venkatachalam et al 2009). The greater the minimum height above sea level for a given subunit of the Hambantota coast the more likely it was to be protected from tsunami intrusion, in terms of both inundation occurrence and distance.…”

“…Use of models is complementary to our questionnaire surveys of 500 fishers along the southern (Hambantota) coast of Sri Lanka (Venkatachalam et al 2009). This study shows that the vulnerability of Sri Lanka's coast to episodic events is governed by a complex interplay of factors.…”

“…Several studies suggested that natural systems, including mangroves, may have reduced tsunami impact in many Indian Ocean countries (e.g., v www.esajournals.org Bambaradeniya et al 2005, IUCN 2005), a view shared by Hambantota fishers (Venkatachalam et al 2009). Subsequent investment in use of bioshields and other natural barriers (e.g., IUCN 2006b) was clearly influenced by these findings although, as noted, some studies have challenged the protective role of mangroves.…”

“…It is noted that Sri Lankan coastal areas experienced mangrove loss, which predated the Asian tsunami, as a result of many factors. Ongoing loss or degradation of mangroves and other coastal systems, could be highly risky and impede certain future coastal development options (but, arguably, create others), as noted by Venkatachalam et al (2009). The conservation importance of wetlands is certainly implicit in national environmental and international legislation (e.g., Convention on Biological Diversity & Ramsar Convention to protect wetlands), to which Sri Lanka is party.…”

“…Our initial research, involving a questionnaire survey of 500 local fishers, identified mangroves, coral reefs and sand dunes as factors perceived to be important in reducing death toll and housing damage (67-94% of respondents) (Venkatachalam et al 2009). Using statistical models, this study further explores this and has two main aims.…”