University of Southern Queensland
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University of Southern Queensland Flood Adaptation Strategies under Climate Change in Nepal: A Socio-hydrological Analysis A dissertation Submitted by Rohini Prasad Devkota MSc (Environmental Science and Technology) For the award of DOCTOR OF PHILOSOPHY 2014 Certificate of Dissertation I certify that the ideas, investigations, analysis, results, discussions, and conclusions reported in this dissertation are entirely my own work, except where otherwise acknowledged. I also certify that the work is original and has not been previously used to earn academic awards. Date:…../……/… … Signature of Candidate – Rohini Prasad Devkota Endorsement Date:…../……/… … Signature of Principal Supervisor – Prof Geoffrey J Cockfield Date:…../……/… … Signature of Co-supervisor – Dr Tek Narayan Maraseni List of Publications/Awards during the PhD Study Period 1. List of Peer Reviewed Publications Devkota, R.P., Maraseni, T.N., & Cockfield G., An assessment of willingness to pay to avoid climate change induced flood, Journal of Water and Climate Change (accepted). Devkota, R.P., Maraseni, T.N. & Cockfield, G. (2014). Perceived Community-based Flood Adaptation Strategies under Climate Change in Nepal, International Journal of Global Warming, vol. 6, no.1, pp. 113-124. Devkota, R.P., Maraseni, T.N., Cockfield, G. & Devkota, L.P. (2013). Flood Vulnerability through the Eyes of Vulnerable People in Mid-Western Terai of Nepal, Journal of Earth Science and Climate Change, vol. 4, no. 1, pp. 1-7. Devkota, R.P., Maraseni, T.N., Cockfield G. & Devkota L.P. (2013). Indigenous Knowledge for Climate Change Induced Flood Adaptation in Nepal, The International Journal of Climate Change: Impacts and Responses, vol. 5, no.1, pp.35-46. Aryal, S., Bhattarai, D. and Devkota, R.P. (2013). Comparison of Carbon Stocks between Mixed and Pine-dominated Forest Stands within the Gwalinidaha Community Forest in Lalitpur District, Nepal, Small-scale Forestry Journal, vol. 12, no.4, pp.659-666. Devkota, R.P., Cockfield, G., Maraseni, T.N., Bhattarai, R., Devkota, B. (2012). Assessment of Gases Emission from the Operation of the Semi-aerobic Landfill Site by Solid Waste of Kathmandu Valley, Nepal, Environmental Research Journal, vol. 6, no. 3, pp. 182-186. Devkota, R.P., Bajracharya, B., Maraseni, T.N., Cockfield, G. & Upadhyay, B. (2011). The Perception of Nepal‟s Tharu Community in Regard to Climate Change and Its Impacts on Their Livelihoods, International Journal of Environmental Studies, vol. 68, no. 6, pp.937–946. 2. Awards Climate Change Adaptation Grant: Knowledge + Partnerships, The National Climate Change Adaptation Research Facility (NCCARF), 2013, Australia. Best poster award „Most Thought Provoking Research‟, University of Southern Queensland research evening, 2011, Queensland, Australia 3. List of Conference/Seminar Papers Community-based Flood Adaptation Strategies under Climate Change in Nepal, NCCARF Climate Adaptation, Knowledge+ Partnerships conference, June 2013, Sydney, Australia. Application and Relevance of Indigenous Knowledge for Flood Management under Climate Change, 2nd International Conference on Earth Science & Climate Change, July 2013, Las Vegas, USA. Impacts of Climate Change on Agricultural Income and Land Inequality in West Rapti River Basin in Nepal, Third International Conference on Addressing Climate Change for Sustainable Development through Up-Scaling Renewable Energy Technologies (RETRUD-011), October 2011, Kathmandu, Nepal. ii Abstract While climate change is global in scale, developing countries and their people tend to suffer the earliest and the most because of their weak economies and low levels of resilience and adaptive capacity. Increases in the frequency and intensity of extreme events such as floods, droughts, fires, pests and diseases are creating tremendous challenges in natural and social systems. Because of the special climatologic characteristics, fragile topography, glacial melting and ever increasing deforestation rates, floods are a particular challenge to Nepal. It is likely that climate change will further exacerbate the problem as the frequency of high intensity rainfall is projected to increase, demanding special attention to flood mitigation and adaptation points of view. The West Rapti river basin, lying in the mid-western part of Nepal, has the general characteristics of other major river basins in that country. This dissertation examines key elements of the West Rapti Basin as a socio-hydrological system in order to develop recommendations for flood mitigation and adaptation strategies. The specific objectives of this dissertation were to: (1) analyse hydro-climatic time series data and develop probable future climate scenarios for the West Rapti River basin, Nepal; (2) perform hydraulic modeling to assess flood inundation in the study area and develop a flood hazard map; and (3) analyse potential adaptation strategies. These objectives were addressed through the integration of three forms of analysis: (1) Hydraulic modelling to determine flood return periods and prepared flood zoning and hazard mapping under four climate change induced flood scenarios (current case: Scenario I; flood of 2030: Scenario II; flood of 2070: Scenario III; and flood of 2100: scenario IV); (2) Economic estimation of the willingness to pay (WTP) for flood mitigation in different flood zones (critical, moderate and low flood prone) and the flood scenarios; and (3) Social assessment to identify potential impacts of flooding in the Basin and some of the possible adaptive responses and preferences of the local people in regard to these responses. In addition, the study examined how adaptation strategies may change over time with exposure to climate change scenarios in different flood prone zones. For the hydraulic modelling, hydro-meteorological time series data enabled investigation of the change in flow-related statistics over time, while spatial data were used to represent the physical settings of the Basin. Contour and land use data were used for flood analysis at different return periods and hydraulic modeling was performed using HEC-RAS to simulate the hydraulic process of the Basin for preparing the flood hazard zones. With regard to economic and social assessments, a multi-stage, multi-level and multi-stakeholder process was followed. Initially, in consultation with central level stakeholders by way of interviews and local level stakeholders through focus group discussions (FGDs). The FGDs were helpful in identifying and understanding pre-flood, during-flood and post-flood adaptation strategies, both at household and community levels, and pre-testing the semi-structured questionnaire for the household survey. This questionnaire was then administered through 240 randomly selected households from all flood zones and a range of socioeconomic backgrounds. In order to elicit information regarding appropriate adaption strategies and WTPs, flood maps of different flood scenarios were shown to all respondents. Finally, key academicians, civil society and government officials were briefed on the issues and priorities identified from the field level survey, and they were also interviewed for possible policy level interventions. Analysis of meteorological data shows that the annual average temperature of the study area is increasing at a faster rate than the national (0.06ºC) and global average (0.03°C). Similarly, the intensity and magnitude of rainfall and thus floods is increasing. Similarly, the monsoon season is iii shifting more towards the currently defined „post-monsoon‟ season, highlighting a need to redefine the timing of the monsoon season and to identify appropriate crops, as well as planting and harvesting times for these. It is predicted that the area of critically hazardous flood zone will gradually increase under future flood scenarios. The average WTP varied by flood hazard zone and, within the zone, by climate change-induced flood scenarios. The average WTP of respondents was highest for the critical flood prone zone, followed by the moderate and low flood prone zones. Similarly, within each zone, average WTP increased with increasingly divergent climate scenarios. As expected, for all scenarios, average annual crop income, livestock income and damage costs were highly positively correlated with average annual WTPs. As floods are part of their life, local people have adopted various adaptation strategies, both at individual and community levels. At an individual or household level, “construction of drain to divert the floods”, “caring children, elderly people and releasing domesticated animals” and “managing household foods and martials” were the three most prioritised pre, during and post flood adaptation strategies, whereas at community level, “developing flood management plan”, “updating contact information” and “exchanging helps to each other” were perceived to be most important. This study found that peoples‟ ways of thinking and their preferences for particular adaptation strategies changed with exposure to climate change scenarios. For example, a less sever flood scenario I, the simplest and least expensive form of adaptation strategy “bamboo mesh with sand filled bags” was most preferred; however, its perceived importance reduced with exposure to the more severe future flood scenarios. With exposure to an intense flood scenario, the most complex and expensive adaptation strategy “reservoir/flood regulating structures” emerged as the most preferred. The process and results of this study highlight two