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Evaluating an adaptation: rice-sediment trade-offs in the Vietnamese Mekong Delta

Evaluating an adaptation: rice-sediment trade-offs in the Vietnamese Mekong Delta
Evaluating an adaptation: rice-sediment trade-offs in the Vietnamese Mekong Delta
The exceptional vulnerability of river deltas to climate change and development pressures means there is an urgent need to implement systemic adaptation actions. One of the most important cases is the Vietnamese Mekong Delta (VMD). This thesis performs a novel application of a system dynamics methodology to evaluate the VMD’s dyke network as a hard adaptation to changes in the region’s hydrological conditions. In doing so it makes a methodological and case study contribution to an emerging research body on the evaluation of adaptation action. Policy analysis and stakeholder consultation are first performed to elucidate the drivers behind the policy to heighten the VMD’s dyke network. A farmer survey is then executed within the rice-growing community in order to quantify the socioeconomic impacts of the adaptation. Finally, a system dynamics model is built to explore the dynamics controlling the impacts of the adaptation and the efficacy of alternative policies for the local agricultural system. A key original theme running through this thesis is its consideration of the socioeconomic role of fluvial sediment in the system.

The principle finding, on which both the model and survey agree, is that the switch to high dyke compartments in the VMD(the adaptation) is exacerbating the divide between land-rich and land-poor farmers through the promotion of triple-cropping and sediment exclusion. Factors including the loss of free sediment-bound nutrients for fertilisation, and increasing fertilisation demands, reduce the resilience of poorer farmers to increasing and unpredictable fertiliser prices. The policy currently recommended by the provincial governments to encourage sediment accretion and mitigate the rate of relative sea-level rise is to advocate triennial inundation of paddies. The data presented herein suggest such a policy is sub-optimal,further increasing the risk of debt for smaller-scale farming operations. The testing of various different success criteria weightings did, however, suggest that the less rigid policy of allowing sporadic floodplain inundation and sediment deposition during intense flooding events is preferable to most stakeholder groups.
Chapman, Alexander
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Chapman, Alexander
56014a74-348e-4bd0-b727-765dbc6f8454
Darby, Stephen
4c3e1c76-d404-4ff3-86f8-84e42fbb7970
Tompkins, Emma
a6116704-7140-4e37-bea1-2cbf39b138c3
Schaafsma, Marije
937ac629-0fa2-4a11-bdf7-c3688405467d

Chapman, Alexander (2016) Evaluating an adaptation: rice-sediment trade-offs in the Vietnamese Mekong Delta. University of Southampton, Faculty of Social, Human and Mathematical Sciences, Doctoral Thesis, 316pp.

Record type: Thesis (Doctoral)

Abstract

The exceptional vulnerability of river deltas to climate change and development pressures means there is an urgent need to implement systemic adaptation actions. One of the most important cases is the Vietnamese Mekong Delta (VMD). This thesis performs a novel application of a system dynamics methodology to evaluate the VMD’s dyke network as a hard adaptation to changes in the region’s hydrological conditions. In doing so it makes a methodological and case study contribution to an emerging research body on the evaluation of adaptation action. Policy analysis and stakeholder consultation are first performed to elucidate the drivers behind the policy to heighten the VMD’s dyke network. A farmer survey is then executed within the rice-growing community in order to quantify the socioeconomic impacts of the adaptation. Finally, a system dynamics model is built to explore the dynamics controlling the impacts of the adaptation and the efficacy of alternative policies for the local agricultural system. A key original theme running through this thesis is its consideration of the socioeconomic role of fluvial sediment in the system.

The principle finding, on which both the model and survey agree, is that the switch to high dyke compartments in the VMD(the adaptation) is exacerbating the divide between land-rich and land-poor farmers through the promotion of triple-cropping and sediment exclusion. Factors including the loss of free sediment-bound nutrients for fertilisation, and increasing fertilisation demands, reduce the resilience of poorer farmers to increasing and unpredictable fertiliser prices. The policy currently recommended by the provincial governments to encourage sediment accretion and mitigate the rate of relative sea-level rise is to advocate triennial inundation of paddies. The data presented herein suggest such a policy is sub-optimal,further increasing the risk of debt for smaller-scale farming operations. The testing of various different success criteria weightings did, however, suggest that the less rigid policy of allowing sporadic floodplain inundation and sediment deposition during intense flooding events is preferable to most stakeholder groups.

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More information

Published date: July 2016
Organisations: University of Southampton, Geography & Environment

Identifiers

Local EPrints ID: 400969
URI: https://eprints.soton.ac.uk/id/eprint/400969
PURE UUID: d21e9427-ad5b-43b2-a6eb-9d7f366c1f29
ORCID for Stephen Darby: ORCID iD orcid.org/0000-0001-8778-4394
ORCID for Marije Schaafsma: ORCID iD orcid.org/0000-0003-0878-069X

Catalogue record

Date deposited: 10 Oct 2016 15:58
Last modified: 14 Jun 2019 00:30

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