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Community-based stream and groundwater monitoring and future change impact modelling of a socio-ecohydrological system to inform drought adaptation in the seasonally-dry tropics

University of British Columbia

With a changing climate and a growing population, droughts are becoming more frequent in many watersheds across the world, necessitating new approaches to improve water security in communities. Drought is typically caused by a combination of hydrological and social drivers. In this thesis, I apply the emerging framework of socio-hydrology (coupled human-water systems). Specifically, the objective of this thesis is to assess current and future socio- and hydrological dynamics and impacts on surface water and groundwater supplies with the goal of informing drought adaptation and improving water security. I focused hereby on two drought-prone rural watersheds in the seasonally-dry tropics of Costa Rica. Using a community-based approach, I implemented a hydrological monitoring network of streams and groundwater with open-source data loggers, and worked with local communities to assemble societal water use data. I then synthesized the watersheds in a hydrological model and assessed current social (water use) and hydrological vulnerabilities to drought. Results showed that communities dominantly relied on groundwater supplies, and that a temporal mismatch between water availability and needs, high domestic water use, and increasing extraction rates are increasing pressure on groundwater. Results also indicated high streamflows during the wet season, and thus a potential to increase surface water use while streamflows are high. Next, I explored the impacts of the El Niño Southern Oscillation (ENSO), future climate change and water use change on water resources in the study watersheds. During an extreme El Niño, groundwater recharge and streamflow decreased by 60% relative to ENSO Neutral. I also found that future climate change may lead to groundwater storage decline, especially if combined with high population growth. In the seasonally-dry tropics, wet season rainfall is essential for recharging groundwater that serves as primary water supply during long dry seasons. Therefore, I developed a novel ‘groundwater recharge indicator’ as a tool to support water managers to respond adaptively to reduced wet season rainfall and increase socio-hydrological resilience to seasonal drought. Overall, this thesis contributes to the field of socio-hydrology and provides novel approaches to improve water security under drought in the seasonally-dry tropics.

Text

2018-11-27

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/67902

Geological Sciences

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/