Mountains in the Chaning World, Mountains in the Chaning World

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On connecting hydrological modelling to stakeholder participation
Steve W. Lyon, Orn-uma Polpanich

Last modified: 2017-09-13


Intensive development over the past half century across Southeast Asia’s mountain-to-valley regions has inevitably affected natural resources. Large areas have been converted from forests for subsistence and commercial agriculture, and urban development. Still, little is done to connect hydrological modelling with stakeholder participation. Here we implement an innovative approach to screen hydrologic data for detecting impacts of large-scale changes on hydrological response. Then we follow up by incorporating agricultural development and climatic changes within the Water Evaluation and Planning hydrological model targeting a participatory approach. This involved four scenario workshops, 400 household surveys and two focus group discussions in the period of 2010–2012 for the ungauged Huai Sai Bat sub-basin as a specific case study in Thailand. Our results indicate that the majority of catchments regionally (64% of those considered) with sufficiently long data records exhibited no discernable trends in hydrological response. Those catchments that did exhibit significant trends in hydrological response were fairly evenly split between increasing trends (between 21% and 24%) and decreasing trends (between 15% and 12%) with time. There was a lack of evidence that these changes where brought about by shifts in precipitation or potential evapotranspiration; however, catchments exhibiting significant increasing trends in hydrological behavior across the mountain-to-valley regions were found to have different land cover compositions (lower percentage of forest coverage and subsequently higher paddy rice coverage) than those exhibiting significant decreasing trends. With regards to the participatory approach, our Thailand case study results indicate future increased streamflow during the wet (monsoon) season in response to shifts in the regional climate. However, modelled land-use and management changes – defined by the visions and hopes within the community – brought about large unmet water demands, primarily in the dry season. Clearly, there is need to close the gap between the plans of the people and the sustainability of the regions water resources. Without this connection, we might be blind to future hydrological shifts that can have significant impact on development.

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