Development of Water Stress Indices for the Watersheds of Thailand to Support Water Footprint Calculations
Shabbir H. Gheewala*, Thapat Silalertruksa, Pariyapat Nilsalab, Naruetep Lecksiwilai, Wanchat Sawaengsak, Rattanawan Mungkung and Jirawat Ganasut
<div style="text-align:justify;"><strong><span style="font-size:medium;line-height:115%;font-family:Verdana, Geneva, sans-serif;background-color:#ffffff;color:#000000;">Abstract: </span></strong><span style="font-size:medium;line-height:115%;font-family:Verdana, Geneva, sans-serif;background-color:#ffffff;color:#000000;">When demands for water cannot be met sufficiently due to lack of available water, the excess demand will possibly cause impacts on freshwater resources. Thus, water footprint (WF) and water stress index (WSI) are gaining recognition as important tools for assessing water use impact leading to support policy makers on development of water resource management policy. The WSI has been widely applied as a characterization factor of water scarcity footprint; a first attempt was made some years ago by determining the WSI for 25 watersheds of Thailand based on a top-down approach. Subsequently, in this study, a bottom-up approach with more refined data was used to determine the annual and monthly WSIs for the 25 watersheds. The most critical watersheds were found to be located in the Central region of Thailand. Cultivating in irrigated or non-irrigated areas and shifting crop calendar can affect the WSI values. Accordingly, the annual and monthly WSI would be recommended as one of the criteria or tools to support the future agricultural policy decision making in various applications, particularly agricultural zoning. The annual WSI may be useful for the top-down vision for a quick assessment and the monthly WSI for a comprehensive assessment.</span></div>