# Assessment of Drought Severity and Vulnerability in the Lam Phaniang River Basin, Thailand
###### Abstract  
The Lam Phaniang River Basin is one of the areas in Northeast Thailand that experiences persistent drought almost every year. Therefore, this study was focused on the assessment of drought severity and vulnerability in the Lam Phaniang River Basin. The evaluation of drought severity was based on the Drought Hazard Index (DHI), which was derived from the Standardized Precipitation-Evapotranspiration Index (SPEI) calculated for 3-month (short-term), 12-month (intermediate-term), and 24-month (long-term) periods. Drought vulnerability was assessed by the Drought Vulnerability Index (DVI), which relied on water shortage, water demand, and runoff calculated from the WEAP model, and the Gross Provincial Product (GPP) data. A drought risk map was generated by multiplying the DHI and DVI indices, and the drought risk level was then defined afterwards. The CNRM-CMS, EC-EARTH, and NorESMI-M global climate simulations, and the TerrSet software were used to evaluate the potential impacts of future climate under RCPs 4.5 and 8.5, and land use during 2021-2100, respectively. The main findings compared to baseline (2000-2017) revealed that the average results of future rainfall, and maximum and minimum temperatures were expected to increase by 1.41 mm, and 0.015 \({}^{\circ}\)C/year and 0.019 \({}^{\circ}\)C/year, respectively, under RCP 4.5 and by 2.72 mm, and 0.034 \({}^{\circ}\)C/year and 0.044 \({}^{\circ}\)C/year, respectively, under RCP 8.5. During 2061-2080 under RCP 8.5, the future annual water demand and water shortage were projected to decrease by a maximum of 31.81% and 51.61%, respectively. Obviously, in the Lam Phaniang River Basin, the upper and lower parts were mainly dominated by low and moderate drought risk levels at all time scales under RCPs 4.5 and 8.5. Focusing on the central part, from 2021-2040, a very high risk of intermediate- and long-term droughs under RCPs 4.5 and 8.5 dominated, and occurred under RCP 8.5 from 2041-2060. From 2061 to 2080, at all time scales, the highest risk was identified under RCP 4.5, while low and moderate levels were found under RCP 8.5. From 2081-2100, the central region was found to be at low and moderate risk at all time scales under RCPs 4.5 and 8.5. Eventually, the obtained findings will enable stakeholders to formulate better proactive drought monitoring, so that preparedness, adaptation, and resilience to droughs can be strengthened. d 2021 202  
carried out by [PERSON] et al. [6] regarding the effects of climate change on rainfed rice yield in Northeast Thailand using the CERES-rice crop growth model. The obtained results revealed that, under the ECHAM4 A2 climate scenario, a declining trend in rice yield was observed by 17.81%, 27.59%, and 24.34% for the 2020s, 2050s and 2080s, respectively, compared to the average yield during 1997-2006. In addition, [PERSON] et al. [7] also studied rainfall characteristics in Northeast Thailand in relation to the impacts of drought on rice production in 2012, as well as assessing drought adaptation strategies of farmers. It was found that the mean annual rainfall recorded at Nakhon Ratchasima Province in 2012 declined by 239 mm compared to the mean value during the reference period 2001-2011 (1204 mm), while the mean annual rainfall observed at Kalasin Province in 2012 was also found to be decreased by 375 mm in comparison to the baseline (1508 mm). Furthermore, the actual yield loss due to drought was estimated to be 59-68% in Nakhon Ratchasima Province and 55-65% in Kalasin Province, respectively, in comparison to the attainable yield. Regarding the adaptation strategies, the farmers introduced crop diversification for short-term adaptation options, changed land use patterns for long-term adaptation options, and built on farm ponds in the paddy fields, in order to cope with drought impacts. Similarly, [PERSON] et al. [8] also investigated past climatic conditions (1984-2013) and assessed the impacts of recent climate trends on rice yields in the Mun River Basin in Northeast Thailand.