# Assessment of Drought Severity and Vulnerability in the Lam Phaniang River Basin, Thailand
## 3 Results and Discussion
### Comprehensive Analysis of Drought Risk Assessment
The remaining light green part falls into moderate drought conditions (Figure 7a), which corresponds to the study of TNMC [46], who found that Nong Bua Lamphu Province (covering most of the area of the Lam Phaniang River Basin) was likely to be drought-prone with high vulnerability for both domestic water and agriculture. The outputs of the 12-month time scale revealed that a low drought risk area was found in six sub-districts located in the midstream of the Lam Phaniang River Basin, i.e., Pha Sam Yot (Sd-13) and Sap Phaiwan (Sd-18) Sub-districts, Erawan District, Loei Province, and Nong Bua Lamphu Province covering Wang Thong (Sd-7), Thep Khiri (Sd-10), and Na Lao (Sd-11) Sub-districts, Na Wang District, and Kut Hae Sub-district (Sd-4), Na Klang District. Twelve sub-districts of Nong Bua Lamphu Province located in the downstream were also identified as low risk zone, i.e., sub-districts within Mueang District including Nong Phai Sun (Sd-14), Lam Phu (Sd-15), Pho Chai (Sd-17), Nong Sawan (Sd-19), Nong Bua (Sd-20), Ban Kham (Sd-23), Ban Phrao (Sd-24), Na Mafueang (Sd-25), Hua Na (Sd-26), and Pa Mai Ngam (Sd-28), Non Sang District including Khok Muang Sub-district (Sd-27), and Si Bun Rueang District including Nong Bua Tai Sub-district (Sd-29), while the remaining sub-districts were at moderate level (Figure 7b). In addition, the entire river basin area was found at a low drought risk level for a 24-month time scale (Figure 7c). It can be noticed that for short- and intermediate-time scales, the upstream dominant field crop together with the dominant paddy field grown in the mid- and downstream areas, were designated to be at moderate risk (see Figure 1 for land use types). As a consequence, the effects may eventually lead to a reduction of crop yield, which requires various drought risk reduction interventions for resilience and disaster preparedness for effective response. Regarding the future drought risk under RCP 4.5 during 2021-2040 (Figure 8a), at the 3-month time scale, high drought risk was mainly located in the middle part of the river basin, i.e., Dan Chang Sub-district (Sd-6), Na Klang District, Nong Bua Lamphu Province, in which the moderate drought risk was identified at the mid- and downstream parts, and the rest was defined as low risk level. When focusing on the 12-month time scale, high drought risk expanded in the central part of the river basin within Nong Bua Lamphu Province covering Na Wang District, i.e., Na Kae (Sd-3), Wang Pla Pom (Sd-5), and Wang Thong (Sd-7) Sub-districts, Na Klang District, i.e., Dan Chang (Sd-6), Fang Daeng (Sd-12), and Uthai Sawan (Sd-16) Sub-districts, and Mueang District, i.e., Na Kham Hai (Sd-9) and Non Khamin (Sd-21) Sub-districts, whereas the up- and downstream parts were mostly at a moderate risk level. At the 24-month time scale, within Nong Bua Lamphu Province, a very high drought risk zone was found in the midstream area including Na Wang District, i.e., Na Kae Sub-district (Sd-3), and Na Klang District, i.e., Dan Chang (Sd-6), Fang Daeng (Sd-12), and Uthai Sawan (Sd-16) Sub-districts, which were encompassed by high risk areas such as Na Wang District, i.e., Wang Pla Pom (Sd-5) and Wang Thong (Sd-7) Sub-districts, Na Klang District, i.e., Na Klang Sub-district (Sd-8), and Mueang District, i.e., Na Kham Hai (Sd-9), Nong Bua (Sd-20), Non Khamin (Sd-21), Nong Wa (Sd-22), Ban Phrao (Sd-24), and Na Mafueang (Sd-25). For RCP 8.5, at the 3-month time scale, the drought risk levels were found to be the same as RCP 4.5, except for a change at the downstream from a low to moderate level at Pa Mai Ngam Sub-district (Sd-28), and vice versa at Nong Bua Sub-district. The drought risk at the 12-month time scale under RCP 8.5 compared to RCP 4.5 was transformed in Nong Bua Lamphu Province from a high to very high level at Na Wang District, i.e., Na Kae (Sd-3) and Wang Thong (Sd-7) Sub-districts and Na Klang District, i.e., Dan Chang (Sd-6), Fang Daeng (Sd-12), and Uthai Sawan (Sd-16) Sub-districts, while the other areas remained almost the same risk levels.