Drought Assessment Using Probability Vegetation Vulnerability Index for Pambar-Kottakaraiyar River Basin, Tamil Nadu

With the aid of the Vegetation Health Index (VHI) and Probability Vegetation Vulnerability Index (PVVI), this study analyses the agricultural drought in the Pambar-Kottakaraiyar Basin. The VCI (Vegetation Condition Index and TCI (Temperature Condition Index) were calculated using MODIS NDVI and LST data. The Vegetation Health Index (VHI) was created by combining the results of the VCI and TCI. Extreme, severe, moderate, mild, and no drought are the different levels of VHI. Based on the severity of the drought, the likelihood (%) of events falling into each class is computed using the weight of each class and ranges from 0 to 40. By adding the data received from each drought class, PVVI was finally determined. The VHI result indicates that extreme and severe drought was noted in R.S Mangalam block occupies 37.94 sq.km and 131.12 sq.km respectively. Moderate and mild droughts were found in Thiruvadanai, Kalayarkovil block in the study basin. The PVVI results shows almost entire study area is in drought but extreme drought conditions are noted in 18 blocks out of 27 blocks. So, proper management practices for drought like consumption of water, cultivating the rainfed crops, rainwater harvesting methods should be thoroughly practiced to reduce the effect on agricultural drought.