Study of Spatial and Temporal Variability of Droughts in the Krishna River Basin in Maharashtra, India

Abstract

Spatial and Temporal Drought Analysis of the Meteorological drought, done by the SPI and PNP at multiple timescales over the 59 stations for the period 1960-2012, in Krishna basin in Maharashtra. The present study explores the usefulness of the SPI and the Run theory in investigating drought characteristics at multiple timescales. The SPI performs better than the PNP in monitoring drought at multiple timescales. In regional drought analysis, the areas affected by the severe drought evolve gradually at every timescale from Moderate to Severe. The Severe drought recedes at successive timescale with a time lag varying from 2-4 months for high-intensity drought (1971-75) and 2-9 months for high-severity drought (2000-07).Sub-Basin Wide Drought Analysis of the Hydrological drought done using Modified SWSI, Metrological drought using SPI and PNP for the five sub-basins for the period of 1972-2008 in the Krishna river basin in the state of Maharashtra, India. From MSWSI analysis, UKE sub-basin is the most droughts prone followed by RB sub-basin, while UB sub-basin is the least droughts prone followed by UKW sub-basin. From SPI analysis it was found that UKE sub-basin is the most droughts prone while UKW sub-basin is the least drought prone. From PNP analysis it was found that UKE and RB sub-basins are most the droughts prone followed by SB and UB sub- basins. UKW is the least drought prone. The spatial and temporal variability in drought trends was observed in the study area. From sub-basin wide drought analysis, the MSWSI drought index is found to be better than the SPI and PNP for the Krishna basin in Maharashtra. It was found that the MSWSI index can be used for a whole year for diverse water resources planning and management as it reflects the real-time availability of water. The SPI and PNP had its own merits as well as demerits. The SPI and PNP indices are most suitable for monsoon season. For local and regional drought analysis, the SPI is a better index than MSWSI and PNP. The study area is susceptible to drought events. Moderate drought month occurs in 80 % of the study area, with one-year return period. Severe drought month occurs for 64 % of the area with 2-year return period. An extreme drought month occurs for 78 % of the area with 5-year return period.