Intensity, frequency and coverage of hydro-meteorological droughts and agriculture in the semi-arid basins of Maharashtra (India)

Abstract

The present investigation attempted to understand the intensity, frequency and spatial coverage of rainfall, runoff, groundwater and agricultural droughts in the semi-arid region of Maharashtra during 1981–2014. For this, various indices similar to Standardized Precipitation Index (SPI) (probabilistic nature) were applied. The linear regression, partial correlation and Student’s t-Test techniques were also used to evaluate inter-connections in hydro-meteorological and agricultural droughts. The hydrological deficiencies mimic the pattern of meteorological droughts in the study area with respect to coverage and intensity. Moderate hydro-meteorological droughts occurred frequently (once in 3 to 4 years). Additionally, the research highlighted an increase in the frequency and intensity of hydrological droughts during the post-1990 period, possibly linked to anthropogenic interventions (dam constructions and irrigation expansion). Despite El Niño events resulting in below-average rainfall, runoff, and groundwater levels in the study area, other phenomena such as Equatorial Indian Ocean Monsoon Oscillation (EQUINOO) / Indian Ocean Dipole (IOD) may have played a crucial role in major drought occurrences in 1986, 2003, and 2012 (events that happen once in > 30 years). The hydro-meteorological droughts lead to agricultural droughts, as they significantly affect the rainfed and irrigated crops in terms of productivity and cropped area. This effect was particularly notable during severe and region-wide droughts in 1985-86, 2002-03, and 2011-12. Furthermore, the investigation suggested that the study area is likely to experience hydro-meteorological deficiencies with ~ 25% probability between 2029 and 2050, coupled with a significant temperature rise (by 1.05 °C). This projected scenario could exacerbate water scarcity and agricultural distress in the future (up to 2050).