ABSTRACT
Drought is a creeping disaster that can be referred to as a regional occurrence of relatively below normal water availability, either in the form of precipitation, river flow, surface and groundwater storage for a certain period. The Bundelkhand region of Madhya Pradesh in India has always been in attention due to many regional issues such as water scarcity, frequent droughts, lack of economic and development activities which are posing threat to agricultural productivity, livelihood and social aspects in the region. The present study has been carried out to analyze the variability of rainfall in the Bundelkhand region using suitable indicators and its relationship with the drought frequency, duration, and magnitude using long-term rainfall data from 1980 to 2017 of five stations Sagar, Damoh, Panna, Tikamgarh and Chhatarpur. The Durbin Watson test revealed good autocorrelation in rainfall time series with slight negative bias at Damoh and Chhatarpur.
The standard deviation, coefficient of variation and interquartile range (IQR) analysis shows very high rainfall variability at Sagar, Damoh and Chhatarpur and high spread in rainfall data as compared to Tikamgarh and Panna. The Bundelkhand region has a very high rainfall concentration in four monsoon months. The average Precipitation Concentration Index (PCI) of the region is 31.9% which indicates a very high monthly concentration in the Bundelkhand region. The proportion of negative Standard Rainfall Anomalies (SRA) indicating dry years have been seen very high in the region and found ranged from -1.41 at Damoh (year 2017) to -2.41 at Tikamgarh (Year 1989) indicating high interannual fluctuations in rainfall. The stations Sagar, Damoh and Chhatarpur where the rainfall variability has been observed very high, are also appeared as severe drought-prone stations with a very high drought frequency causing 1 drought year after every 3 to 5 years. Thus high variability, negative rainfall anomalies and high PCI values of rainfall are observed indicative of severe and frequent drought possibilities. This indicates the seriousness of droughts and the need of developing and managing water resources and adopting suitable conservation practices for drought mitigation.
The Standardised Precipitation Index (SPI) analysis was carried out for assessment of drought frequency, severity, and magnitude of dry events on 1, 3, 6, 9, 12-month time scales. The drought severity was found higher in the eastern part covering the Chhatarpur and Panna district of the Bundelkhand region. The analysis has shown more moderate and severe dry events on a 6-month time scale as compared to remaining other time scales whereas more extreme dry events were evident on a 12-month time scale. It was seen that evidence of drought also increased with the increase of the SPI time scale. However extreme drought events were seldom in the region on a 1-month time scale. The drought frequency has been seen as very high at all five stations of Bundelkhand. The probability distribution analysis indicated these all stations as drought-prone. Similar results are seen for SPI analysis which has shown that these stations were experienced a significant drought on a time scale of 6, 9, 12-month. However, SPI outcomes seem to be is more sensible to severe drought events than the probability distribution analysis and gives the best result using only rainfall data without other meteorological parameters. The assessment of rainfall variability and its relation with drought frequency and magnitude is very important to comprehend and monitoring water scarcity situations for decision making and adopting appropriate strategies for mitigation.
