A new study centred on the Indus River basin in India – has revealed a strong correlation between elevation and drought, with wetting trends observed in low-lying areas and drying trends prevalent in the highlands.
The researchers used meteorological parameters to understand the connection between elevation and drought occurrence in the Indus River Basin.
“The study reveals a strong correlation between elevation and drought, with wetting trends observed in low-lying areas and drying trends prevalent in the highlands. Understanding the impact of elevation on drought is important for effective drought risk assessment and water management,” the study states.
The Indus River Basin holds immense importance in terms of agricultural productivity and water supply in the Indian subcontinent. Furthermore, the wide range of elevations within the basin, ranging from 93 to 8,489 meters, provides an ideal setting to explore the connection between elevation and drought characteristics.
The study was conducted by Indian Institute of Technology-Mandi in Himachal Pradesh and has been published in Atmospheric Research journal.
The study is co-authored by Dr. Deepak Swami, Associate Professor, School of Civil and Environmental Engineering, IIT Mandi, Dr. Vivek Gupta, Assistant Professor, School of Civil and Environmental Engineering, IIT Mandi and Dr. Nitin Joshi from Department of Civil Engineering, IIT Jammu along with their Ph. D scholar Amit Dubey from IIT Mandi.
“According to a report by India’s Ministry of Earth Sciences, the period from 1951 to 2016 witnessed an increase in the frequency of droughts in India, with more than 2 droughts per decade in many areas. Understanding drought dynamics is therefore crucial for effective water management and planning,” said Dr Swami.
“We saw a strong correlation between drought and elevation. Areas below 2,000 meters experienced wetting trends, while altitudes between 2,000 and 6,000 meters showed drying trends. However, elevations above 4,000 meters had a slower rate of drying,” said Dr Gupta.
The research team employed statistical techniques using extensive data on monthly precipitation, and maximum and minimum temperatures spanning 42 years (1979–2020) to study drought patterns. The drought quantification was done using a drought indicator based on climatic water balance, which is integral to understand droughts.
Furthermore, the research findings highlighted the significant heterogeneity in drought trends across different seasons. Monsoon and post-monsoon seasons experienced larger areas with wetting trends, while the pre-monsoon season saw a larger area with drying trends. Notably, extreme drought frequencies in the study region ranged from 0 per cent to 5 per cent from 1979–2020. Ultimately, the findings of the study point towards dryness of the region at higher altitudes whereas wetting is associated with lower elevations.
These insights hold particular importance for India, as rain-fed agriculture is prevalent in the highlands of the Indus River basin. The topography of the region restricts water storage and proper irrigation infrastructure, making it vulnerable to water scarcity and decreasing crop yields during dry periods. Understanding the effect of elevation on meteorological variables is crucial for effective policy formulation to mitigate the negative impacts of drought.