Meghalaya’s wettest regions face rising drought risk as rainfall becomes more erratic: Study

Meghalaya’s Mawsynram and Cherrapunji, among the world’s wettest places, are facing an increasing risk of drought as climate change brings more intense rainfall, fewer rainy days and rising temperatures, according to a new study.

Published recently in Theoretical and Applied Climatology, the study analysed projected climate and hydrological data for Meghalaya and adjoining areas for the period 1981-2100.

Researchers Ashesh Rudra Paul and Pankaj Kumar Roy found that rainfall in the region is increasingly occurring in intense spells, while light rainfall and the number of rainy days are declining.

The study recorded an increase in the Simple Daily Intensity Index (SDII), with a maximum local rise of 0.08 mm per day per year. At the same time, the number of rainy days declined by an average of 0.40 days per year.

The researchers said the changing pattern could increase drought risk despite the overall high rainfall in Meghalaya.

The steep terrain and shallow soils of the State are particularly significant, as intense rainfall can quickly run off rather than being absorbed into the ground. This reduces groundwater recharge and can leave less water available during the drier months.

Rising temperatures are adding to the pressure by increasing evapotranspiration, or the loss of water from soil, vegetation and other surfaces. Minimum temperatures were projected to rise by as much as 0.08 degrees Celsius per year.

To assess drought conditions, the researchers used the Standardized Precipitation Evapotranspiration Index (SPEI) at a three-month timescale. Their analysis indicated an increase in the frequency and intensity of moderate, severe and extreme drought events, particularly under the high-emission SSP585 scenario.

The study projected that drought occurrences would generally increase from the near future to the far future under the scenarios examined, with the strongest increase under SSP585.

The researchers also examined projected changes in river flows in the Sari-Gowain and Surma-Meghna basins, which originate in or receive significant flows from Meghalaya.

Under the SSP585 scenario, mean annual streamflow was projected to decline by up to 9.8% in the Sari-Gowain basin and 11.6% in the Surma-Meghna basin in the far future.

The study found that river flows would remain heavily concentrated during the monsoon, peaking around June and July before declining. This could increase the risk of water shortages later in the year.

The researchers cautioned that the study did not account for human-induced factors such as deforestation, urban expansion, land-use change and groundwater extraction, which can also influence water availability.

They called for water-management strategies that take into account rainfall intensity and distribution, rising temperatures and basin-level water flows, and stressed the need for cooperation between scientists, policymakers and local communities.

Residents in Sohra and Mawsynram have also reported signs of increasing water stress. Several waterbodies and waterfalls have reportedly been drying up earlier this year.

P Hujon, a Mawkisyiem resident who runs a guest house, said, “Many waterfalls in Sohra area are getting dried, and I am seeing this as early as mid September.”