22-05-2025
Surplus rain sends groundwater level up in Trichy
There is good news for Trichiites on the drinking water front. Despite soaring temperatures, groundwater levels are higher than last year in Trichy as well as most central districts, thanks to surplus unseasonal rains since March and a good monsoon last year.
The surge is helping the region meet its drinking water requirements.
In Trichy, the groundwater level was at 5 metre below ground level in April compared to 7.91 metre in the same month last year, indicating a difference of 2.83 metre. The level was also higher in Tiruvarur, Nagapattinam, Karur, Perambalur, and Ariyalur and lower than last year in Thanjavur, Pudukottai and Mayiladuthurai districts.
"The occasional unseasonal rain has augmented groundwater tables for the past few months.
Hence, the levels are higher than last year despite hot temperatures now," a senior official of the water resources department in Trichy said. According to officials at the regional meteorological centre of Indian Meteorological Department in Chennai, the surplus rainwater is replenishing underground acquifers.
In Trichy, the state water resources department and Central Ground Water Board monitor groundwater levels at 142 observation wells every month.
Tamil Nadu Water Supply and Drainage Board observes the levels at 47 observation wells twice a year. Similarly, the levels in other districts are also observed. TWAD Board sources told TOI that they observed a rise in the height of the groundwater level from 20 metre in May 2024 to 13 metre in January 2025 after a good northeast monsoon.
"The level is rising again after January due to unseasonal rains. The availability helps us (TWAD) and local bodies to supply drinking water as per requirements," a TWAD official said.
The rainfall boost has not aided districts like Thanjavur and Pudukottai unlike other central districts like Trichy, Perambalur, and Ariyalur. The levels were lower than last year in those two districts.
Darwin Annadurai, an environmental scientist and founder of Eco Society India, said, "Despite monsoon and unseasonal rains, groundwater levels may not be high as expected when the extraction is higher than recharge. When there is higher extraction for purposes such as drinking water, agriculture, and industries, or when there are environmental damages like excavation, the groundwater levels may not be high in comparison.
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With Mettur dam scheduled to open on June 12 and Cauvery river water expected to arrive in the days that follow, officials and experts said the groundwater level will rise further due to recharge caused by river water percolation.
