Rains recharge groundwater table in Andhra Pradesh

Visakhapatnam: The heavy rainfall spurred by a series of low pressures over the Bay of Bengal and active monsoon spells at the end of August and September proved to be a blessing for the groundwater table in the state. The long spell of rains have helped the water to percolate deep into the soil and replenish the levels.

On an average, coastal Andhra Pradesh registered a 1.67-metre increase in the groundwater level compared to August 2016 and 0.8-metre increase from September 2015. In Rayalaseema, the levels in the aquifers have improved to 14.17 metres against the 14.40 metres in August. It was 20.77 metres in September, 2015.

Other than a slight dip in the groundwater levels of Anantapur, Chittoor and Nellore districts, all districts registered at least a metre of improvement since August 2016.

The south-west monsoon, which started on a positive note in June, turned out to be a mixed bag with a long dry spell in July and August months, logging a rainfall deficiency of about 20 per cent as of August 20. But the formation of back to back weather systems thereafter turned the rainfall table, raising the shallow groundwater table to normal levels in the state.

For instance, the groundwater level, which was 32.5 metres in September 2015 in Chittoor district has come down to 13.66 metres this September.

Groundwater Departm-ent deputy director K.S. Sastry said the good showers helped in recharging the aquifers. “For example, the groundwater level of Visakhapatnam in Sept-ember averaged around 5.5 metres. Now, the level is at 4.5 metres, which indicated percolation of an additional 8 TMC of water into the soil in the district,” Mr Sastry added.

The Groundwater depar-tment of AP keeps a tab on the groundwater levels th-rough about 1,256 piezo-metres set up in several ar-eas of the state. Due to the bountiful rains, water levels in the wells of Garividi of Vizianagaram, Nagaya-lanka of Krishna district, Durgi of Guntur district, G. Sigadam of Srikakulam district and Narava of Visakhapatnam district had seen a drastic fall with water availability being at less than 0.1 metres below the ground level.

Prof. N. Subbarao of the Geology department of Andhra University opined that the torrential rains of short duration would hardly help in water table recharging, as the maximum surface run-off mostly ends up at far-off places. “A lengthy duration of rainfall that is low in intensity is critical for recharging of groundwater, which has happened in the last 15 days. Several other factors such as geographical layout would also play a role,” Prof. Subba Rao added.