The gross storage at the Krishnaraja Sagar (KRS) reservoir across the river Cauvery was 20.54 thousand million cubic ft (tmc ft) on September 27, 2023, against the gross capacity of 49.45 tmc ft. This is the second lowest level of gross storage in the dam since 2011.
The previous lowest was in 2016, when the gross storage in the reservoir on the same day had dipped to 14.84 tmc ft owing to monsoon failure.
Details of quantum of water in the reservoir on the same day since 2011 indicates that the storage was comfortable and above 43 tmc ft in most years barring in 2015 and 2016 while it was 35.35 tmc ft in 2021. In 2015, the gross storage was 25.13 tmc ft on September 27 but heavy rains in the post-monsoon season helped shore up the storage to nearly 33 tmc ft by November giving a breather to the State.
As per the statistics available from the Karnataka State Natural Disaster Monitoring Centre (KSNDMC), the situation was similar in 2017 when the gross storage was 28.58 tmc ft on September 27 but unseasonal rains in October augmented the storage to almost 34 tmc ft by the last week of November. Whether the Cauvery catchment area in the State will benefit from post-monsoon rains in this year of drought remains to be seen. But there was no such relief in 2016.
Meanwhile, owing to the continuous release of water from the KRS in compliance with the Cauvery Water Management Authority (CWMA), the water level in the reservoir was down to 97 feet against the full reservoir level (FRL) of 124.80 feet. The water level on the same day last year was 123.92 ft and the gross storage was 48.22 tmc ft.
The cumulative storage in major reservoirs across the Cauvery basin in the State has been dipping and neared 50% of the installed capacity as on Wednesday. The gross storage capacity of the four major dams is 114.57 tmc ft while the actual storage as on September 27 was 59.43 tmc ft which is 52% of the actual capacity. The cumulative storage across the four dams on the same day last year was 111.86 tmc ft.
The gross storage in the other dams were as follows: Kabini (13.52 tmc ft); Hemavathi (18.42 tmc ft) and Harangi (6.95 tmc ft). The gross storage capacity of Harangi is only 8.50 tmc ft and it is 19.52 tmc ft for Kabini while it is 37.10 tmc ft for Hemavathi.
The water levels in the dams are also dipping and at KRS it was 97 feet against the maximum level of 124.80 feet. At Kabini, the water level was 2273.59 feet against the FRL of 22884 feet. The water level at Hemavathi was 2897.60 against the FRL of 2922 while at Harangi it was 2845.26 against the maximum level of 2859 ft.