In all, 19 districts in Karnataka have received bountiful rain between October 1 and 23, including those in the Cauvery catchment area, augmenting the inflow into the reservoirs significantly. However, Krishnaraja Sagar (KRS) has not reached full reservoir level (FRL) this year so far.
The cumulative rainfall from October 1 to 23 in the 11 districts of south-interior Karnataka was 213.6 mm as against a normal of 109.6 mm. The rainfall was significantly high in Bengaluru Urban, which received 224.6 mm of rainfall as against a normal of 124.1 mm, Bengaluru Rural (actual 254.9 mm, normal 119.1 mm), Chickballapur (actual 265.1 mm, normal 114.4 mm), and Tumakuru (actual 241.8 mm, normal 107.9 mm).
According to the Karnataka State Natural Disaster Monitoring Centre (KSNDMC), rainfall was “large excess’ in 15 districts, which is defined as 60% above normal rainfall. Parts of the Cauvery catchment area also received large excess rainfall and hence the inflow into the KRS in Mandya district has increased.
The inflow to the reservoir on Saturday evening was at the rate of 10,122 cusecs and the water level in the reservoir was hovering at 121.2 feet as against the FRL of 124.8 ft.
But it is significant to note that the KRS has not attained the FRL so far this year as the south west monsoon in Kodagu — the major catchment for the Cauvery — was 23% below normal for the period June 1 to September 30 and received only 1,693 mm rainfall.
In contrast, the reservoir had attained the FRL by August second week last year and the volume of water flowing into the reservoir was steady and hence the reservoir level hovered above 120 ft till December 12, 2020. But the water level not only failed to reach the FRL feet this year, it had begun to recede and had plummeted to 112 ft by October 1. However, the rain since then has augmented the inflow.
At Kabini
The water level at Kabini reservoir has also increased and was hovering at 2,282.73 ft on Saturday morning as against the FRL of 2,284 ft due to recent rain in the Wayanad region of Kerala. The cumulative outflow from both the KRS and the Kabini reservoirs as on October 22 was 135 thousand million cubic (tmc) ft, according to the KSNDMC and this does not include water accruing to the rivers due to heavy rain that lashed during the last three weeks downstream of both the dams.
