Almost a month after the onset of the southwest monsoon, uncertainty over its intensity remains with concerns over its lack of vigour as all 11 districts in south-interior Karnataka have received below normal showers in June. As against the normal of 64.2 mm of rainfall for June, the region has received only 40.6 mm of rainfall — which is 37% below normal. What is perturbing is that Kodagu district, which is the catchment for the Cauvery, has received 31% below normal rain during June. As against 622.4 mm of rainfall, it has received 431.8 mm of rainfall.
Mysuru, Mandya, and Chamarajanagar districts — part of the catchment of the Cauvery and its tributaries in the basin — have also received below normal rain.
While Mysuru has received only 48.9 mm of rainfall as against the normal of 89.1 mm during June, 45% below normal, Mandya has received 58% rain below normal. As against an average of 54.1 mm of rainfall, the district has received only 22.6 mm of rainfall, according to the Karnataka State Natural Disaster Monitoring Centre (KSNDMC). Chamarajanagar has received 61% below normal, the actual rainfall being 20.3 mm as against the normal of 52.1 mm of rainfall for June. Hassan district, which is a major contributory to the Cauvery by way of inflow from the Hemavathi, has also received below normal rainfall for June. As against the normal of 143.6 mm of rainfall, the district has received 123.4 mm of rainfall.
The remaining districts of south interior Karnataka which have received below normal rainfall include Bengaluru Urban (-37% ), Bengaluru Rural (-40%), Ramanagaram (-47%), Kolar (-14%), Chickballapur (-17%), Tumakuru (-29%), Chitradurga (-38%), and Davanagere (-24%).
This is in contrast to the pre-monsoon rain for January to May 31 when south-interior Karnataka was lashed with heavy showers and received 36% above rainfall. As against the normal of 150.2 mm of rainfall, it received 204.2 mm and only Davanagere and Chitradurga, of the 11 districts, had below normal rainfall.
Moderate to heavy rains augment inflow into KRS, Kabini reservoirs
The catchment areas of the Cauvery which is spread across parts of Kodagu have experienced intermittent bursts of heavy rains followed by light to moderate rainfall in the last few days. As a result, there is an increase in the inflow into the Krishnaraja Sagar (KRS) reservoir which was at the rate of 7,818 cusecs on Friday — the highest rate of flow this season so far. Similarly, heavy rains in the catchment area of the Kabini in the preceding days has augmented the inflow into the Kabini reservoir at Beechanahall in H.D. Kote. The inflow on Friday was at the rate of 7,680 cusecs.
The KRS reservoir level was 71.20 ft as against the full reservoir level of 124.80 ft. The reservoir level during the corresponding period last year – which was also an year of drought — was 73.65 ft, according to the Karnataka State Natural Disaster Monitoring Centre. This is in contrast to the KRS reservoir level in 2011 which was an year of normal monsoon and the water level had touched the 100 ft mark in the last week of June while the water level of Kabini had reached 22,822 ft as against its FRL of 2,284 ft. Under these conditions, concerns also stems from the State’s obligation to comply with the final orders of the Cauvery Water Disputes Tribunal towards which it had to release 10 tmcft of water in June to Tamil Nadu. But owing to deficit rainfall, the outflow was less than half that quantum. Besides, Karnataka has to release 30 tmcft of water in July, 50 tmcft in August, and 40 tmcft in September before it tapers down for which vigorous monsoon over extended period was a must.
