Rainfall distribution skewed in State, with deficiency in Malnad, south-interior parts

Kodagu which is the catchment area for the Cauvery has received 953 mm of rainfall which is 37% below normal; with southwest monsoon slackening since the last few days of July till August 5, the rate of inflow into reservoirs has depleted considerably

The water-level at Krishnaraja Sagar on Saturday. | Photo Credit: M.A. SRIRAM

The southwest monsoon shows skewed distribution pattern with deficiency in Malnad region, apart from Mysuru-Chamarajanagar belt for the period June 1 to August 5, while it is normal for the rest of the State.

While the entire State was under the deficient category till mid-July, heavy to very heavy rain for almost 10 days since the second week of July bridged the deficiency. As a result, the average rainfall for the entire State is 12 per cent below long period average (LPA).

But under the Indian Meteorological Department parameters, a variation in the rainfall from 19% below LPA to 19% above LPA is considered normal.

As against 514 mm of rainfall which is normal for the period, the State has received 452 mm. Though the State has received 12% below LPA for the period June 1 to August 5, it is categorised as normal rains, according to Karnataka State Natural Disaster Monitoring Centre (KSNDMC).

In deficient category

But the distribution is skewed within the State and the average figures paint a wrong picture. The entire belt comprising Chamarajanagar, Mysuru, Kodagu, Hassan, Chikkamagaluru, and Shivamogga have received rainfall 19% below LPA and hence are in the deficient category. Besides these districts, Ramanagara, Bengaluru Urban, Chickballapur, Ballari, and Bagalkot are the other districts where rainfall is under the deficient category.

Mysuru has received 176 mm of rainfall which is 25% below normal while Chamarajanagar has received 96 mm and is 29% below normal. Similarly, Kodagu which is the catchment area for the Cauvery has received 953 mm of rainfall which is 37% below normal.

Rainfall in Hassan (340 mm), Chikkamagaluru (662 mm), and Shivamogga (1,031 mm) too have been categorised under deficient category and the rainfall is 26%, 31%, and 24% below normal in the three districts respectively.

For August, the rainfall across the State is under the large deficit category, which means rainfall is 60% below normal. Only the coastal belt is under deficient category as the shortfall is 51% of the normal, as per KSNDMC.

The reservoir levels were an issue of concern till mid-July but as the monsoon gained traction, the storage improved considerably. The cumulative storage in the four major dams in the Cauvery basin is 111.50 tmcft as against the gross storage capacity of 114.57 tmcft. The storage on the same day last year was 111.50 tmcft and the reservoirs have 81% of their gross capacity as of August 5.

Monsoon slackening

But with southwest monsoon slackening since the last few days of July till August 5, the rate of inflow into the reservoirs has also depleted considerably. While the four major reservoirs accrued 1.2 tmcft of water during the last 24 hours, the reservoirs in the Krishna basin accrued 10.2 tmcft of water during the same period, underlining the variation in monsoon activity.