Dam floods · Krishna River · Maharashtra

Maharashtra’s Upper Krishna Basin again faces prospects of Dam Floods?

Seven major dams with high storage capacities in Upper Krishna Basin in Maharashtra’s Satara and Sangli districts have huge 1422.12 Million Cubic Meters (MCM) water in live storage as on May 30, 2020, just about a week away from the prospects of beginning of monsoon. The Wadnere committee’s efforts not withstanding, there is no doubt that almost simultaneous water release from these seven dams played a major role in creating highest ever flood levels in Maharashtra’s Upper Krishna Basin in August 2019. Though on this day last year, these seven dams had much lower water in live storage at 556.49 MCM, the almost simultaneous water release from these dams hugely contributed to the unprecedented flood disaster in Sangli district last year. With 256% water in live storage this year compared to last year on this date, the risk of these dams contributing to flood disaster in Sangli district is even greater this year. Unless the authorities in the water resources department, district administration and disaster management authorities wake up and ensure that these dams help moderate rather than contribute to floods.

[The Wadnere Committee submitted its report on May 28, 2020, but what kind of report it may have submitted is apparent from the way one of the members, Shri Pradeep Purandare had to resign, see: https://sandrp.in/2020/05/26/maharashtra-floods-2019-dont-waste-the-crisis/ ]

Seven major dams in Sangli and Satara In the table below we have given the current water stored in live storage capacity in the seven biggest capacity dams in Sangli and Satara districts as on May 30, 2020 as per the Maharashtra Water Resources Department’s daily bulletin[i], along with their full live storage capacity and % water stored this year and last year.

Dam Live Storage Capacity MCM Storage on May 30 2020 Storage on May 30 2019
MCM % of L S capacity MCM % of L S capacity
Koyna 2835.54 836.59 29.5 (20) 322.40 11.37
Warna 779.35 145.56 18.72 86.27 11.07
Dhom 331.05 108.5 32.77 (18) 11.42 3.45
Urmodi 273.27 169.36 61.98 (45) 28.23 10.33
Kanher 271.68 63.85 23.5 (21) 47.73 17.57
Tarali 165.46 66.87 40.42 54.98 33.23
Dhom Balkwadi 112.13 31.09 27.73 5.46 4.87
TOTAL 4768.26 1422.12 29.82 556.49 11.67

It can be seen that in case of each of these seven reservoirs, the storage this year on May 30 is much higher than what was the storage last year. The figures in bracket in fourth column is the average of storage on the same day of last ten years (available from CWC’s weekly reservoir bulletin of May 28, 2020[ii], only four of these dams are included there), the storage this year is also higher than all of these.

If we compare the dam storages on May 30 with the storages 10 days back, then all the dams have released water and have brought their Live storage down. In case of Kolhapur district dams like Radhanagari, Dudhganga and Tulshi this reduction is substantial in 10 days. Radhanagari is now at 0% live storage from 55.2% just 10 days back. Warna dam in Sangli is at 18.72% from 58.31% ten days back.

This is appreciable. However, we cannot forget that dam levels (with the exception of Radhanagari in Kolhapur) are still higher than last year and more importantly, they are higher than 10 years average too.

In addition, there has been no communication in public domain from the Maharashtra Government’s Water Resources Department as to how Flood Management this year will be different than last year. Efforts in towns which were hit by flood have been mostly around evacuation, distributing a rafts, readying relief shelters etc. This is needed but this has to be a part of a bigger scheme of things of flood management, including prevention and not only rescue and relief.

To this end, what has been the status of securing the Blue and Red Lines? Even the maps for this region are not complete by the Maha WRD. Carrying Capacity of rivers is not known, there is no communication about how dams will be filled and how will they be operated. The rule curves or Reservoir Operation Schedule, the O & Manual and Emergency Action Plans are not in public domain. This is very relevant and crucial information which the people need and deserve to know.

Lessons from Maharashtra Upper Krishna Basin floods of 2019 One of the things that authorities can immediately do for the remaining period from now to the onset of SW monsoon 2020 is that they can try and reduce the water storages in these seven dams to closer to the levels last year. There are other factors responsible for contributing to the flood disaster, these includes the encroachment on river beds, lack of preparedness including flood management plan, early warning system, evacuation plans at various levels of discharges in river and reliable and dam catchment & sub basin specific rainfall forecast and also rainfall measurement at all key locations and system to assess the likely river flows for various rainfall patterns and also inundation maps for various river flows. The standard operating procedure for various structures along the river and its tributaries is also very important, including for all the dams and barrages. Latest assessment of carrying capacity of the various rivers at various locations is also very important so that dam operators know that releases beyond such levels would create disaster, keeping in mind the downstream catchment rainfall and river flows. In areas closer to the Karnataka border, the Krishna river flows with very low slope, and hence its drainage capacity is low, and this becomes even more crucial at confluences with various tributaries. The performance of drainage from Urban areas can create additional issues and ensuring functional drainage system is very important as also removing all the dumping that would have been done in the riverbeds and river channels.

One hopes this early warning helps ensuring that dams do not contribute to floods and damages due to floods, also ensuring that the dams do not end up releasing water simultaneously and in quantities that downstream rivers cannot carry.

SANDRP (ht.sandrp@gmail.com)

END NOTES:

[i] https://d3suziiw6thyiv.cloudfront.net/reports/storage-comparison/standard/pdf/view?MenuID=1317

[ii] http://cwc.gov.in/sites/default/files/28.05.2020-fb-pdf.pdf

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