Scanned by CamScanner KRISHNA SUB-BASIN BHIMA SUB-BASIN Preface Floods have been a recurrent phenomenon which brings devastation to settlements, misery to human lives and losses to infrastructure and public utilities. All of these were experienced in months of August & September 2019 in Krishna basin in Maharashtra & Karnataka state. Sangli, Kolhapur and few districts in Karnataka suffered heavily during this flood event. Study Committee of 10 members appointed by Government of Maharashtra has brought out this detailed report on various TORs concerning analysis & reasons of occurrence of 2019 flood in Krishna basin, technical measures to be undertaken in future and also study on back water effect in Maharashtra due to Almatti & other structures in Karnataka. Various experts from IMD/IITM, MRSAC, WRD, CWC, MWRRA, NGOs, individuals inducted in committee studied different TORs and through their valuable reports, put fourth their opinions/conclusions/recommendations. The Committee held discussions and visited flood prone areas in Maharashtra, Almatti / Hippargi projects in Karnataka, various renowned institutes/organisations and brought out this technical report in three volumes. Volume-I comprises of main report, Volume-II contains Annexures including study reports of experts and Volume-III contains maps. Broadly, there are three factors which are responsible for flood- Meteorological which is natural where prolonged heavy rainfall during monsoon, cloudburst, typical cyclones play role, Topological viz. Lack of drainage from the area, saturated subsoil and Human where uncontrolled encroachment on flood plains, drying and sedimentation of natural drainage channels due to human activities, damming & diversions of river, destruction of natural barriers to flooding take place. In Krishna sub basin the Committee transpired that persistent & simultaneous occurrence of heavy precipitation in short durations both in dam & free catchment, typical topographic features, river meandering, large encroachments in flood plains, reduced flood carrying capacity of river channels, poor land drainage in urban areas, sedimentation are some important causes of flood. However inspite of all these constraints it is observed that the dam operators in Maharashtra had tried to keep the outflows from spillway on lower scale compared to inflows. Committee has proposed pragmatic & useful measures both structural & non-structural. Flood storages & diversions, straightening of meanders, restoration of natural drainage, raising river banks, control on development in flood plains, establishing flood lines, rehabilitation/removing encroachment in restricted/prohibited zones, providing spillway gates are some of the structural measures. Few of them are permanent and temporary. Integrated ROS, revising ROS and flood lines, Robust rainfall forecasting, Reinforcing RTDAS/RTDSS, vulnerability maps, Technology updation, Institutional Arrangements, policy measures especially for flood mitigation & climate change, Adaptation of Maharashtra state climate change Adaptation Policy(MSAPCC 2017) are proposed as non structural measures. Committee with due consideration proposed useful recommendations based on detail studies done by various Institutes, Experts concerning Analysis and causes thereof. It request for immediate implementation of few important actions included for Preparedness, robust systems for forecasting, Flood resilient infrastructure, Operational Reforms and Disaster management, policy reforms/Legal provisions and other number of recommendations related to flood management. Very importantly, Hydrodynamic analysis has been done using HEC-RAS software to study back water effect due to Almatti & other reservoirs from Karnataka on river Krishna. Specific chapter is included in report along with findings/conclusions. This study also showed effect of meandering, confluence of tributaries & inundation caused due to back water which has helped to better understand causes of submergence for longer periods in Sangli and Satara districts. Flood management, Reservoir Management, Flood forecasting, Disaster Management, Dam Safety are all public interest activities. Thus all information in this regard must remain in public domain. Dams are tools to moderate flood to certain extent with adaptation of rule curves properly understood, along with rigid to semi rigid concept of ROS and switching over process from normal to emergency schedules backed by additional actionable efficient weather forecasting would help dam operators to manage floods in better way. Reservoir when not operated properly, may prove to be potential source of disaster if flood is taken as hazard. We also recommend revisiting designs of various structures constructed in river Krishna & its tributaries. During last 2-3 decades the trend in flood damages have been growing exponentially. In the climate change scenario, one of the main threats would be floods at one side and droughts on other side simultaneously. So we will have to take it seriously in planning our goals. Advanced Weather Forecasting System, NOW CAST, RTDAS/RTDSS, vulnerability mapping by Remote Sensing, well equipped disaster management units ready with evacuation plans, training/mock drills for volunteers, government staff & public is of prime importance. To acquire value added actionable information from IMD (more clear quantitative forecast) for efficient flood operation can be helpful. Proper co-ordination system amongst IMD/WRD/Disaster Management Units & various related government authorities is utmost essential during flood mitigation operations to look after the public safety and minimising the losses. Encroachment, that is human interference in river plains is a serious concern causing flood disasters. Flood plains have been severely affected by urbanization particularly in Sangli & Kolhapur districts. State Government by an enactment may establish Flood Zoning Authorities on pilot basis for Sangli & Kolhapur districts with necessary powers, functions & duties for regulation of land use & to overall control future encroachment/ unauthorised constructions etc. Krishna being an Interstate river, apart from present routine co-ordination process viz. exchange of flood data between Maharashtra & Karnataka state, it is prudent rather mandatory to establish advanced forecast modelling system like RTDSS on entire Krishna basin as a whole for effecting proper control on floods everywhere and minimising losses. In a state game of reservation and allocation of water, each state stand entitled to get their optimum share to safeguard the interest of that state. However, flood management in whole Krishna basin is a national game where all interstate players must play in harmony to achieve goal set for the nation. It is necessary & my privilege to place on record that all honourable members & invitees contributed their best in preparing this report. Their deep sense of commitment is praiseworthy. Submission of this exhaustive report got delayed owing to certain unavoidable reason and more so due to current pandemic/lockdown in our country. Nevertheless, the team worked from home & brought out this report. I hope that it would prove to be useful to various organisations, Institutes, Departments, Individuals, Dam operators and those all related to Flood Management. Government of Maharashtra is requested to accept recommendations and may take quick steps to implement important measures at the earliest. Clear her path, Let her flow... Along with her, ensure we grow... Respect the River! Er NANDKUMAR VADNERE (Retd. Principal Secretary WRD, GOM) CHAIRMAN, EXPERT STUDY COMMITTEE Acknowledgement Preparation of such exhaustive technical report on various flood issues related to Krishna sub basin of Maharashtra is a stupendous task. It involved collection of large hydrological/ hydrometeorological data, geographical features, various reports, literature, references from many concerned organisations/institutions viz. IMD, IITM, CWC, MRSAC, WRD, MWRRA, NGO etc Committee is grateful to Government of Maharashtra for entrusting the responsibility of preparation of this technical report to us. At the outset, chairman want to place on record his deep appreciation & thanks to the following honourable members. Er. Vinay Kulkarni, Technical member MWRRA painstakingly guided & carried out Hydrodynamic study using HEC-RAS software for back water of Krishna river along with Er. H.T Dhumal SE(WRD) without whom this study could not have been complete. They brought out excellent technical study report and drawn various conclusions related to main TOR and allied issues. Technical Member voluntarily offered his studious suggestions on other TORs too for achieving further refinements. Er. Sanjay Ghanekar Secretary (P&M WRD) along with Dr. Subrato. N. Das, Director MRSAC Nagpur and Mr. Vivekanand Ghare, Senior Consultant MRSAC, Mumbai with assistance from various WRD officials & organisations formulated proposals on measures to be adopted. The study report by MRSAC on Remote sensing and GIS based Analysis of Flood 2019 was proved to be very much useful in proposing measures. Prof. Ravi Sinha, IIT, Mumbai with the assistance from Mr. Rohan Shinde offered suggestions on mathematical modelling. Prof. Subimal Ghosh IIT, Mumbai examined & generally agreed with the conclusions drawn in back water study. Er. Nitya Nand Rai, Director(Hydrology) South CWC , New Delhi also carried out back water study on river Krishna using MIKE-II software. He participated in all technical discussions