Report on Rule Levels for Major Reservoirs of KSEBL May, 2019 RULE CURVE FOR MAJOR RESERVOIRS OF KSEBL MAY 2019 CONTENTS 1. Introduction ................................................................................................................................................... 1 2. Data Collection ............................................................................................................................................... 2 3. Methodology .................................................................................................................................................. 2 3.1 Variables ................................................................................................................................................ 2 3.2 Procedure .............................................................................................................................................. 3 4. Rule Levels for Idukki reservoir ...................................................................................................................... 4 4.1 General .................................................................................................................................................. 4 4.2 Salient Levels ......................................................................................................................................... 4 4.3 Elevation - Storage - Area Details .......................................................................................................... 4 4.4 Scheduled release for power generation .............................................................................................. 5 4.5 Inflow to Idukki Reservoir in critical years ............................................................................................ 6 4.6 10-Daily inflow series ............................................................................................................................ 7 4.7 10-Daily inflow series with 50% and 90% percentage of dependability ............................................. 11 4.8 Deriving Rule Levels ............................................................................................................................ 12 4.9 Rule levels corresponding to 50% dependable inflow ........................................................................ 13 4.10 Upper Rule Levels ................................................................................................................................ 13 4.11 Lower rule Level .................................................................................................................................. 15 4.12 Rule Curve ........................................................................................................................................... 16 4.13 Lay out - Idukki Hydro Electric Project including Diversion Structures ............................................... 17 5. Rule levels of Idamalayar Reservoir ............................................................................................................. 18 5.1 General ................................................................................................................................................ 18 5.2 Salient Levels ....................................................................................................................................... 18 5.3 Elevation - Storage – Area Details ....................................................................................................... 18 5.4 Scheduled release for power generation ............................................................................................ 19 5.5 Inflow to Idamalayar Reservoir in critical years .................................................................................. 19 5.6 10-Daily inflow series .......................................................................................................................... 20 5.7 10-Daily inflow series with 50% and 90% percentage of dependability ............................................. 24 5.8 Deriving Rule Levels ............................................................................................................................ 25 5.9 Rule levels corresponding to 50% dependable inflow ........................................................................ 26 5.10 Upper Rule Levels ................................................................................................................................ 27 5.11 Lower rule Level .................................................................................................................................. 27 5.12 Rule Curve ........................................................................................................................................... 29 5.13 Layout Map – Idamalayar Hydro Electric Project ................................................................................ 30 6. Rule Levels for Kakki reservoir ..................................................................................................................... 31 6.1 General ................................................................................................................................................ 31 6.2 Salient Levels ....................................................................................................................................... 31 6.3 Elevation - Storage - Area Details ........................................................................................................ 31 6.4 Scheduled release for power generation ............................................................................................ 32 6.5 Inflow to Kakki reservoirs in critical years ........................................................................................... 32 6.6 10-Daily inflow series .......................................................................................................................... 33 6.7 10-Daily inflow series with 50% & 90% dependability ........................................................................ 35 6.8 Deriving Rule Levels ............................................................................................................................ 36 6.9 Rule levels corresponding to 50% dependable inflow ........................................................................ 37 6.10 Upper Rule Levels ................................................................................................................................ 37 6.11 Lower rule Level .................................................................................................................................. 38 Page ii RULE CURVE FOR MAJOR RESERVOIRS OF KSEBL MAY 2019 6.12 Rule Curve ........................................................................................................................................... 40 6.13 Lay out of Structures of Hydroelectric Projects in Pamba basin ......................................................... 41 7. Rule levels of Banasurasagar Reservoir........................................................................................................ 42 7.1 General ................................................................................................................................................ 42 7.2 Salient Levels ....................................................................................................................................... 42 7.3 Elevation - Storage Details .................................................................................................................. 42 7.4 Inflow to Banasurasagar Reservoir in critical years ............................................................................ 43 7.5 10- Daily Dependable inflow series ..................................................................................................... 43 7.6 Deriving Rule Levels ............................................................................................................................ 44 7.7 Rule levels corresponding to 50% dependable inflow ........................................................................ 44 7.8 Upper Rule Levels ................................................................................................................................ 45 7.9 Layout of Structures under Kuttiyadi Hydro Electric Project .............................................................. 46 8. Rule levels of Sholayar Reservoir ................................................................................................................. 47 9. Recommendations ....................................................................................................................................... 47 Annexures ANNEXURE A1 - Idukki Reservoir – Flood Hydrograph - 100 Yr return period ..................................................... 50 ANNEXURE A2 - Idukki Reservoir – Flood routing with flood - 100 Yr return period ........................................... 51 ANNEXURE B1 - Idamalayar Reservoir – Flood Hydrograph - 100 Yr return period ............................................ 54 ANNEXURE B2 - Idamalayar Reservoir – Flood routing with flood - 100 Yr return period ................................... 55 ANNEXURE C1 - Kakki Reservoir- Flood Hydrograph - 100 Yr return period .......................................................