O & M Manual of Tawa Dam May 2020
GOVERNMENT OF MADHYA PRADESH
TAWA Operation and Maintenance (O&M) Manual Project ID Code: MP08HH0326
Prepared by SPMU DRIP (BODHI), Bhopal May, 2020
O & M Manual of Tawa Dam May 2020
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O & M Manual of Tawa Dam May 2020
Government of Madhya Pradesh Water Resources Department
Disclaimer
This Operation and Maintenance Manual for Tawa Dam no way restricts the dam owner in digressing from her/his responsibilities. The State Dam Safety Organization or the Central Water Commission cannot be held responsible for the efficacy of this manual developed based on documents provided by the dam owner. The Dam Owner and her/his Operators must exercise appropriate discretion when implementing and using the operation and maintenance manual for managing the workings of the dam and appurtenant structures.
The manual was developed for the purpose of organizing and managing the operation, inspection and maintenance of the dam for reducing risk and optimizing performance of the dam.
Executive Engineer Tawa Division Itarsi Water Resources Department District Hoshangabad Ph-07572-266087 Email [email protected]
Copy right @2019 Water Resources Department.All rights reserved.This publication is copy right and may not be resold or reproduced in any manner without the prior consent of WRD, MP.
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O & M Manual of Tawa Dam May 2020
Government of Madhya Pradesh Water Resources Department
PREFACE.
This Operation and Maintenance (O&M) Manual for Tawa Dam is a detailed written description of step-by-step procedures for ensuring that the dam is safely operated and properly maintained. Timely inspection and maintenance are necessary for the safe functioning of the dam and continued productive use of the dam and reservoir. The term “O&M” as employed in this manual includes operation, inspection, maintenance and repair of dam components, replacement of equipment and appurtenant structures, as required. This manual is provided to assist the dam owner in management of their project in a safe and efficient manner. The Dam Safety Bill, 2019, was passed by the LokSabha on 2nd August 2019 after the Cabinet approval. The draft Dam Safety Bill requires State Dam Safety Organizations (SDSO) to keep perpetual vigilance, carry out inspections regularly, and monitor the operation and maintenance of all dams for prevention of dam failure related disasters and to provide for institutional mechanism to ensure their safe functioning. This manual was prepared following the Guidelines for preparing O&M Manuals for dams (Doc. No. CDSO_GUD_DS_O3_v1.0) published by CWC in the year 2018 under DRIP.
Director, State Project Management Unit, DRIP, Bhopal.
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Team Members Involved in Preparing this O&M Manual.
Shri G. P. Soni Chief Engineer BODHI Overall review & Water Resources Department, Approval Bhopal. Shri Rakesh Agrawal Chief Engineer, Reviewer Hoshangabad, Shri B. P. Dubey Director, State Project Reviewer Management Unit, DRIP, Bhopal. Shri S. K. Saxena Superintending Engineer, Reviewer Tawa, Hoshangabad Shri I. D. Kumre Executive Engineer, Reviewer Tawa Division Itarsi, Hoshangabad Shri Navalkishore Sub Divisional Officer Assisted in making Suryavanshi Water Resources Sub Division, available all Tawa Project necessary information. Shri Makrand Golwalkar Deputy Director, SPMU, DRIP, Prepared original Bhopal Draft Ms Shweta Kushwaha Assistant Director, SPMU, Prepared original DRIP, Bhopal Draft Shri Sameer Soni Assistant Director, SPMU, Prepared original DRIP, Bhopal Draft
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O & M Manual of Tawa Dam May 2020
Contents Disclaimer ...... iii PREFACE...... v Team Members Involved in Preparing this O&M Manual...... vii CHAPTER 1.GENERAL INFORMATION...... 1 1.1. Purpose, Location, Description of Dam: ...... 1 1.1.1. Purpose...... 1 1.1.2. Description of dam...... 1 1.2. Assignment of Responsibility: ...... 2 1.3. Collection &Reporting of Dam and Reservoir Data: ...... 2 1.4. Public Utilities and Safety: ...... 3 1.5. Restricted Area...... 3 1.6. Communication& Warning system: ...... 3 1.6.1. Communication system: ...... 3 1.6.2. Warning System: ...... 3 1.7. Distribution of Operation & Maintenance Manual: ...... 4 1.8. List of Supporting Documents & Reference Material: ...... 4 1.9. Schedule of duties for operating personnel: ...... 5 CHAPTER 2.PROJECT OPERATION...... 7 2.1. Basic data: ...... 7 2.1.2. Area capacity curve...... 11 2.1.3. Data of Historic floods ...... 12 2.1.4. Latest Design Inflow Flood and Flood Routing Studies: ...... 12 2.2.Operation Plan: ...... 12 2.3 Normal Operation Procedures: ...... 13 2.3.1. Rule Curve/Reservoir Operations...... 13 2.3.2.Discharge through gated spillway for different reservoir levels...... 13 2.3.3.Operating instructions for gates and hoists of irrigation outlet...... 20 2.3.4.Methodology to work out gate opening for passing the required discharge through the irrigation outlet at different reservoir levels...... 23 2.3.5.SafetyAspects: ...... 31 2.4. Emergency Operation: ...... 31 2.5. Reservoir Capacities: ...... 31 2.6. Record Keeping: ...... 32 CHAPTER 3.PROJECT INSPECTION...... 34 3.1. Objective of Dam inspection: ...... 34 3.2. Types of Dam Safety Inspections: ...... 34 3.2.1. Informal Inspections ...... 34 3.2.2. Scheduled Inspections: ...... 35 3.2.3. Special (Unscheduled) Inspections: ...... 36 3.2.4.Comprehensive Evaluation Inspections: ...... 36
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3.2.4.1. Details to be provided to DSRP before inspection: ...... 37 CHAPTER 4.PROJECT MAINTENANCE...... 40 4.1. Maintenance Plan: ...... 40 4.2. Maintenance Priorities: ...... 40 4.2.1. Immediate Maintenance ...... 40 4.2.2. Condition based maintenance ...... 41 4.2.3. Routine Maintenance ...... 41 4.3. Procedures for undertaking routine Maintenance works: ...... 42 4.3.1. Earth work in earthen dam...... 42 4.3.2. Upstream Riprap ...... 44 4.3.3. Controlling Vegetation ...... 44 4.3.4. Controlling Animal Damage ...... 45 4.3.5. Controlling Ants and Termites (White Ants) ...... 45 4.3.6. Controlling Damage from Vehicular Traffic ...... 46 4.3.7. Masonry/Concrete Spillway ...... 46 4.3.8. Gates and Hoisting Equipments ...... 46 4.3.8.1.Radial Gates ...... 46 4.3.8.2 Electrically operated fixed hoists ...... 48 4.3.8.3 Maintenance of Electrical components of Fixed Rope Drum Hoists50 4.3.9. Electrical System: ...... 58 4.3.10. Metal Component maintenance: ...... 58 4.3.11. Access Road: ...... 58 4.4. Material Requirements during monsoon period: ...... 59 4.5. Establishment structure at Tawadam...... 60 4.6. Preparation of O&M Budget: ...... 60 4.7. Maintenance of records: ...... 61 CHAPTER 5.INSTRUMENTATION AND MONITORING...... 62 CHAPTER 6: PREVIOUS REHABILITATION EFFORTS...... 65 CHAPTER 7: UPDATING THE MANUAL...... 68 7.1 Training and Exercises: ...... 68 Appendix-I Scheduled Dam Safety Inspection Form: ...... 71 Appendix-II: Checklist of various instruments installed on large dams: ...... 105 Appendix-III: Summary Table for Annual O&M Budget: ...... 109 Appendix-IV: Basic Drawings of the Dam &Spillway...... 112 1. Index Map: ...... 114 2. Satellite map TawaDam: ...... 115 3. Location Map: ...... 116 4. Cross section of dam: ...... 118 5. L-section of dam (with location & log of Drill Holes & Test Pits): ...... 120 6. L-section of dam (with Layout Plan of Instruments installed): ...... 121 7. Section and Plan of Spillway: ...... 122
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8. Layout Plan of Project: ...... 123 9. Plan of Foundation Gallery of Masonry Dam: ...... 124 10. Area Capacity Curve:...... 125 11. Inflow in the reservoir and discharge passing over dam: ...... 127 12. Discharge for Sethani Ghat, Hoshangabad:...... 129 13. Gauge Discharge curve of River Narmada for Sethani Ghat, Hoshangabad: ...... 130
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O & M Manual of Tawa Dam May 2020
CHAPTER 1.GENERAL INFORMATION.
This Operation and Maintenance (O&M) Manual contains procedures for carrying out Reservoir and Gate operations, inspections and Maintenance for Tawa dam. It will be helpful in ascertaining that the dam functioning safely and to keep it in a good condition by periodic repairs/maintenance. Timely maintenance is important for the continued safe functioning of the dam and productive use of the dam and reservoir.
The term “O&M” as employed in this manual includes operation, maintenance, general repairs of dam components including replacement, as necessary.
The Manual is prepared primarily for the dam operations staff and their supervisors who are assigned the responsibility for the physical operations and maintenance of the dam. It contains all information and instructions necessary for them to perform their allotted tasks. In addition to instructions for dam operations staff, the manual defines responsibilities of various dam officials and provides the systematic procedures, guidance and standard forms to ensure safe operation, extend the life and achieve the intended purpose of the dam.
If any unusual and emergency condition arises, then the procedures laid down in the Emergency action Plan (EAP) are to be followed.
1.1.Purpose, Location, Description of Dam:
1.1.1. Purpose. Tawa dam is a multipurpose project situated upstream of Ranipur village and downstream of Tawa and Denwa confluence which are tributaries of Narmada river, in Hoshangabad district. The project has an annual irrigation potential of 332785 ha, Culturable Command Area of 246972 ha. and Gross Command Area of 401685 ha.
1.1.2. Description of dam. This is a major multipurpose project, completed in the year 1978-79. It is built across Tawa River under Narmada basin intercepting a catchment area of 5982.90 km2. The project comprises of homogeneous earth dam having the length 690.372 m and 521.208 m on the left and right sides respectively of 237.74 m long central ogee spillway portion having 13 nos. radial gates each of size 15.2 x 12.19 m. The height of the dam above deepest foundation level is 57.791 m and 49.987 m above lowest river bed. The design spillway discharge capacity spillway crest has an ogee shape. In addition to above two earthen saddle dams of length 182.88 m each are there at left flank. A hydro power house (owner-HEG Company Ltd) of power generation capacity 13.5 MW is located on the left toe of the dam. It is essentially an irrigation project with an annual irrigation of 3.33 Lakh hectares. About 563 villages are
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O & M Manual of Tawa Dam May 2020 benefitted by irrigation. Annual fish production is also about 350 tones. There is water supply of 7.5 MCD to Ordnance Factory Itarsi for their different uses.
1.1.3. Location.
Tawa dam is a multipurpose project providing water for irrigation in Hoshangabad and Harda Districts, power supply, and other benefits like fish production. Its latitude is220-33’-40” N andlongitude is 770-58’-30’’E. It is located in Narmada Basin.
The dam site is approachable by all-weather motorable road from NH-69 which is at a distance of 20 km from dam site. itarsi Junction is the nearest railway station at a distance of 33 km from the dam site. Bhopal airport is 129 km away from project site.
1.2.Assignment of Responsibility: Sl. Function Officers having responsibility No. Executive Engineer, Tawa Division, 1. Project Administration-Officer-in-Charge Itarasi Assistant Engineer/SDO (Civil), 2. Operations of Equipment at the dam Tawa Division, Itarasi Authorizing releases for irrigation and water Executive Engineer, Tawa Division, 5. supply, Itarasi Assistant Engineer/SDO,Tawa 6. Recording reservoir data Division, Itarasi
Assistant Engineer/SDO,Tawa Division, Itarasi 7. Routine inspection & Executive Engineer, Tawa Division, Itarasi Assistant Engineer/SDO,Tawa Division, Itarasi& 8. Maintenance Executive Engineer, Tawa Division, Itarasi Executive Engineer, Tawa Division, 9. Dam safety surveillance including instrumentation. Itarasi
1.3.Collection &Reporting of Dam and Reservoir Data: Routine data for the following is to be recorded Reservoir water surface elevation – on daily basis during non-monsoon and hourly basis during monsoon Spillway outflow on hourly basis during monsoon. Irrigation releases on daily basis. Hydro – Meteorological data on daily basis.
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Surveillance and monitoring
1.4.Public Utilities and Safety: Inconformity to the public safety norms a signboard is provided near spillway of the dam containing the safety instructions & protection measures for convenience of the public. Nearest Government Hospital is in Chandon, another is Ordnance Factory Hospital District Hoshangabad which is about 18.6 km and 16 km respectively from the dam site and police station is at Pathrota which is about 22.5 km from the dam site. The following safety equipments are available at the dam site. 1. Helmet 2. First Aid Kit
1.5.Restricted Area. Restricted areas of Tawa Dam are:
Spillway approach areas, ogee spillway and stilling basin. Head regulator well.
1.6.Communication& Warning system:
1.6.1. Communication system:
During monsoon a control room is opened at dam site to monitor flood situation and its effect on safety of project. All the officers of the project are connected telephonically and through Group WhatsApp. Hence any unusual development in project is communicated to highest level with immediate effect and appropriate action is taken. Rain fall is monitored daily by rain gauge installed at Tawa Nagar, Pachmarhi, Betul, Shahpur, Ghodadongri in catchment of Tawa reservoir.
Directory of contact numbers of key persons of civil administration i.e. District Magistrate, Superintendent of Police, ambulance, fire station etc. is available in control room. Regular revision / updating of the Directory is being carried out from time to time. The proper accessibility with motorable all-weather roads has been ensured to the dam site for constant monitoring during emergent situations.
1.6.2. Warning System: There is downstream warning system through siren and wireless system in the Dam. During monsoon period gates are operated for releasing the excess water of reservoir to the river through the radial gates. It is essential that the population situated in the areas downstream of dam is informed in time about such releases. Communication of flood warning is made to the
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O & M Manual of Tawa Dam May 2020 civil / public authorities of head quarter at Hoshangabad city. The Assistant Engineer in-charge of the dam would be responsible for issuing such public warnings. He should ensure that the warnings are received by civil and police authorities well in time prior the release of water. Records of such warning should be maintained by the concerned Assistant Engineers.
The flood warning should also be communicated simultaneously to the Collector, flood control unit at Hoshangabad and downstream in Narmada River.
1.7.Distribution of Operation & Maintenance Manual:
The following officers/ field staff at different levels in the Division under the supervision of Superintending Engineer Tawa, Water Resources Circle Hoshangabad and administrative control of Chief Engineer Hoshangabad are entrusted with the specific responsibility for carrying out O & M activities forTawadam.
1) Executive Engineer, Tawa Division, Itarasi 2) Assistant Engineer/ SDO, Tawa Division, Itarasi 3) Sub- Engineer, Tawa Division, Itarasi 4) Work charge personnel of Dam
The list of offices to whom the O&M Manual of Tawa dam are to be distributed are: 1. Tawa Division, Itarasi 2. Sub-Division, Tawa 3. Water Resources Circle, Hoshangabad 4. Office of Chief Engineer, Hoshangabad 5. Office of Chief Engineer BODHI, Swara Bhawan, Bhopal
1.8.List of Supporting Documents & Reference Material: These are as under:
1. Operating criteria for the reservoir & outlets.
2. Emergency action plan.
3. Irrigation operating instructions.
4. Administrative procedures.
5. Major maintenance procedures
6. Maintenance schedules
7. Manufacturer’s instructions & drawings.
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8. Instrumentation reports and/or results
9. Report on design flood review and flood routing study carried out under DRIP
10. All drawings of the dam (Civil, Mechanical, Electrical)
1.9.Schedule of duties for operating personnel: The duty schedules for operating personnel are given below. All activities should be recorded in dam log book /site registers.
Sl. No. Component Frequency Personnel Visual inspection of crest of the dam (dam top) and visible portions of dam (upstream and SDO / Assistant 1. downstream faces), foundation, abutment Fortnightly Engineer. contacts, Galleries, Spillway , Outlets, appurtenant structures, etc. Daily in non- monsoon and 2. Record water surface elevation. Junior Engineer hourly in monsoon Record Depth of flow over spillway during Hourly in 3. Junior Engineer monsoon. monsoon Outflow over spillway during monsoon (To be Hourly in 4. Junior Engineer estimated from depth of flow over the spillway). monsoon 5. Record releases from outlets /sluices. Daily Junior Engineer Record seepage from Earth dam, Toe drains, 6. Daily Junior Engineer Gallery drains etc. 7 Record meteorological data. Daily Junior Engineer 8. Check security and safety devices. Daily Junior Engineer. SDO/Assistant 9. Drainage systems - Toe drains, etc. Fortnightly Engineer Inspection of crest of dam (i.e. dam top) & 10. Drainage systems - Toe Drains, Gallery drains Monthly Executive Engineer etc. SDO/Assistant 11. Measuring devices/Instruments. Monthly Engineer SDO/Assistant 12. Communication Devices. Monthly Engineer SDO/Assistant 13. Status of Vegetation growth. Monthly Engineer Check Sign/Warning display boards near SDO/Assistant 14. Monthly vulnerable locations. Engineer Visual inspection of Upstream and downstream Executive Engineer 15. faces of dam, galleries, spillway, outlets, Monthly appurtenant structures etc.
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Sl. No. Component Frequency Personnel Visual inspection of visible portions of Executive Engineer 16. Monthly foundation. Visual inspection of abutment contacts and Executive Engineer 17. Monthly spillway and outlet structures SDO/Assistant 18. Rodent problems. Monthly Engineer Damage in spillway, energy dissipation SDO/Assistant 19. Monthly arrangement, d/s area etc. of spillway. Engineer Damage in spillway, energy dissipation 20. Quarterly Executive Engineer arrangement, d/s area etc. of spillway. Checking condition of V-Notch/other seepage SDO/Assistant 21. Quarterly measuring devices. Engineer Pre & Post 22. Operation of Radial gates of spillway Executive Engineer Monsoon Checking paint on gates of spillway and outlet SDO/Assistant 23. Bi-annual works Engineer (E&M) Checking lubrication of wire ropes and SDO/Assistant 24. application of cardium compound on spillway Bi-annual Engineer (E&M) and outlet works Checking mechanical hoist bearings and SDO/Assistant 25. flexible coupling bearings of spillway and outlet Bi-annual Engineer (E&M) works Checking gear systems of spillway and outlet SDO/Assistant 26. Bi-annual works Engineer (E&M) Checking rubber seals and seal clamp bar in SDO/Assistant 27. Bi-annual spillway and outlet works Engineer (E&M) SDO/Assistant 28. Lubricate gate rollers Bi-annual Engineer (E&M) SDO/Assistant 29. Change oil in Generator Bi-annual Engineer (E&M) SDO/Assistant 30. Exercise gate and valves Bi-annual Engineer (E&M) Every 10 31. Review Dam operation procedures and EAP Executive Engineer years
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CHAPTER 2.PROJECT OPERATION.
The operation of Tawa dam will involve regulation of its reservoir as per project specific requirements, keeping records and ensuring public safety. Proper operating procedures are crucial for maintaining a safe structure.
2.1. Basic data: 2.1.1. Salient features
A. HYDROLOGY
a. Catchment area : 5982.90km2
b. Mean annual rainfall : 1564.13 mm
c. Maximum annual rainfall : 2506.22 mm
d. Minimum annual rainfall : 873.76 mm
e. Mean monsoon rainfall : 1318.51 mm
f. Maximum Design flood : 29619 cumec (Revised)
: 30800 cumec (originally)
B. RESERVOIR
a. Gross storage capacity at FRL : 2311 Mm3
b. Dead storage at DSL : 367 Mm3
c. Live storage capacity : 1944 Mm3
d. FRL : 355.39 m
e. MWL : 356.69 m
f. DSL : 334.25 m
g. MDDL/LSL : 336.80 m LBC
: 340.46 m RBC
g. Area of submergence at FRL : 200 km2
h. Top level of Dam : 359.664 m
C. MAIN DAM a. Type : Masonry & Earthen dam b. Total length of dam : 1964.43 m
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: 690.372m Left Earth Dam
: 521.208 M Right Earth Dam c. Maximum height of dam : 57.91 m Masonry dam
: 32.528 m Earthen dam d. Top width : 7.52 m Masonry dam
: 7.62 m Earthen dam
D. SPILLWAY
a. Type : Gated ogee spillway.
b. Location : Central Spillway
c. Length of spillway : 237.74 m
d. Number of Bay : 13
e. Width of Pier : 3.3 m
f. Crest elevation of spillway : 343.205 m
g. No. of gates : 13 Nos. of Radial gate with size of 15.24 m
(W) X 12.19 m (H)
h. Gate Hoisting Arrangement : Rope Drum Type with electro-mechanical Control arrangement
E. IRRIGATION OUTLET
Right Bank Canal
a. Location : Offtakes from village Kamti in Sohagpur
Tehsil about 16 km away from Tawa Dam
through 4.0 km long tunnel and 3.6 km
open cut.
b. Number and size : 3 Nos with size of 1.524 m (W) X 2.438 m (H)
d. Invert level : 335.00 m
e. Discharge : Main canal 26.77 cumecs
: Bagra branch 13.22 cumecs
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O & M Manual of Tawa Dam May 2020
: Pipariya Branch 13.70 cumecs
Left Bank Canal
a. Location : Saddle dam No. 1
b. Number and Size : 4 no. of RCC duets each of size
2.438 m (W) x 2.743 m (H)
c. Invert level : 334.243m
d. Discharge : 103.578cumecs
F. GATES & HOISTSOF IRRIGATION
For Right Bank Main Canal a. Service Gate
1. Location : Right flank about 16km away from Dam
2. Number and Size : 3 Nos with size of 1.524 m (W) X 2.438 m
(H)
3. Sill level of gate in outlet : 335.00 m
4. Operation arrangement of gate : Rope Drum hoist arrangement
5. Maximum Vertical lift of gate : 3.00 m. b. Emergency Gate
1. Number and size : 3 Nos with size of 1.524 m (W) X
2.438 m (H)
2. Sill Level : 335.00 m
3. Operation arrangement : Rope Drum hoist mechanism
4. Maximum vertical lift of the gate : 3.00 m
For Left Bank Main Canal a. Service Gate
1. Location : Saddle dam No. 1 2. Number and Size : 4 Nos with size of 2.286 m (W) X 2.438 m
(H)
3. Sill level of gate in outlet : 334.243 m
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4. Operation arrangement of gate : Rope Drum hoist arrangement
5. Maximum Vertical lift of gate : 3.00 m. b. Emergency Gate
1. Number and size : 4 Nos with size of 2.286 m (W) X 2.438 m
(H)
2. Sill Level : 334.243 m
3. Operation arrangement : Rope Drum hoist mechanism
4. Maximum vertical lift of the gate
: 3.00 m
G. DISTRIBUTION SYSTEM
a. Gross command area : 333000 ha
b. Cultivable command area : 246972 ha c. Area irrigated during kharif : -
d. Area irrigated during Rabi : 264000 ha
e. Total Annual irrigation : 264000 ha
f. Total length of distribution system,
RBC Main canal : 7.65 km (Tunnel and exit Channel)
RBC Branch canal : Pipariya Branch Canal 49.880 Km
Bagra Branch Canal 27.35 Km
RBC Distributary : 240 km
RBC Minors : 203 km
LBC Main canal : 131 km
LBC Branch canal : Handia Branch Canal 54.50 Km
LBC Distributary : 655 km
LBC Minors : 1344 km
g. Sill level of head regulator : RBC 335.00 m, LBC 334.24 m
h. Bed width of canal at head : RBC 3.5 m, LBC 10.67 m
i. Bed level of main canal at head : RBC 335.00 m, LBC 334.24 m
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2.1.2. Area capacity curve. A drawing showing area-capacity curves of Tawa dam is at Appendix-IV
In tabular form it is given as under
Area Capacity Reservoir Elevation S. No. (Thousand (Million Sq (Million Acre (Feet) (m) (MCM) Acres) m) Feet)
1 1060 323.088 2.348 9.502 0.034 41.938 2 1065 324.612 2.878 11.647 0.054 66.608
3 1070 326.136 3.409 13.796 0.067 82.643
4 1075 327.660 3.939 15.941 0.084 103.612
5 1080 329.184 4.470 18.089 0.100 123.348
6 1085 330.708 5.674 22.962 0.135 166.520
7 1090 332.232 6.878 27.834 0.168 207.225
8 1092 332.842 7.360 29.785 0.181 223.260
9 1095 333.756 8.082 32.707 0.202 249.163
1096.60 10 334.244 8.349 33.787 0.220 271.366 DSL
11 1100 335.280 9.286 37.579 0.236 291.101
12 1105 336.804 10.935 44.252 0.298 367.577
13 1110 338.328 12.704 51.411 0.361 445.286
14 1115 339.852 14.414 58.331 0.425 524.229
15 1120 341.376 16.123 65.247 0.487 600.705
16 1125 342.900 18.709 75.713 0.540 666.079
17 1130 344.424 21.297 86.186 0.680 838.766
18 1135 345.948 23.883 96.651 0.864 1065.727
19 1140 347.472 26.471 107.124 0.990 1221.145
20 1145 348.996 29.655 120.010 1.156 1425.903
21 1150 350.520 32.838 132.891 1.204 1485.110
22 1155 352.044 38.079 154.100 1.394 1719.471
23 1160 353.568 43.322 175.318 1.584 1953.832
24 1165 355.092 48.518 196.345 1.826 2252.334
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1166 25 355.397 49.557 200.550 1.874 2311.542 FRL
26 1170 356.616 53.714 217.373 2.058 2538.502
1171 27 356.921 54.530 220.675 2.126 2622.378 MWL
28 1176 358.445 57.797 233.896 2.351 2899.911
29 1180 359.664 61.881 250.423 2.645 3262.555
2.1.3. Data of Historic floods The project was completed during the year 1978-79.The dam has faced severe floods during the year 1994. The maximum water released 15574.266 cumec (550000 cusecs) on 14.09.1994 with 9.144 m (30 feet) opening of radial gate. This is the first occasion after completion of dam. After this event on September 1998, 06.08.2012 and 22.08.2013 the maximum water released was 15576 cumec, 15580 cumec and 17324 cumec respectively.
2.1.4. Latest Design Inflow Flood and Flood Routing Studies: In terms of the Indian Standard IS 11223:1985 classification criteria, Tawa Dam is classified as an “Large Dam” and, therefore, qualifies for PMF (Probable Maximum Flood) as the design flood. The design flood studies submitted to CWC and PMF examined for the project by the Hydrology (DSR) Directorate, CWC is 29619.00cumec cumec as against the original design flood of 30800 cumec for which project was designed is found to be safe and there is no need of revision. Flood routing studies were carried out by the State DSO.
2.2.Operation Plan: The operation of the dam includes observation of reservoir levels, keeping records and ensuring both dam and public safety. This Manual covers the normal operation procedures to be followed during both monsoon and non-monsoon. Special operational procedures are to be followed during an emergency situation as per the Emergency Action Plan.
Proper communication and information is provided for the downstream inhabitants regarding discharge of flood water through the spillway when there is a forecast of heavy rain fall in catchment areas.
Mock drills and exercising of the service gates of the head regulator is carried out before every crop season.
All the gates and hoists of the head regulator are inspected and their parts lubricated and repaired as necessary before operation.
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The O&M Manuals of the Gates Manufacturer’s would however govern the overall maintenance of Gates & Hoists whenever there is any contradiction with the instructions given in the Manual.
2.3 Normal Operation Procedures:
2.3.1. Rule Curve/Reservoir Operations. Tawa dam has a gated spillway with 13 Nos. radial gates of size 15.24x12.20 m. Presently there is no rule curve available. Various observations such as reservoir water level, tail water level, general behavior of dam, seepage, gallery seepage and pressures, observation of dam temperature and deflection of dam are recorded throughout the year. The dam and reservoir is closely watched round the clock during the rainy season.
The reading of tank gauge is taken daily at 8.00 a.m. by the gauge reader during normal period and hourly during rainy season.
2.3.2.Discharge through gated spillway for different reservoir levels. Spillway discharge is given below in tabular form. This is verified at site as per actual measurements/Hydraulic Model Studies and modified.
Discharge Passing Through single Radial Gate for Different Reservoir Level and Gate Opening (Cusecs) Gate Reservoir Level (feet) Opening 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 (Feet) 1 351 454 539 611 676 733 787 841 887 925 2 805 993 1149 1285 1409 1521 1629 1728 1823 3 1344 1603 1826 2020 2196 2362 2515 2633 4 1955 2279 2559 2807 3037 3249 3450 5 2630 3012 3347 3648 3924 4184 6 3364 3800 4187 4535 4860 7 4151 4641 5074 5470 8 4992 5522 6009 9 5879 6463 10 6813 Gate Reservoir Level (feet) Opening (Feet) 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1 977 1014 1058 1098 1131 1171 1208 1240 1267 1306 2 1913 1991 2071 2156 2232 2302 2379 2447 2507 2572 3 2799 2926 3049 3170 3287 3400 3510 3619 3751 3813 4 3640 3813 3984 4147 4301 4458 4608 4750 4886 5021 5 4428 4654 4871 5082 5278 5472 5666 5848 6017 6192 6 5161 5441 5712 5969 6213 6449 6680 6906 7116 7323 7 5837 6175 6499 6810 7100 7384 7857 7920 8173 8421
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8 6447 6850 7232 7597 7941 8271 8592 8897 9187 9479 9 6986 7461 7908 8331 8728 9112 9479 9832 10164 10493 10 7740 8000 8519 9007 9462 9900 10320 10719 11100 11470 11 7791 8454 9058 9617 10138 10633 11107 11560 11987 12405 12 8805 9512 10156 10748 11309 11841 12348 12828 13292 13 9863 10610 11287 11916 12516 13031 13615 14133 14 10957 11741 12458 13127 13757 14400 14934 15 12092 12912 13666 14367 15024 15654 16 13263 14120 14906 15635 16330 17 14471 15360 16173 16940 18 15711 16628 17479 19 16879 17933 20 18284 Gate Reservoir Level (feet) Opening 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 (Feet) 1 1309 1382 1402 1442 1478 1498 1517 1536 1555 1594 2 2624 2705 2784 2803 2880 2956 2995 3053 3091 3149 3 3892 4007 4103 4186 4282 4358 4474 4531 4608 4685 4 5132 5274 5409 5505 5664 5760 5875 6010 6086 6202 5 6340 6515 6676 6810 6983 7142 7277 7411 7565 7680 6 7511 7722 7916 8077 8289 8461 8659 8813 8966 9158 7 8642 8893 9124 9318 9556 9767 9978 10195 10368 10560 8 9740 10024 10295 10525 10796 11036 11284 11514 11750 11962 9 10798 11123 11426 11697 12004 12275 12551 12820 13069 13344 10 11812 12180 12524 12828 13175 13440 13791 14087 14375 14663 11 12789 13194 13582 13926 14306 14653 14999 15327 15642 15969 12 13724 14172 14596 14984 15404 15784 16170 16535 16383 17280 13 14611 15107 15573 15997 16462 16883 17301 17706 18090 18476 14 15452 15980 16508 16975 17476 17940 19399 18837 19261 19684 15 16239 16835 17395 17910 18453 18954 19457 19935 20392 20855 16 16973 17622 18236 18797 19388 19932 20471 20993 21491 21966 17 17649 18355 19023 19638 20275 20867 21448 22007 22548 23084 18 18259 19031 19757 20425 21116 21754 22383 22984 23562 24142 19 18798 19642 20433 21158 21903 22595 23270 23919 24540 25156 20 19252 20180 21043 21834 22637 23382 24111 24806 25475 26133 21 19603 20635 21582 22445 23313 24115 24899 25647 26362 27068 22 20986 22036 22983 23923 24791 25632 26435 27203 27955 23 22387 23438 24464 25402 26308 27165 27990 28796 24 23789 24916 25940 26918 27884 28723 29583 25 25267 26395 27452 28454 29399 30317 26 26746 27911 28993 30010 30993 27 28262 29447 30548 31603 28 29798 31003 32142 29 31354 32596
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O & M Manual of Tawa Dam May 2020
30 32947 Gate Reservoir Level (feet) Opening 1158 1159 1160 1161 1162 1163 1164 1165 1166 (Feet) 1 1621 1651 1670 1690 1709 1747 1766 1796 1824 2 3149 3245 3340 3379 3398 3456 3514 3533 3590 3 4742 4838 4934 5030 5088 5146 5222 5280 5357 4 6278 6394 6528 6624 6739 6835 6912 6989 7104 5 7795 7930 8083 8218 8333 8486 8602 8678 8813 6 9274 9446 9619 9754 9926 10080 10253 10368 10502 7 10752 10925 11136 11290 11482 11674 11846 12019 12192 8 12154 12403 12614 12806 13018 13229 13440 13613 13848 9 13555 13805 14093 14285 14534 14765 14995 15206 15437 10 14938 15206 15494 15763 16013 16282 16531 16762 17030 11 16257 16589 16896 17165 17491 17760 18048 18298 18586 12 17562 17908 18278 18566 18893 19238 19256 19814 20122 13 18829 19213 19517 19949 20294 20640 21005 21293 21638 14 20070 20481 20903 21268 21677 22042 22406 22771 23117 15 21277 21721 22170 22573 22996 23424 23808 24173 24595 16 22449 22929 23411 23841 24301 24743 25190 25574 25997 17 23580 24100 24618 25081 25569 26049 26509 26957 27398 18 24678 25231 25789 26289 26809 27316 27815 28276 28781 19 25736 26329 26920 27460 28017 28556 29082 29581 30100 20 26749 27387 28019 28591 29188 29764 30232 30849 31405 21 27727 28401 29076 29689 30319 30935 31530 32089 32673 22 28662 29378 30090 30747 31417 32066 32701 33297 33913 23 29549 30313 31068 31761 32475 33164 33832 34868 35121 24 30390 31200 32003 32739 33489 34222 34931 35599 36292 25 31177 32041 32890 33673 34466 35236 35988 36697 37423 26 31910 32828 33731 34560 35401 36213 37002 37755 38521 27 32586 33562 34518 35401 36288 37148 37980 38769 39579 28 33197 34237 35251 36188 37129 38035 38915 39746 40593 29 33735 34848 35927 36922 37916 38876 39802 40681 41570 30 34190 35387 36538 37597 38650 39663 40671 41568 42505 31 34541 35841 37076 38208 39325 40397 41430 42409 43392 32 36192 37531 38747 39936 41073 42163 43196 44233 33 37882 39201 40475 41688 42839 43930 45020 34 39552 40929 42222 43450 44605 45754 35 41280 42676 43988 45216 46429 36 43027 44443 45755 47040 37 44794 46209 47579 38 46560 48033 39 48384 40 49992
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O & M Manual of Tawa Dam May 2020
Discharge Passing Through single Radial Gate for Different Reservoir Level and Gate Opening (Cumec)
Reservoir Level (m) Gate Opening (m) 343.81 344.12 344.42 344.73 345.03 345.34 345.64 345.95 346.25 346.56
0.30 9.94 12.86 15.26 17.30 19.14 20.76 22.29 23.81 25.12 26.19 0.61 22.80 28.12 32.54 36.39 39.90 43.07 46.13 48.93 51.62
0.91 38.06 45.39 51.71 57.20 62.18 66.88 71.22 74.56
1.22 55.36 64.53 72.46 79.49 86.00 92.00 97.69
1.52 74.47 85.29 94.78 103.30 111.12 118.48
1.83 95.26 107.60 118.56 128.42 137.62
2.13 117.54 131.42 143.68 154.89
2.44 141.36 156.37 170.16
2.74 166.47 183.01
3.05 192.92
Gate Reservoir Level (m) Opening (m) 346.86 347.17 347.47 347.78 348.08 348.39 348.69 349.00 349.30 349.61 0.30 27.67 28.71 29.96 31.09 32.03 33.16 34.21 35.11 35.88 36.98 0.61 54.17 56.38 58.64 61.05 63.20 65.19 67.37 69.29 70.99 72.83 0.91 79.26 82.86 86.34 89.76 93.08 96.28 99.39 102.48 106.22 107.97 1.22 103.07 107.97 112.81 117.43 121.79 126.24 130.48 134.51 138.36 142.18 1.52 125.39 131.79 137.93 143.91 149.46 154.95 160.44 165.60 170.38 175.34 1.83 146.14 154.07 161.75 169.02 175.93 182.62 189.16 195.56 201.50 207.36 2.13 165.29 174.86 184.03 192.84 201.05 209.09 222.49 224.27 231.43 238.46 2.44 182.56 193.97 204.79 215.12 224.86 234.21 243.30 251.93 260.15 268.42 2.74 197.82 211.27 223.93 235.91 247.15 258.02 268.42 278.41 287.81 297.13 3.05 219.17 226.53 241.23 255.05 267.93 280.34 292.23 303.53 314.32 324.79 3.35 220.62 239.39 256.49 272.32 287.08 301.09 314.52 327.34 339.43 351.27 3.66 249.33 269.35 287.59 304.35 320.24 335.30 349.66 363.25 376.39 3.96 279.29 300.44 319.61 337.42 354.41 369.00 385.53 400.20 4.27 310.27 332.47 352.77 371.72 389.55 407.76 422.88 4.57 342.41 365.63 386.98 406.83 425.43 443.27 4.88 375.57 399.83 422.09 442.73 462.41 5.18 409.77 434.95 457.97 479.69 5.49 444.89 470.85 494.95 5.79 477.96 507.81 6.10 517.75 Gate Reservoir Level (m) Opening (m) 349.91 350.22 350.52 350.82 351.13 351.43 351.74 352.04 352.35 352.65 0.30 37.07 39.13 39.70 40.83 41.85 42.42 42.96 43.49 44.03 45.14 0.61 74.30 76.60 78.83 79.37 81.55 83.70 84.81 86.45 87.53 89.17 0.91 110.21 113.47 116.18 118.53 121.25 123.40 126.69 128.30 130.48 132.66 1.22 145.32 149.34 153.17 155.88 160.39 163.11 166.36 170.18 172.34 175.62 1.52 179.53 184.48 189.04 192.84 197.74 202.24 206.06 209.86 214.22 217.47 1.83 212.69 218.66 224.16 228.72 234.72 239.59 245.20 249.56 253.89 259.33
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O & M Manual of Tawa Dam May 2020
2.13 244.71 251.82 258.36 263.86 270.60 276.57 282.55 288.69 293.59 299.03 2.44 275.81 283.85 291.52 298.03 305.71 312.50 319.53 326.04 332.72 338.73 2.74 305.77 314.97 323.55 331.22 339.92 347.59 355.40 363.02 370.07 377.86 3.05 334.48 344.90 354.64 363.25 373.07 380.58 390.52 398.90 407.05 415.21 3.35 362.14 373.61 384.60 394.34 405.10 414.93 424.72 434.01 442.93 452.19 3.66 388.62 401.31 413.31 424.30 436.19 446.95 457.88 468.22 463.91 489.32 3.96 413.74 427.78 440.98 452.98 466.15 478.07 489.91 501.38 512.25 523.18 4.27 437.55 452.50 467.45 480.68 494.87 508.00 549.32 533.40 545.41 557.39 4.57 459.84 476.71 492.57 507.15 522.53 536.72 550.96 564.50 577.44 590.55 4.88 480.62 499.00 516.39 532.27 549.01 564.41 579.67 594.46 608.56 622.01 5.18 499.76 519.76 538.67 556.09 574.12 590.89 607.34 623.17 638.49 653.67 5.49 517.04 538.90 559.46 578.37 597.94 616.00 633.82 650.83 667.20 683.63 5.79 532.30 556.20 578.60 599.13 620.22 639.82 658.93 677.31 694.90 712.34 6.10 545.16 571.43 595.87 618.27 641.01 662.10 682.75 702.43 721.37 740.00 6.40 555.10 584.32 611.13 635.57 660.15 682.86 705.06 726.24 746.49 766.48 6.71 594.26 623.99 650.81 677.42 702.00 725.82 748.56 770.30 791.60 7.01 633.93 663.69 692.74 719.30 744.96 769.23 792.59 815.41 7.32 673.63 705.54 734.54 762.23 789.59 813.34 837.70 7.62 715.48 747.42 777.35 805.73 832.49 858.48 7.92 757.36 790.35 820.99 849.79 877.62 8.23 800.29 833.85 865.02 894.90 8.53 843.79 877.91 910.16 8.84 887.85 923.02 9.14 932.96 Gate Reservoir Level (m) Opening (m) 352.96 353.26 353.57 353.87 354.18 354.48 354.79 355.09 355.40 0.30 45.90 46.75 47.29 47.86 48.39 49.47 50.01 50.86 51.65 0.61 89.17 91.89 94.58 95.68 96.22 97.86 99.51 100.04 101.66 0.91 134.28 137.00 139.72 142.43 144.08 145.72 147.87 149.51 151.69 1.22 177.77 181.06 184.85 187.57 190.83 193.55 195.73 197.91 201.16 1.52 220.73 224.55 228.89 232.71 235.96 240.30 243.58 245.73 249.56 1.83 262.61 267.48 272.38 276.20 281.07 285.43 290.33 293.59 297.38 2.13 304.46 309.36 315.34 319.70 325.13 330.57 335.44 340.34 345.24 2.44 344.16 351.21 357.19 362.63 368.63 374.60 380.58 385.48 392.13 2.74 383.83 390.91 399.07 404.51 411.56 418.10 424.61 430.59 437.13 3.05 423.00 430.59 438.74 446.36 453.44 461.05 468.11 474.65 482.24 3.35 460.35 469.75 478.44 486.06 495.29 502.91 511.06 518.14 526.30 3.66 497.30 507.10 517.58 525.73 534.99 544.76 545.27 561.07 569.79 3.96 533.18 544.05 552.66 564.89 574.66 584.46 594.80 602.95 612.72 4.27 568.32 579.96 591.91 602.24 613.82 624.16 634.47 644.80 654.60 4.57 602.50 615.07 627.78 639.20 651.17 663.29 674.17 684.50 696.45 4.88 635.68 649.28 662.93 675.10 688.13 700.64 713.30 724.18 736.15 5.18 667.71 682.44 697.10 710.21 724.03 737.63 750.65 763.34 775.82 5.49 698.80 714.46 730.26 744.42 759.15 773.50 787.63 800.69 814.99
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O & M Manual of Tawa Dam May 2020
5.79 728.76 745.55 762.29 777.58 793.35 808.62 823.51 837.64 852.34 6.10 757.45 775.51 793.41 809.61 826.51 842.82 856.07 873.55 889.29 6.40 785.14 804.23 823.34 840.70 858.54 875.98 892.83 908.66 925.20 6.71 811.62 831.89 852.05 870.66 889.63 908.01 925.99 942.87 960.31 7.01 836.73 858.37 879.75 899.37 919.59 939.10 958.02 987.35 994.52 7.32 860.55 883.49 906.22 927.07 948.30 969.06 989.14 1008.05 1027.68 7.62 882.83 907.30 931.34 953.51 975.97 997.77 1019.07 1039.14 1059.70 7.92 903.59 929.59 955.16 978.63 1002.44 1025.44 1047.78 1069.10 1090.79 8.23 922.73 950.37 977.44 1002.44 1027.56 1051.91 1075.47 1097.82 1120.75 8.53 940.03 969.48 998.20 1024.73 1051.38 1077.03 1101.95 1125.48 1149.47 8.84 955.27 986.79 1017.34 1045.51 1073.66 1100.85 1127.07 1151.96 1177.13 9.14 968.15 1002.05 1034.64 1064.63 1094.45 1123.13 1151.67 1177.07 1203.61 9.45 978.09 1014.90 1049.88 1081.93 1113.56 1143.92 1173.17 1200.89 1228.72 9.75 1024.84 1062.76 1097.19 1130.86 1163.06 1193.92 1223.17 1252.54 10.06 1072.70 1110.05 1146.12 1180.47 1213.07 1243.96 1274.82 10.36 1119.99 1158.98 1195.59 1230.37 1263.07 1295.61 10.67 1168.92 1208.45 1245.60 1280.37 1314.72 10.97 1218.39 1258.49 1295.64 1332.02 11.28 1268.42 1308.49 1347.29 11.58 1318.43 1360.14 11.89 1370.08 12.19 1415.62
The inflow forecasting is an essential feature of the gate operation. The river gauge and discharge station on the u/s of the reservoir at Matkuli and Sohagpur on the Denwa and Tawa river respectively are installed at 48 km and 42 km. u/s of the dam. At present there is no means of communication (such as telephone/wireless) to the dam site. The inflow reports from the two above stations can be collected through special messenger.
There are also rain gauge stations located at following places within the catchment area.
1. 'Betul
2. Sohagpur
3. Bori
4. Khapa
5. Pattan
6. Tamla
7. Kala Akhar
8. Matkuli
9. Panchmarhi
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O & M Manual of Tawa Dam May 2020
10. Sarni
11. Tawa Nagar.
Presently the hourly information from Panchmarhi and Tawa Nagar are communicated at dam site during monsoon.
The information of heavy rainfall from Betul and Sarni and releases from Sarni dam should be obtained from Itarsi police station and DSM.E.B, Itarsi respectively with should be communicated to the dam site through canal telephone and during its interruption through special messenger. The Executive Engineer, Tawa Project Division, Itarsi will be responsible for intimation the rainfall till the wireless stations are fixed at these stations.
The wireless stations are proposed at above 10 stations except at Sarni and at Itarsi. The gate operation study is based considering the rise in water level above FRL. The rainfall figures have also been considered for the purpose of assessment of inflow and corresponding probable rise of water level in the reservoir, based on the irrigation requirement for next irrigation seasons. The FRL and MWL of the Tawa reservoir are fixed at 1166 ft. and 1170.25 ft respectively.
Accordingly, gates are supposed to be operated when water level in the reservoir reaches RL 1166 ft. The moderated discharge of spillway is 7.50 lakh cusecs. It may be mentioned that Hoshangabad city on the bank of Narmada River is about 52 km d/s of the dam. It is observed that when the Narmada river is flooding i.e. flowing at the level of 964 ft or above at Sethani Ghat, and if the spillway of Tawa reservoir is operated during this period, there are fair chance of the populated area of Hoshangabad city to be submerged. In order f to stagger the out flow from the reservoir with flood in Narmada river, the rulling levels for Tawa reservoir should be 1163 ft. up to 15th Aug. and 1163 ft from 15th August to 31st August.
After 15th/31st August, the gates should be operated after the reservoir fills up to FRL subjected to the conditions that there is flood in Narmada River at Hoshangabad. In case there is no flood in Narmada river, the water level can be maintained at the level as decided by the Superintending Engineer.
It has been further assumed that when reservoir is full FRL the designed flood starts approaching the reservoir at the same time.
Expected hourly discharge has been worked out from the design hydrograph adopted for the design of spillway. The hourly inflow data are then calculated. The capacity curve on an enlarged scale between FRL and MWL has also been plotted. (Annexure V, Pt. 8, 9).
Considering the hourly inflows, trials were made and suitable sequence of gate operation worked out which is as per the table enclosed. This provides range of average hourly rise
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O & M Manual of Tawa Dam May 2020 reservoir level due to this discharge and corresponding operation of gates to dispose of flood, without allowing the water level either to cross MWL or overtop the gates, FRL is however maintained.
For assessment of probable rise in reservoir level, arrangement to obtain daily/hourly rainfall figures of Tawa Nagar, Pachmarhi and Betul stations, located in the catchment area be made. For this purpose, 24 hourly runoff has been worked out with a run off factor as 0.8 based on this factor the run off rainfall in million etc. has been tabulated for 24 hourly rainfall.
2.3.3.Operating instructions for gates and hoists of irrigation outlet. The gates are raised or lowered as and when it is desired to release water for irrigation purposes. The gates are operated manually. Skilled and authorized personnel need only be allowed to operate the gates.
The maintenance instructions shall be strictly followed to ensure smooth and troublefree operation of gates.
All the head regulator gates, hoists and allied structures are being inspected as given below before every crop season before operating them.
O & M Manual of Tawa Dam May 2020
Head Regulator for Left Bank Main Canal
Cross Regulator cum Escape at CH 15 of Left Bank Main Canal
O & M Manual of Tawa Dam May 2020
Inspection and testing of Vertical Gates (for Irrigation sluices at RBC/LBC)
Embedded parts
All debris and blockages over the embedded parts (sill beam, side seal seats, top seal seat, guide and wheel track) should be cleared. The surfaces of embedded parts should be checked for pitting and should be suitably rectified if pitting is noticed. The welding of stainlesssteel plates on side seal seat, sill beam, top seal seat and wheel track should be checked for weld cracks and shall be repaired if crack is noticed in weld joint. Due to wear and tear, surface may become uneven and may have indentations such as roller mark over the track path. The entire gate track should be thoroughly checked so that there is no obstruction for travel of gate.
Gate leaf with accessories.
All debris and scaling should be removed from the gate leaf. The skin plate and other components should be tapped lightly by hammer to examine the soundness.
The weld joint between skin plate to horizontal stiffeners and end vertical girders, end vertical girders to horizontal stiffeners and hoist bracket to top horizontal stiffeners should be checked thoroughly and suitably rectified if defects are noticed. The hoisting connection on the gate should be checked for shearing and wear and tear and should be rectified if any defect is noticed.
Alignment of seals should be checked by means of feeler gauge. The rubber seals should be checked for twist, over tapping, bulb flatness, deformation etc. All un-desirable materials on the rubber seal and between the rubber seal and skin plate should be cleaned thoroughly and should be free from oil and grease etc. All nuts and bolts fixing the rubber seal to the skin plate should be checked for slackness and rusting and should be tightened/replaced as considered necessary. Rubber seals when damaged or found leaking profusely should be adjusted, repaired or replaced as considered necessary.
The wheel pins and bushes should be lubricated properly.
Each wheel should be checked for improper adjustment of wheel pin and retainer plate and shall be rectified by adjusting the retainer plate which is provided with eccentricity adjustment. Whenever necessary the wheel assembly should be opened for rectification of defects. The brass spacer rings should be checked for wear and shall be replaced if found worn out. No defective part shall, however, be refitted. The guide shoes shall be inspected for any damage or bending and shall be repaired if damaged or bent. The welding between the end vertical girder and guide shoe should be checked and defects if found should be suitably rectified.
The hoist pin should be lubricated. All nuts, bolts and screws etc. should be checked
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O & M Manual of Tawa Dam May 2020 for slackness and should be tightened if necessary. The wheel assemblies should be adjusted by the eccentric arrangement provided in retainer plates to ensure that all wheels bear uniformly on wheel tracks, particularly in closed position of gates.
Restraining Arrangements.
The welding of eye piece and flanges to the stems should be checked thoroughly and defects, if noticed, shall be rectified suitably. The split bushes and the stems should be lubricated properly. All bolts and nuts should be checked for slackness and shall be tightened if necessary. The defective Bolts, nuts and screws etc. should be replaced. The stem nuts should be checked for straightness and shall be rectified if found bent. The screw rod and the intermediate stems should be checked for binding and rectified it found bent.
Testing.
1) The gate should be tested for smooth travel throughout the groove without appreciable swing. All wheels shall always be in contact with the wheel track face during the entire travel.
2) The gate should neither be subjected to under pressure nor any extra effort be needed to operate the gate in no load condition.
3) There should not be undue vibration in the gate and structure during its travel while on load. If undue vibrations are noticed the reasons should be investigated and the reservoir level at which this occurs should be recorded. The gate shall not be kept in the position where vibration is noticed until remedial measures are taken.
4) In closed position, the gate should be watched against any leakage under maximum head condition during the year.
2.3.4.Methodology to work out gate opening for passing the required discharge through the irrigation outlet at different reservoir levels.
Tawa dam having two intake structure one on left bank and one on right bank of Tawa River. Right bank canal Off takes from village Kamti in Sohagpur Tehsil about 16 km away from Tawa Dam through 4.0 km long tunnel and 3.6 km open cut. Left bank canal offtakes from saddle dam no 1.
(a) Right Bank Canal: Right bank canal Off takes from village Kamti in Sohagpur Tehsil about 16 km away from Tawa Dam through 4.0 km long tunnel and 3.6 km open cut.
Approach channel; A 337m long approach channel has been constructed to connect Intake structure with
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O & M Manual of Tawa Dam May 2020 the reservoir. Cut and cover section has been provided due to likely danger of sloughing of slopes and resultant silting in the approach channel which passes through shale and siltstone. The shape and size of this section has been kept the same as that of tunnel. A Trash rack has been provided at the entry.
The salient features of approach channel are as under:
1. Shape : Horse shoe 2. Finished Diameter : 3.81m 3. Length : 337.00 m 4. Bed Slope : 1 in 184
Intake Structure & Tunnel: The approach channel enters into a double D-shaped reinforced concrete intake well. The diaphragm of the intake structure has three service and three emergency gates. The water level in upstream chamber will be the same as in the reservoir whereas the water level in downstream chamber will be regulated by the gate opening to drive required discharge in the tunnel. The energy dissipation arrangement consisting of stilling basis, chute blocks and sill are provided to the floor of the downstream chamber.
The salient features of intake structure are as under: 1. Shape : Double “D” 2. Finished Diameter : 18 m 3. Height : 27.48 m
The salient features of tunnel are as under:
1. Shape : Horse shoe 2. Finished Diameter : 3.81m 3. Length : 3960 m 4. Bed Slope : 1 in 6000 5. Full Supply Discharge : 26.96 cumecs (951 cusecs)
Discharge through the RBC Intake well is calculated by formula given below:
푄 = 퐴 × 0.70 2푔ℎ (cusec) Where, A = Area of opening of gate g = Gravitational constant (32.20 in FPS unit) h = difference of head of water level on upstream and downstream
Right Bank Exit Channel: Tawa Right Bank exit channel starts from the downstream end of the tunnel and meets
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O & M Manual of Tawa Dam May 2020
Langha Nalla at Ch 104. The complete exit channel is stipulated as an open cut channel. However RCC cut and cover section has to be provided in certain reaches due to likely danger of sloughing of slopes.
The salient features of exit channel are as under:
1. Total Length : 3.6 km (including Langha nalla up to Pickup Weir 2. Maximum Cutting : 19 m 3. Bed width of channel : 4.85 m 4. Bed Slope : 1 in 3500 5. Full Supply Discharge : 26.96 cumecs (951 cusecs)
RBC Pickup Weir:
Pickup Weir is constructed across the Langha Nalla. Bagra Branch Canal (BBC) and Pipariya Branch Canal (PBC) starts from the Pickup Weir.
The salient features of exit channel are as under:
1. Length of Pickup Weir : 60 m 2. Crest Level of BBC & PBC : 336 m 3. Crest level of overflow portion : 337.44 m 4. Top level of the road : 341.675 m 5. Upstream floor level : 334 m 6. Downstream floor level of stilling Basin : 334 m 7. Full Supply Discharge of BBC : 13.224 cumecs (467 cusecs) 8. Full Supply Discharge of PBC : 13705 cumecs (484 cusecs)
For Bagra Branch Canal and Pipariya Branch Canal discharge is calculated using formula given below with the Depth of water at SWF at system Pickup Weir.
푄 = 1.70× 퐶 × 퐵 × 퐷( ⁄ ) (cumec)
Where, C = constant (value taken equal to 1) B = Bed width at throat (3.75m) D= Depth of water at SWF
Discharge value is given in tabular form below.
S. No. depth of water at SWF (m) discharge (cumec) discharge (cusec)
1 0.20 0.570 20 2 0.30 1.019 36 3 0.40 1.611 57
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O & M Manual of Tawa Dam May 2020
4 0.45 1.924 68 5 0.50 2.254 80 6 0.55 2.600 92 7 0.60 2.963 105 8 0.65 3.341 118 9 0.70 3.734 132 10 0.75 4.141 146 11 0.80 4.562 161 12 0.85 5.012 177 13 0.90 5.443 192 14 0.95 5.918 209 15 1.00 6.375 225 16 1.05 6.859 242 17 1.10 7.355 260 18 1.15 7.862 278 19 1.20 8.380 296 20 1.25 8.909 315 21 1.30 9.449 334 22 1.35 10.024 354 23 1.40 10.560 373 24 1.45 11.131 393 25 1.50 11.712 414 26 1.55 12.318 435 27 1.60 12.884 455 28 1.63 13.224 467 29 1.65 13.535 478 30 1.67 13.705 484 31 1.70 14.102 498 32 1.75 14.781 522 33 1.80 15.395 544
(b) Left Bank Canal: The Left Bank main canal off takes from saddle no. I, situated on left side of main dam. The design of intake structure for left bank canal was supplied by C.W.C. P C 4 Nos. of R.C.C. duets each of size of 2.438 m x 2.743 m (8'x9') and have been provided to pass a maximum discharge of 113.27 cumec (4000 cusecs). The length of Barrel is 100.584 m (330') have been divided in sections of length varying to take in to account the varying geology of the foundation.
The intake structure has been provided with 4Nos. of steel service gate of 2.286 m (W) x 2.438 m (H) (7.5'x8') with 4 Nos. of emergency gate of same size and Rope Drum hoisting arrangement has also been provided.
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O & M Manual of Tawa Dam May 2020
For LBMC actual discharge for canal is calibrated with the Gauge installed at CH 90. Discharge has been calibrated with height of the water in respective gauge Height, Which is given below in tabular form.
S. No. Gauge (feet) Outlet Discharge (Cusec) Gauge (m) Outlet Discharge (Cumec)
1 1.0 55 0.305 1.557 2 1.1 65 0.335 1.841 3 1.2 75 0.366 2.124 4 1.3 85 0.396 2.407 5 1.4 97 0.427 2.747 6 1.5 108 0.457 3.058 7 1.6 121 0.488 3.426 8 1.7 134 0.518 3.794 9 1.8 147 0.549 4.163 10 1.9 161 0.579 4.559 11 2.0 176 0.610 4.984 12 2.1 191 0.640 5.409 13 2.2 207 0.671 5.862 14 2.3 223 0.701 6.315 15 2.4 239 0.732 6.768 16 2.5 256 0.762 7.249 17 2.6 274 0.792 7.759 18 2.7 292 0.823 8.269 19 2.8 311 0.853 8.807 20 2.9 330 0.884 9.345 21 3.0 349 0.914 9.883 22 3.1 369 0.945 10.449 23 3.2 390 0.975 11.044 24 3.3 411 1.006 11.638 25 3.4 432 1.036 12.233 26 3.5 454 1.067 12.856 27 3.6 476 1.097 13.479 28 3.7 499 1.128 14.130 29 3.8 523 1.158 14.810 30 3.9 546 1.189 15.461 31 4.0 571 1.219 16.169 32 4.1 595 1.250 16.849 33 4.2 621 1.280 17.585 34 4.3 646 1.311 18.293 35 4.4 672 1.341 19.029 36 4.5 699 1.372 19.793 37 4.6 726 1.402 20.558 38 4.7 753 1.433 21.323
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O & M Manual of Tawa Dam May 2020
39 4.8 781 1.463 22.115 40 4.9 810 1.494 22.937 41 5.0 839 1.524 23.758 42 5.1 868 1.554 24.579 43 5.2 898 1.585 25.429 44 5.3 928 1.615 26.278 45 5.4 959 1.646 27.156 46 5.5 990 1.676 28.034 47 5.6 1021 1.707 28.912 48 5.7 1053 1.737 29.818 49 5.8 1086 1.768 30.752 50 5.9 1119 1.798 31.687 51 6.0 1152 1.829 32.621 52 6.1 1186 1.859 33.584 53 6.2 1221 1.890 34.575 54 6.3 1255 1.920 35.538 55 6.4 1291 1.951 36.557 56 6.5 1326 1.981 37.548 57 6.6 1363 2.012 38.596 58 6.7 1399 2.042 39.615 59 6.8 1436 2.073 40.663 60 6.9 1474 2.103 41.739 61 7.0 1512 2.134 42.815 62 7.1 1551 2.164 43.919 63 7.2 1590 2.195 45.024 64 7.3 1629 2.225 46.128 65 7.4 1669 2.256 47.261 66 7.5 1709 2.286 48.393 67 7.6 1750 2.316 49.554 68 7.7 1791 2.347 50.715 69 7.8 1833 2.377 51.905 70 7.9 1875 2.408 53.094 71 8.0 1918 2.438 54.312 72 8.1 1961 2.469 55.529 73 8.2 2005 2.499 56.775 74 8.3 2049 2.530 58.021 75 8.4 2094 2.560 59.295 76 8.5 2139 2.591 60.570 77 8.6 2184 2.621 61.844 78 8.7 2230 2.652 63.147 79 8.8 2277 2.682 64.477 80 8.9 2324 2.713 65.808 81 9.0 2371 2.743 67.139 82 9.1 2419 2.774 68.498 83 9.2 2467 2.804 69.858
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84 9.3 2516 2.835 71.245 85 9.4 2566 2.865 72.661 86 9.5 2615 2.896 74.049 87 9.6 2666 2.926 75.493 88 9.7 2717 2.957 76.937 89 9.8 2768 2.987 78.381 90 9.9 2820 3.018 79.854 91 10.0 2872 3.048 81.326 92 10.1 2925 3.078 82.827 93 10.2 2978 3.109 84.328 94 10.3 3032 3.139 85.857 95 10.4 3086 3.170 87.386 96 10.5 3141 3.200 88.943 97 10.6 3196 3.231 90.501 98 10.7 3252 3.261 92.086 99 10.8 3308 3.292 93.672 100 10.9 3364 3.322 95.258 101 11.0 3422 3.353 96.900 102 11.1 3479 3.383 98.514 103 11.2 3537 3.414 100.157 104 11.3 3596 3.444 101.827 105 11.4 3655 3.475 103.498 106 11.5 3715 3.505 105.197 107 11.6 3775 3.536 106.896 108 11.7 3836 3.566 108.623 109 11.8 3897 3.597 110.351 110 11.9 3959 3.627 112.106 111 12.0 4021 3.658 113.862 112 12.1 4084 3.688 115.646 113 12.2 4147 3.719 117.430 114 12.3 4211 3.749 119.242 115 12.4 4275 3.780 121.055 116 12.5 4340 3.810 122.895 117 12.6 4405 3.840 124.736 118 12.7 4471 3.871 126.605 119 12.8 4537 3.901 128.474 120 12.9 4604 3.932 130.371
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O & M Manual of Tawa Dam May 2020
LBMC of Tawa Dam
LBMC Intake
O & M Manual of Tawa Dam May 2020
Branch Canal of RBC
2.3.5.SafetyAspects:
The safety and security of dam against the structural damages by vandals, public and unauthorized operation of outlet gates is of paramount importance. The Division has formed the water users’ association among the cultivators. The combined effort of the both dam authorities and water users’ association ensuresproper O & M of the irrigation outlet. The water users’ association is imparted capacity building training in this regard from time to time by WALMI, Govt. of Madhya Pradesh.
2.4. Emergency Operation: The emergency operation will be carried out following the Emergency Action Pan (EAP). The emergency conditions are outlined in Chapter 4 under clause 4.2.1 on Immediate Maintenance. The EAP together with this Manual will be available at site at all times.
2.5. Reservoir Capacities: The reservoir capacity may reduce with time because of reservoir sedimentation. Bathymetric survey on a periodic basis is to be considered after every 10 years.
O & M Manual of Tawa Dam May 2020
2.6. Record Keeping: Following records of reservoir operations are being maintained:
1. Rainfall record on daily basis throughout the year. 2. Reservoir levels on daily basis during non-monsoon and hourly basis during monsoon. 3. Depth of outflow over the spillway on hourly basis during monsoon. 4. Estimated spillway outflows during monsoon on hourly basis. 5. Irrigation releases. 6. Water audit register to be maintained for estimating the inflows on hourly basis during monsoon and daily basis during non-monsoon by accounting all the releases/outflows and the incremental change in storage in the reservoir. 7. All operating procedures
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O & M Manual of Tawa Dam May 2020
CHAPTER 3.PROJECT INSPECTION.
An effective inspection programme is essential for identifying problems and providing safe performance of the dam.
The current practice of Inspection is adopted as per Madhya Pradesh Water Resources Department, Operation and Maintenance series technical circular no. 3, “August 2015, Periodical (Bi-annual) Inspection of Dams (Head Works)”.
3.1. Objective of Dam inspection: The main purpose of dam safety inspections is to determine whether the structural and operational aspects of the dam and its component parts are functioning safely in accordance with the design and established standard/ acceptable practices. It helps to identify deficiencies or concerns that potentially affect the safety of the dam and to take corrective actions to remedy those deficiencies before serious consequences develop.
Detailed description on project inspections is available in the Guideline for Safety Inspection of dams(DocNo.CDSO_GUD_DS_07_ v1.0), CWC 2018 (https://damsafety.in/ecm includes/PDFs/Guidelines_for_Safety_Inspection_of_Dams.pdf). However an overview of the various types of inspections to be carried out in Tawa dam is given below. Note that for uploading Inspection Data into DHARMA, the Inspection Instructions & Forms given in the aforementioned Guideline for Safety Inspection of Dams should be used.(see Appendix I)
3.2. Types of Dam Safety Inspections: The type of inspection to be conducted will depend on the purpose of the inspection. Dam safety inspections are conducted to determine the status of a dam and its features relative to its structural and operational safety.
Four types of dam safety inspections are to be carried out. They are:
1) Informal inspections
2) Scheduled inspections
3) Special (unscheduled) inspections
4) Comprehensive evaluation inspections.
3.2.1. Informal Inspections The informal inspections are performed by the Engineer-in-charge of the dam and his staff while carrying out their regular duties. Informal inspections assist in a continuous surveillance of the dam which is critical to proper operation and maintenance of the dam. They consist of frequent inspections for observing the general issues/problems and functioning of
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O & M Manual of Tawa Dam May 2020 the dam and appurtenant structures. The informal inspections are important and performed at every available opportunity. The informal inspections are not as detailed as comprehensive, scheduled, and special inspections. They require that a formal report be submitted to the dam authorities only if a condition is detected that might endanger the dam.
3.2.2. Scheduled Inspections: Scheduled inspections are performed to gather information on the current condition of the dam and its appurtenant works. The scheduled inspections consist of pre-monsoon and post monsoon inspections and other scheduled inspections. The Pre- & Post monsoon inspections are conducted by field engineers every year as per the inspection schedule below.
The deficiencies, thus noticed, and shall be endorsed to State Dam Safety Organization for scrutiny and suggestion for possible remedial measures.
Inspection Schedules
Type of Inspection Last date for
Completion of inspection Sending inspection reports to SDSO
Pre- monsoon 15th May 15th June
Post-monsoon 15th November 31st December
(Note – To be conducted by Executive Engineer, Tawa Division Itarsi and Superintending Engineer, Water Resources Circle, Hoshangabad)
Other scheduled inspections are conducted at least once in every 3 years by the engineers of State DSO along with Geologist and representative of Mechanical Wing.
All scheduled inspections are to be carried out as per the Guideline for Safety Inspection of dams (Doc No. CDSO_GUD_DS_07_ v1.0), CWC 2018 (https://damsafety.in/ecm- includes/PDFs/Guidelines_for_Safety_Inspection_of_Dams.pdf).These inspections will include the following components as a minimum:
1. Review of the past inspection reports, Monitoring data & photographs, Maintenance records and other pertinent data. 2. Inspection of the dam and its appurtenant works. 3. Preparation of a report with relevant documentation and photographs.
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3.2.3. Special (Unscheduled) Inspections:
Special inspections are performed to resolve specific problems of the dam. This is performed by an Independent Expert Panel or Dam Authorities. Special inspections are not regularly scheduled activities but are usually made before or immediately after the dam or appurtenant works have been subjected to unusual events or conditions, such as an unusually high flood or a significant earthquake. Japan Water Agency (JWA) has developed an excellent system of carrying out inspections after an earthquake event. For details refer “Inspection Manual for Dam Field Engineers after Seismic Events, Ichari Dam, Uttarakhand(CDSO_GUD_DS_0_v1.0, September2017). The manual is available at the followinglink:https://damsafety.in/ecm- includes/PDFs/Inspection_Manual_for_Dam_Field_Engineers_After_Seismic_Events.pdf.
3.2.4.Comprehensive Evaluation Inspections:
For comprehensive dam safety evaluation an independent panel of experts known as Dam Safety Review Panel(DSRP), is to be set up by the MPWRD which shall consist of experts from the fields of Geology, Hydrology, Designs, and Construction for determining the condition of dam and appurtenant works. The main objective of the DSRP is to carry out an independent expert review of the overall health status of the dam and to propose remedial action, prior to the initiation of rehabilitation activities. The panel would undertake the evaluation of the dam once in 10years or after occurrence of any extreme events, if required. The State Dam Safety Organization arranges the meetings and site visits of DSRP. Terms of Reference (ToR) of comprehensive dam safety evaluation shall include but will not to be limited to: 1. General assessment of hydrologic and hydraulic conditions, review of design flood, flood routing for revised design flood and mitigation measures. 2. Review and analysis of available data of dam design, construction, operation maintenance and performance of dam structure and appurtenant works. 3. A visual inspection or field examination of the dam, its appurtenant works, and the surrounding areas. 4. Review of the instrumentation records and structural behavior reports, if any. 5. Evaluation of procedures for operation, maintenance and inspection of dam and to suggest improvements / modifications. 6. Evaluation of any possible hazardous threat to the dam structure such as dam abutment slope stability failure or slope failures along the reservoir periphery.
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3.2.4.1. Details to be provided to DSRP before inspection: All relevant details / data / drawings for the dam project to be examined by the DSRP shall be provided at least 3 months in advance of the proposed visit.
This will include:- a) General Information
1. Scope of project 2. Basic data and salient features 3. Issues related to safety of dam including any earlier dam safety related incidents 4. Emergency preparedness – Communications, Auxiliary power, Downstream Warning system and security at site. b) Hydrology
1. Description of drainage basin 2. Original inflow design flood, MWL and routed outflow 3. Revised design flood and flood routing study carried out by the project authorities and approved by CWC. 4. Area – Capacity curves. c) Geology
1. Dam site geology including geological reports. 2. Any Special problems and their treatment. 3. Reservoir competency as per geological report. 4. Slope stability issues along reservoir rim. d) Drawings of the dam and HM works
1. Layout plan 2. Upstream & Downstream Elevation. 3. Cross – Sections of the Dam and Spillway 4. Foundation treatment details 5. Junction between Earthen embankment & Concrete/Masonry abutment of spillway. 6. Irrigation Outlet details 7. Layout details of Gates and Hoists of Irrigation outlet 8. Instrumentation details e) Dam and Spillway
1. Geological reports 2. Special problems encountered, if any.
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3. Foundation treatment including treatment of faults / shear zones / weak zones, curtain / consolidation grouting, drainage provisions, any other special treatment, cut-off trench, etc. 4. Design criteria and result of stability analysis 5. Adequacy of design – from dam safety considerations 6. Hydraulic design of Spillway 7. Pre-construction material testing reports including adequacy of field and laboratory investigations, appropriateness of materials selected etc. 8. Post-construction testing reports, if any,
3.2.4.2.Field Inspection – Observation & Recommendations regarding Remedial Measures: Each component of the project is inspected, evaluated and specific problems are to be brought out. Recommendations for necessary remedial measures need to be included in the panel’s report.
Various project components to be inspected include: a) Dam
1. Upstream face 2. Downstream face 3. Top of dam 4. Structural behaviour as observed visually and as per evaluation of instrumentation data (any visible cracking, deflections etc.) 5. Seepage assessment 6. Condition of natural / excavated slopes in the abutments, both on u/s and d/s of the dam. 7. Any specific problems / deficiencies. b) Surplus Escape (Spillway)
1. Civil structure 2. Spill channel, drop structures etc. 3. Downstream safe carrying capacity of river / channel c) River / Canal Outlets
1. Civil structures 2. Conduits / outlets through Embankment dam. d) Flood Hydrology
1. Extent & Sufficiency of data available
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2. Method used for estimating the design flood. 3. Design flood review study. 4. Flood routing studies with the revised flood. 5. Adequacy of free board available. f) Miscellaneous services / facilities
1. Access Roads 2. Communication facilities (Telephone, Mobile etc.)
3.2.4.3.Components Involved A comprehensive evaluation inspection of a dam typically consists of five components:
1. Project records review (i.e. study of all design / construction records / drawings, history of the dam’s performance, past inspection notes / reports, notes on distress observed etc.). 2. Inspection of the dam and its appurtenant works. 3. Preparation of a detailed report of the inspection. 4. Education and training of the dam engineers on the issues observed during dam inspection, identification of potential dam failure modes & to carryout additional field investigations & laboratory testing as required. Dam engineers should be made part of the inspection process so that they take ownership and are committed to implementing the recommended remedial measures. 5. Design studies e.g. review of design flood, checking of the adequacy of spillway capacity, freeboard requirements, dam stability, any special study as required & submission of the report.
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O & M Manual of Tawa Dam May 2020
CHAPTER 4.PROJECT MAINTENANCE.
A good maintenance program will protect a dam against deterioration, prolong its life, and greatly reduce the chance of failure. The dam authorities and operating and main- tenance personnel must be aware of the potential problems which can lead to failure of a dam. Nearly all the components of a dam and its materials are susceptible to damage and deterioration if not well maintained.
This Manual is to be referred to mainly for routine maintenance works.
The designs, drawings and technical specifications for most of the condition based and immediate maintenance works will need to be provided by the State DSO/Designs offices. Guidance of experienced engineers/panel of experts will need to be taken.
4.1. Maintenance Plan: Timely maintenance assures that a dam and reservoir would remain in a good working condition and prevents more harmful conditions from developing.
4.2. Maintenance Priorities: Maintenance activities need to be prioritized.
4.2.1. Immediate Maintenance The following conditions are critical and require immediate action by Dam authorities.
Evidence of excessive seepage through the Earth dam, exiting on its downstream face or anywhere on the downstream of the dam and increasing in volume.
Earth Dam showing signs of piping or internal erosion indicated by increasingly cloudy seepage or other symptoms.
An increase in the reservoir level to near the top of the dam.
Water overtopping the earthen dam.
An Earth dam about to be breached by erosion, slope failure etc.
An EAP is to be activated when any of the above conditions are noted. Summary of the alert conditions during emergency are given in Appendix–IV.
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4.2.2. Condition based maintenance The following maintenance works are undertaken as soon as possible after the defective condition is noted which may include:
Removal of all vegetation and bushes from the dam and restoring any eroded areas and to establish good grass cover.
Fill animal burrows.
Repair livestock trails and fences to keep livestock off dam.
Restore and reseed eroded areas and gullies on embankment dams.
Repairs of any cracks in earth dam.
Cleaning and repair of drains.
Repair of defective gates and other hydro-mechanical equipment.
Repair any concrete or metal components that have deteriorated.
Repair for any damages on the spillway including its glacis, piers, training walls/abutments, energy dissipaters, downstream fall structures, spill channel etc.
4.2.3. Routine Maintenance Following tasks are performed on a continuous basis. These include:
To measure flow rate of seepage and turbidity from Earth dam. Maintain turfing on d/s slope of Earth dam. Repair any gullies formation in Earth dam Clean the surface drains on the downstream slope of Earth dam Remove silt from the d/s toe drain and outfall drains of Earth dam. Rodent damage: Remove or destroy the rodents and fill any burrow holes immediately. Upstream slope riprap: Repair the upstream riprap disturbed due to high water or wave action. Noxious weeds: Remove any noxious weeds on and around the dam embankment, reservoir, and spillways. Remove any vegetation growing on the earth dam and spillway. Ensure approach road to the dam to be in good condition. Test the communication equipment. Checking the operation of instruments in the dam.
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Servicing and lubrication of gates of Head Regulator, Keeping the gate slots clear of silt/debris.
4.3. Procedures for undertaking routine Maintenance works:
4.3.1. Earth work in earthen dam The surfaces of an earthen dam may deteriorate due to several reasons. For example, wave action may cut into the upstream slope, vehicles may cause ruts in the crest or slopes, trails left by livestock can result in erosion, or runoff waters may leave erosion gullies on the downstream slope. Other special problems, such as shrinkage cracks or rodent damage, may also occur. Damage of this nature must be repaired constantly.
The maintenance procedures to be described in the O&M Manual will be used for repairs of routine earthwork problems. However, this section is not intended to be a technical guide, and the methods discussed should not be used to solve serious problems. Conditions such as embankment slides, structural cracking, and sinkholes threaten the immediate safety of a dam and require immediate repair under the directions of experienced engineers/Expert panels.
The material selected for repairing embankments should be free from vegetation, organic materials, trash, and large rocks.
If flow-resistant portions of an embankment (such as impervious core) are being repaired, materials that are high in clay or silt content should be used. If the area is to be free draining or highly permeable (such as pervious shell of an embankment dam) the material should have a higher percentage of sand and gravel. It is usually satisfactory to replace or repair damaged areas with soils like those originally in place.
An important soil property affecting compaction is moisture content. Soils that are too dry or too wet do not compact well. One may test repair material by squeezing it into a tight ball. If the sample keeps its shape without cracking and falling apart (which means it is too dry), and without depositing excess water onto the hand (which means it is too wet), the moisture content is near the proper level.
Before placement of earth, the repair area needs to be prepared by removing all inappropriate material. All vegetation, such as bushes, roots, and tree stumps, along with any large rocks or trash need to be removed. Also, unsuitable earth, such as organic or loose soils, should be removed, so that the work surface consists of exposed, firm, clean embankment material.
Following cleanup, shape and dress the affected area so that the new fill can be compacted to the level specified in the technical specifications. Also it should properly key
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O & M Manual of Tawa Dam May 2020 with the existing fill for which benches of suitable dimensions need to be made in the existing fill. Further trim the slopes and roughen the surfaces by scarifying or plowing to improve the bond between the new and existing fill and to provide a good base to compact against.
Place soils in loose layers up to 20 centimeters thick and compact manually with pneumatic tampers or mechanically to form a dense mass free from large rock or organic material. Keep soil moisture in the proper range. The fill should be watered and mixed to the proper wetness and allowed to dry if too wet.
Erosion is one of the most common maintenance problems in embankment structures. Erosion is a natural process and its continuous forces will eventually wear down almost any surface or structure. Periodic and prompt maintenance is essential to prevent continuous deterioration and possible failure.
Turfing, free from weeds and bushes, is an effective means of preventing erosion.
Rills and gullies should be filled with suitable soil, compacted, and then seeded for growing the turfing. Erosion in large gullies can be slowed by stacking bales of hay or straw across the gully until permanent repairs can be made.
Paths due to pedestrian, livestock, or vehicular traffic (two and four-wheeled) are a problem on many embankments. If a path has become established, vegetation will not provide adequate protection and more durable cover will be required unless traffic is eliminated. Stones may be used effectively to cover such footpaths.
In addition, steps can be provided/ constructed at regular intervals along the length of the dam for going from downstream toe to the dam top. All vehicular traffic, except for maintenance, should be restricted from the dam.
Erosion is also common at the point where an embankment and the concrete walls of a spillway or other structure meet. Poor compaction adjacent to such walls during construction and later settlement can result in an area along the wall that is lower than the grade of the embankment.
Runoff, therefore, often concentrates along these structures, resulting in erosion. People also often walk along these walls, wearing down the vegetative cover. Workable solutions include re-grading the area so that its slopes away from the wall, adding more resistant surface protection, or constructing steps.
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4.3.2. Upstream Riprap The upstream face of a dam is required to be protected against wave erosion. Rip-rap is normally provided for the purpose with filter layers below.
Nonetheless, erosion can still occur in existing riprap. Water running down the slope under the riprap can erode the embankment. Sections of riprap that have slumped downward are often signs of this kind of erosion.
Effective slope protection must prevent soil from being removed from the embankment.
When erosion occurs on the upstream slope of a dam, repairs should be made as soon as possible. Repairs can be made following the same design details as provided in the embankment dam. Proper preparation of surface of the existing embankment as described in the earlier para including cutting benches as per site conditions for better bonding is necessary. IS 8237- Code of practice for protection of Slopes for Reservoir Embankments may also be referred to.
4.3.3. Controlling Vegetation Keep the entire dam clear of unwanted vegetation such as bushes or trees. Excessive growth may cause several problems such as:
It can obscure the surface of an embankment and not allow a proper inspection of the dam.
Large trees can be uprooted by high wind or erosion and leave large holes that can lead to breaching of the dam.
Some root systems can decay and rot, creating passageways for water, and thus causing erosion.
Growing root systems can lift concrete slabs or structures.
Rodent habitats can develop.
All bushes/trees should be as far as possible removed by roots. The resulting holes should be filled with well compacted earth. It would be desirable to remove the plants/vegetation at their early stage to prevent their growing into big tree/bushes. In cases where trees and bushes cannot be removed, the root systems should be treated with herbicide (properly selected and applied) to retard further growth. Use of harmful chemicals should be avoided. Concerned Government Agencies should be consulted for selection of appropriate herbicides & their use for control of vegetation on dam structures.
Further, it is desirable that there are no trees or bushes within 500 m of the toe drain on the downstream side of the dam.
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4.3.4. Controlling Animal Damage Livestock should not be allowed to graze on an embankment surface. When soil is wet, livestock can damage vegetation and disrupt the uniformity of the surface. Moreover, livestock tend to walk in established paths and thus can promote erosion. Such paths should be re-graded and seeded, and the livestock permanently fenced out of the area.
The burrows and tunnels of burrowing animals (beaver, muskrat, groundhogs and others) weaken earthen embankments and serve as pathways for seepage from the reservoir. Large burrows on an embankment should be filled by mud packing. This method involves placing vent pipe in a vertical position over the entrance of the den. Making sure that the pipe connection to the den does not leak, the mud-pack mixture is poured into the pipe until the burrow and pipe are filled with the soil-water mixture. The pipe is removed and more dry earth is tamped into the entrance. As per some US publications, the mud pack is generally made by adding water to 90% earth & 10% cement mixture until a slurry or thin cement consistency is attained. For bigger holes, bentonite coated stones can also be used. All entrances should be plugged with well-compacted earth & vegetation re-established. Dens should be eliminated without delay. Different repair measures will be necessary if a dam has been damaged by extensive small rodent tunneling or large rodent activity. The area around the entrance can be excavated and then backfilled with impervious material. This plugs the passage entrance so that water is prevented from saturating the dam’s interior.
4.3.5. Controlling Ants and Termites (White Ants) Ants and termites have become one of the most serious pests for Embankment dams. They both need water to survive and have been found on most of the embankment dams in India including in the Tawadam. These insects can create problems in the dam itself and with any of its electrical components.
In some habitats, ants and termites can move as much or more soil as earthworms, thereby reducing soil compaction. Nest galleries can penetrate in a V-shaped pattern below the nest, penetrating as much as more than one meter deep in the soil. These galleries can create pathways for surface water to penetrate in the dam, resulting in internal erosion and collapse of the surface.
Ants and termites left undisturbed can build mounds that can become quite large. These can create problems for mowing. However, frequent mowing can induce the colonies to migrate to neighboring, undisturbed areas.
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There are many options for managing ants and termites. Use only pesticides labeled as suitable for the location you want to treat. Make every effort to avoid contaminating water with pesticides.
4.3.6. Controlling Damage from Vehicular Traffic Vehicular traffic is restricted on top of dam. Regular maintenance of the road at dam top is mandatory.
4.3.7. Masonry/Concrete Spillway Various issues that may need routine maintenance in concrete and masonry dams/spillways and appurtenant works may include but are not limited to:
Removal of vegetation growth on the surfaces of the dam, spillways, energy dissipaters and spill channel.
Monitoring of seepage in galleries.
Removal of leached deposits from galleries and general cleaning.
To ensure proper access & lighting in galleries.
Minor repairs of concrete/masonry can be carried out during routine maintenance.
4.3.8. Gates and Hoisting Equipments A satisfactory operation of Tawa dam envisages proper operation of the Gates & Hoisting Equipment of its Irrigation outlet.
If routine inspection of the Hydro-Mechanical Equipment shows the need for maintenance, the work should be completed as soon as possible.
The O&M manuals of the gates manufacturer’s would however govern the overall maintenance of Gates & Hoists whenever there is any contradiction with the instructions given in the Manual
4.3.8.1.Radial Gates Radial gates are provided in the spillway of the BALIMELA dam. The aspects to be inspected and maintained periodically for ensuring proper operation of these gates are as under:
i) Rubber Seals
Seals shall be inspected for leakages. Locations of excessive leakages shall be recorded for taking remedial measures. Weeping or slight flow in localized area will
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not require immediate remedial measures. However, measures like tightening of bolts are carried out. Further adjustment is carried out during annual maintenance.
If leakage is excessive & immediate repair is considered necessary, the seals should be repaired as soon as the reservoir water level is below the spillway crest level. ii) Trunnion block assembly and its anchorages
All the nuts and bolts of Trunnion block assembly and its anchorages shall be checked for tightness.
Check all the welds for soundness and rectify defects.
Check whether the Yoke girder and thrust block is covered or not. If not, cover it with mild steel plates.
Cover the trunnion pin with anti- corrosive jelly.
Remove all dirt, grit etc. from trunnion assembly and lubricate trunnion bearings of the gate with suitable water resisting grease as recommended by bearing manufacturers (Table1). iii) Gate structure
Check all the welding for soundness and rectify defects.
Check welding between arms and horizontal girders as well as between latching bracket and skin plate with the help of magnifying glass for cracks/defects and rectify the defects.
Clean all drain holes including those in end arms and horizontal girders.
Check all the nuts and bolts and tighten them. Replace damaged ones.
Check upstream face of skin plate for pitting, scaling and corrosion. Scaling may be filled with weld and grinded. Corroded surface shall be cleaned and painted. iv) Embedded Parts
All the sill beams and wall plates shall be inspected for crack, pitting etc. and defects shall be rectified.
The guide roller pins shall be lubricated (Table-1). v) General Maintenance
Defective welding should be chipped out and it should be re-welded duly following the relevant Codal provision (IS: 10096, Part-3).
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Damaged nuts, bolts, rivets, screws etc. should be replaced.
Any pitting should be filled up by welding and finished by grinding if necessary.
The gate leaf, exposed embedded metal parts, hoists and hoist supporting structure etc., should be thoroughly cleaned and repainted when required keeping in view the original painting system adopted and as per the guidelines contained in IS: 14177.
Trunnion bearing should be greased as and when required (Table-1). Keeping trunnion bearings in perfect working condition is very important. All other bolted connections should also be checked up for proper tightness.
Bolts and Trunnion bearing housing should be tightened wherever required.
The seals of the gate should be checked for wear and tear and deterioration. These should be adjusted/replaced as and when necessary.
The wall plates, sill beams shall be checked and repaired if necessary.
Wire ropes should be properly lubricated (Table-1).
Oil level in the worm reduction unit should be maintained by suitable replenishment. Oil seals should also be replaced if required. Lubrication of other parts of hoists such as chains, position indicators and limit switches should also be done (Table-1).
The stroke of the brake should be reset to compensate for lining wear. Worn out brake linings should be replaced in time.
Flexible couplings should be adjusted if required. • Repairs and replacements of all electrical relays and controls should be attended to.
Maintenance of alternative sources of Power such as Diesel Generating sets and alternative drives wherever provided should be carried out.
The list of essential spare parts to be kept available should be reviewed and updated periodically. The condition of spares should be checked periodically and protective coating given for use.
4.3.8.2 Electrically operated fixed hoists i) General Instructions
Operation of fixed hoist without lifting the gate is not possible and need not therefore be attempted. It will be possible to operate the unit and observe operation of load carrying hoist component when gate is being lifted or lowered.
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Never open any bolt or nut on motor, gear boxes, rope drums and other load carrying hoist components when the gate is in raised position. The gate should be fully closed or rested on the gate latches before carrying out any work on hoist components including motor brake and other electrical equipment. b) Inspection and Maintenance
The aspects to be inspected and maintained periodically for ensuring proper operation of Rope drum hoists are as under;
Entrance to all hoist platforms shall be kept locked. All keys shall remain with the shift supervisor.
A cursory daily inspection shall be made of hoist and gate to ensure that there is no unusual happening.
Clean all hoisting equipment and hoist platform.
Check oil level in gearboxes and replenish as and when required with oil of proper grade.
Apply grease of suitable grade by grease gun (Table-1).
Lubricate all bearings, bushings, pins, linkages etc. (Table-1).
Check all the fuses on the power lines.
All bolts and nuts on gear boxes, hoist drum and shaft couplings should be checked for tightness.
Check the supply voltage.
Drain sample gear oil from each of the gear boxes. If excessive foreign particles or sludge is found, the gear box shall be drained, flushed and filled with new oil.
All the geared couplings shall be greased (Table-1).
Raise and lower the gate by hoist motor and check for smooth, and trouble free operation of gate without excessive vibration.
Observe current drawn by motor at the time of lifting and check if it is more than normal. If so, stop the hoist and investigate the cause and rectify.
Check the condition of painting of various components and remove rust wherever noticed and repaint the portion after proper cleaning as per painting schedule.
All trash, sediments and any other foreign material shall be cleared off the lifting rope and lifting attachment.
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All ropes shall be checked for wear and tear and if broken wires are noticed, the rope shall be replaced.
All the wire ropes shall be checked and all visible oxidation shall be removed.
All wire ropes shall be greased with cadmium compound (Table-1).
Check the overload relays for proper functioning.
Check all the nuts, bolts, rivets, welds and structural components for hoisting platform and its supporting structure for wear, tear and damage. All damages shall be rectified. All bolts shall be tightened. The portion with damaged painting shall be touched up.
Check the pulleys, sheaves and turn-buckles.
Raise and lower the gate for its full lift several times (at least three to four) and observe the following: -
- Check the limit switches and adjust for design limits
- The effectiveness and slip of the breaks shall be checked by stopping the gate in raising and lowering operations. The brakes shall be adjusted if needed.
- When the gate is operated, there should not be any noise or chatter in the gears.
Adjust the rope tension of wires if unequal.
Check for all gears and pinions for uneven wear and adjust for proper contact. Grease the gears (Table-1).
Repaint the hoist components, hoisting platform and its supporting structures as per requirement.
The periodic maintenance of commercial equipment like motors, brakes, thrusts etc. shall be carried out as per manufacturers operation and maintenance manual.
4.3.8.3 Maintenance of Electrical components of Fixed Rope Drum Hoists The Electrical components to be inspected and maintained periodically are as under;
Starters should be cleaned free of moisture and dust.
Each individual contactor should be tried by hand to make sure that it operates freely.
All wearing parts should be examined in order to take note of any wear which may have occurred during operation.
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If the contactor hums, the contact faces should be cleaned.
Examine all connections to see that no wires are broken and no connections are loose.
Clean the surface of the moving armature and magnet core which comes together when the contactor closes, free of dust or grease of any kind.
Examine the mechanical interlocks between the reversing contactor and see when the contact tips of one of the contactor units are touching, it is impossible to get the contact tips of the other unit to touch.
The contact tips should be kept free from burns or pits by smoothening with fine sand paper or emery paper.
Replace the contact tips which have worn away half-way.
Do not lubricate the contacts.
Blow out windings thoroughly by clean and dry air to clear air passage in the stator and the rotor of any accumulated dirt. The air pressure shall not be too high to damage the insulation.
Examine earth connections and motor leads.
Examine motor windings for overheating
Examine control equipment’s
Examine starting equipment for burnt contacts
Check and tighten all nuts and bolts
Clean and tighten all terminals and screw connections all contact surfaces shall be made clean and smooth.
Lubricate the bearings
Overhaul the controllers
Inspect and clean circuit breakers.
Wipe brush holders and check bedding of brushes.
Blow out windings thoroughly by clean and dry air. The pressure shall not be so high that insulation may get damaged.
Check the insulation resistance of the motor between any terminal and the frame. If the measured resistance is less than the prescribed value, then steps shall be taken
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to dry- out the motors either by passing a low voltage current through the windings or by placing the stator and rotor only in a warm dry place for a day or so.
Important: The complete motor shall never be put in an oven for drying as that may melt the grease out of bearings.
Coat the windings with an approved high temperature resisting insulation enamel or varnish.
Over haul the motor, if required.
Check the switch fuse units and renew, if required.
Check resistance or earth connections.
Check air gap.
Solenoids Operated Brakes
All fixing bolts shall be checked and tightened at least once in three months.
The magnet stroke should be reset to compensate for wear.
Re-adjust the brake when the magnet stroke reaches the value given on the instruction plate.
Brake lining should be checked and replaced when required.
Examine all electrical leads and connections.
Rubber bushes or couplings should be checked and replaced if defective.
The pins should be tightened.
Brake drum shall be cleaned to remove any dust or grease.
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13 Nos. Radial Gates on Central Spillway of dam
4.3.8.4. Head Regulator Gates of Irrigation Outlet. The maintenance of head regulator gates, hoists and ancillary components are being done regularly. Proper records of inspection, testing and maintenance should be kept by the officers in charge of the work.
The following maintenance works should be attended to:
1) The workout bolts, screws etc. should be replaced. Any pitting to embedded portion should be filled up by welding and finished by grinding. Weld joints of major components should be checked thoroughly and defects if any should be rectified by welding and grinding. The gates, hoists and allied structures should be painted once in three years normally. However painting of gate, hoist and allied parts may be carried out earlier, as necessary, based on regular inspection for the condition of paint/ surface.. The original specifications of painting done at the time of commissioning of gate and hoists should be kept in view while painting in subsequent years. 2) The wheel pins and bushes should be lubricated. All bolts and nuts of wheel assembly should be checked for slackness and should be tightened if found loose. The screws fixing the retainer plates to the end vertical girders should be checked for slackness and should be tightened if found loose. The spacer rings should be checked for wear and tear. 3) The rubber seals of the gate should be checked for wear and tear and damage and should be repaired/replaced as considered necessary.
O & M Manual of Tawa Dam May 2020
4) The bolts and nuts fixing the rubber seals to the skin plate should be checked for slackness and should be tightened if found loose. Damaged bolts and nuts should be replaced. 5) Drain holes provided in horizontal stiffeners of the gates should be cleaned to avoid stagnation of water on the horizontal stiffeners. 6) The lifting pin and lifting bracket bush if provided should be lubricated properly. 7) The sill beam, side seal seat, top seal seat, guide and wheel track should be checked for pitting and should be rectified suitably. The welding of stainless steel flats on wheel tracks, bottom sill beam, side seal seats and top seal seats should be checked for weld cracks and should be re-welded and ground smooth if weld cracks are noticed. 8) Gap between guide and guide shoe should be checked and suitably rectified if excessive sway on gate is noticed. 9) Distance between face to face of guide, centre to centre of track and side seal seats and distance between the bottom sill beam and centre of top seal seat should be checked and remedial measures may be taken if felt necessary. 10) The stems of restraining arrangement and the split bushes should be lubricated properly. The bolts and nuts of restraining brackets and stem flanges should be checked for slackness and should be tightened if found loose. 11) The stem should be checked for straightness and suitable remedial measures may be taken if the stems are found bent. 12) The welding of eye piece to the bottom stem and other weld joints shall be checked and suitably rectified if defects are noticed. 13) The worm, worm wheel, worm shaft, bronze bushes, thrust bearings and screw rod should be lubricated properly. 14) The screw rod, worm and worm wheel should be checked for damage to teeth or hair cracks etc. and should be rectified/replaced as considered necessary. 15) The thrust bearings should be opened and checked for damage to the inner/ outer cones & rollers etc. & shall be rectified/replaced as considered necessary. 16) The wheel track, guide, side seal seat and top seal seat should be lubricated properly. 17) The emergency gates, provided in Tawa dam are also maintained in similar manner. 18) In addition to the above, other defects noticed during inspections shall also be attended to urgently.
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Maintenance Schedule:
1. Quarterly Maintenance: 1. Wheel Assembly. The wheel pins and bushes should be lubricated. 2. Stems and Split bushes. The stems and split bushes should be lubricated. 3. Lifting bracket bush and pin. The lifting bracket bush and pin should be lubricated. 4. Gear Box Assembly. a. The screw rod should be lubricated. b. The worm, worm wheel, worm shaft & thrust bearing should be lubricated.
2. Yearly maintenance:
1. Grease shall be applied to guide, wheel track side seal seat and top seal seat. 2. All bolts and nuts should be checked for slackness and shall be tightened if found loose. 3. The rubber seals should be checked for deformation and damage etc. and shall be repaired/replaced.
4.3.8.5.Painting of Spillway & Head Regulator Gates and Hoists. i) Protection of painted surfaces is considered essential for protection & enhancement of service life.
Gates, its embedded parts, gate leaf, hoists and its supporting structures need to be protected against corrosion due to climatic condition, weathering, biochemical reaction and abrasion etc. These equipments are likely to deteriorate/ damage to the extent that replacement of parts may become necessary and such replacement may become difficult and costly. ii) Surface preparation & Painting requirements.
Painting for hydro-mechanical works is to be carried out as prescribed in IS 14177 for both newly manufactured as well as old & used gates, hoists and associated works after proper surface preparation. The preparation includes thorough cleaning, smoothing irregular surfaces, rusted surfaces, weld spatters, oil, grease, dirt, earlier applied damaged layers of primers/paint by use of mechanical tools, by use of solvents, wire brush etc. The sand/grit blasting process is used for surface preparation to a level of Sa 2½ of the Swedish standard.
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O & M Manual of Tawa Dam May 2020 iii) Surfaces not requiring painting & their protection during surface preparation, painting & transportation process.
a) The following surfaces are not to be painted unless or otherwise specified:
• Machine finished or similar surface • Surfaces which will be in contact with concrete • Stainless steel overlay surfaces. • Surfaces in sliding or rolling contact • Galvanized surfaces, brass and bronze surfaces. • Aluminum alloy surfaces
b) The Surfaces of stainless steel, nickel, bronze and machined surface adjacent to metal work being cleaned or painted shall be protected by using sticky protective tape or by other suitable means over the surfaces not to be painted.
c) All embedded parts which come in contact with concrete shall be cleaned as detailed above and given two coats of cement latex to prevent rusting during the shipment while awaiting installation. iv) Application of primer & finish coats on embedded parts and gates a) Embedded parts • The prescribed primer shall be applied as soon as the surface preparation is complete and prior to the development of surface rusting and within the specified time prescribed by Indian Standards or the Paint Manufacturer. In case there is lapse of considerable time beyond the prescribed time limit, the surfaces shall be again cleaned prior to priming. • Two coats of zinc rich primer with epoxy resin shall be applied to all embedded parts surfaces which are not in contact with concrete and shall remain exposed to atmosphere or submerged in water to obtain a dry film thickness of 75 microns. • This shall be followed by three coats at an interval of 24 hours of coal-tar blend epoxy resin so as to get a dry film thickness of 80 microns in each coat. Total dry film thickness of paint shall not be less than 300 microns. b) Gates Primer Coat Over the prepared surface one coat of inorganic zinc silicate primer giving a dry film thickness of 70 ± 5 microns should be applied. Alternatively two coats of zinc rich primer, which should contain not less than 85% zinc on dry film should be applied to give a total dry film thickness of 75 ± 5 microns.
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Finished paint Two coats of solvent less coal tar epoxy paints. These shall be applied at an interval of about 24 hours. Each coat shall give a dry film thickness of 150±5 microns. The total dry film thickness of all the coats including primer coating shall not be less than 350 microns. Table – 1
(For Radial Gates and Hoists) Sl. Parts to be Method of Lubricants When to Lubricate No. Lubricated Lubrication Recommended Trunnion Assembly Volume grease Mobil Grease Quarterly 1 (Brushes and Pins) gun No. 2
Guide roller Mobil Grease 2 Assembly (bushes Hand grease gun Quarterly No. 2 and pins) Gears and Pinions 3 of end reduction By brush/hand Quarterly Dorcia 150 gear boxes Hinges, pins and spring of Mobil Grease 4 Hand grease gun Quarterly Electromagnetic No. 2 brake Gears and pinions 5 of position By brush/hand Quarterly Dorcia 150 Indicators Bushes of position 6 By oil can Quarterly DTE oil Medium Indicators Electric Motor Mobil Grease 7 Hand grease gun Yearly Bearings No. 2 Cadmium 8 Wire ropes By brush/Hand Half Yearly compound Servo C-60 or Fill upto mark on Change oil in 9 Worm gear reducer Servo Mark 59 dip stick alternate year SAE-140 Anti-friction Mobil Grease 10 Hand grease gun Yearly bearings No. 2 Pins of Wire rope attachment turn Mobil Grease Yearly 11 buckles and By grease gun No. 2 equaliser plate turn- buckle thread Volume grease Mobil Grease 12 Drum shaft bushing Yearly gun No. 2
13 Limit Switches By oil can Yearly Mobil Oil (Head Regulator Gates and Screw Hoists)
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Sl. Parts to be Method of Lubricants When to Lubricate No. Lubricated Lubrication Recommended Wheel Assembly Volume Grease Mobil Grease 1. Quarterly (Pin & Bushes) Gun No. 2 Worm Wheel, 2. Worm, Worm shaft Smear Quarterly Mobil Grease and screw rod 3. Bushes of Gear Box By Oilcan Quarterly DTE Oil Restraining stems & 4. Smear Quarterly Mobil Grease split bushes Lifting Bracket Bush 5. Smear Quarterly Mobil Grease and Pin Mobil Grease 6. Thrust Bearing Smear Quarterly No. 2 Guide, Wheel Track 7. side Seal Seat & Smear Yearly Dorcia 150 Top Seal Seat Note: Lubricants of other make equivalent to the lubricants specified above can also be used.
4.3.9. Electrical System: Head regulator shutters are operated manually and spillway is gated. There is supply of electricity to the project site. Lighting arrangement has been made at site till date.
4.3.10. Metal Component maintenance: Head regulator shutters of bare ferrous metal will tend to rust. To prevent corrosion, shutters must be either appropriately painted (following the paint manufacturer’s directions) or heavily greased in respect of moving parts & on surfaces like guide channels on which there is movement of gates. When areas are repainted, it should be ensured that paint is not applied to gate seats, wedges, or stems (where they pass through the stem guides), or on other friction surfaces where paint could cause binding. Heavy grease should be applied on friction surfaces to avoid binding. As rust is especially damaging to contact surfaces, existing rust is to be removed before periodic application of grease.
4.3.11. Access Road: For a dam to be operated and maintained there must be a safe means of access to it at all times. Access road surfaces must be maintained to allow safe passage of automobiles and any required equipment for servicing the dam in any weather conditions. Routine observations of any cut and fill slopes along the sides of the road should be made. If unstable conditions develop assistance of experienced Engineers/Expert Panels should be obtained and remedial measures initiated.
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Drains are required to be provided and maintained along roads to remove surface and subsurface drainage. This will prolong the life of the road and help reduce deterioration from rutting. Road surfacing should be repaired or replaced as necessary to maintain the required traffic loadings. In most cases, specialized contractors will be required to perform this maintenance.
An all-weather black topped approach road with carriage way width of 3.5 m to the dam has been constructed for movement of machines and dam authorities throughout the year.
Repair of Approach Road under DRIP
4.3.12. General cleaning:
For proper operation of spillways, sluiceways, approach channels, inlet and outlet structures, stilling basin/ energy dissipation arrangements, discharge conduit, dam slopes, trash racks, debris control devices etc. Cleaning and removal of debris is necessary. Cleaning is especially important after large floods, which tend to send more debris into the reservoir.
4.4. Material Requirements during monsoon period: Materials required during monsoon period for both immediate maintenance and preventive maintenance should be stocked in adequate quantity. A 24x7 hour patrolling is to be carried out during the monsoon period.
The materials normally required to be stocked in sufficient quantity are:-
Gunny Bags
Sand, Boulders/Wire crates
Bamboos/Balli’s
O & M Manual of Tawa Dam May 2020
Baskets, ropes
Petromax Lamps with Spares
Torches with spare cells
Kerosene Oil
Match Boxes
Rain Coats
Gum Boots
Warning sign indicator
Danger zone lights
4.5. Establishment structure at Tawadam.
Executive Engineer, Tawa Division, Itarsi, Hoshangabad
S.D.O./Assistant Engineer, Tawa Division, Itarsi,
Sub Engineer, Tawa Division, Itarsi, Hoshangabad
Work Charged Staff Work Charged Staff
Head Works Distribution System
4.6. Preparation of O&M Budget: The O&M budget for Tawa dam should essentially include but not be limited to the following items:
Establishment Cost of Regular Staff - Salaries and allowances, Bonus, Medical Reimbursement, LTC, Leave Encashment, TA and DA etc. pension benefits, etc. (as applicable).
Establishment Cost of Work charged Staff - Salaries and allowances, Bonus, Medical Reimbursement, LTC, Leave Encashment, Pension benefits, TA and DA, etc. (as applicable).
Establishment Cost of Daily wage Staff - Salaries and allowances, TA and DA etc. (as applicable).
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Office Expenses – Rent for office, Telephone/Mobile/any other Telecommunication bills, Electricity bills, water bills, Office stationery, Day to day office requirements.
Motor Vehicles - Running and Maintenance cost of inspection vehicles, Cost of hiring of vehicles as required
Maintenance of Colony - Maintenance of staff quarters, colony roads, Electricity, Sanitary and Water supply systems etc.
T&P - The T&P requirements for offices, colony, works etc. as applicable.
Works -Painting, oiling, greasing, Repair/replacement of gates seals, specific requirements for all Civil works, vegetation removal and mowing of turffing on earth dams, maintenance/cleaning of drains in dam,maintenance of access roads & basic facilities, provision for flood contingency works during monsoon, unforeseen events/items etc.
A summary table for the O&M budget is given in Appendix-III.
4.7. Maintenance of records: Maintenance records are of utmost importance. A record should be kept of all maintenance activities-Immediate, Preventive and Routine maintenance works. Information that should be recorded includes the following as a minimum:
Date and time of maintenance,
Weather conditions,
The type of maintenance,
Name of person or contractor performing maintenance,
Description of work performed,
The length of time it took to complete the work with dates,
Equipment and materials used, and
Before and after photographs.
The data should be recorded by the person responsible for maintenance.
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CHAPTER 5.INSTRUMENTATION AND MONITORING.
There are instruments installed in the dam but at present many are inoperable. However, it has been proposed to install following instruments on Tawa dam. The detail of the instruments proposed to be installed is given below:
S.No. Description Quantity A Seismological Instrumentation 1 Seismograph 1 2 Accelerograph 3 Budget estimates for 5 years based on MoU with IIT Roorkee 3 (Scientific staff, Technical staff, Visits to site, Miscellaneous for reports & sundry/consumable items )
B Hydro-meteorological, Geodetic, and Geotechnical Instruments
1 Survey Markers (Target Points) for Total Station 40 2 Tilt meter Biaxial fixed vibrating wire type 2 3 Normal Plumb line with automatic readout 1 4 Joint meters 12 5 Water level Sensor for sensing up to 70m 1 6 V Notch for flow measurement Manual reading 15 7 Thermometer/ Temperature meters- :Vibrating wire type 5 8 Uplift Gauges/PWP Gauges 12
Automatic Weather Stations with sensors of Rainfall, Atmospheric 9 Pressure, Temperature, Solar Radiation, Humidity and Wind Velocity with web based data transmission system 1 10 Man Month cost for installation or other technical services 1 11 On line monitoring System. Provision of data on a 24x7 basis through cloud server, one lot for each type of Data Logger 1 Similarly frequency of measurements for different instruments is as follows:
Sl. Instrument Frequency Personnel No.
Junior 1 Seismological Instruments Daily Engineer
Daily during non-monsoon Junior 2 Tilt meter biaxial and hourly during monsoon Engineer
Daily during non-monsoon Junior 3 Joint meter and hourly during monsoon Engineer
Automatic Reservoir level Daily during non-monsoon Junior 4 Recorder and hourly during monsoon Engineer
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Automatic Weather Station with sensors for rainfall, atmospheric pressure, temperature, solar Daily during non-monsoon 5 radiation, humidity, wind velocity and hourly during monsoon Junior with web-based data Engineer transmission system
Daily during monsoon and Junior 6 V-Notch with 60 L/S capacity weekly during non-monsoon Engineer
Daily during monsoon and Junior 7 V-Notch with 120 L/S capacity weekly during non-monsoon Engineer
Daily during non-monsoon Junior 8 Uplift pressure meter and hourly during monsoon Engineer
Water quality sensor (Ph, Daily during non-monsoon Junior 9 Turbidity & DO) and hourly during monsoon Engineer
Note:- Monsoon – 15Th June to 15th October Non- Monsoon – 15th Nov. to 14th June of the water year.
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CHAPTER 6: PREVIOUS REHABILITATION EFFORTS.
Before DRIP, maintenance activities were limited to routine greasing, oiling, and patch painting of shutter gates, routine mowing, vegetation removal, repair of eroded section, etc. Apart from these routine maintenance activities, the foundation has been treated with curtain grouting from the u/s face of foundation gallery. On the u/s edge of foundation gallery 27.43 m deep holes of 40 mm diameter were drilled at 3.05 m centres along the gallery, the cement grout was injected through these holes at an average pressure of about 14.24 kg/cm2.
Under DRIP, major Rehabilitation Works have been carried out for Tawa dam at a total cost of about INR 710.94 Lakhs.
The rehabilitation works carried out under DRIP include:
1. Repair Work of Energy Dissipation Arrangement:
Dewatering of stilling basin,
Cleaning of stilling basin,
Repair of damage with M-25 Concrete and epoxy bonding,
Repair of eroded surface of dent and chute block by polymer Plaster.
2. Renewal of old tar Approach road:
Renewal of old tar approach road to tawa dam from NH69 and Bagra
3. Remedial Measure Work (E& M):
Supplying and installation of drainage motor pump set-04 no,
Rewiring work of inspection galley-o1 job,
Upgrading work of motor control panels of radial crest gates of Tawa Dam,
Repair work of 100 N4T gantry crane,
Design fabrication supply and installation of lifting beam assembly,
Alterative power supply arrangement 1 job,
Replacement of rubber seals of redial crest gates of Tawa Dam
4. Remedial Measure Work Drilling and grouting:
Controlling of excessive seepage in non-over flow section of Tawa Dam,
Cleaning of porous drain & drainage holes of Tawa Dam.
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Other non-structural measures carried out under DRIP include preparation of Inundation maps and Emergency Action Plan (EAP); Review of design flood; Preparation of O&M Manual; Data entry to DHARMA; etc.
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CHAPTER 7: UPDATING THE MANUAL.
The O & M Manual is to be reviewed and updated periodically. Updating of O&M Manual should be done whenever any major changes occur like revision of design flood, construction of additional Surplus Escape (Spillway), construction of dam on the upstream etc.
Aspects to be considered when updating include:
Increase/decrease in the frequency of inspection or routine maintenance based on additional data/ experience acquired.
Changes in the operation and/or maintenance procedures based on additional data/experience acquired.
Alterations to the project data because of changes/modifications in the dam by way of construction of any additional surplus escape (Spillway), u/s and d/s developments etc.
All up-dates/revisions of the O&M Manual need to be sent to all the locations/addresses to which the copies of the original O&M Manual had been sent earlier. The O&M Manual is to be normally reviewed/ updated after every 10 years or earlier by the Executive Engineer, Tawa Division, Itarsi, Hoshangabad.
Updates in the O & M Manual will be approved by the Chief Engineer of the project after getting the needful checking done through the DSO of MPWRD.
7.1 Training and Exercises: Training: The training of the personnel, involved in implementation of the O & M Manual will be conducted by the SE once in a year so as to make the implementing staff familiar with the elements of the O&M plan, their responsibilities and duties, the available equipment, detection of problems and remedial measures.
A sufficient number of people will be trained to ensure adequate expertise atall times.
Exercises (Testing): The SE shall carry out orientation meetings with personnel involved in implementation of the O&M Manual and organize mock drills for head regulator gates before every crop season.
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REFERENCES
1. CWC:2018 Guidelines for preparing O&M Manuals for dams (Doc. No. CDSO_GUD_DS_O3_v1.0)
2. Japan Water Agency: 2017 Inspection Manual for Dam Field Engineers after Seismic Events, Ichari Dam, Uttarakhand (CDSO_GUD_DS_0_v1.0,).
3. CWC:2018 Guidelines for Safety Inspection of Dams (Doc. No. CDSO_GUD_DS_O7_v1.0)
4. IS 14177: 1994 Guidelines for Painting system for Hydraulic Gates and Hoists
5. IS 8237:1985 Code of Practice for protection of slopes for Reservoir Embankments
6. IS 11223:1985 Guidelines for fixing Spillway Capacity
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Appendix-I Scheduled Dam Safety Inspection Form:
Scheduled Dam Safety Inspection Form
Part 1a - Inspection Details:
Project ID Code Dam Name: Tawa MP08HH0326 (PIC):
Dam Type: Masonary & earthen Dam Purpose:
Hazard Dam Owner: Classification:
Dam Operator: Type of Inspection:
Commissioning Inspection by: Date:
City/State/PIN: Date of Inspection:
Reservoir water District: Hoshangabad level in metre on the date of inspection:
Storage Capacity 2311 (Gross) Latitude: 220-33’-40” N (MCM): 1944 (Live)
Longitude: 770-58’-30’’E Weather Conditions:
FRL – 355.39 m MWL – 356.69 m Important DSL – 334.25
Controlling Level MDDL – 340.46 m (RBC) 336.80 m (LBC) TBL – 359.664 m
Part 1b - Inspection Remarks: Please provide any additional information or comments not covered by Part 1a form above.
Part 2a - Inspection Checklist:
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA A-Reservoir
A-1.1 General Condition
1.1.1 Is the reservoir water level unusually high or low?
1.1.2 Are there signs of decline in water quality?
1.1.3 Are there signs of recent sediment deposition?
1.1.4 Is floating debris present?
1.1.5 Any indications of major active or inactive landslide area in the reservoir rim If so, indicate their locations and extent.
1.1.6 Are there people or livestock in and around reservoir?
1.1.7 Any other issues?
B-Dam and Dam Reach (Embankment)
B-1.1 General Condition
1.1.1 Any major alterations or changes to the dam since the last inspection?
1.1.2 Is there any new nearby development in the downstream floodplain?
1.1.3 Any misalignment of poles, fencing or walls due to dam movement?
B-1.2 Upstream Slope
1.2.1 Any signs of bulging or concavity (depressions)? If so, indicate their locations and extent. (Check up the cross-sections with tape and
level at random locations, at least two)
1.2.2 Does the section of the dam and upstream
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA slope appear structurally sound and stable?
1.2.3 Presence of longitudinal or transverse cracks?
1.2.4 Whether any signs of distress to stability of slopes noticed at any time in any part of the dam? If so, give brief details of the incidents and location, the method of treatment adopted and its effectiveness. Indicate the general condition of upstream pitching.
1.2.5 Any degradation to slope protection (rip- rap)?
1.2.6 Is there any profuse growth of bushes or weeds over any portion of the dam? If so, indicate the locations.
1.2.7 Does the upstream slope shows existence of crab holes or holes made by rodents or burrowing animals or ant hills? If so, indicate the locations.
1.2.8 Any other issues?
B-1.3 Crest of Dam
1.3.1 Is the crest profile at proper elevation? (To be test checked at random locations by taking level)
1.3.2 Does it show any signs of excessive and/or uneven settlement? If so, indicate such locations and extent of settlement. (Surface settlement points must be installed for observing this aspect)
1.3.3 Is the surface of the crest free from undulations and local depressions or heaving?
1.3.4 Does it provide an all-weather road surface?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.3.5 Any degradation to access road (sealed/unsealed)?
1.3.6 Does it develop any visible cracks in transverse or longitudinal directions? If so, attach a map showing their locations and extent. Depth of cracks must be ascertained by taking open trenches extending below the bottom of cracks.
1.3.7 What is the condition of the edges of crest? Have got eroded and cut up resulting in reduced effective width?
1.3.8 Is the crest free from local slips throughout its length on either sides?
1.3.9 Do the headers, guard stones and parapet wall provided at the edges of the crest appear in proper profile and plumb?
1.3.10 Any degradation to upstream parapet or downstream curb wall?
1.3.11 Evidence of livestock on dam crest?
1.3.12 Trees or profuse growth of weeds/bushes at any location?
1.3.13 Proper lighting arrangement at dam top?
1.3.14 Any other issues?
B-1.4 Downstream Slope
1.4.1 Any signs of bulging or concavity (depressions)? 1.4.2 Are there any wet or slushy patches or any concentrated leaks, springs or trickles observed on the downstream slopes or the toe? If so, indicate their locations and extent. Please look out for patches of extensive vegetation growth and examine them carefully and record the findings. 1.4.3 Presence of longitudinal or transverse cracks?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.4.4 Any signs of distress to the stability of slopes?
1.4.5 Are rain cuts/erosion channels present at any location?
1.4.6 Are all the rain cuts and erosion channels properly treated and made good? Please indicate location of recurring damages, if any.
1.4.7 Is there any profuse growth of bushes or weeds over any portion of the dam? If so, indicate the locations.
1.4.8 Does the downstream slope shows existence of crab holes or holes made by rodents or burrowing animals or ant hills? If so, indicate the locations.
1.4.9 Any other degradation to slope protection (turffing)? Indicate the general condition of downstream pitching/ turffing and rock toe.
1.4.10 Is the downstream area clear of debris and free draining?
1.4.11 Any other issues?
B-1.5 Downstream Drainage
1.5.1 Are there any signs of water logging, slushy conditions or growth of aquatic weeds on the downstream of the dam? To be checked up to 300 m downstream of toe
1.5.2 Are there any standing pools of water in the downstream of dam? If so, give their locations and extent. To be checked up to 300 m downstream of toe
1.5.3 Are there any boils observed in the vicinity of the downstream toe of the dam? If so, give locations.
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.5.4 Is the downstream area sufficiently clear and free draining?
1.5.5 What is the depth of ground water table on a) Max. the downstream as evident from the existing Ground wells in the vicinity of thedam water level……… To be checked up to 300 m downstream of ……… toe. Does the water tableshow any marked variationinaccordance withthe variations in b) Location reservoir water level? …………… c) Date……… …… d) Correspond ing Reservoir level……
1.5.6 Are all the exposed drains working satisfactorily?
1.5.7 Toe drains and cross drains. i. Are the portions of longitudinal toe drain and exposed cross drains beyond the downstream toe of the dam in regular section and freely draining? ii. Is the pitching to these drains intact? iii. Is there any weed growth in these drains? iv. Indicate other defects noticed in the drains, if any. 1.5.8 Outfall Drain: (a) Is the outfall drain in proper shape and grade and freely draining? (b) Is the outfall drain properly cleaned and maintained? Does the outfall drain show any stagnant pools of water or weed growth?
B-1.6 Surface Drainage of Downstream Slope
1.6.1 Is the condition of the downstream slope drainage arrangements, if provided, satisfactory?
1.6.2 Is the paving to these drains intact?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.6.3 Are all the drains properly maintained and free of vegetation growth and debris?
1.6.4 Does the slope have a tendency to develop severe rain cuts at any location?
1.6.5 Enumerate any other defects noticed in the surface drainage of downstream slope.
B-1.7 Seepage Measurement
1.7.1 Is the quantity of seepage being daily or periodically measured and recorded? Please check the registers and record observations. 1.7.2 Does it show any abnormal rise or fall? If so, does it have any relation to a certain reservoir level elevation? 1.7.3 Does the seepage show a turbid colour at any stage? Was such a phenomenon observed at any stage at any location in the past? 1.7.4 What is the measured rate of seepage flow with date and reservoir level; a ) Date i. On the day of present inspection b) Rateofseepa ii. Maximum since last June ge flow (lpm) iii. Minimum since last June c) Reservoirlev el (m) 1.7.5 Is the portion upstream and downstream of measuring points of seepage easily accessible with proper steps and paths and free of vegetation growth?
1.7.6 Are the measuring points properly located, constructed and maintained so as to give accurate and reliable measurements of seepage in accordance with the relevant IS Codes?
1.7.7 Is the method of taking seepage measurements satisfactory?
B-1.8 Breaching Section (if provided)
1.8.1 Is the breaching section easily accessible?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.8.2 Is the condition of the breaching section satisfactory?
1.8.3 Is the note of instructions as to when and how to operate the breaching section available on record?
1.8.4 For reconstruction after the breach are the following items decided in advance? a) Quarry for embankment material b) Suitable routes of access Is the maintenance staff fully aware of the instructions related to operation of the beaching section and for reconstruction after the breach
1.8.5 Ascertain and indicate the latest event of operation of breaching section and its performance.
1.8.6 Evidence of recent degradation?
1.8.7 Any other issues?
B-1.9 Junction of Earth work with Masonry/Concrete dam sections and outlets
1.9.1 Is there any existence of leaks, springs or wet spots in the earth work in the vicinity of the junctions between earth work and masonry works? If so, what is the approximate rate and colour of the leakage? Does it turn turbid at any time? Please ascertain from enquiries and record the findings. 1.9.2 Is there any tendency for separations, cracking, settlement or upheaval of the earth work in the vicinity of masonry or concrete? If so, indicate the locations and the exact nature of deficiency. 1.9.3 Is there any tendency for surface erosion or slope instability at the junction?
1.9.4 If the outlet conduit is located in the earth dam section, is the entire length of the conduit in perfect order and profile and free from offsets, open joints, cracks and
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA leakage? Examine the conduit carefully from the downstream or from inside, if possible, and indicate the deficiencies observed, if any.
1.9.5 Any other issues?
B-1.10 Relief Wells
1.10.1 Are the relief wells in good working condition and functioning well?
1.10.2 Are the relief properly surged and cleaned periodically?
1.10.3 Please indicate the dates of last surging and cleaning and the next surging due.
1.10.4 Are the necessary plant and equipment for cleaning the relief wells, available with the office?
1.10.5 Is the record of periodical measurements of discharge from each relief well maintained? If so, indicate total discharge and maximum discharge observed from a single well on the date of inspection.
B-1.11 Abutment Contacts
1.11.1 Any presence of leaks, springs or wet spots near the abutment?
1.11.2 Any presence of cracking, settlement or upheaval of earthwork?
1.11.3 Any evidence of erosion or slope instability?
1.11.4 Trees or profuse growth of weeds/bushes?
1.11.5 Any degradation to up/downstream slope protection (rip-rap, turfing)?
1.11.6 Any other issues?
C-1 Dam and Dam Block/Reach (Concrete/Masonry)
C-1.1 General Condition
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.1.1 Any major alterations or changes to the dam since the last inspection?
1.1.2 Is there any new nearby development in the downstream floodplain?
1.1.3 Any misalignment of poles, fencing or walls due to dam movement?
C-1.2 Upstream Face
1.2.1 Evidence of surface defects (honeycombing, staining, stratification)? 1.2.2 Concrete/masonry deterioration (spalling, leaching, disintegration)? 1.2.3 Is cracking present (structural, thermal, along joints)? 1.2.4 Evidence of differential settlement (displaced/offset/open joints)? 1.2.5 Presence of vegetation (growth in joints between blocks)? 1.2.6 Evidence of any other damage to joints and/or water stops? 1.2.7 Any other issues?
C-1.3 Crest of Dam
1.3.1 Evidence of differential settlement (displaced/offset/open joints)? 1.3.2 Presence of cracking (structural, thermal, along joints)?
1.3.3 Profuse growth of weeds/grass/plants at any location?
1.3.4 Any degradation to access road?
1.3.5 Any degradation to upstream parapet or downstream curb wall?
1.3.6 Any other issues?
C-1.4 Downstream Face
1.4.1 Evidence of surface defects (honey-
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA combing, staining, stratification)?
1.4.2 Concrete/masonry deterioration (spalling, leaching, disintegration)?
1.4.3 Presence of cracking (structural, thermal, along joints)?
1.4.4 Evidence of differential settlement (displaced/offset/open joints)?
1.4.5 Presence of vegetation (growth in joints between blocks)?
1.4.6 Evidence of any other damage to joints and/or water stops?
1.4.7 Excessive seepage/sweating at any location on downstream face?
1.4.8 Significant leakage at any location on downstream face?
1.4.9 Any other issues?
C-1.5 Abutment Contacts
1.5.1 Any presence of leaks, springs or wet spots in vicinity of abutment?
1.5.2 Any presence of cracking or settlement?
1.5.3 Profuse growth of weeds/grass/plants at any location?
1.5.4 Any other issues?
D Gallery/Shaft and Drainage (Concrete/Masonry)
D-1.1 General Condition
1.1.1 Slushy condition or water logging immediately downstream of dam?
1.1.2 Any evidence of boiling in vicinity of dam toe?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA D-1.2 Gallery/Shaft Condition
1.2.1 Any problems accessing or inspecting gallery/shaft (obstruction)?
1.2.2 Any safety issues (inadequate handrails, lighting or ventilation)?
1.2.3 Problems of inadequate drainage (slippery stairs, water logging of gallery, clogged porous or foundation drains)?
1.2.4 Evidence of differential settlement (displaced/offset/open joints)?
1.2.5 Excessive seepage/sweating at any location along gallery/shaft?
1.2.6 Significant or excessive leakage at any location along gallery/shaft / porous drain? If yes, provide location(s).
1.2.7 Are proper arrangements made for the measurement of seepage into the gallery? Is the seepage measured separately from- 1. Porous pipes? 2. Foundation drains? And 3. Monolith Joints? Aretheabovearrangementssatisfactory ?
1.2.8 Has there been substantial progressive reduction in the seepage through the foundations? Is it due to choking of the drain holes? If so, indicate number of holes choked.
1.2.9 Are all the foundation and porous holes periodically cleaned with reaming tool and air water jetting? Indicate the last date of such cleaning and extent of variation observed in the seepage discharge before and after the cleaning.
1.2.10 Is the seepage water and the deposit, if any, from the seepage being regularly examined for chemical composition? If so, indicate the
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA result and the probable source of dissolved salts, if any.
1.2.11 Are any seepage water springs observed in the downstream area anywhere? If so, indicate the locations and state the physical nature of this seepage. Look out for such seepage spots particularly near the dykes, fault zone etc. Ascertain if chemical testing are made of water samples from such springs for dissolved salts.
1.2.12 Is there any leachate deposition? If yes provide location
1.2.13 Any other issues?
D-1.3 Drain Condition
1.3.1 Is the flow in the drain unusually high or low?
1.3.2 Presence of calcium or other deposits in drain?
1.3.3 Is dewatering pumping station fully operational?
1.3.4 Any problem inspecting pump?
1.3.5 Any obstruction preventing or impairing smooth operation? 1.3.6 Any deterioration of pump and associated equipment? 1.3.7 Is sump well clean and maintained? 1.3.8 Is V-notch before sump well clean and maintained?
1.3.9 Any other evidence of the drain being blocked/having reduced section?
1.3.10 Is the flow in the drain noticeably sporadic/irregular?
1.3.11 Does the drainage water have unusual color (leachate)?
1.3.12 Any other issues?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA D-1.4 Body Wall (Masonry/Concrete) of ‘NOF’ Dam and Spillway
1.4.1 What is the total seepage into gallery from the porous pipes in the dam at lake full condition? How does it compare with the seepage when the reservoir was first filled? (For the corresponding water level)
1.4.2 If there has been substantial reduction in this seepage? Ascertain and indicate the probable reasons therefore.
1.4.3 Has there been a tendency for gradual reduction of drainage through pipes and progressive appearance of sweating on the downstream face of the dam?
1.4.4 Has there been considerable leaching from the seepage water and deposition of lime near the seepage exit spots? 1.4.5 Are the samples of the seepage water and reservoir water being regularly tested for reactive and corrosive properties? 1.4.6 Is there excessive seepage, sweating at any locations on the downstream face of the dam?(Examine the monolith or construction joints for such seepage and leaching and indicate the findings) 1.4.7 Is there any swelling or cracking observed on the downstream face especially near the points of concentration of stresses like the toe or locations of abrupt change in geometry of the face of the opening? If so, indicate the details of observations. 1.4.8 Is the pointing on upstream face of the dam in good condition? If not, indicate the nature and extent of deficiency.
1.4.9 Are the registers and graphs showing the periodical measurements of seepage discharge from the porous drains in the gallery and from the downstream face at various lake levels maintained at site?
D 1.5 Waste Weir Bar and Tail Channel
1.5.1 Is the Concrete/masonry spillway bar in
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA good condition? Is there any leakage through the masonry or from the foundation? If so, what remedial measures are proposed/taken for minimizing the leakage? Is the record of leakage measurement maintained? What is the quantity of Seepage/Leakage on the date of inspection?
1.5.2 Is the coping over the spillway bar in good condition?
1.5.3 Does the upstream and downstream face of waste weir bar need pointing?
1.5.4 Is there any scouring on downstream side of the bar and/or EDA? If so what remedial measures are proposed/taken?
1.5.5 Are there any damages or undermining to guide walls, divide wall and other appurtenant? If so, what remedial measures are proposed/taken?
D 1.6 Structural performance of the ‘NOF’ and ‘OF’ Portions of Dam Foundations
1.6.1 Are there any signs of structural distress noticed in the dam spillway and foundations in the form of- i. Excessive deflection with respect to permissible deflection at the time of design ii. Tendency of gradual sliding iii. Cracking and upheaval or settlement in any part of the body wall or foundations,
iv. Excessive uplift, v. Excessive seepage and leaching through the body of the dam and the foundation. 1.6.2 Conspicuous weathering of materials or components in any portion of the body wall or the foundations.
E Spillway and Energy Dissipation Structure
E 1.1 Spillway
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.1.1 Any problems inspecting spillway (obstructed access, damaged catwalk)?
1.1.2 Any obstructions in or immediately downstream of the spillway?
1.1.3 Evidence of abrasion, cavitation or scour on glacis (e.g. exposed reinforcement)?
1.1.4 Presence of displaced, offset or open joints?
1.1.5 Presence of cracking (structural, thermal, along joints)?
1.1.6 Evidence of surface defects (honeycombing, staining, stratification)?
1.1.7 Concrete/masonry deterioration (spalling, leaching, disintegration)?
1.1.8 Presence of vegetation (growth in joints between blocks)?
1.1.9 Evidence of any other damage to joints and/or water stops?
1.1.10 Excessive seepage/sweating at any location on spillway glacis?
1.1.11 Significant leakage at any location on spillway glacis?
1.1.12 Any other issues?
E-1.2 Energy Dissipation Structure
1.2.1 Any problems inspecting energy dissipation structure?
1.2.2 Any obstructions in or immediately downstream of dissipation structure?
1.2.3 Evidence of abrasion, cavitation or scour on dissipation structure?
1.2.4 Presence of displaced, offset or open joints?
1.2.5 Presence of cracking (structural, thermal, along joints)?
1.2.6 Evidence of surface defects (honeycombing,
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA staining, stratification)?
1.2.7 Concrete/masonry deterioration (spalling, leaching, disintegration)?
1.2.8 Presence of vegetation (growth in joints between blocks)?
1.2.9 Evidence of any other damage to joints?
1.2.10 Any problems with under-drainage (blockage of open drain holes)?
1.2.11 Can the tail pond be drained easily for inspection of the stilling basin or bucket? If not, what are the alternatives available for dewatering? Please ascertain and indicate the last event of inspection of stilling basin (or bucket).
1.2.12 From the examination of the levels and contour plans and reference marks in tail channel; ascertain if there is progressive erosion and retrogression in the tail channel. If so, indicate the extent and location of such erosion with reference to the various components of dam, spillway, outlet, power house etc.
1.2.13 Is the concrete surface of the stilling basin and apron (or bucket) in good condition? Are there any indications of pitting, cracking, spalling or wearing of the surface of bedding concrete? If so, please give details of the nature and extent of the damage.
1.2.13 Is there any indication of abrasion and cavitation damage (pitting of concrete) especially at friction blocks, chute blocks and slotted roller teeth, the surface near the lower tangent point and the end sill? If so, please give the details of nature and extent of damage.
1.2.14 Is the under drainage of the stilling basin (or bucket) satisfactory? Are all the open drain holes clear and functioning well?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.2.15 Any other issues?
F Intake/Outlet and Water Conveyance Structure
F-1.1 Intake/Outlet Structure
1.1.1 Any problems inspecting intake/outlet structure (obstructed/unsafe access)?
1.1.2 Any obstructions in, upstream or downstream of intake/outlet structure?
1.1.3 Evidence of abrasion, cavitation or scour on intake/outlet structure?
1.1.4 Any evidence of structural distress (displaced/offset/open joints, cracking)?
1.1.5 Any evidence of surface defects and/or concrete/masonry deterioration?
1.1.6 Any other issues?
F-1.2 Water Conveyance Structure
1.2.1 Any problems inspecting intake/outlet structure (obstructed/unsafe access)?
1.2.2 Any obstructions in, upstream or downstream of water conveyance structure?
1.2.3 Evidence of abrasion, cavitation or scour on structure?
1.2.4 Any evidence of structural distress (displaced/offset/open joints, cracking)?
1.2.5 Any evidence of surface defects and/or material deterioration?
1.2.6 Any evidence of seepage or leakage from water conveyance structure?
1.2.7 Any other issues?
G-1 Hydro-Mechanical Component and Pump
G-1.1 Spillway Gates (Radial gates, Vertical lift gates, Automatic gates)
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.1.1 Any problems inspecting gate/Stop-logs (obstructed/unsafe access)?
1.1.2 Is the condition of the steel surface and the surface paint deteriorated?
1.1.3 Are any connection bolts of rubber seals loosened or damaged? If so, indicate the details of defects.
1.1.4 What is the general condition of rubber seals? Do any of the rubber seals show signs of weathering, hardening, cracking or tearing and damage?
1.1.5 Are the rubber seals of side and bottom touching uniformly all along the sealing surface?
1.1.6 Do the rollers(wherever applicable) touch the trackplates uniformly? Are the rollers well lubricated?
1.1.7 Are the embedded parts of spillway gates, emergency gates and stop-logs in sound condition and free from corrosion, uneven wear, cracking, chipping and dents? If not, state the nature of defects or deficiencies and observation, if any, regarding such defects.
1.1.8 Check the following for structural soundness of all members and welded, bolted and riveted connections, uneven wear, uneven bearing, cracking, chipping and dents and indicate the findings:
(1) Gate leaf and stiffeners (2) End arms (3) Trunnion girders / Yoke girder (4) Stop logs (5) Lifting beams (6) Gantry cranes (7) Tracks (8) Trunnion bracket
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA (9) Chains/ wire ropes (10) Bridge structure
1.1.9 Are the trunnion bearings of radial gates properly lubricated?
1.1.10 Is there any damage orwear caused to the seal plates? If so, indicate the nature of damage noticed.
1.1.11 Are any of the mechanical or structural components and fasteners or seals subjected to excessive wear? If so, please give details. Is there any tendency for recurring damage to any particular component? If so, please give details.
1.1.12 Is sufficient stock of spares which need frequent replacement maintained at the site?
1.1.13 Any issues with storage of equipment (emergency stop logs, lifting beam and gate leaves)?
1.1.14 Any deterioration, corrosion? Scaling? Pitting? Or cracking? Of equipment (connecting bolts, welds?) 1.1.15 Any obstructions preventing or impairing smooth operation? 1.1.16 Any problems with the rollers (not touching tracks, inadequate lubrification)? 1.1.17 Any debris, etc., in the gate grooves? 1.1.18 Any damages to Radial Gate trunnion pins? Gate arms? Lubrication? etc.?
1.1.19 Any damage to embedded parts above waterline? Access structure?
1.1.20 Any damage to concrete grooves?
1.1.21 Is the staff posted at the site for maintenance and operation of gates, hoists, equipments and electrical installations, well experienced, fully trained and conversant with the job requirements and
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA responsibilities?
1.1.22 Are the following documents maintained at the respective location of all the units? (1) Maintenance schedules specifying each operation, its frequency and ‘due’ and’ done’ dates. (2) Operating instructions with ‘dos’ and ‘don’t’ for all operational units.
1.1.23 Are the trunnion hub and the brackets well maintained?
1.1.24 Are the trunnions likely to get submerged during actual working of the spillway? If so, ascertain the causes for the same and specify. Please enquire for occurrence of such events, if any.
1.1.25 Are all the nuts of connecting bolts and anchorages properly tightened?
1.1.26 Any other issues?
G-1.2 Hoists, Cranes and Operating Mechanisms
1.2.1 Are the hoists working satisfactorily?
1.2.2 Any problems inspecting hoist/crane/operating mechanism?
1.2.3 Is sufficient stock of spares which need frequent replacement maintained at the site?
1.2.4 Is the full length of the chains or wire rope of the hoist in sound condition and free from broken strands?
1.2.5 Is the electrical wiring in sound condition?
1.2.6 Is the alternative power system for gate operation working properly?
1.2.7 Is the alternate hand operation system of hoist working
1.2.8 Any deterioration of equipment (connecting
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA bolts, welds, surface, paint work?)
1.2.9 Any wear or damage to wire cables and other moving parts?
1.2.10 Any obstructions preventing or impairing smooth operation?
1.2.11 Any health and safety concerns (e.g. lack of "danger" sign during maintenance)?
1.2.12 Any other issues?
G 1.3. Spillway Bridge, Hoist Bridge, Trunnion Level Bridge Catwalks
1.3.1 Are the decking, girders and structural supports of spillway bridge, hoist bridge, trunnion level bridge and catwalks structurally sound?
1.3.2 Is the chequered platform of the bridge structurally sound and safe?
1.3.3 Is there satisfactory arrangement to prevent unauthorized entry into the control structures and bridges?
1.3.4 Are the structural members and joints soundand free from corrosion?
1.3.5 When were the steel components painted last?
1.3.6 Is the surface of steel work and paints satisfactory?
1.3.7 Is the parapet or railing over the bridges sound, safe and painted?
1.3.8 Is the walkway properly encored to the piers?
1.3.9 Are the track rails for gantry cranes structurally sound and intact?
G-1.4
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.4.1 Any problems inspecting valve?
1.4.2 Any obstructions preventing or impairing smooth operation?
1.4.3 Any deterioration of valve and associated equipment?
1.4.4 Any other issues?
G-1.5 Walls: Guide walls/Divide walls/Junction walls/Return walls/Spray walls etc. (Strike out whichever is not applicable)
1.5.1 Are all the locations of such wall accessible for inspection, maintenance and repairs?
1.5.2 Is the drainage of back sides of the walls (wherever applicable) from the weep holes satisfactory? If not, indicate the nature of deficiencies.
1.5.3 Is there any tendency for the water to undercut the ends of the walls?
1.5.4 Is there any foundation erosion or scour noticed in the vicinity of such walls? If so, give the details of nature and extent of such damage.
1.5.5 Is there any surface erosion/damage caused, to face or body of such walls?
1.5.6 Do any of the walls show symptoms of unusual settlement, developments of cracks and tilting? If so, give details of the defects noticed.
1.5.7 Is there any damage to guide bunds? If so, give details of the damage.
G-1.6 EndWeir
1.6.1 Is it accessible?
1.6.2 Is there any erosion, pitting or spalling of the concrete or masonry surface? If so, give details
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.6.3 Is there any scour noticed on the immediate downstream of such weir? If so, give details of location and extent of such damage.
G-1.7 HydraulicPerformanceofEnergy DissipationArrangements
1.7.1 Do the flow conditions in the stilling basin (or bucket) have a tendency to draw material into the bucket and causes its churning and abrasion damage to the surface of buckets baffle blocks, apron and end sill? Is the hydraulic performance in agreement with the results of model studies? (wherever applicable) Ascertain the performance from observed tail water rating curves and deficient observation, if any, such as sweep outs and excessive erosion under plunge pools and locations of secondary rollers and retrogression.
G-1.8 Trash Racks
1.8.1 Is the trash rack fixed or movable?
1.8.2 What is the mode of cleaning? Is it manual or by TRCM?
1.8.3 Is the welding work on Trash Rack in sound health?
1.8.4 Any problems inspecting trash rack? 1.8.5 Problems of excessive debris and/or inadequate cleaning? 1.8.6 Any deterioration of trash rack (rust, corrosion, and damaged blades)? 1.8.7 Any other issues?
G-1.9 Trash Rack Cleaning Machines
1.9.1 Any problems inspecting trash rack cleaning machine?
1.9.2 Missing or inadequate spare parts (particularly requiring regular replacement)?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.9.3 Any deterioration of equipment (wheel trolleys, gantry structures, operating mechanism, connecting bolts, welds, surface, paint work?)
1.9.4 Any wear or damage to wire cables and other moving parts?
1.9.5 Any obstructions preventing or impairing smooth operation?
1.9.6 Missing or inadequate provision of back- up/standby power supply?
1.9.7 Any health and safety concerns (e.g. lack of "danger" sign during maintenance)?
1.9.8 Any other issues?
G-1.10 Pumps
1.10.1 Any problems inspecting pump? 1.10.2 Any obstructions preventing or impairing smooth operation? 1.10.3 Any deterioration of pump and associated equipment? 1.10.4 Any other issues? G-1.11 Approachb r i d g e ,operationplatformandcabin(foroutlets):
1.11.1 Are the decking, girders and structural supports of approach bridge structurally sound? 1.11.2 Is the floor of theoperating platform structurally sound and safe? 1.11.3 Is there satisfactory arrangement to prevent unauthorized entry into the control structures of the outlet? 1.11.4 Are the structural members and joints soundand free from corrosion? 1.11.5 When were the steel components painted last? 1.11.6 Is the surface of steel work and paint satisfactory? 1.11.7 Is the parapet or railingover the control tower, operating platform and approach bridge sound and safe?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA G-1.12 Outlet 1.12.1 Is the air vent periodically cleaned?
1.12.2 Are there any structural damages to the intake well? 1.12.3 Is there any leakage observed through the well proper and the conduit concrete or masonry? If so, give details of its location and extent. 1.12.4 Isthereanydamagenoticedtotheconduitconcr ete, breastwallandgateslots? 1.12.5 Isthebye-pass valve/filling-in-valve (wherever provided) operating satisfactory? (a) Take operation trials of the following as provided andrecord the observations and defects noticed, if any. (1) Service gate(s). (2) Emergency gate(s). (3) Stop-log gate(s). (4) Sluice valves.
Note- (i) The operating trial for the emergency gate shall be taken with service gate in partially open position to test the capability of emergency gate for self- closing under these conditions. The trial for the operation of the emergency gate under balanced condition of water pressure also needs to be taken (ii) To guard against the possibility of outlet gate hoist being operated forcibly after closed position of gate a “Distinctive Mark” should be insisted or check the functioning of the limit switches. 1.12.6 Aretherevibrationsandnoisenoticedinoperati onofout-letgatesatanytime? Ifso,areanyperiodicalobservationstaken toascertaintheirseverity?
1.12.7 Is the energy dissipation arrangement working satisfactorily for all the discharges? Is there any structural damage to the energy dissipation structure? If so, give details of nature and extent of damage.
1.12.8 Is the conduit structurally sound and
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA reasonably leak proof? If not, give details of nature and extent of the defects.
1.12.9 Is there any seepage noticed around the conduit as ascertained from the observations of the downstream conditions? If so, is it likely to cause (In case of earth dams) erosion and piping?
G-1.13 OutletGates
1.13.1 Is the surface of gates and the paint deteriorated? 1.13.2 Are the connecting bolts of rubber seals properly tightened or damaged? 1.13.3 Do the rubber seals show signs of weathering and damage and need replacements? 1.13.4 Aretherubbersealsofsidesandbottom touchingthebearing surfaceuniformly? 1.13.5 Doalltherollerstouchthetrackplates? 1.13.6 Aretherollerswell lubricated? 1.13.7 Arethestemrodsforliftingthegates perfectly straight? 1.13.8 Is the operation of outlet gates smooth? Are the actual operations of lifting and lowering of the gates and hoist mechanisms adequate and smooth?
1.13.9 Are all the gears and hoist mechanisms well lubricated?
1.13.10 Is the storing arrangement for emergency gate leaves and the stop logs in satisfactory condition?
1.13.11 Arethesealplates/seatsinsoundcondition?
1.13.12 Isthefulllengthofwirerope(whereverapplicable )ofthehoistinserviceableconditionandfreefro manybrokenstrands?
1.13.13 Are allthenutsofconnectingbolt andanchorsproperly tightened?
1.13.14 Are all the lifting beams in proper working
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA order and in levelled condition? If not ascertain the nature and extent of problems. Do any of the mechanical or structural parts of the gate, fasteners of hoist show signs of excessive wear? If so, please give details.
1.13.15 Is there any tendency for recurring damage to any particular component or components? If so, please give details.
1.13.16 Is sufficient stock of spares, which need frequent replacement, maintained at the site?
G-1.14 River Outlet/River Sluice
1.14.1 Is the overall condition of river outlet works/river sluices satisfactory? Is the operation of the gate (Service/Emergency/Stop-log) satisfactory as ascertained by taking operating trial? If not, indicate the defects noticed.
1.14.2 Are the trash racks (wherever provided) cleaned before monsoon?
1.14.3 Is there excessive silting on the upstream of the sluice?
1.14.4 When the gates were last opened for desilting, etc.?
1.14.5 Please indicate the approximate quantity of the leakage through the gates, if any.
1.14.6 Is there any seepage or leakage through the conduit surface?
1.14.7 Is there any damage to the upstream and downstream convergence of the conduit?
1.14.8 Is the condition of energy dissipation arrangement satisfactory? If not, indicate nature and extent of damage. Is there any retrogression noticed in the downstream channel? If so, give details of
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA nature and extent of damage.
H-1 Access Road
H-1.1 General Condition
1.1.1 Any problems ensuring security of dam site (including gates and fencing)?
1.1.2 Is there a properly constructed andwell maintainedall weatheraccess road to the dam site?
1.1.3 What is the type of the pavement of the Bituminous access road and its condition? road and concrete road, in good condition.
1.1.4 Are there properly constructed and well maintained access road arrangements to the following components for inspection, maintenance and repairs? Top of Dam Spillway Gates and hoisting arrangement Drainage gallery, adits and exits Bridge structure Downstream stilling basin Junction and abutments Outlet control tower Outlet gates Toe of earth dam, downstream drainage arrangements and berms. All saddle dams.
1.1.5 What is the general condition of all the masonry structures on various access roads?
1.1.6 Are all the structures on the access roads adequately safe for allowing passage of plant machinery for emergent repairs?
1.1.7 Any obstructions along or at entrance to access road (temporary or long-term)?
1.1.8 Any slope stability issues (road embankment or adjacent slopes)?
1.1.9 Profuse growth of weeds/grass on or in vicinity of access road?
1.1.10 Any drainage problems (standing water on or adjacent to road)?
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.1.11 Any other degradation to road surface (ruts, potholes, cavities, cracking)?
1.1.12 Any other issues?
I-1 Instrumentation
I-1.1 General Condition
1.1.1 Are all the instruments installed accessible? As per (Attach separate list). Appendix-I Are all the locations properly lighted, ventilated and adequately protected from possibilities of damage? 1.1.2 Any problems inspecting instrument (obstructed/unsafe access)? 1.1.3 Is the instrument vulnerable to damage or theft (inadequate protection)? 1.1.4 Any problems ensuring correct functioning of instrument (lighting, ventilation)? 1.1.5 Any evidence of degradation to condition of instrument (rusting, vandalism)? 1.1.6 Are all the instruments in working order? Ascertain the cases of instruments going out of order and indicate. 1.1.7 Are all the registers of observations posted up-to-date? Please take test observations and initial the register. 1.1.8 Are all the plotting of the instrumentation data completed up-to-date? Are sufficient stocks of spares, gauges, master gauges, and stationary items etc., maintained at the site for uninterrupted data collection? 1.1.9 Operator or public safety issues? 1.1.10 Any other issues?
I-1.2 CommunicationFacilities
1.2.1 Are following facilities available at dam site? (1) Wireless Telephone / mobile/Fax/Internet.
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.2.2 Any other issue (please indicate part, location, etc., as necessary)
K-1 Emergency Preparedness
K-1.1. Emergency Action Plan
1.1.1 Is the Emergency Action Plan (EAP) prepared for the dam as per the national guidelines? If not, the expected date of preparation of guidelines
1.1.2 When EAP was last updated?
1.1.3 If not, are any dam staff unaware or insufficiently conversant with the EAP?
1.1.4 Any concerned authorities unaware or insufficiently conversant with the EAP?
1.1.5 Are communication directories/contact details and other dynamic information are being updated annually?
1.1.6 Any problems accessing or operating the communication/ warning system?
1.1.7 Are inundation maps updated and available to concerned authorities?
1.1.8 Are the concerned authorities informed about the system of emergency reporting procedures and warning?
1.1.9 Are available safety spots on the downstream of the dam identified and made known to the concerned authorities? Are adequate warning devices and facilities provided at the dam?
1.1.10 Are proper arrangements made for security of the dam and preventing cases of unauthorized trespass, vandalism and sabotage to the dam works?
1.1.11 Date of last annual stakeholder consultation meeting along with mock drill exercise conducted.
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Observations and Conditionb recommendations, if (Unsatisfactory/ Responsea any, of the S. No. Inspection Item Poor/Fair/ authorized Satisfactory) inspecting officer Y N NA 1.1.12 Does the EAP disseminated to all theconcerned stakeholders?
1.1.13 Any other issues?
K-1.2 Inspection of Records
1.2.1 Whetherfollowing Dam Safety Documents areprepared and approved by the competent authority? I. As Built Drawings II. EAP III. Completion Report IV. DataBook V. OandM Manual 1.2.2 Are the relevant documents reviewed and updated from time to time? 1.2.3 Are all the members of the maintenance staff adequately trained and fully conversant with their responsibilities concerning. (a) Designer’s Operation Criteria. (b) Standing Operating Procedures. (c) Maintenance and Vigilance Procedures of the dam. (d) Maintenance and operation of all control equipments. (e) Reservoir Operation Schedules, Gate Operation Schedule (f) Maintenance and Operation of all instruments. (g) Identification of signs of deficient behaviour. (h) Reporting Procedures of emergency situations. (i) Emergency repairs
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L-1.1 Inspection Photographs
1.1.1 Information to be furnished as per Annexure – II
Respond either yes (Y), no (N) or not applicable (NA).
Condition: Please rate the condition as either Satisfactory, Fair, Poor or Unsatisfactory as described below:
1. Satisfactory - No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the applicable regulatory criteria or tolerable risk guidelines.
2. Fair - No existing dam safety deficiencies are recognized for normal loading conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
3. Poor - A dam safety deficiency is recognized for loading conditions which may realistically occur. Remedial action is necessary. Poor may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Further investigations and studies are necessary.
4. Unsatisfactory - A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
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Part 2b – Consolidated Dam Health Status Report:
Observations/Significant SN Remedial Measures Suggested Deficiencies Noticed
1. NO
2.
3.
4.
..
..
10.
Overall condition of dam based on above inspection – Unsatisfactory/Poor/Fair/Satisfactory (tick appropriate)
* Overall Safety Category of the Dam -
*Category I– deficiencies which may lead to failure;
Category II – major deficiencies requiring prompt remedial measures;
Category III – minor remedial measures which are rectifiable during the year
Name of Official(s) and Signature(s):
Date:
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Appendix-II: Checklist of various instruments installed on large dams:
CHECKLIST OF VARIOUS INSTRUMENTS INSTALLED ON LARGE DAMS Name of Dam: Tawa Location:
Date last Analysis of Whether in Agency Since when calibration Observation data done Data sent to Sl. working responsible for Name of Instruments Nos. Location installed s maintained at field DSO regularly? Remarks No. condition Date for next data collection (Month/ Year) (Yes/No) level (Yes/No) (Yes/No) calibration and processing (Yes/No) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) HYDRO-METEOROLOGICAL INSTRUMENTS
1. Raingauge on Dam
2. Raingauge in the Catchment
3. Pan Evaporimeter
4. Wind Velocity Recorder
5. Wind Direction Recorder
6. Wave Height Recorder
7. Wet and dry bulb Thermometer
8. Barometer
9. Thermometers for air Temp.
10. Thermometers for Reservoir Water Temp.
11. Automatic Weather Station
12. Reservoir level gate (i) Staff gate (ii) Automatic
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Date last Analysis of Whether in Agency Since when calibration Observation data done Data sent to Sl. working responsible for Name of Instruments Nos. Location installed s maintained at field DSO regularly? Remarks No. condition Date for next data collection (Month/ Year) (Yes/No) level (Yes/No) (Yes/No) calibration and processing (Yes/No) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) 13. Other Hydro-meteorological Instruments, if any (i) . (ii) . (iii) .
GEO-TECHNICAL INSTRUMENTS
1. Piezometers (i) Stand pipe (ii) Casagrande (iii) Twin Tube (iv) Vibrating wire
2. Uplift pressure cell (i) For permeable foundation (ii) For Rock foundation
3. Strain Gauge (i) Mechanical Strain Gauge (ii) Electrical Strain Gauge
4. Strain Meter (i) Vibrating wire
5. Thermometers (i) Resistance (ii) Vibrating Wire
6. Stress Meter (i) Mechanical (ii) Electrical
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Date last Analysis of Whether in Agency Since when calibration Observation data done Data sent to Sl. working responsible for Name of Instruments Nos. Location installed s maintained at field DSO regularly? Remarks No. condition Date for next data collection (Month/ Year) (Yes/No) level (Yes/No) (Yes/No) calibration and processing (Yes/No) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) 7. Seepage Measurement (i) V-Notch (ii) Other devices
8. Automation (i) Data logger (ii) Data Acquisition system (iii) Computers
9. (i) Plumb Bob – Direct
(ii) Plumb Bob – Inverted
(iii) Detachable Gauges for Surface Displacement
(iv) Joint meter for internal joint movement
(v) Tilt Meter
(vi) Foundation Settlement Deformation Meter
(vii) Inclinometer
10. Other Geotechnical Instruments, if any (i) . (ii) . (iii) .
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Date last Analysis of Whether in Agency Since when calibration Observation data done Data sent to Sl. working responsible for Name of Instruments Nos. Location installed s maintained at field DSO regularly? Remarks No. condition Date for next data collection (Month/ Year) (Yes/No) level (Yes/No) (Yes/No) calibration and processing (Yes/No) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) GEODETIC INSTRUMENTS
1. Total Station
2. Survey Markers
3. Settlement Plates
SEISMIC INSTRUMENTS
1. Seismograph
2. Accelerograph
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Appendix-III: Summary Table for Annual O&M Budget:
CURRENT YEAR PREVIOUS BUDGET NO. BUDGET ITEM YEAR COST REMARKS (YR ……..) (Rs) (Rs) A. ESTABLISHMENT 1 SALARY OF REGULAR STAFF INCLUDING ALL OTHER BENEFITS 2 TRAVEL EXPENSES 3 OFFICE EXPENSES 4 MOTOR VEHICLE EXPENSES 5 MAINTENANCE OF OFFICE & COLONY COMPLEX SUB-TOTAL - A B. WORKS 1 CIVIL WORKS 1.1 CONCRETE / MASONRY DAM 1.2 EARTHEN DAM 1.3 INTAKE &OUTLETS IN EARTHEN DAMS/ ABUTMENTS 1.4 SLUICES IN CONCRETE / MASONRY DAMS 1.5 APPROACH / INSPECTION ROADS WITHIN DAM AREA 2 SLUICE GATES 2.1 OUTLETS IN EARTHEN DAMS - SERVICE / EMERGENCY GATES, 2.2 SLUICES IN CONCRETE / MASONRY DAMS – SERVICE / EMERGENCY GATES, 3 INSTRUMENTATION 4 MISCELLANEOUS WORKS 5 SALARY OF WORK- CHARGED STAFF INCLUDING ALL BENEFITS 6 MATERIALS TO BE STORED BEFORE MONSOON SUB-TOTAL - B 7 CONTINGENCY (10%) ON
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CURRENT YEAR PREVIOUS BUDGET NO. BUDGET ITEM YEAR COST REMARKS (YR ……..) (Rs) (Rs) SUB-TOTAL OF A & B 8 TOOLS & PLANTS SUB-TOTAL- C 9 TOTAL ANNUAL COST
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Appendix-IV: Basic Drawings of the Dam &Spillway.
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O & M Manual of Tawa Dam May 2020 1. Index Map:
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O & M Manual of Tawa Dam May 2020 2. Satellite map TawaDam:
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O & M Manual of Tawa Dam May 2020 3. Location Map:
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O & M Manual of Tawa Dam May 2020 4. Cross section of dam:
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O & M Manual of Tawa Dam May 2020 5. L-section of dam (with location & log of Drill Holes & Test Pits):
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O & M Manual of Tawa Dam May 2020 6. L-section of dam (with Layout Plan of Instruments installed):
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O & M Manual of Tawa Dam May 2020 7. Section and Plan of Spillway:
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O & M Manual of Tawa Dam May 2020 8. Layout Plan of Project:
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O & M Manual of Tawa Dam May 2020 9. Plan of Foundation Gallery of Masonry Dam:
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O & M Manual of Tawa Dam May 2020 10. Area Capacity Curve:
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O & M Manual of Tawa Dam May 2020 11. Inflow in the reservoir and discharge passing over dam:
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O & M Manual of Tawa Dam May 2020 12. Discharge for Sethani Ghat, Hoshangabad:
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O & M Manual of Tawa Dam May 2020 13. Gauge Discharge curve of River Narmada for Sethani Ghat, Hoshangabad:
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