August 2020 O&M Manual of Chimoni Dam

Operation and Maintenance Manual for CHIMONI DAM (KL07HH0050) Water Resources Department State of Kerala

August 2020 O&M Manual of Chimoni Dam

Operation and Maintenance Manual for Chimoni Dam

(Prepared By)

KERALA WATER RESOURCES DEPARTMENT STATE OF KERALA

August 2020

August 2020 O&M Manual of Chimoni Dam

Government of Kerala Operation and Maintenance Manual Chimoni Dam

August 2020 O&M Manual of Chimoni Dam

KERALA WATER RESOURCES DEPARTMENT

DISCLAIMER

This Operation and Maintenance Manual for Chimoni Dam in no way restricts the dam operators in digressing from her/his responsibilities. The Dam Operators must exercise appropriate discretion and good judgment based on actual site condition when implementing and using the operation and maintenance manual for managing the workings of the dams and appurtenant structures.

The manual was developed for the purpose of organising and managing the operation, inspection and maintenance of the dams for reducing risk and optimizing performance of the dams as a general guide.

For any information, please contact:

THE CHIEF ENGINEER PROJECT II KERALA STATE WATER RESOURCE DEPARTMENT THIRUVANANTHAPURAM, KERALA Email: [email protected]

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August 2020 O&M Manual of Chimoni Dam

FOREWARD

Globally, the Operation and Maintenance (O&M) Manual of a dam/barrage is one of the most important documents which is supposed to be put in practice right from the initial filling of reservoirs. In order to address the operation and maintenance aspects, ongoing Dam Rehabilitation and Improvement Project (DRIP) has requisite scope to prepare new or update existing O&M manuals for all DRIP dams, which will become very helpful to Dam/Barrage Owners in addressing the dam specific issues comprehensively in future.

This Operation and Maintenance (O & M) Manual developed is a detailed set of written descriptions with step-by-step procedures for ensuring that the dam is safely operated, frequently inspected and properly maintained. Timely inspection and preventative maintenance is necessary for the safe functioning of the dam and continued productive use of the dam and reservoir.

The format of this manual is prepared following the principles published in 2018 CWC Guidelines for Operation and Maintenance of dams for the use by all Dam/Barrage Owners in developing their own site-specific manuals. Each section of the document provides the necessary instructions to operate inspect and maintain their dams.

It is recommended that all dam officials in charge to use this manual for ensuring that the dam is operated and maintained in a sustainable manner and will continue to derive benefits.

Chief Engineer Projects – II Thiruvananthapuram

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PREFACE

The Chimoni dam is owned and operated by the Water Resources Department of Government of Kerala. Chimoni Dam is constructed in Chimonipuzha, a tributary of Karuvannur River in District.

The content of this Operation and Maintenance Manual for Chimoni Dam serves as a model for the sole purpose for managing the operation, inspection and maintenance required to be carried out to reduce risks and optimizing performance of the dam. It will assist in ensuring that the dam is functioning safely and is being properly operated and maintained. Timely inspection and maintenance is necessary for the safe functioning of the dam and continued productive use of the dam and its 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.

The Manual has been prepared based on the available data from existing DPR and from Mechanical department as per the Guidelines for preparing Operation and Maintenance Manuals for Dams (Doc. No. CDSO_GUD_DS_O3_v1.0) published by CWC in the year 2018 under DRIP.

It is recommended that all dam officials involved with the operation of the dam, use this Manual to ensure that the dam is operated and maintained in a sustainable manner and in order to continue to derive benefits.

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Team Members Involved In Preparing This O&M Manual.

Sri. JoshyK.A Chief Engineer, IDRB Sri. Binu Jayakumar J (in full addl charge) Overall review & Sri. SenT.G Chief Engineer, Project II Approval Sri. Alex Varghese (in full addl charge) Sri.D.Biju Director. IDRB Sri. Priyesh R (in full addl Reviewer chargr) Sri.Mohan I. K Superintending Engineer , Irrigation Reviewer Central Circle(Full Addl.charge) Sri. Balashankar Executive Engineer, Irrigation Division, Thrissur. Sri. Jayaraj T K (in Full addl Charge)

Sri. Anandakrishan Assistant Executive Engineer, Chimoni Dam Project Sub Division Prepared Draft Sri. Rappai Echippara manual using available data

Sri. Sibu T A Assistant Engineer, Chimoni Dam Project Section No.1 & 2 Sri. Shajan K A Echippara

Smt. Sukanya R

Overseer, Chimoni Dam Project Smt Soumya Sudheesh Assisted in preparing Section , Echippara the manual

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CONTENTS Disclaimer ...... i

FOREWARD ...... ii

PREFACE ...... iii

Team Members Involved In Preparing This O&M Manual...... iv

Contents ...... v

LIST OF FIGURES ...... viii

LIST OF TABLES ...... ix

ABBREVIATIONS ...... x

CHAPTER 1. GENERAL INFORMATION ...... 1

1.1 Purpose, Location & Description of Chimoni dam ...... 1

1.2 Assignment of Responsibility ...... 15

1.3 Collection and Reporting of Dam and Reservoir Data ...... 19

1.4 Public and Project Staff - Health and Safety ...... 22

1.5 Restricted Areas ...... 22

1.6 Staff Position, Communication & Warning System ...... 22

1.7 Distribution of Operation & Maintenance Manuals ...... 29

1.8 Supporting Documents & Reference Material ...... 29

1.9 Typical Schedule of Duties ...... 29

1.10 Hydro-Mechanical Inspection /Checks ...... 33

CHAPTER 2. PROJECT OPERATION ...... 34

2.1 Basic data ...... 34

2.2 Operation Plan ...... 41

2.3 Normal Operations ...... 43

2.4 Emergency Operations ...... 54

2.5 Drawdown Facility ...... 59

CHAPTER 3 - PROJECT INSPECTIONS ...... 61

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3.1 Types of Inspections ...... 61

3.2 Informal Inspections ...... 62

3.3 Scheduled Inspections ...... 63

3.4 Special (Unscheduled) Inspections ...... 65

3.5 Comprehensive Evaluation Inspections ...... 65

CHAPTER 4- PROJECT MAINTENANCE ...... 71

4.1 Maintenance Plan ...... 71

4.2 Maintenance Priorities ...... 72

4.3 Maintenance Items ...... 74

4.4 Materials Requirements for Maintenance during Monsoon Period ...... 96

4.5 Establishment Requirement ...... 97

4.6 Preparation of O&M budget ...... 97

4.7 Maintenance Records ...... 102

CHAPTER 5 - INSTRUMENTATION AND MONITORING ...... 104

5.1 Instrumentation at Chimoni Dam ...... 105

5.2 FREQUENCY OF MONITORING ...... 105

5.3 Data Processing and Evaluation ...... 106

5.4 Visual Observations ...... 108

CHAPTER 6 – REMEDIAL MEASURES TAKEN EARLIER ...... 109

CHAPTER 7 – UPDATING THE MANUAL ...... 114

ANNEXURE- A - BASIC DRAWINGS OF CHIMONI DAM ...... 115

ANNEXURE B- HYDROLOGIC REVIEW REPORT ...... 122

ANNEXURE C- Gate Manufacturer’s Operation Manual ...... 132

ANNEXURE D- Report of Dam Safety Authority during the Inspection of 27-10-06 ...... 146

ANNEXURE –E- Check list for Inspection ...... 149

ANNEXURE F- Pre & Post Monsoon Inspection report of the Project ...... 186

ANNEXURE G – NOTIFICATION FOR STRENGTHENING OF ALARM AND WARNING SYSTEM FOR SAFETY OF PEOPLE FROM SUDDEN RELEASE OF

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WATER FROM DAMS ISSUED BY NATIONAL DISASTER MANAGEMENT AUTHORITY (OCTOBER 2015) ...... 210

Annexure- H- Glossary ...... 211

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LIST OF FIGURES Figure 1. 1 Spillway ...... 5

Figure 1. 2 Earthen dam ...... 5

Figure 1. 3 River sluice ...... 6

Figure 1. 4 Hoist Mechanism ...... 6

Figure 1. 5 Earthen dam downstream pitching ...... 7

Figure 1. 6 Upstream Spillway portion ...... 7

Figure 1. 7 DEM of Karuvannur basin ...... 8

Figure 1. 8 Longitudinal section ...... 9

Figure 1. 9 Non overflow section ...... 10

Figure 1. 10 Over flow section ...... 11

Figure 1. 11 Cross Section of Earthen Dam ...... 12

Figure 1. 12 Cross section through outlet pipe ...... 13

Figure 2. 1 Spillway and stilling basin ...... 41

Figure 2. 2 Photograph of spillway and stilling basin ...... 41

Figure 2. 3 Section of Radial gate ...... 42

Figure 2. 4 Photograph of radial gate ...... 43

Figure 2. 5 Rule Curve ...... 46

Figure 5. 1 Masonry Dam parapet before painting ...... 110

Figure 5. 2 Masonry Dam parapet after painting ...... 110

Figure 5. 3 Guniting Upstream face ...... 111

Figure 5. 4 Camp Office cum Watchman Cabin ...... 111

Figure 5. 5 Access Road ...... 112

Figure 5. 6 Earthen dam before parapet construction ...... 112

Figure 5. 7 Earthen dam parapet after construction ...... 113

Figure 5. 8 Flat type Quarters ...... 113

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LIST OF TABLES Table 1. 1 Overall Responsibilities for Chimoni Dam ...... 15

Table 1. 2 Roles& Responsibilities of AEE & AE ...... 16

Table 1. 3 Roles & Responsibilities of SE & EE ...... 17

Table 1. 4 Roles & Responsibilities of the Chief Engineer ...... 18

Table 1. 5 Example Proforma for recording Flow Data ...... 21

Table 1. 6 Table Showing Schedule of Duties/Inspection ...... 30

Table 2. 1 Troubleshooting for Motors ...... 50

Table 4. 1 O&M BUDGET COSTS (ANNUAL) ...... 98

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ABBREVIATIONS

BIS Bureau of Indian Standards CDSO Central Dam Safety Organisation CWC Central Water Commission SDSO State Dam Safety Organisation O & M Operation and Maintenance DRIP Dam Rehabilitation and Improvement Project DSRP Dam Safety Review Panel DTM Digital Terrain Model EAP Emergency Action Plan FMIS Flood Management Information System GPS Global Positioning System (uses GPRS for data transmission like browsing the web) FRL Full Reservoir Level MWL Maximum Water Level MDDL Minimum Draw Down Level DSL Dead Storage Level RT-DAS Real Time Data Acquisition system SCADA Supervisory Control and Data Acquisition DDMS Dam Deformation Monitoring System EDA Energy Dissipation Arrangement HM works Hydro-Mechanical works DG set Diesel Generator set ADAS Automated Data Acquisition System RMU Remote Monitoring Unit PC Personal Computer AE Assistant Engineer AEE Assistant Executive Engineer EE Executive Engineer SE Superintending Engineer CE Chief Engineer

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CHAPTER 1. GENERAL INFORMATION

This document represents a detailed Operation and Maintenance (O&M) Manual for Chimoni Dam, Kerala, providing written descriptions of procedures for ensuring that the dam operates safely and is kept in a good condition by periodic inspections, repairs, and maintenance in a sustainable manner. Timely maintenance is important for the continued safe functioning and productive use of the dam and reservoir. The Manual has been prepared primarily for the dam operation’s staff and their supervisors who are assigned the responsibility for the physical operations and maintenance of the dam. It contains, as a minimum, all information and instructions necessary for them to perform their allotted tasks in a safe manner. In addition to instructions for dam operations staff, the Manual includes all necessary instructions for other staff directly or indirectly involved in operating and maintaining the dam. It is essential that the Manual or a copy of the Manual along with supporting data including drawings and technical documents are available at site for ready reference.

1.1 PURPOSE, LOCATION & DESCRIPTION OF CHIMONI DAM

Chimoni Dam constructed in Chimonipuzha, a tributary of Karuvannur River in . The project is proposed to irrigate a gross area under crop of 35700 hectares. Besides the Irrigation benefit the project also ensures protection of 5600 hectares of land in the - Chettuva area from saline intrusion. The project also affords benefits by way of moderating floods in Karuvannur Basin.

The Chimoni dam and the reservoir is situated 38.00 Km east of Thrissur. Nearest Railway Station is 29 Km away from Chimoni Dam. The project consists of a dam across Chimoni River, a tributary of Karuvannur River, at Echippara in Thrissur district to irrigate 13000 Hectare of Paddy fields and to make possible two crops and single crop in Kole lands. AS there is no canal system in this project. The regulated flow from the reservoir is let down into the River and is diverted to fields by means of Regulators constructed at various points. The Storage capacity of the reservoir is 179.00 Mm3 and the water spread area is 10.10 Km2.The project area lies between latitude 10°20’ &10°35’N and longitude 76°06’ & 76°30’E.

In the view of the high density of population and heavy deficit in rice production in the state and intensive drive for additional food production was launched by the state Government. Accordingly a special division for the investigation of the development of Karuvannur Basin was formed as per the Government order No. M.S/151/PW Dated 19-07-1968. The investigation for the project started in 1968. The construction started in 1974 and completed in 1996.

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Salient Features

1. Name of Project : Chimoni Dam project (CDP) 2. Name of River Basin : Karuvannur 3. Year of Completion : 1996 4. Name of District, Thaluk, Village : Thrissur, Chalakkudy, 5. Ayacut Area : 13000 ha in Thrissur Kole Lands 6. Type of Dam : Masonry and Earth 7. Maximum water level : +79.700MSL 8. Full Reservoir Level : +79.400MSL 9. River Sluice Level & Dead Storage : +40.000MSL 2.85Mm3 10. Spillway Crest Level : +72.200MSL 11. Top Level of Masonry dam : +81.200MSL 12. Top Level of Earth dam : +82.700MSL 13. River Bed Level : +28.380 MSL 14. Height above deepest foundation : 52.82m 15. Energy Dissipation arrangement : Flip bucket 16. Length of Masonry dam : 495m 17. Length of Earthen dam : 686.50m 18. Top Width of dam : 5m 19. Spillway Length : 40.00m Clear 20. Type and Size of Shutter : 4 Nos Radial 10.00x7.50m Each 21. Type of out let : River sluice 22. Size of outlet pipe : 180cm 23. Water spread area at FRL : 10.10 Sq.Km 24. Catchment Area : 72.13 Sq.Km

i) Brief History Of Dam/Project

The project investigation was first started in 1959 by Irrigation Division, Thrissur. A dam across Chimoni River was proposed and some piece –meal investigation work was continued for several years till 1968.The detailed investigation was taken up after the formation of Investigation Division in 1968.Gauging of the river and other Hydrological data were collected. The reservoir area was surveyed and detailed boring along the dam line was also taken.

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The project construction was proposed to be completed in four years. The main dam across the river is to be constructed in rubble in cement mortar and saddle dam with earth. The Division and Sub division offices were proposed at Echippara estate area near the saddle dam proposed. The work was proposed to be executed by contract agency. The cost of the project was estimated to Rs.561.56 Lakhs.

Chimoni Project is one of the most economical projects of Kerala. There is no canal system for distribution of water as the river itself able to convey water to the fields thus saved not only costly canals but also time lag in utilisation of the potential, which is the general feature of the projects of Kerala.

The cost of the Integrated project per hectare of the Project benefitted was Rs.9574/-

The benefit cost ratio worked out to 5.12 at 5% interest. By commissioning of the project 11000 hectares of paddy fields in Kole area got entire water for Puncha and 6200 hectares of Kole fields got additional Mundakan crop besides the 5400 hectares of paddy fields in Chettuvai, Vallivattom, and area. Flood control is an added advantage.

ii) Vicinity Map, Google Map, Catchment Area Plan

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iii) Photographs

Figure 1. 1 Spillway

Figure 1. 2 Earthen dam

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August 2020 O&M Manual of Chimoni Dam

Figure 1. 3 River sluice

Figure 1. 4 Hoist Mechanism

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Figure 1. 5 Earthen dam downstream pitching

Figure 1. 6 Upstream Spillway portion

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Figure 1. 7 DEM of Karuvannur basin

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iv) SECTIONS

Figure 1. 8 Longitudinal section

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Figure 1. 9 Non overflow section

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Figure 1. 10 Over flow section

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Figure 1. 11 Cross Section of Earthen Dam

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Figure 1. 12 Cross section through outlet pipe

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MASONRY DAM BLOCK WISE DETAILS

Block No Chainage (m) Type

Block-1 40.00 – 70.00

Block-2 70.00 – 100.00

Block-3 100.00 – 130.00

Block-4 130.00 – 160.00 Left non overflow Block Block-5 160.00 – 1900.00

Block-6 190.00 – 220.00

Block-7 220.00 – 250.00

Block-8 250.00 – 275.00

Block-9 275.00 – 299.50 Spillway Block Block-10 299.50 – 326.50

Block-11 326.50 – 350.00

Block-12 350.00 – 368.00

Block-13 368.00 – 410.00 Right non overflow Block

Block-14 410.00 – 440.00

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1.2 ASSIGNMENT OF RESPONSIBILITY The Executive Engineer, Irrigation Division Thrissur, is the owner and has the final authority and responsibility for the operation and maintenance of the dam. Identification of all areas of responsibilities connected with the operation and maintenance of the dam are covered in this section. The officer’s responsibilities for the various functions are identified by their designation and, in particular, the responsibilities of operating personnel are specifically identified in below and include regularly scheduled duties which staff personnel are required to perform as outlined in the following tables.

Table 1. 1 Overall Responsibilities for Chimoni Dam

Sl No Particulars Remarks

1 Implementing Agency Water Resources Department (Irrigation Department)

2 Project Administration Officer in charge Chief Engineer Project II, Thiruvanandhapuram

3 Operations of Equipment at the Dam Assistant Executive Engineer, Chimoni Dam Project Sub-Division

4 Reservoir inflow and Flood forecasting Assistant Executive Engineer, Chimoni Dam Project Sub-Division

5 Authorizing spillway flood releases Assistant Executive Engineer, Chimoni Dam Project Sub-Division

6 Authorizing releases for various purposes Assistant Executive Engineer, Chimoni like irrigation, water supply hydro-power, Dam Project Sub-Division etc.

7 Recording reservoir Data Assistant Engineer, Chimoni Dam Project Section No.2

8 Routine inspection Executive Engineer, Irrigation Division , Thrissur

9 Maintenance Assistant Engineer, Chimoni Dam Project Section No.2

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1.2.1 Roles and Responsibilities of the AEE and AE during Monsoon Table 1. 2 Roles& Responsibilities of AEE & AE

(Flood condition assessment, warning, flood mitigation, and other responsibilities)

1 Coordinate with the Chief Engineer of Project II & to get the information about the rainfall in the catchment and inflow status at the state boundary and to bring it to the notice of the EE/SE/CE

2 Assist the EE/SE/CE to issue notification to the villagers downstream in Newspapers, Radio, TV News channel to be alert regarding the flood situation

3 Assist the EE/SE/CE to coordinate with the Revenue authorities (District Administration) to alert the downstream villagers to evacuate the flood zone to prevent loss of life and live stock

4 Assist the EE/SE/CE to coordinate with the CWC flood monitoring authorities on the flood condition

5 Maintain the reservoir water level gauge register and to update on hourly basis during floods and to bring to the notice of EE/SE/CE

6 Assess the inflows in the reservoir as per the approved reservoir operation and to prepare Performa consisting of the status of the reservoir capacity and releases from the reservoir as per the standard Performa and to submit to the EE/SE/CE

7 Submit to the EE/SE/CE on the inflows and releases from the reservoir and status of the reservoir twice in the day

8 Maintain the spillway crest gate operation log book

9 Operate the Spillway crest gates for flood mitigation as per the instructions of the EE/SE/CE and to update the Gate operation Log book

10 Observe the seepages in the drainage Gallery with respect to the reservoir head and record the seepages in the infiltration gallery and to immediately bring to the notice of the EE/SE/CE in case of excessive seepage ,leakage in any specific blocks and porous drains

11 Maintain the pump operation log books for the dewatering pumps in the drainage gallery and to submit to EE/SE/CE

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12 Observe the gates and to see that the drain holes are not clogged and floating debris is not deposited in the gate components

13 Monitor the condition of the Welding transformers, gas cutting sets, umbrellas, tool kits torches chain blocks ropes bellies etc. on daily basis and to see that things are in place to handle any emergency situation

14 Observe the Gates ,hoists and handling equipment during operation for the smooth movements and to immediately report any untoward excessive sounds in the motors, pumps or vibrations in the gate

15 Observe the dam top, embankment, catwalk, approach roads are well maintained by housekeeping personnel

16 Observe the performance of the Dam and its appurtenant structures / Gates and Hoists during flood water releases and to report to the EE/SE/CE in case of any untoward incidents or malfunctioning of the gates of excessive seepages, leakages etc.

17 Assist EE/SE/CE to coordinate with the downstream structure operators and getting the flow data

18 Assist EE/SE/CE to share the flow data and the reservoir storage details to the Media on day to day basis

19 Assist EE/SE/CE to coordinate with the Chief Engineer, Project II and sharing the details of the flood condition in the river and the reservoir releases.

1.2.2 Roles and Responsibilities of the SE and EE during Monsoon

Table 1. 3 Roles & Responsibilities of SE & EE

(Flood condition assessment, warning, flood mitigation and other responsibilities)

1 Coordinate with the Chief Engineer Project II & to get the information about the rainfall in the catchment and inflow status and to bring it to the notice of the CE

2 To issue notification to the villagers downstream in Newspapers, Radio, TV News channel to be alert regarding the flood situation

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3 Assist the CE to coordinate with the Revenue authorities (District Administration) to alert the downstream villagers to evacuate the flood zone to prevent loss of life and live stock

4 Assist the CE to coordinate with the CWC flood monitoring authorities on the flood condition

5 Submit to the CE on the inflows and releases from the reservoir and status of the reservoir twice in the day

6 Operate the Spillway crest gates for flood mitigation as per the instructions of the CE and to update the Gate operation Log book

7 Observe the seepages in the drainage Gallery with respect to the reservoir head and record the seepages in the infiltration gallery and to immediately bring to the notice of the CE in case of excessive seepage ,leakage in any specific blocks and porous drains

8 Observe the Gates ,hoists and handling equipment during operation for the smooth movements and to immediately report any untoward excessive sounds in the motors, pumps or vibrations in the gate

9 Observe the dam top, embankment, catwalk, approach roads are well maintained by housekeeping personnel

10 Observe the performance of the Dam and its appurtenant structures / Gates and Hoists during flood water releases and to report to the CE in case of any untoward incidents or malfunctioning of the gates of excessive seepages, leakages etc.

11 Assist CE to share the flow data and the reservoir storage details to the Media on day to day basis

12 Assist CE to coordinate with the Chief Engineer Project-II and sharing the details of the flood condition in the river and the reservoir releases

1.2.3 Roles and Responsibilities of the Chief Engineer during Monsoon Table 1. 4 Roles & Responsibilities of the Chief Engineer

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(Flood condition assessment, warning and flood mitigation)

1 To issue notification to the villagers downstream in Newspapers, Radio, TV News channel to be alert regarding the flood situation based on the input by Executive Engineers of the Dam, to the information on the rainfall in the catchment and inflow status and also to Coordinate with the Revenue authorities (State Administration)

2 Coordinate with the CWC flood monitoring authorities on the flood condition

3 Issue necessary instructions to the engineers to Operate the reservoir based on the in- flows, rainfall data, releases from the upstream reservoirs and status of the reservoir

4 Observe the performance of the Dam and its appurtenant structures / Gates and Hoists during flood water releases and to issue necessary instructions to the AEE/EE/SE

5 Coordinate with the downstream Dam Project Executive Engineers

6 Conduct Pre and Post Monsoon inspections of the Dam

1.3 COLLECTION AND REPORTING OF DAM AND RESERVOIR DATA A Performa is provided to ensure that dates and times for the collection and reporting of vital information is recorded and documented for the record.

 Reservoir water surface elevation.

 Reservoir inflow.

 Spillway outflow.

 River releases.

 Irrigation and hydropower releases.

 Weather related data

 Instrumentation data

 Water quality

Instructions and a standard Performa for collection and reporting of inflow and outflow data, and other pertinent data, is shown in Table below. Records [Logbooks] of the following operations at Chimoni Dam are to be maintained in a Chronological manner for reference.

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These records are helpful for identifying preventative maintenance measures that may need to be taken up, troubleshooting the cause of potential equipment failure and documenting development of any unusual conditions.

 Date and Time

 Attendance statement during normal operations ¡V both during monsoon and non- monsoon periods.

 Operations of the spillway gates and outlet works.

 Operating hours of mechanical equipment.

 Testing / Operation of spillway gates, stop-logs and associated controls.

 Testing/operation of Outlet gates, valves and associated controls,

 Maintenance activities carried out.

 Reservoir and dam inspections.

 Unusual conditions or occurrences, including acts of vandalism.

 Attendance statement at the dam during emergency operations.

 Changes to normal operating procedures.

 Communication network checks.

 Safety and special instructions.

 Names of officers and staff carrying out inspections and maintenance.

 Any other item pertaining to the operation and maintenance of the dam.

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Table 1. 5 Example Proforma for recording Flow Data CHIMONI DAM WATER RELEASE DETAILS Out Flow Discharge Inflow During Daily In Flow During Daily Time Water Storage Shutters - 4 Nos KSEB Date Valve Total The Discharge The Inflow Remarks Level Mm3 (Size 10.00 x 7.50 mtr) S1 S2 S3 S4 Discharge Opening in Discharge Period Mm3 Period Mm3 12 Hr 24 Hr Mm3/DayMm3/Day Cumecs Mm3/Day Cumecs Opening Opening Opening Opening M m3/Day cm M m3/Day Mm3 Mm3

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1.4 PUBLIC AND PROJECT STAFF - HEALTH AND SAFETY As safety of Project Staff is of prime concern, safety instructions & protection measures at the dam are carried out by all staff / project personnel. Warning boards located on the left and right abutment provide public notices of events and status of security of the dam and downstream river conditions.

Medical dispensary 200m Police station 16km Safety equipment Centre 100m Public conveniences 2Km 1.5 RESTRICTED AREAS Certain areas of the dam and reservoir are restricted for entry of the general public. The purpose of restrictions is for security of the dam, public safety and uninterrupted safe operation of the dam.

Restricted areas will include the following:  Confined spaces such as audits, galleries, etc.

 Spillway approach areas, chutes and stilling basins.

 Control buildings and valve areas.

 Intake or outlet channels adjacent to hoist structures. 1.6 STAFF POSITION, COMMUNICATION & WARNING SYSTEM The number & description of operating unit personnel posted/placed at different locations of the dam are noted in supporting documents and referenced in this Manual. Staff positions vary according to requirement during monsoon / non-monsoon periods. An engineering organizational chart is shown below.

Available communication means including landline and mobile phones at different locations on the dam. Equipment room with essential small tools, chain blocks and ropes, dewatering pumps and consumables are available to facilitate O&M requirements.

A brief description of the warning systems including alarms at the dam is mentioned in the Manual. This includes information on downstream inundation areas during scheduled or unscheduled release of flood outflows from the spillway.

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One security personal at the watchman cabin near left abutment and other security personal at watchman cabin near the main entrance to masonry dam near Block No.16.

Communication details of Dam Site

Dam Site Office

Assistant Executive Engineer Email :[email protected] Asst. Executive Engineer Office No: 0480 27655544

Assistant Engineer, Chimoni Dam Project Section-2 Asst. Engineer Email :[email protected]

Assistant Engineer, Asst. Engineer Chimoni Dam Project Section-1 Email : [email protected]

Superintending Executive Engineer Engineer Office Office

Superintending Engineer Executive Engineer Email :[email protected] Email :[email protected] Office No: 0487 2332465 Office No: 0487 2332486

Chief Engineer, Project II, Thiruvananthapuram

Email : [email protected] Chief Engineer Office No:0471-2324394

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Communication details of Electrical Wing

Electrical Wing

Assistant Executive Engineer Electrical (Irrigation) Sub Division Asst. Executive Chalakkudy Engineer Email :[email protected]

Assistant Engineer, Electrical Section Chalakkudy Asst. Engineer Email :[email protected]

Executive Engineer Office

Executive Engineer, PWD Electrical Irrigation Division, Thrissur Email :[email protected]

Chief Electrical Engineer PWD, Thiruvananthapuram dapuram Chief Engineer Email :[email protected]

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Communication details of Mechanical Wing

Mechanical Wing

Assistant Executive Engineer

Mechanical Sub Division, Iringol P.O Perumbavoor Asst.Executive Email :[email protected] Engineer Office No: 0484-2592309 Office No: 04802765544

Assistant Engineer, Section No:2 Office of the Assistant Executive Engineer Mechanical Sub-Division, Iringol P.O Email :[email protected] Asst.Engineer Office No: 0484-2592309

Superintending Executive Engineer Office Engineer Office

Superintending Engineer Executive Engineer Irrigation Mechanical ,Kakkanad, Civil Station, Mechanical Division, Malampuzha, 678 682 030 651 Email :[email protected] Email :[email protected]

Chief Electrical Engineer

Chief engineer Mechanical, Thiruvananthapuram Email [email protected]

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Chart 1. 1 Organisation Chart – Civil

Chief Engineer Project II Thiruvananthapuram

Superintending Engineer

Irrigation Central Circle Thrissur

Executive Engineer

Irrigation Division Thrissur

Assistant Executive Engineer Chimoni Dam project Sub Division Echippara

Assistant Engineer Assistant Engineer Chimoni Dam project Section No.1 Chimoni Dam project Section No.2 Echippara Echippara

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August 2020 O&M Manual of Chimoni Dam

Chart 1. 2 Organisation Chart – Electrical

Chief Electrical Engineer - PWD Thiruvananthapuram

Executive Engineer PWD Electrical Division Thrissur

Assistant Executive Engineer Electrical (Irrigation) Sub Division Chalakkudy

Assistant Engineer Electrical (Irrigation) Section Chalakkudy

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Chart 1. 3 Organisation Chart – Mechanical

Chief Engineer Mechanical Thiruvananthapuram

Superintending Engineer Mechanical Irrigation Circle Kakkanad

Executive Engineer Mechanical Division Malampuzha

Assistant Executive Engineer Mechanical Sub Division Iringol, Perumbavoor

Assistant Engineer Section No.2 Mechanical Sub Division, Iringol

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1.7 DISTRIBUTION OF OPERATION & MAINTENANCE MANUALS Table showing designation of officer/office to whom O&M Manual and number of copies to be supplied

Authority No. of Copies

Water Resources Secretary 2 Chief Engineer, Project II 2 Chief Engineer, IDRB 2 Dam Owners and Representatives 2 District Collector 2 State Dam safety Organisation 1 Central Dam safety Organisation 1 State Emergency Operation center, 1 Kerala Disaster Management Authority National Disaster Management Authority 1 District Police Chief 1

1.8 SUPPORTING DOCUMENTS & REFERENCE MATERIAL This O&M Manual is the key instruction document. Supporting documents and necessary instructions for all phases of the operation, inspection and maintenance of the dam, reservoir and appurtenant works shown below are available at the dam control room.

 Detailed drawings of the Project  Emergency Action Plan  Latest Hydrology Review Report  Latest DSRP Report  Flood forecasting and operating criteria  Administrative procedures  Maintenance schedules  Gate Manufacturer’s manual and drawings  Regional communication directory  Instrumentation reports / results 1.9 TYPICAL SCHEDULE OF DUTIES

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Schedules of duties being performed by the staff assigned to various locations and components of Chimoni Dam are provided in this section.

General Schedule of duties / Inspections to be carried out for the operation and maintenance of the dam by the concerned official are tabulated below.

Table 1. 6 Table Showing Schedule of Duties/Inspection

SL. Component /Duty Frequency Personnel No.

1. Visual inspection of dam including Crest Daily Assistant Engineer/ of dam (Dam top), Upstream and Dam Operators on downstream faces, visible portions of foundation and abutments, Galleries, contract Spillway and its energy

2. Record water surface elevation, reservoir Daily(Hourly basis Assistant Engineer/ inflow and spillway discharge. during monsoon) Dam Operators on contract

3. Record meteorological data, Record Daily Assistant Engineer/ releases from canal sluices Dam Operators on contract 4. Check security and safety devices, Daily Assistant Engineer Complete logbook / site register which

include the above information.

5. Record seepage from drainage systems, Weekly Assistant Engineer/ Gallery drains etc. and record Dam Operators on meteorological data. contract

6. Visual inspection of dam including Crest Weekly Assistant Engineer of dam (Dam top), Upstream and

downstream faces, visible portions of foundation and abutments, Galleries, Spillway and its energy

7. Check stand by generator (DG Sets), Weekly Assistant Engineer Drainage systems, Gallery drains etc.

8. Visual inspection of dam including Crest Fort nightly Assistant executive

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of dam (Dam top), Upstream and Engineer downstream faces, visible portions of foundation and abutments, Galleries, Spillway and its energy

9. Check security and safety devices, Fort nightly Assistant executive logbook and site register which include Engineer the above information.

10. Check standby generator (DG Sets), Fort nightly Assistant executive Drainage systems, Toe drains & Gallery Engineer drains

11. Measuring devices, communication Fort nightly Assistant executive devices, status of instruments, vegetation Engineer growth

12. Check Sign/Warning display boards near Fort nightly Assistant executive vulnerable locations Engineer

13. Visual inspection of dam including Crest Monthly Executive Engineer of dam (Dam top), Upstream and

downstream faces, visible portions of foundation and abutments, Galleries, Spillway and its energy

14. Check measuring devices/Instruments, Monthly Executive Engineer Security and safety devices, Communication Devices, Status of Vegetation growth, – rectification, if needed.

15. Check Sign/Warning display boards near Monthly Executive Engineer vulnerable locations

16. Replace fuse light bulbs, Inspect to Monthly Assistant Engineer maintain ventilation system, cleaning of control panel boards.

17. Check outlet works, updating operating Quarterly Executive Engineer instruction, check gate air vents, clean gate control switchboxes, check operation of gates, grease gate hanger/dogging

18. Check condition of canal sluice works Quarterly Executive Engineer

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& its d/s structure, Check operation of Emergency gate & regulation gates for canal sluices 19. Check condition of spillway structure, Quarterly Executive Engineer Check for debris in inlet channel, Check operation of spillway gates, Check for damages in spillway glacis, energy dissipation arrangement, d/s area etc. Check and clear spillway bridge drains, check various operations being conducted from Control room etc. 20. Check for adherence to instrumentation Quarterly Executive Engineer schedule, Record pertinent information in Operation of Gates, Check condition of V- notch/seepage measuring devices, Check hydro mechanical components. 21. Inspection of Spillway & outlet works, Half yearly (Pre and Superintending Engineer hydro mechanical components, Check Post Monsoon) along with Executive paint on gates, Check lubrication of wire ropes etc. and application of cardamom Engineer in charge of dam compound, Check mechanical hoist bearings and flexible coupling bearings, Check gear systems, Exercise gates, Check lubrication of gate rollers, Check rubber seals and seal clamp bar.

22. Submission of Inspection report to State Half yearly Chief Engineer/ DSO, CWC and uploading into DHARMA. Superintending Engineer

23. Comprehensive inspections Annually Dam safety Authority along with Dam Owners 24. Inspect dam and gate structures, energy Five Yearly Chief Engineer/ dissipation arrangement, which normally are underwater (by dewatering or by Superintending Engineer divers). Review Dam operation procedures and EAP and update as necessary.

25. Comprehensive inspection of Ten Yearly DSRP performance of the dam and gate structures and reservoirs, energy dissipation arrangement and allied structures including dam operating systems

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1.10 HYDRO-MECHANICAL INSPECTION /CHECKS Frequent inspections/checks for hydro-mechanical components are to be conducted and necessary action to be taken up during maintenance. Routine maintenance is carried out for Spillway gates, Intake gates and Outlet Valve as part of routine maintenance before the onset of monsoon. Details are given under the Chapter Project Maintenance.

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CHAPTER 2. PROJECT OPERATION

Chimoni dam operation plan consists of step-by-step instructions for operating the dam and reservoir during routine (normal) and emergency conditions. The operating procedures for normal operations are discussed in in this chapter including operating criteria for the reservoir, spillway & outlets. The operation of a dam involves regulation of its reservoir as per project specific requirements. This includes the use of area capacity curves and design flood; both are described below.

With reference to Original FRL of 79.40m, first warning level was 77.90 m and Second warning level was 78 40 m.

Dam safety authority during the Inspection of 27-10-2006 directed that the water level in the Reservoir shall keep below the FRL by 3.0 meter; until the rehabilitation was completed satisfactorily (details are at Annexure - D).

As such, Present FRL is - 76.40m and first warning level is 74 90 m and Second warning level is 75.40 m.

2.1 BASIC DATA Karuvannur River will take over the supply of irrigation water required for 11000 hectares of Kole lands of Thrissur District. The dam site is located at 100 26’ North Latitude and 760 28’ East Longitude. The dam is of Masonry gravity type.

The Chimoni River originates from the Western Ghats in Kerala state at an Elevation of +1160m.Average bed level at dam site is +28.00m above MSL. The catchment area of the reservoir is 72.13Km2 .95% of the catchment is reserve forest. The average monthly rainfall in the catchment is 3534mm.

The average annual runoff from the catchment from 1946 is 300.39Mm3, maximum runoff calculated as 398.05Mm3 in the year 1961 and minimum annual run off 194.48Mm3 in the year 1965.

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2.1.1 Stage Capacity curve

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WATER LEVEL - CAPACITY TABLE

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Note: Water level mentioned above MSL

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2.1.2 Data of historic flood

In Chimoni dam the maximum rain observed was 289mm on 16-08-2018, water level in the reservoir raised up to 76.63m at 09:00am and four shutter raised to 120cm with a discharge of 156.67m3/s. Shutter lowered to 100cm at 09:00pm with a discharge of 130.56m3/s. Gradually reduced the shutter till 24-08-2018 to 1cm with a discharge of 1.31 m3/s.

2.1.3 Design Flood and Features Related to Safety

The maximum flood design at Chimoni Dam site is 1680 m3/s. The spillway is designed for this design flood. The value of the maximum design flood after review (June 2020 by CWC) comes to 1918 cumecs. The Design Flood review study of Chimoni dam by CWC is attached as Annexure -B

2.1.4 Sequence of operation of spillway gates during monsoon

The Assistant Engineer in charge of the dam shall be responsible for the operation of the spillway shutters. All the water reaching the reservoir from the catchment shall be impounded until the level in the reservoirs reaches about two feet below the full reservoir level. Daily readings of the reservoir level shall be taken at 8:30 am. All the data regarding the reservoir shall be sent to the Assistant Executive Engineer, Executive Engineer, Superintending Engineer, Chief Engineer and to Dam Safety Head Quarters from time to time. When the water level is raising and reaches + 76.40 m the water level shall be noted every 6 hours. When the level reaches +78.40 m the level shall be noted every two hours.

When the level reaches +78.80 m the water level shall be noted every hour and the inflow rates should be computed. When the reservoir level is raising rapidly it is expected that the spillway shutters may have to be opened to let down the flood water, timely flood warning shall be given to the people in the downstream areas. When the water level reaches +78.40 m the Assistant Engineer in charge of the dam shall give the first warning by sending message (SMS/Email) “ Chimoni Reservoir level at +78.40 m only one metre below Full Reservoir Level” to the following officers:-

1. The District Collector, Thrissur 2. The District Police Chief, Thrissur 3. The Tahsildar, Mukundapuram 4. The Tahsildar, Thrissur

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When the level is nearing +78.80 m, the Assistant Engineer shall closely watch the inflow rate, rise in the water level etc. and obtain further instructions from the Assistant Executive Engineer regarding the opening of the spillway shutter.

When the reservoir level reaches +78.80 m, the following messages (SMS/Email) “Chimoni Reservoir level at +78.80 m shutter being opened” shall be sent to the following officers:-

1. The District Collector, Thrissur 2. The District Police Chief, Thrissur 3. The Chief Engineer, DSO, IDRB, Thiruvananthapuram 4. The Superintending Engineer, Irrigation Central Circle, Thrissur 5. The Executive Engineer, Irrigation Division, Thrissur

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2.1.5 Discharge through spillway for different reservoir levels with different gate opening in tabular form

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2.2 OPERATION PLAN

Operation plan consists of step-by-step instructions for operating the dam and reservoir. Operating procedures are developed based on:  Reservoir operation studies, relevant design documents, hydraulic model studies etc.  Equipment Operating and Maintenance Instructions (Manufacturers' Instructions)

2.2.1 Spillway and energy dissipation arrangements

Figure 2. 1 Spillway and stilling basin

Figure 2. 2 Photograph of spillway and stilling basin

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2.2.2 Hoisting Arrangements for Radial Crest Gates, operating and maintenance instructions

Figure 2. 3 Section of Radial gate

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Figure 2. 4 Photograph of radial gate

2.3 NORMAL OPERATIONS

The operating procedures developed for normal or ―day-to-day operation of a dam shall include the following:  Instructions for operating control mechanisms.  Instructions for operating the reservoir in accordance with reservoir operation rule curve.  General instructions for the safe operation of the dam and appurtenances.

The following aspects also need to be included:

 Releases to be made for various purposes round the year including releases to be made as per Inter-State Agreements/ MOU‘s with various States/Agencies/Projects, riparian releases etc.  Rule curves.

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 Inflow forecasting  Flood release procedure  Limitation on reservoir drawdown rate to prevent failure of u/s slope of the embankment/landslides along reservoir periphery

Site security is a matter of concern at all major dams. This includes terrorism implications and preventing structural damage by vandals and unauthorized operation of outlet or spillway gates. In most cases restricting public access is essential, and in some instances electronic security devices should be considered.

2.3.1 Instructions for Operating Control Mechanisms

The Procedures include instructions for operating all necessary equipment associated with a dam including the spillway gates and outlet gates /valves. The gate manufacturer‘s O&M Manual for Gates & Hoists will however govern the overall Gate operations whenever there as any contradiction with the instructions given in the Manual. The frequency and nature (e.g. flow test, static test, dry test) of operational check testing of the equipment‘s should be specified. Correct sequence should be emphasized and sketches, drawings and photographs to aid in identifying specific handles, buttons, levers, etc., should be included. Provisions and uses of backup equipment should be outlined.

The correct method and sequence of opening and closing guard gates, gate usage during low and high flow, and openings at which excessive vibration are experienced, and operating problems peculiar to a specific gates are also included.

An auxiliary power system such as a petrol or diesel-operated generator or other appropriate energy source, is essential if the outlets, spillway gates and other dam facilities are electrically operated. This system should be located at levels higher than the extreme flood levels. Access and lighting during extreme events is essential. All the spillway and outlet gates should be tested on a regular schedule along with testing of alarms and associated indicators. The test should include use of both the primary and auxiliary power systems.

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2.3.2 Operation of the Reservoir

2.3.2.1 Rule Curve

Rule curve is the target level planned to be achieved in a reservoir, under different conditions of probabilities of inflows and/or demands, during various time period in a year. Rules curves are developed as per IS 7323 - Operation of Reservoirs – Guidelines or as per any other suitable reference. A rule curve is generally based on detailed sequential analysis of various critical combinations of hydrological conditions and water demands. These should indicate reservoir levels and releases during different times of the year, including operational policies. Rule curves once prepared should be constantly reviewed and, if necessary, modified so as to have the best operation of the reservoirs. A draft rule curve for Chimoni dam has been developed and is shown in Figure 2.5.

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Figure 2. 5 Rule Curve

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2.3.2.2 Sequence of Opening or Closing of Gates.

It is recommended that all 4 gates are operated for releasing water over the spillway. The gates are numbered 1 to 4.

If, even when water is being released through the turbines at full capacity, the reservoir level tends to rise above 1*76.40m (79.40 m for the higher FRL, During the inspection on 27-10- 2006 KDSA directed to keep the reservoir level below FRL by 3.00m until satisfactory completion of strengthening works like Grouting, Guninting etc. Then onwards, spillway opening level is fixed to 76.40m, refer Annexure D), the crest gates should be opened, starting with the end gates first (i.e., gate No.1 and 4), then the gates at the center (gates 2 and 3). No gates are opened more than 0.20 m at a time.

If the release over the spillway is to be further increased, the gates are opened further in a similar manner, no gate opening being more than 0.40m. Further opening of gates, if required is done in the same way, keeping the difference in the openings if any two adjacent gates not more than 0.20 m.

During the recession part of the inflow hydrograph, it may be necessary to close the crest gates in order to maintain the reservoir level at the rule curve elevation. In such a case, the closure of the gates should be done in the reverse order; the gate opened last being closed first, the entire operation being such that the difference between the adjacent gate openings never exceeds 0.20m.

2.3.2.3 Gate Operations

The Gate Operation for flood management and Gate operation Schedule during normal conditions were explained in the Rule Curve for Chimoni Dam.

2.3.2.4 Operation of Radial Crest Gates of Chimoni Dam

Brief Description.

Crest Gates of Chimoni Dam have been designed with spillway crest of 72.20 m and FRL of 79.40 m. The basic principal of the design is that the water pressure is transferred to piers and abutments through skin plates, stiffeners horizontal girders, arms, trunnion, tie flats and anchor girders. The skin plates between bottom and top horizontal girders are designed as supported on the girders.

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In order to make design structurally sound and most economical, appropriate elevation for two horizontal girders have been chosen.

4 Nos. of Gates of Size 10.00 X 7.50 m have been provided with Electro-mechanical Rope drum hoist.

The crest gates of Chimoni Dam spillway have been designed and fabricated for the full height of 7.50 m corresponding to FRL 79.40. The frame of the gate, consisting of inclined arms, horizontal girders and the stiffeners have been erected as designed and fabricated for the full height. The top horizontal girder, as per design up to the full height is located at about RL 79.40 m.

Operating Instructions

The Gates are operated by Electro-mechanical Rope drum hoist. The hoists are capable of fully opening or fully closing the gates holding them fully opened or in any intermediate position, during either the opening or closing operation. The closing time and the opening time is 10 minutes by electrical means.

Checklist before Operation

The following steps are to be taken before operation of the gates to ensure critical functions are in good working condition.

Sequence Description Actions to be carried out

Step 1 Seal Clamp The seal clamp fixing should be such as to ensure that the side seals are flexible enough

Step 2 Guide Roller The location and alignment of guide rollers should be checked.

Step 3 Switch Switches shall be checked for satisfactory operation (function) to stop the hoist when the gate reaches the fully opened or fully closed position

Step 4 Nut & Bolts All nuts, bolts and screws shall be checked for wear, tear and tightness

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Step 5 Pins Gate pin, connecting pin and all other pins should be in proper position and ensure that the nuts and split pins are tight and proper

Step 6 Trunnion Lubrication To check and apply the high pressure lubricating grease in trunnion bushing from the hole provided in trunnion hub

Step 7 Control Panel Control Panel shall be checked for its suitability for the purpose envisaged. The check may include items such as weather proofing, conducting wires, etc.

2.3.2.5 Operating Instructions for Electro-mechanical Rope drum hoist of Spillway

1. Before starting the drive motor check shall be made for supply components and fittings are properly cleaned and connected correctly.

2. Check the alignment of electrical motor.

3. Check and tighten all the fittings and joints provided in the Electro-mechanical Rope drum hoist system.

4. Connect electric supply to the motor and also to electrically operated solenoid values through proper isolators as per electric circuit diagram. 2.3.2.6 Auxiliary Power Supply System

20 KW diesel generator provided for Auxiliary Power Supply System.

2.3.2.7 TROUBLE SHOOTING

For trouble shooting of the major Electro-mechanical Rope drum hoist system components like motor hoist, chain pulley, etc., brief observations and possible causes are shown below. These can be used as a ‘first-sight’ trouble-shooting of the above stated hoist components. Observations of potentially defective or failing parts/equipment are critical to maintain a safely operated dam.

Electrical motor.

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Excessive Noise  Damaged bearings.  Improper assembly of rotor, fan cover etc.  Excessive speed.

Ensure that the system is not overloaded, if not try to close the protecting device

Table 2. 1 Troubleshooting for Motors

TROUBLE CAUSES DIAGNOSIS

1. Motor fails to start A) No power A) Check power supply

B) Single phasing of Power B) Check blown fuse or dead circuit line and replace if necessary

C) Single phasing of Motor C) Ensure that all finger starter contact simultaneously when closed.

D) Tripping of over load D) Ensure that the system is Protecting device as open not overloaded , if not try to circuit of con-tracts close the protecting device

2. Motor Vibrators A) Ball Bearing damaged A) Replace the Bearings Indicated through Rattling noise of the Machine during Running

3. Motor slows down or A) Phase drop out A) Switch off and check And stops fuses replace if required

4. Fuses fail when motor A) Fuses too weak A) Replace with Correctly starts rated fuses.

B) Short circuit in Motor B) check for short Circuit and re-winding Necessary

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2.3.2.8 RIVER OUTLET WORKS. RIVER SLUICE: The Chimoni dam is provided with 1 No of River Sluice of size 1.5m Dia. in Block No. 8 at Level 40.00m. Another branch to KSEB Power house 1.8m Dia. at 40.00m Level.

Operation: a. General

Water is released at downstream side when the water level depletes below crest level of 72.20 M through river sluices safely as per the requirements of Kole lands at Thrissur for irrigation purpose. Release can also be done through KSEB Power house. b. Restrictions:

There are no restrictions for operation of river sluice as per water requirements from the Kole lands. c. Operation of Sluice:

River Sluice is operated manually. 2.3.2.9 ACCESS ROADS a. Description Type of road, length, bridges, maintaining agency, etc.) Type of road : Asphalt road. Length : 8.883 Km Bridges : 1 Maintaining agency : Irrigation Department b. Condition General: Road is in good condition c. Deficiencies and problems Neighboring people and forest department are using the same road. 2.3.3 Safety Aspects

The public safety is of paramount importance at all dams and reservoirs. The general instructions in this regard are as under:

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 State procedures to be followed for restricting access to the dam or confining traffic to designated areas. Indicate the procedures to be followed when tourists visit the facility.  Designate speed limits to keep the traffic within acceptable and safe limits.  Establish standards for maintaining sanitary conditions.  Prevent contamination or pollution of water for human consumption and/or recreational use.  Eliminate safety hazards by:

- Posting warning signs. - Removing unsafe conditions where possible. - Restricting public access to chutes, stilling basins, and control rooms. - Posting safety instructions at visible and key locations. - Maintaining warning buoys upstream of the dam. - Providing adequate security.

 Ensure provision of all downstream warning systems like sirens, hooters etc. An adequate system of giving information to downstream areas regarding release of flood outflows from spillway should be there.

2.3.4 Flood Release Procedure

Surplus waters during floods are released through a spillway. The spillway maintains the reservoir at Full Reservoir level (FRL). Its function is to pass expected flood flows past the dam safely. It may be gated or un-gated. It is necessary to ensure that all gates are in working condition. Normally these spillways are standard ogee, chute, or side-channel spillways i. The end gates are normally be opened first to prevent cross-flows striking against the walls and junctions. ii. During the operation of different gates, the difference in gate opening of any two consecutive bays should not exceed 0.5 meters. iii. After opening the end gates, the gates at the center should be opened and the other gates are opened in symmetrical manner starting from the center towards the end through gradual increase in the openings.

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iv. While closing the gates, the gate that was opened last should be closed first. The procedure to be followed for closing the gates should be generally reverse of the procedure followed for opening the gates. Complete closures of the gates are accomplished by gradual lowering of the gates by 0.20 to 0.30 m in the proper sequence. 2.3.5 Inflow Forecasting

The gross storage of Chimoni Dam at FRL 79.40m is 176.78Mm3 .Chimoni Dam have been designed for a probable maximum flood (PMF)of 1680 cumecs.

During monsoon, incident rains in the catchment area cause the flash floods in Chimoni River. These floods may lead to problems like people getting displaced from their homes, huge damage to crops and other assets. The floods can have disastrous impact on the environment also. Adequate measures are required to be taken up in advance to control and regulate the flow water in the river.

The regulation of flood water released from the Dams in Kerala is very important and has a most impact in low laying areas of Kerala.

The following measures are essential for effective management of floods in Chimoni River during Monsoon.

1) Nomination of liaising officers for respective reservoirs.

2) Sharing of Sub-basin wise directory of concerned officers responsible for flood management.

3) Exchange of data regarding rainfall, releases from dams, reservoir water levels.

4) Reservoir operation schedules.

Inflow Computation

Inflow into reservoirs is normally estimated by the reservoir gauging method (also called the rise and fall method or inflow-outflow method). All the outflows are added together and to it the rate of rise in storage (Positive if the level rises, and negative if it falls) is added. Expressed as an equation, this will be.

Inflow (cumecs) = Total outflow (cumecs) + Rate of increase in storage (cumecs)

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The rate of increase (or decrease) in storage can be determined from the observed rate of increase (or decrease) in reservoir level and the elevation capacity tables. For easy computation. Table 11 has been developed showing the rate of change of storage in the Chimoni reservoir for a rate of rise in reservoir level of 1-cm/hour. The same information is shown graphically in Figure 6 which can be used for interpolation.

Example 1: Water level at 70.31m, after 1hour reaches 70.43m. Spillway crest level 72.20m and river sluice closed condition.

Calculation

From the stage capacity Chart Storage for 70.31m = 107.33 Mm3

Storage for 70.43m = 108.23 Mm3

Difference in Storage = 0.90 Mm3/ hour

= 0.90 x 106/ (60x60)

= 250 m3/s

Example 2: Water level at 76.20m, after 1hour reaches 76.25m. Spillway crest level 72.20m and river sluice closed condition, for spillway shutter opened 10 cm.

From the table 5 - Discharge through Spillway = 4 x 0.282 Mm3/day

= 1.128 Mm3/day

= 0.047 Mm3/hour

From the Storage Capacity Table Water level at 76.20m = 149.90 Mm3

From the Storage Capacity Table Water level at 76.25m = 150.31 Mm3

Difference in Storage = 0.410Mm3/hour

Total Change in Storage = Difference in Storage +

Discharge

= 0.410+0.047

= 0.457Mm3/hour

= 126.95 m3/s 2.4 EMERGENCY OPERATIONS

Flood warning system in catchment area:

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The regulation of flood from the dams on downstream of Chimoni reservoir is very crucial to quantify the inflow of floods into Chimoni dam. The agencies of Central water Commission will be coordinated to assist in the flood forecasting accordingly, sequence of opening or closing of gates will be taken up in accordance with the approved gate operation schedule.

Flood communication system:

Authority Name, Title, Phone Address District Collector Civil Station, Mobile No: 9447129013 Ayyanthole, District Collector, Thrissur Office No:0487 2361020 Thrissur, Kerala 680003 E-mail : [email protected] Dr.Sekhar L Kuriakose Member Secretary Observatory Hills Museum State Emergency Operation E-mail: [email protected] Vikas Bhavan Centre, Kerala Disaster Mobile No. 9400202927 P.O Thiruvananthapuram Management Authority Office No. 0471-2331345 Kerala 695033

Superintendent of Police Office of the District Police Mobile No: 9497996978 District Police Chief, Thrissur Chief (Rural) Thrissur Office No:0487 2361000 Deputy Collector (General & Civil Station, Deputy Collector ADM) Ayyanthole, Thrissur, Kerala Mobile No: 8547610081 680003 Office No:0487 2360626 Dy.SP, Special branch, Phone No :04872363604 Office of the Dy.SP, Thrissur E-mail : dyspsbtsrrl.pol@ Special branch, kerala.gov.in Thrissur Mobile No: 9447731443 Taluk Office Thrissur, Office No:0487 2331443 Mini Civil Station, Tahsildar, Thrissur E-mail : Chembukavu, [email protected] Thrissur – 680020 Addl. Tahsildar, Thrissur Mobile No: 8547614401 Taluk Office, Thrissur Office No: 0487 2331443 Mobile No: 9447725259 Taluk Office Mukundapuram, Office No:0480 2825259 Mini Civil Station, Tahsildar, Mukundapuram E-mail : Chemmanda Road, [email protected] – 680125 Addl. Tahsildar, Mukundapuram Mobile No: 8547614301 Taluk Office, Mukundapuram Office No: 0480 2825259 Taluk Office , 3rd Ph: 04802705800 Floor, Tahasildar, Chalakudy E-mail : [email protected] Municipal Town Hall Building Chalakudy – 680307

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Authority Name, Title, Phone Address Taluk Office , Ph: 04872507350 Tahasildar, Chavakkad Vanjikadavu road, E-mail : [email protected] Chavakkad – 680506 Fire Station, Thrissur Fire Station, Fire & Rescue Service Phone No: 0487 2423650 Municipal Office Road Thrissur Circle Inspector Circle Inspector, Office of the Circle Inspector, Mobile No: 9497962533 Kodakara Office No:0480 2720287 Sub Inspector Office of the Sub Inspector, Mobile No: 9497980537 Sub Inspector, Kodakara Kodakara Office No:0480 2720287 Circle Inspector Office of the Circle Inspector, Mobile No: 9497987139 Circle Inspector, Irinjalakuda Irinjalakuda Office No:0480 2826600 Sub Inspector Office of the Sub Inspector, Mobile No: 9497980533 Sub Inspector, Irinjalakuda Irinjalakuda Office No:0480 2825228 Phone No :04802755400 Office of Circle Inspector of Circle Inspector of Police, E-mail : cipdkdtsrrl.pol@ Police, Pudukad kerala.gov.in Pudukad Phone No :04802760150 Office of Sub Inspector of Sub Inspector of Police E-mail : sivplytsrrl.pol@ Police, kerala.gov.in Varandarappilly Phone No :04802755400 Office of Circle Inspector of Circle Inspector of Police, E-mail : cipdkdtsrrl.pol@ Police, Chalakudy kerala.gov.in Chalakkudy Village Office Irinjalakuda 8547614302 [email protected] Village Office Porathisseri 8547614303 [email protected] Village Office Vallivattom 8547614304 [email protected] Village Office Kattur 8547614306 [email protected] Village Office 8547614307 [email protected] Village Office Kaaralam 8547614309 [email protected] Village Office Nellai 8547614315 [email protected] Village Office Parappukara 8547614318 [email protected] Village Office Amballur 8547614319 [email protected] Village Office Kallur 8547614320 [email protected] Village Office 8547614320 [email protected] Village Office Thoravu 8547614321 [email protected] Village Office 8547614321 [email protected]

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Authority Name, Title, Phone Address Village Office 8547614340 [email protected] Madayikkonam Village Office Chengalur 8547614341 [email protected] Village Office 8547614342 [email protected] Village Office 8547614343 [email protected] Village Office 8547614347 [email protected] Village Office Anandapuram 8547614316 [email protected] Village Office 8547614451 [email protected] Village Office 8547614406 [email protected] Village Office Chalakkal 8547614406 [email protected] Village Office 8547614407 [email protected] Village Office 8547614407 [email protected] Village Office 8547614432 [email protected] Village Office 8547614432 [email protected] Village Office Manalur 8547614433 [email protected] Village Office Karamukk 8547614434 [email protected] Village Office 8547614435 [email protected] Village Office 8547614436 [email protected] Village Office 8547614437 [email protected] Village Office 8547614438 [email protected] Village Office 8547614439 [email protected] Village Office 8546614440 [email protected] Village Office 8547614440 [email protected] Village Office Kurunpilavu 8547614441 [email protected] Village Office 8547614442 [email protected] Village Office Manakkodi 8547614443 [email protected] Village Office 8547614443 [email protected] Village Office Peringavu 8547614444 [email protected] Village Office Killannur 8547614445 [email protected] Village Office 8547614446 [email protected] Village Office 8547614508 [email protected]

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Authority Name, Title, Phone Address Village Office Brahmakulam 8547614508 [email protected] Village Office 8547614509 [email protected] Village Office 8547614512 [email protected] Village Office 8547614512 [email protected] Village Office Venkidangu 8547614513 [email protected] Village Office 8547614517 [email protected] Village Office 8547614517 [email protected] Village Office Kodakara 8547614333 [email protected] Village Office 8547614314 [email protected] Village Office 8547614317 [email protected] Village Office Nadipulam 8547614344 [email protected] Village Office 8547614317 [email protected] Varantharappilli Village Office 8547614322 [email protected]

The widely time tested Communication to reach every corner of the flood affected zones have been radio and television and private media for the people to move to safer places by themselves in an emergency.

Communication is very important in such occasions. These days due to revolution in the telecommunication system, there is available, network of mobile phones. Advantage of this facility will be taken. Mobile numbers of all such staff will be listed and made available to all the personnel who have been assigned duty of disaster management.

Following liaising officers for flood co-ordination of Chimoni Dam are as listed below

Kerala State:

1) Chief Engineer, Project II ,Thiruvananthapuram

2) Superintending Engineer, Irrigation Central Circle, Thrissur

3) Executive Engineer, Irrigation Division, Thrissur.

4) Assistant Engineer, Chimoni Dam project Section No.1

5) Assistant Engineer, Chimoni Dam project Section No.2

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Summary of Flood Regulation Procedure.

The flood regulation procedures at Chimoni can be summarized in the following 5 steps: ·

1. Observe the reservoir level at 1 hour intervals.

2. Determine the total outflow occurring at all outlets (including river sluices, canals, spillway, and turbines)

3. Estimate the inflow.

4. Determine the gate opening.

5. Open all 4 gates to the extent required. 2.5 DRAWDOWN FACILITY

All water release facilities, including outlet works, sluices, gated spillways, and power penstocks should be considered available for evacuation to the extent that their reliability in an emergency situation can be reasonably certain. In the case of canal outlet works, there must be a bypass or waste way in order for such outlet works to be considered available for emergency releases. Otherwise releases through them will be considered equal to the design capacity of the canal.

Reservoir level may be required to be lowered if a critical/emergency condition occurs or for carrying out repairs to the dam on its upstream slope/face in dry condition. For general guidance the ACER Technical Memorandum no. 3 - Criteria and Guideline for evacuating storage reservoirs and sizing low level outlet works & IS: 15472 – Guidelines for planning of low level outlets for evacuating storage reservoirs may be referred to. Care is to be taken to restrict the reservoir drawdown rates to prevent failure of upstream slope of the Embankment/ landslides along reservoir periphery etc. This will vary from dam to dam and project to project. The actual drawdown rates both under normal and emergency conditions have to be decided by the Dam Designers. In Chimoni Dam the Lowest Outlet Level is at 40.00m and discharge capacity 32.32m3/s.

2.6 Record Keeping Operating a dam includes keeping accurate records of items pertaining to project operation. These include but not limited to the following:-

1. Rainfall and Reservoir Levels – On daily basis during non-monsoon and monsoon.

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2. Release through outlet/sluices on daily basis for irrigation, water supply, hydropower etc.

3. Outflows through spillway during monsoon on hourly basis.

4. Records of drawdown with reservoir levels, quantity of water released, drawdown rates, reason for drawdown.

5. Other Procedures – Maintain a complete record of all operating procedures for gates and sluices.

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CHAPTER 3 - PROJECT INSPECTIONS

The current practice of Inspection at Chimoni dam envisages the Divisional Officers to carryout pre-monsoon and post-monsoon inspections. The checklist proforma included in this document is currently in use at Chimoni dam.

Detailed description on project inspections is available in the Guideline for Safety Inspection of dams (Doc No. CDSO_GUD_DS_07_ v1.0), CWC 2018. However an overview of the various types of inspections to be carried out at Chimoni 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 must be used. An effective inspection program is essential to identify problems and to keep Chimoni Dam in a good and healthy condition. This Chapter provides guidance on carrying out other inspections. 3.1 TYPES OF INSPECTIONS

Four different types of dam safety inspections are available for being carried out at Chimoni Dam. These include, but not limited, to the following:

1. Comprehensive evaluation inspections

2. Scheduled inspections (Pre & Post monsoon inspections & other scheduled inspections)

3. Special (unscheduled) inspections

4. Informal inspections

The frequency of each type of inspection depends on the condition of the dam and State DSO regulations, etc. Typical inspection elements and the detail of the safety inspections are provided below. More detailed descriptions are given in the “Guideline for Safety Inspection of Dams” (CWC 2018). Comprehensive Evaluation Inspections

For comprehensive dam safety evaluation for each dam an independent panel of experts known as Dam Safety Review Panel (DSRP) needs to be constituted for determining the condition of the dam and appurtenant works. The panel will undertake evaluation of the dam once in 10 years or on occurrence of any extreme hydrological or seismic event or any unusual condition of the

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dam or in the reservoir rim. The terms of reference of the comprehensive dam safety evaluation shall include but not be limited to;

General assessment of hydrologic and hydraulic conditions, review of design flood, flood routing for revised design flood and mitigation measures.

 Review and analysis of available data of dam design including seismic safety, construction, operation maintenance and performance of dam structure and appurtenant works.

 Evaluation of procedures for operation, maintenance and inspection of dam and to suggest improvements / modifications.

 Evaluation of any possible hazardous threat to the dam structure such as dam abutment slope stability failure or slope failures along the reservoir periphery.

A comprehensive evaluation inspection of Chimoni Dam consists of five major parts:

1. Review of project records (i.e. study of all design / construction records/drawings, history of the dam’s performance, past inspection notes/reports, notes on distress observed/ any rehabilitation measures undertaken earlier, instrumentation data and its interpretation including.

2. Inspection of the dam and its appurtenant works.

3. To review the results and reports of additional field investigations & laboratory testing as required.

4. Review of design studies e.g. review of design flood, checking of the adequacy of spillway capacity, freeboard requirements, dam stability, and any special study as required.

5. Preparation of a detailed report of the inspection. 3.2 INFORMAL INSPECTIONS

An informal inspection, is a continuing effort by on-site personnel (dam owners/operators and maintenance personnel) performed during their routine duties. Informal inspections are critical to the proper operation and maintenance of the dam. They consist of frequent observations of the general appearance and functioning of the dam and appurtenant structures.

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Operators, maintenance crews, or other staff who are posted at Chimoni dam site conduct informal inspections. These people are the “first-line of defense” in assuring safe dam conditions, and it is their responsibility to be familiar with all aspects of the dam. Their vigilance in walking the dam, checking the operating equipment, and noting changes in conditions may prevent serious mishaps or even dam failures.

Informal inspections are important and are performed at every available opportunity. These inspections may only cover one or two dam components as the occasion presents itself, or they may cover the entire dam and its appurtenant structures. The informal inspections are not as detailed as comprehensive evaluation, scheduled, and special inspections and will only require that a formal report is submitted to the dam owner’s project files if a condition is detected that might endanger the dam. Report is to be submitted detailing the condition discovered along with photographs, time, and reservoir water level (RWL), etc. 3.3 SCHEDULED INSPECTIONS

Scheduled inspections shall consist of Pre-monsoon & Post-monsoon inspection and any other inspections carried out by the State Dam Safety Organisation / any Expert panels constituted by the dam owner.

These inspections are performed to gather information on the current condition of the dam and its appurtenant works. This information is then used to establish needed repairs and repair schedules, and to assess the safety and operational adequacy of the dam. Scheduled inspections are also performed to evaluate previous repairs.

The purpose of scheduled inspections is to keep the dam and its appurtenant structures in good operating condition and to maintain a safe structure. As such, these inspections and timely maintenance will minimize long-term costs and will extend the life of the dam. Scheduled inspections are performed more frequently than comprehensive evaluation inspections to detect at an early stage any developments that may be detrimental to the dam. These inspections involve assessing operational capability as well as structural stability and detection of any problems and to correct them before the conditions worsen. The field examinations should be made by the personnel assigned responsibility for monitoring the safety of the dam. If the dam or appurtenant works have instrumentation, the individual responsible for monitoring should analyze measurements as they are received and include an evaluation of that data. Dam Inspection Report or an inspection brief should be prepared following the field visit (Dam Inspection Report is recommended).

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Scheduled inspections include the following four components as a minimum:

 File review of past inspection reports, monitoring data, photographs, maintenance records, or other pertinent data as may be required;

 Visual inspection of the dam and its appurtenant works;

 Preparation of a report or inspection brief, with relevant documentation and photographs. The report should be filed in the dam owner’s project files.

3.3.1 Pre- and Post-Monsoon Checklist and Example of Report Proforma

Detailed checklists are required to ensure the health of the dam and to ensure that it continues to operate in satisfactory and safe condition. The proforma to be used for inspection should be the one enclosed in the Doc No. CDSO_GUD_DS_07_ v1.0, CWC 2018 on the Guidelines for Safety Inspection of Dams.

Pre-monsoon Inspection to be carried out during April – May

Post-monsoon Inspection to be carried out during December - January

Inspecting Officers Deputy Chief Engineer along with SPMU Executive Engineer, Field Executive Engineer, Concerned field Assistant Executive Engineer and Assistant Engineer

Preparation of Inspection Report Executive Engineer, Field (Dam Health Engineer)

Submission of Pre-monsoon Inspection Report Before June 30th

Submission of Post-monsoon Inspection Report Before January 15th

Checking and approval of report Deputy Chief Engineer, SPMU

Uploading corrected document in DHARMA Executive Engineer, Field

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3.4 SPECIAL (UNSCHEDULED) INSPECTIONS Special inspections may need to be performed to resolve specific concerns or conditions at the site on an unscheduled basis. 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. These inspections are to be carried out after an initial assessment based on informal inspection carried out by project personnel reveal dam safety related concerns like cracking in the dam, damages, erosion/ scour, undermining/ piping/ sink holes/ liquefaction or any such undesirable feature. A special inspection may also be performed during an emergency, such as an impending dam breach, to evaluate specific areas or concerns. They are also made when the ongoing surveillance program identifies a condition or a trend that appears to warrant a special evaluation. Special inspections should focus on those dam components that are affected by the unusual event and should include at least three elements: 1) review of relevant files or data, 2) visual inspection, and 3) report preparation.

More detailed site investigations / studies may be required (such as drilling, surveys, or seepage flow estimates) if the special inspection reveals the need for the same. Photographic documentation is to be included as part of the inspection.

3.5 COMPREHENSIVE EVALUATION INSPECTIONS

3.5.1 General

For comprehensive dam safety evaluation for each dam an independent panel of experts known as Dam Safety Review Panel (DSRP) needs to be constituted for determining the condition of the dam and appurtenant works. The panel would undertake evaluation of each dam once in 10 years or on occurrence of any extreme hydrological or seismic event or any unusual condition of the dam or in the reservoir rim. The terms of reference of the comprehensive dam safety evaluation shall include but not be limited to;

1. General assessment of hydrologic and hydraulic conditions, review of design flood, flood routing for revised design flood and mitigation measures.

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2. Review and analysis of available data of dam design including seismic safety, construction, operation maintenance and performance of dam structure and appurtenant works.

3. Evaluation of procedures for operation, maintenance and inspection of dam and to suggest improvements / modifications.

4. Evaluation of any possible hazardous threat to the dam structure such as dam abutment slope stability failure or slope failures along the reservoir periphery. 3.5.2 Details to be provided to DSRP before inspection

All relevant details/data/drawings for the dam project to be inspected by the Panel of Experts 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 4. Details of key personnel 5. Emergency preparedness – Communications, Auxiliary Power, Downstream Warning system & Security of site.

(b) Hydrology 1. Description of drainage basin 2. Original inflow design flood 3. Spillway capacity at FRL & original MWL 4. Surface area & storage capacity of the reservoir 5. Flood routing criteria & results

(c) Geology 1. Dam site geology including geological reports 2. Quality and sufficiency of the geological investigations. 3. Special problems and their treatment 4. Reservoir competency as per geological report.

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5. Slope stability issues along reservoir rim. (d) Layout including Drawings 1. Dam 2. Spillway 3. Junction between Embankment &Concrete/Masonry dams 4. River/Canal outlets

5. Instrumentation

(e) Dam and Spillway 1. Geology 2. Special problems 3. Foundation treatment including treatment of faults/shear zones/ weak zones, curtain/consolidation grouting, drainage provisions, any other special treatment, cutoff trench, diaphragm walls etc. 4. Design criteria and result of stability analysis 5. Special studies (Finite element/ Dynamic Analysis etc.) 6. Adequacy of design – from dam safety considerations 7. Hydraulic design of Spillway and Energy Dissipation Arrangements including past model study reports. 8. Instrumentation – analysis and interpretation of instrumentation data including structural behavior reports. 9. Pre-construction material testing reports including adequacy of field and laboratory investigations, appropriateness of materials selected etc. 10. Post-construction testing reports, if any. 11. Seismicity (Seismic Parameters approved by the National Committee for Recommending Seismic Design Parameters for Dams) f) Construction history g) Dam incidents/failures, remedial measures/modifications undertaken h) Reservoir Operation & Regulation Plan 1. General 2. Reservoir filling 3. Water releases – normal and during floods.

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3.5.3 Field Inspection – Observations & Recommendations regarding Remedial Measures

Each component of the project is to be 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 shall include but will not be limited to; (a) Dam 1. Upstream face 2. Downstream face 3. Top of dam 4. Structural behavior 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) Spillway 1. Civil structure 2. Energy Dissipation Arrangements (EDA) 3. Spill channel, drop structures etc. if any. 4. Condition of EDA and its performance

5. Spillway Gates & Hoists 6. Downstream safe carrying capacity of river / channel. (c) River / Canal Outlets 1. Civil structures 2. Outlet Gates, Hoists & Controls 3. Conducts / Outlets through Embankment dams and sluices through Masonry / Concrete dams (Condition, problems etc.) 4. Trash racks, if any 5. Separate energy dissipation arrangements, if any. (d) Review of Sedimentation of the Reservoir.

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1. Assessment of sedimentation and its effect on flood routing, operation/ life of reservoir. (e) Flood Hydrology 1. Extent & sufficiency of data available 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 / Bridges / Culverts 2. Elevators 3. Stand by power arrangements 4. Flood forecasting arrangements, if any 5. Communication facilities (Telephone, Satellite, Wireless, Mobile etc.)

(g) Hydraulic Model studies, if any new studies carried out.

(h) Earlier reports of experts / DSRP etc., if any, as annexures.

(i) Photographs of dam project showing problem areas.

3.5.4 Components Involved

A comprehensive evaluation inspection of a dam will typically consist 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/ any rehabilitation measures undertaken earlier etc.). 2. Visual inspection or field examination of the dam and its appurtenant works. 3. Preparation of a detailed report of the inspection. 4. Education and training of the dam owner on the issues observed during dam inspection, identification of potential dam failure modes & to carryout additional field investigations & laboratory testing as required. Dam owners should be made part of the inspection process so that they take ownership of the results and are committed to implementing the recommended remedial measures.

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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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CHAPTER 4- PROJECT MAINTENANCE APTER 4 - PROJECT MAINTENANCE A good maintenance program protects Chimoni Dam against accelerating deterioration, prolongs its life, and greatly reduces the chance of failure. Nearly all the components of Chimoni Dam and its materials are susceptible to damage and deterioration if not well maintained. Moreover, the cost of a proper maintenance program is small compared to the costs of major repairs, loss of life and property and litigation. Preventative maintenance not only protects the dam and its owner but the public as well. If maintenance of a dam is neglected the consequences and costs will multiply.

Preventive maintenance assures that a dam and reservoir are in good working condition and prevents more harmful conditions from developing. Individual maintenance tasks are noted, with a description of the area where the maintenance is to be performed, the schedule for performing the tasks, and reporting procedures. Typical routine maintenance tasks performed includes mowing grass, removing vegetation, bushes and trees, removing litter and other debris, re-grading the crest and/or access roads, repairing fencing to keep livestock off the dam, etc. Other maintenance works that need to be performed on the embankment includes restoration of embankment to its design section, seepage problems, erosion, displaced riprap, cracking in embankment etc. In concrete / masonry dams there may be issues like cracking and disintegration in concrete, choking of drainage holes in dam body/ foundation, damages to spillway glacis/piers/energy dissipaters due to abrasion/ cavitation/unsymmetrical flows, damages to pointing on upstream & downstream faces of masonry dams, heavy seepages through some drains in foundation/inspection galleries etc.

A basic maintenance program has been developed primarily based on systematic and frequent inspections. 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. Individual maintenance tasks should be noted, with a description of the area where the maintenance is to be performed, the schedule for performing the tasks, and reporting procedures. Typical routine maintenance tasks performed at most dams include mowing grass, removing vegetation, bushes and trees, removing litter and

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other debris, re-grading the crest and/or access roads, repairing fencing to keep livestock off the dam, etc. Other maintenance works that may need to be performed in an Earth dam may include restoration of embankment to its design section, seepage problems, erosion, displaced riprap, cracking in embankment etc. In concrete / masonry dams there may be issues like cracking and disintegration in concrete, choking of drainage holes in dam body/ foundation, damages to spillway glacis/piers/energy dissipaters due to abrasion/ cavitation/unsymmetrical flows, damages to pointing on upstream &downstream faces of masonry dams, heavy seepages through some drains in foundation/inspection galleries etc.

4.2 MAINTENANCE PRIORITIES

For Chimoni Dam, maintenance activities require to be prioritized as immediate maintenance or preventative maintenance 4.2.1 Immediate Maintenance

The following conditions are critical and call for immediate attention & reservoir lowering, if warranted. These conditions may include, but are not limited to:

 The dam is about to be overtopped or being overtopped during high flood.

 The dam is about to be breached by erosion, slope failure etc.

 The dam showing signs of piping or internal erosion indicated by increasingly cloudy seepage or other symptoms.

 The spillway being blocked or with some inoperable gates.

Evidence of excessive seepage appearing anywhere on the dam site, e.g., the Embankment becomes saturated, defective water stops, etc., and seepage exiting on the downstream face is increasing in volume.

Although the remedy for some critical problems may be obvious (such as clearing a blocked spillway or repairing the spillway gates so that they are in working condition), the problems listed above generally demand the services of experienced engineers/expert panels familiar with the design, construction and maintenance of dams. The emergency action plan (EAP) should be activated when any of the above conditions are noted.

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4.2.2 Preventive Maintenance

This can be further classified as Condition based Maintenance and Routine Maintenance. 4.2.2.1 Condition Based Maintenance

The following maintenance should be completed as soon as possible after the defective condition is noted. These includes but are not limited to:

 Remove all vegetation and bushes from the dam and restoring any eroded areas and to establish a good grass cover.  Fill animal burrows.  Restore and reseed eroded areas and gullies on embankment.  Repair of defective gates, valves, and other hydro-mechanical equipment.  Repair any concrete or metal components that have deteriorated.  Cleaning of the choked drainage holes in the dam body/ foundations in concrete / masonry dams.  Repair any damages on spillway glacis, piers, energy dissipaters, training/divide walls, downstream areas etc.  Repairs on the upstream face of masonry dams, in case the pointing is damaged, due to which there is increased seepage.  Controlling any heavy seepage in the foundation/ inspection galleries in Concrete/Masonry dams from drainage holes.  Repairs of any cracks/cavities/joints in concrete/masonry dams/structures. However many of these works will require the services of experienced engineers/expert panels. 4.2.2.2 Routine Maintenance

Several tasks should be performed on a continuous basis. These include but are not limited to the following:

 Routine mowing, restore and reseed eroded areas and gullies on downstream face of the left flank embankment and general maintenance including repairs/cleaning of surface drains on downstream face and in the downstream area.

 Maintenance and treatment of any cracks/joints/ cavities in Concrete/Masonry dams and spillways based on the recommendations of experienced engineers / expert panels.

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 Observation of any springs or seepage areas, comparing quantity and quality (clarity) with prior observations in the embankment.

 Monitoring of downstream development which could have an impact on the dam and its hazard category.

 Maintenance of Electrical & Hydro-Mechanical equipment and systems e. g. Servicing of spillway gates & stop logs, hoisting arrangements, gantry crane, and gates/hoist of outlet works/sluices & stand by generator.

 Maintaining proper lighting at dam top, galleries, etc.

 Monitoring of seepage in galleries.

 Monitoring/ cleaning & removal of leached deposits in porous concrete / formed drains in dam body and foundation drainage holes.

 Maintenance of all dam roads & access roads.

 Operation of electrical and mechanical equipment and systems including exercising gates & valves.

 To keep the gate slots clear of silt/debris.

 Maintenance/testing of monitoring equipment (instruments) and safety alarms.

 Testing of security equipment.

 Testing of communication equipment.

 Any other maintenance considered necessary.

4.3 MAINTENANCE ITEMS

The O&M Manual includes detailed instructions and schedules for performing periodic maintenance works at the site. This includes maintenance of the dam, the appurtenant works, and the reservoir areas. Methodology / Specifications for carrying out maintenance works of general & recurring nature should be included in the Manual.

Dam repairs are scheduled based on severity of the problem, available resources, and weather conditions. For example, if a severe settlement problem (more than envisaged in designs) or cracking is detected on the crest of the dam, it should have a high priority since further degradation could lead to dam breaching. The causes of all major issues / problems should be

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identified and evaluated by experienced engineers/ Expert Panels so that appropriate remedial measures can be finalized. Correcting minor rill erosion on the downstream slope could be assigned a low priority since it is not a dam safety concern. This type of repair will also be weather dependent, since grass can only be planted during specific times of the year, and the embankment should be dry so that more damage is not inflicted to the embankment slopes.

4.3.1 Earthwork

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 described here are effective in repairing minor 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 such as the core of an embankment dam 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

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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 placed and compacted in horizontal lifts to the level specified in the technical specifications. Also it must be properly keyed (benched) with the existing material for which proper construction practices are carried out to “knit” the new fill in to the existing soils to ensure proper bonding. This can be accomplished by using the following simple procedures

1. Scarify the existing soil layer

2. Place new moisturized soils in loose layers up to 20 centimeters thick

3. Compact to required density at optimum moisture content (OMC)

4. Scarify compacted layer 10 centimeters

5. Moisturize the layer before placement of soils compact

6. Continue process until lines and grades are accomplished. Overbuild can be trimmed back to design lines and grades

7. Seed of turf the fill to minimize erosion processes

8. Water routinely to ensure turf root system is fully developed.

Erosion is one of the most common maintenance problems at 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 deleterious materials, is an effective means of preventing erosion. Rills and gullies should be filled with suitable soil, compacted, and then seeded or turfed as necessary. Large eroded gullies can be slowed by stacking bales of hay or straw across the gully until permanent repairs can be made.

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. People often walk along these walls, wearing down the vegetative cover. Workable solutions include re-grading the area so that it slopes away from the wall, adding more resistant surface

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protection, or constructing steps. 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.

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.

Runoff often concentrates along embankment slopes where the hinge point on the crest is lower than the surrounding crest and runoff ponds in these low areas. The concentrated runoff flows downs the slope cutting the soils and forming rills and gullies resulting in loss of design lines and grades and affecting stability of the structure.

4.3.2 Upstream Riprap

The upstream face is protected against wave erosion. Rip-rap is 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 finer filter materials under the riprap and soils leaving voids and loss of grade. Wave run-up will also undermine the filter layer especially along the full reservoir level and over time wash outliner material. This can be checked through observance of linear embankment settlement. Sections of riprap that have slumped downward are often signs of this kind of erosion. When erosion occurs on the upstream slope of dam, repairs should be made as soon as possible. Repairs can be made following the same design details as provided in the embankment section. Proper preparation of the surfaces of the existing embankment as described in the earlier paragraph for placement and compaction of embankment. Please refer to IS 8237- Code of practice for protection of Slopes for Reservoir Embankments is recommended to be reviewed and followed for carrying out this repair work. 4.3.3 Controlling Vegetation

Keep the entire dam clear of unwanted vegetation such as bushes or trees. Excessive growth may cause several problems:

 It can obscure the surface of an embankment and not allow proper inspection of dam.

 Large trees can be uprooted by high wind or erosion and leave large voids that can lead to breaching of the dam.

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 Some root systems can decay and rot, creating passageways for water, leading to piping erosion.

 Growing root systems can lift concrete slabs or structures.

 Rodent habitats can develop undetected.

All bushes/trees should be as far as possible removed by root to prevent regrowth. The resulting voids must be backfilled with suitable, well-compacted soils. It is recommended to remove the plants/vegetation at their early stage to prevent or minimize their growing into big trees/bushes, etc. In cases where trees and bushes cannot be removed, the root systems should be treated with environmentally-friendly herbicides (properly selected and applied) to retard further growth. Concerned Government Agencies must be consulted for selection of appropriate herbicides &their use for control of vegetation on dam structures or any water bodies. 4.3.4 Controlling Animal Damage

Livestock are not allowed to graze on the embankment section of the dam. 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.

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 found on the 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 slurry or thin cement consistency is attained. For bigger holes, betonies coated stones can also be used. All entrances should be plugged with well compacted earth and grassy vegetation re-established. Dens should be eliminated without delay. Different repair measures will be necessary if a dam has been damaged by extensive small or large rodent tunneling activity. The area around the entrance can be excavated and then backfilled with impervious material. This will plug the passage entrance to prevent water entry and saturation of the embankment

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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 . 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 path ways 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.

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 and ensure. 4.3.6 Controlling Damage from Vehicular Traffic As mentioned earlier, vehicles driving across an embankment dam can create ruts in the crest if it is not surfaced with roadway material. The ruts can then collect water and cause saturation and softening of the dam. Other ruts may be formed by vehicles driving up and down a dam face; these can collect runoff and cause severe erosion. Vehicles, except for maintenance, should be restricted on the dam top and kept out by fences or barricades. Any ruts should be repaired as soon as possible.

In the case of existing dams having permission for movement of nearby villagers, heavy traffic movement may be avoided. If possible, separate connectivity may be explored for such cases.

In the case of barrages and dams having provisions for roads of National/State Highways etc., all efforts should be made to restrict the speed of vehicles. Regular maintenance of bridge and roads shall be mandatory.

In Chimoni Dam vehicle traffic is not allowed on the top of the Dam.

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4.3.7 Masonry / Concrete Dams & Spillways

Various issues/problems that may require maintenance/repairs on the Chimoni Concrete/Masonry Dam and Spillway include but not limited to:

 Damages on spillway glacis, spillway piers, training/divide walls, energy dissipaters, downstream areas (probable causes are cavitation, abrasion, unsymmetrical flows, unfavorable down-stream conditions)

 Vegetation growth in unattended areas such as spillway, spillway channel, etc.

 Seepage in the galleries and on the downstream face of the dam.

 Cleaning and removal of leached deposits from choked porous and foundation drains.

 Repair to upstream face of masonry dams in case the pointing is damaged, leading to increased seepage.

 Ensuring safe access to and within the gallery, lighting is also required as well as all outside areas during the evening hours.

 Ensuring the dam is behaving as designed based on instrumentation programs.

 Periodic maintenance should be performed of all concrete surfaces which are approachable to repair deteriorated areas.

For remedial measures of problems of special nature advice of experienced engineers /Panel of needs to be obtained 4.3.7 Outlet Works

Outlet conduits should be inspected thoroughly once a year. Circular conduits that are one and a half meter or more in diameter can be entered and visually inspected. Common problems are improper alignment (sagging), separation and displacement at joints, cracks, leaks, surface wear, loss of protective coatings, corrosion, and blockage. Problems with conduits occur most often at the joints. Further collars at joints used to also lead to inadequate compaction. Hence, special attention should be given to them during the inspection. The joints should be checked for gaps caused by elongation or settlement and loss of joint-filler material. Open joints can permit erosion of embankment material or cause leakage of water into the embankment during pressure flow. The outlet should be checked for signs of water seeping along the exterior surface of the

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pipe. A depression in the soil surface over the pipe may be a sign that soil is being removed from around the pipe.

Listed below are common concerns regarding repairs to outlet works:

 Asphalt mastic is not recommended for other than temporary repairs. Asphalt mastic used as joint filler becomes hard and brittle, is easily eroded, and as per literature survey it may provide a satisfactory seal for about five years. Mastic should not be used if the conduit is expected to flow under pressure  The instructions on the label should be followed when using thermosetting plastics (epoxy). Most of these products must be applied to a clean and dry surface to set up an effective bond. However cementitious materials are to be preferred in view of their UV resistance & longer life.  Material used as joint filler should be impervious to water and should be flexible throughout the range of expected air and water temperatures.  The internal surfaces of the conduit should be made as smooth as possible when repairs are made so that high-velocity flow will not damage the repair material.  Minor cracks in concrete are not considered a dangerous problem. Repair is not necessary unless the cracks widen or leak. The general practice now is not to go in for Pre-cast concrete/MS pipe conduits with collars but to construct RCC conduits at site without any collars and joints. PVC water stops are provided at joints and the exterior faces of the conduits are given a slope to enable better contact at the interface with earth. 4.3.9 Trash Racks

River Sluices

The sluices should be inspected thoroughly once a year for any damages such as cracks and seepage. As regards to Hydro-mechanical works, reference may be referred to the appropriate paragraphs in this chapter.

4.3.10 Gates & Hoisting Equipment

The safe and satisfactory operation of Chimoni Dam depends on proper operation of its Gates &Hoisting Equipment. Maintaining spillway gates in working condition is critical for dam safety and is to be assigned the highest priority. If routine inspection of the Hydro-Mechanical Equipment shows the need for maintenance, the work should be completed as soon as possible.

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The simplest procedure to ensure smooth operation of gates is to operate them through their full range at least once, and preferably twice annually (before monsoon& after monsoon keeping a gap of at least six months).Because operating gates under full reservoir pressure can result in large discharges, exercising of gates should preferably be carried out during dry conditions or lean times of the year using the stop logs/emergency gates. Commonly used Gates and Hoists including their inspection/ maintenance requirements are discussed below. 4.3.10.1 Vertical lift fixed wheel and Slide Gates

The aspects to be inspected and maintained periodically for ensuring proper operation of these gates are as under:

i) The gate slot and bottom platform/sill beam should be cleaned periodically. Scales formed over the embedded parts should be removed. Second-stage concrete should be checked for any development of cracks / leakages and repairs should be attended to immediately.

ii) The gate leaf should be thoroughly cleaned and repainted as and when necessary according to the procedure or guidelines- indicated in IS: 14177 or as per the recommendations of the paint manufacturer. All drain holes provided in the gate assembly should be cleaned.

iii) Rubber seals should be smoothed, if required, for proper alignment. All nuts and bolts fixing the seal to the gate should be tightened uniformly to required torques. Seals, if found damaged or found leaking excessively should be adjusted, repaired or replaced as considered necessary.

iv) The wheel shall be rotated to check their free movement. Gate roller bearings and guide roller bushes should be properly lubricated. Whenever necessary these should be opened for rectifications of defects, cleaning and lubrication and should thereafter be refitted. These may be replaced if repairs are not possible.

v) Hoisting connection of the gate leaf should be lubricated where necessary and defects if any should be rectified.

vi) All nuts, bolts, check nuts and cotter pins of the lifting devices should be checked periodically.

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v) All components should be greased and lubricated. Recommended and approved oils and grease only should be used.

viii) Roller assembly should be adjusted by the eccentricity arrangement to ensure all rollers rest uniformly on the track plates particularly in the closed position of the gate.

ix) Where filling valves are provided as part of the gate structure, all the nuts, bolts, check nuts etc. should be tightened.

x) All welds shall be checked for cracks/ damages. Any weld that might have become defective should be chipped out and redone following the relevant codal provisions. Damaged nuts, bolts, rivets, screws etc. should be replaced without delay.

xi) The filling-in valves allow passage of water when it is lifted by lifting beam & crane due to creation of space between stem seat and exit passage liner. The springs and associated components should be checked periodically for damages and replaced if necessary.

xii) The guide-assemblies, wheel-assemblies and sealing-assemblies shall be cleared off grit, sand or any other foreign material.

xiii) The wheel pin shall be coated with corrosion resistant compound.

xiv) All nuts and bolts shall be tightened. The aspects to be inspected and maintained periodically for ensuring proper operation of these gates are as under:

4.3.10.2 Radial Gate a) Embedded Parts: b) Radial Gate Leaf: i) Rubber Seals: i) 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 not require immediate remedial measures. However, measures like tightening of bolts are carried out. Further adjustment is carried out during annual maintenance.

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ii) If leakage is excessive & immediate repair is considered necessary, the stop log gates shall be dropped and seals repaired or replaced. NOTE: - During monsoon period, stop log gates shall NEVER be lowered in spite of heavy leakage through seals.

ii) Trunnion blocks assembly and anchorages:

(i) All the nuts and bolts of Trunnion block assembly and its anchorages shall be checked for tightness.

(ii) Check all the welds for soundness and rectify defects.

(iii) Check whether the Yoke girder and thrust block is covered on not. If not, cover it with mild steel plates.

(iv) Cover the trunnion pin with anti- corrosive jelly.

(v) 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. iii) Gate structures: i) Check all the welds for soundness and rectify defects.

ii) Check welds 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. iii) Clean all drain holes including those in end arms and horizontal girders. iv) Check all the nuts and bolts and tighten them. Replace damaged ones.

v) 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: i) All the sill beams and wall plates shall be inspected for crack, pitting etc. and defects shall be rectified.

ii) The guide roller pins shall be lubricated. v) General Maintenance:

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i) Defective welding should be chipped out and it should be re-welded duly following the relevant code provision (IS: 10096, Part-3).

ii) Damaged nuts, bolts, rivets, screws etc. should be replaced. iii) Any pitting should be filled up by welding and finished by grinding if necessary. iv) 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. v) Trunnion bearing should be greased as and when required. Keeping trunnion bearings in perfect working condition is very important. All other bolted connections should also be checked up for proper tightness. vi) Bolts and trunnion bearing housing should be tightened wherever required. vii) The seals of the gate should be checked for wear and tear and deterioration. These should be adjusted/replaced as and when necessary. viii) The wall plates, sill beams shall be checked and repaired if necessary. ix) Wire ropes should be properly lubricated. x) 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.

xi) The stroke of the brake should be reset to compensate for lining wear. Worn out brake linings should be replaced in time.

xii) Flexible couplings should be adjusted if required.

xiii) Repairs and replacements of all electrical relays and controls should be attended to.

xiv) Maintenance of alternative sources of Power such as Diesel Generating sets and alternative drives wherever provided should be carried out.

xv) 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.

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4.3.10.3 Electrically Operated Fixed Hoists a) 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. 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. Lubricate all bearings, bushings, pins, linkages etc. 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. 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.

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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. 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 cardium compound. 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 turnbuckles. Raise and lower the gate for its full lift several time (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. Repaint the hoist components, hoisting platform and its supporting as per requirement. The periodic maintenance of commercial like motors, brakes, thrusts etc. shall be carried out as per manufacturers operation and maintenance manual 4.3.10.3.1 Maintenance of Electrical Components of Fixed Rope Drum Hoists

The electrical components to be inspected and maintained periodically are as under; i) Starters should be cleaned free of moisture and dust. ii) Each individual contactor should be tried by hand to make sure that it operates freely. iii) All wearing parts should be examined in order to take note of a wear which may have occurred during operation. iv) If the contactor hums, the contact faces should be cleaned.

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v) Examine all connections to see that no wires are broken and no connections are loose. vi) 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. vii) 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. viii) The contact tips should be kept free from burns or pits by smoothening with fine sand paper or emery paper. ix) Replace the contact tips which have worn away half-way. x) Do not lubricate the contacts. xi) 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. xii) Examine earth connections and motor leads. xiii) Examine motor windings for overheating xiv) Examine control equipment‘s xv) Examine starting equipment for burnt contacts xvi) Check and tighten all nuts and bolts xvii) Clean and tighten all terminals and screw connections all contact surfaces shall be made clean and smooth. xviii) Lubricate the bearings xix) Overhaul the controllers xx) Inspect and clean circuit breakers. xxi) Wipe brush holders and check bedding of brushes. xxii) Blow out windings thoroughly by clean and dry air. The pressure shall not be so high that insulation may get damaged. xxiii) 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 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.

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xxiv) Coat the windings with an approved high temperature resisting insulation enamel or varnish. xxv) Over haul the motor, if required. xxvi) Check the switch fuse units and renew, if required. xxvii) Check resistance or earth connections. xxviii) Check air gap.

Solenoids Operated Brakes

i) All fixing bolts shall be checked and tightened at least once in three months. ii) The magnet stroke should be reset to compensate for wear. iii) Re-adjust the brake when the magnet stroke reaches the value given on the instruction plate. iv) Brake lining should be checked and replaced when required. v) Examine all electrical leads and connections. vi) Rubber bushes or couplings should be checked and replaced if defective. vii) The pins should be tightened. viii) Brake drum shall be cleaned to remove any dust or grease.

A. INTRODUCTION:

Long service life and functional reliability of, any rope hoist system & its components are dependent on proper maintenance activities.

Maintenance of rope hoist system covers all the activities related to commissioning, servicing, Repair, Storage etc. of the Rope hoist System Elements.

Although commissioning of hoist system is not directly related to maintenance but after years of experience by users it is realized that, careful commissioning means less troubles in further service life, maintenance, servicing and repairing.

B) ROUTINE MAINTENANCE:

After careful commissioning certain points should also be taken Care of for routine maintenance.

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1. Check the fluid level continuously during commissioning of the equipment, after then daily, and later weekly.

2. During commissioning filter should be checked after every two to three hours of running the unit and cleaned if necessary. There after they must be checked and cleaned every week.

3. Measure the oil temperature in the oil reservoir and also in the region of pump bearings.

4. Check every week all the pipe joints and tighten them up if found loose.

5. Main pressure and pilot pressure of the system must be checked up periodically.

6. Check the alignment of pump motor set regularly.

4.3.10.4 Stop Logs, Lifting Beam and Gantry Crane

There is no Stop logs are provided in Chimoni Dam.

4.3.10.5 Surface Preparation and Painting of HM Works i) Protection of painted surfaces is considered essential for protection & enhancement of service life. Gates, their 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. This equipment is likely to deteriorate or get damaged to any extent that the 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.

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:

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• 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 pre-scribed 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 24hours 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:

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• 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.

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 than350 microns. v) Hoist and supporting structure: a) Structural components:

Primer coats of zinc phosphate primer shall be applied to give a dry film thickness of 40±5 Microns

Final Coats: One coat of alkalized based micaceous iron oxide paint to give a dry film thickness of 65 ± 5 microns followed by two coats of synthetic enamel paint confirming to IS 2932 – 1974 to give a dry film thickness of 25 ± 5 microns per coat. The interval between each coat shall be 24hours. The total dry thickness of all coats of paint including the primer coat shall not be less than 175microns. b) Machinery: Except machined surfaces all surfaces of machinery including gearing, housing, shafting, bearing pedestals etc., shall be given:

Primer coats: One coat of zinc phosphate primer paint to give minimum film thickness of 50 microns. Motors and other bought out items shall be painted if necessary.

Finished coats: The finished paint shall consists of three coats of aluminum paint confirming to IS2339 – 1963 or synthetic enamel paint confirming to IS 2932 – 1977 to give a dry film thickness of25±5 microns per coat to obtain a total minimum dry film thickness of 125 microns. c) Machined surfaces:

All machined surfaces of ferrous metal including screw threads which will be exposed during shipment or installation shall be cleaned by suitable solvent and given a heavy uniform coating of gasoline soluble removable rust preventive compound or equivalent. Machined surfaces shall be protected with the adhesive tapes or other suitable means during the cleaning and painting operation of other components.

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vi) Application of paint:

Mix the contents thoroughly as directed by paint manufacturer before and during use.

Painting at shop can be done by any of the three methods namely Brush / roller, Conventional spray, Airless spray etc.

The paint can be made to suit the adopted method. But once the gate and equipment is in erected position the general method adopted is only brush / roller. In case of spray lot of precautions are to be taken.

For More details: Refer IS: 14177 Part (II) – 1971.

A – Brushing of paint

B – Spraying of paint

C – Spray painting defects: Causes and remedies.

Removal of old paint / rust and carrying out fresh painting:

The carrying out of fresh painting is to be considered under the following conditions:

• The rusting is noticed all over the surface or

• Rusting is severe or

• Cracking and blistering has damaged the primer coat exposing the metal and is noticed all over the surface or

• The paint film has eroded badly, the scrap of entire paint film to the base metal and carry out fresh painting.

Note: In case of maintenance and renovation: Refer IS 14177 (Part II) – 1971 for checking and repainting. vii) Removal of old paint for repainting:

Caution should be exercised while removing the old paint. The surfaces shall be de-rusted and descaled by either mechanically by one or more of the methods, namely:

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a) Wire brushing, Scraping, and chipping. Sand papering or cleaning with steel wool or abrasive paper

b) Power tool cleaning c) Flame cleaning d) Sand blasting or shot blasting and e) Chemical rust removal.

Note: The method of application shall be decided based on conditions existing. After cleaning painting is to be carried out as originally proposed. Some are painted without removal of old paint and rusting this will amounts to no painting and deteriorate faster than the original one. viii) Inspection and testing of painting of H. M works: a) The following steps are involved in inspection of painting:

 General inspection before and during painting

 Viscosity test of paints Paint thickness test – using Elco-meter.

 Inspection of general appearance of finished work. b) General:

The aim of inspection and testing is to ascertain whether the recommended practice is being employed correctly during every stage of application and whether the final results fulfill the object of painting. Any test carried out should be of non – destructive nature or, if it is of destructive nature, it should be either restricted to areas which can be restored without marring the general appearances or be such that it is possible to restore easily without necessitating a complete repetition of the work. c) Inspection of surfaces prior to painting:

Inspection methods will depend on whether it is to be painted for the first time or is to be repainted. d) New Works (Not previously painted): The following shall be decided by inspection:

 The method of pre cleaning feasible or recommended;

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 The intermediate protective treatments to be applied, if found necessary;

 The final painting schedule and the specifications for the paint for ensuring the particular performance.

 The method of application, whether by brush, roller or spray. e) Old Work (Which requires repainting):

The following shall be decided by inspection:

 Whether the entire existing paint requires removal; and/or

 Whether repainting without paint removal would be adequate.

4.3.11 Electrical System

Electricity is typically used at a dam for lighting and to operate the gates, hoists, recording equipment, and other miscellaneous equipment. It is important that the Electrical system be well maintained, including thorough check of fuses and a test of the system to ensure that all parts are properly functioning. The system should be free from moisture and dirt, and wiring should becheckedforcorrosionandmineraldeposits.Allnecessaryrepairsshouldbecarriedoutimmediatelyan drefhe works kept. Maintain generators used for auxiliary emergency power -- change the oil, check the batteries and antifreeze and make sure fuel is readily available. Monitoring devices usually do not need routine maintenance. Open areas are particularly susceptible to vandalism. As such all electrical fittings like bulbs, lights, loose wires etc. in open areas should be checked routinely and replaced / repaired where needed. The recommendations facture should also be referred to.

4.3.12 Metal Component Maintenance

All exposed, bare ferrous metal of an outlet installation, whether submerged or exposed to air, will tend to rust. To prevent corrosion, exposed ferrous metals must be either appropriately painted (following the paint manufacturer’s directions) or heavily greased in respect of moving parts & on surfaces like guides & track seats 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

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especially damaging to contact surfaces, existing rust is to be removed before periodic application of grease. 4.3.13 Access Roads

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.

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. 4.3.14 General Cleaning

As already suggested, 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., regular and thorough 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 MATERIALS REQUIREMENTS FOR MAINTENANCE DURING MONSOON PERIOD

Materials required during monsoon period for both immediate maintenance and preventive maintenance must be stocked in adequate quantities for emergency situations that may arise. Needful instructions in this regard are enclosed in the O&M Manual. At Chimoni Dam, a 24/7 hour patrol schedule is carried out during monsoon period. At the same time the additional management requirements during monsoon period are enhanced. General List of Maintenance Records

Maintenance records are of utmost importance. Records are kept of all maintenance activities, both immediate and preventive maintenance works. Essential information to be recorded include the following:

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 Date and time of maintenance,

 Weather conditions,

 Type of maintenance,

Name of person, title and / or contractor performing maintenance,

 Description of work performed,

 Length of time it took to complete the work with dates,

 Equipment and materials used, and

 Before and after dated photographs. The data is recorded by the person responsible for maintenance.

4.5 ESTABLISHMENT REQUIREMENT The requirements of annual and monsoon establishment for the operation and maintenance of a dam is to be decided by the Dam Owners on a case to case basis. A typical organization set up for dams as per its height covering supervision staff down to Junior Engineer level is given at 1.6.1 for guidance. In addition there will be other supporting staff (skilled/unskilled), regular/ work charged staff/labour and clerical staff depending upon the requirements in monsoon & non-monsoon period. The staff requirements would vary from project to project depending upon its size, importance and hazard potential. 4.6 PREPARATION OF O&M BUDGET

In order to prepare O&M budget for a dam project all possible costs associated with implementation of O&M Program need to be identified and considered. Typical O&M budget for a project should essentially include but not limited to the following items: i) Establishment Cost of Regular Staff - Salaries and allowances, Bonus, Medical Reimbursement, LTC, Leave Encashment, pension benefits, etc. (as applicable). ii) Establishment Cost of Work charged Staff - Salaries and allowances, Bonus, Medical reimbursement, LTC, Leave Encashment, Pension benefits, TA and DA , etc. (as applicable). iii) Establishment Cost of Daily wage Staff - Salaries and allowances, TA and DA etc. (as applicable).

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iv) Office Expenses – Rent for office, Telephone/Mobile/any other Telecommunication bills, Electricity bills, water bills, Office stationery, Day to day office requirements. v) Motor Vehicles - Running and Maintenance cost of inspection vehicles, Cost of hiring of vehicles as required vi) Maintenance of Colony - Maintenance of staff quarters, colony roads, Electricity, Sanitary and Water supply systems etc. vii) T&P - T&P requirements for offices, colony, works etc. as applicable. viii) Works -Painting, oiling, greasing, overhauling of HM equipment’s, Repair/replacement of gates seals & wire ropes, POL for pumps & generator sets, Electricity charges and maintenance of Electric systems of dam site, specific requirements for all Civil, H.M & Electrical maintenance works, vegetation removal and mowing of Turfing on earth dams, maintenance/cleaning of drains in dam, maintenance of lift/elevators in dam (as applicable), maintenance of access roads & basic facilities, provision for flood contingency works during monsoon, unforeseen events/items (about 10% of the cost of works) etc.

Table 4. 1 O&M BUDGET COSTS (ANNUAL)

SL.NO. BUDGET ITEM PREVIOUS CURRENT YEAR REMARKS YEAR BUDGET(YEAR- COST(Rs.) )(Rs.)

A.Establishment

1 SALARY REGULAR STAFF INCLUDING ALL OTHER BENEFITS

2 TRAVEL EXPENSES

3 OFFICE EXPENSES

4 MOTOR VEHICLE EXPENSES

5 MAINTANANCE OF OFFICE & COLONY

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SUB –TOTAL -A

B.Works

1 CIVIL

1.1 CONCRETE / MASONRY DAM

1.2 EARTHEN DAM

1.3 INTAKE / OUTLETS IN EARTHEN DAMS

1.4 SLUICES IN CONCRETE / MASONRY DAMS

1.5 APPROACH / INSPECION ROADS WITHIN DAM AREA

2 HYDRO-MECHANICAL

2.1 SPILLWAY GATES & HOIST

2.2. SPILLWAY STOP – LOGS & GANTRY CRANE

2.3 OUTLETS IN EARTHEN DAM’S SERVICE / EMERGENCY GATES & HOISTS

3 ELECTRICAL

3.1 ELECTRICAL FITTINGS,MOTORS, CONTROLS FOR ALL

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GATE HOISTS

3.2 POWER SUPPLY LINES

3.3 ELECTRICAL FITTINGS ON DAM TOP, DAM GALLERIES , ETC

3.4 STANDBY POWER / DIESEL GENERATOR

3.5 REMOTE CONTROL / CCTV

4 INTRUMENTATION

5 MISCELLANEOUS WORKS

6 SALARY WORK CHARGED STAFF INCLUDING ALL BENEFITS

7 MATERIALS TO BE RESTORED BEFORE MONSOON

SUB – TOTAL –B

C Others

8 CONTINGENCY (10%) ON SUB TOTAL OF A&B

9 TOOLS & PLANTS

SUB – TOTAL C

10 TOTAL ANNUAL COST

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Organization set up for the project

Chief Engineer Project II Thiruvananthapuram

Superintending Engineer

Irrigation Central Circle Thrissur

Executive Engineer Irrigation Division Thrissur

Assistant Executive Engineer Chimoni Dam project Sub Division Echippara

Assistant Engineer Assistant Engineer Chimoni Dam project Section No.1 Chimoni Dam project Section No.2

Echippara Echippara

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4.7 MAINTENANCE RECORDS Maintenance records are of utmost importance. A record shall be kept for all maintenance activities, both immediate and preventive maintenance works. Information that must be recorded includes, but not limited to, the following:

 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.

General Comment : Ensure that O&M manual for HM equipment should cover the following in sequence:  Description of Each gates , valves with their operating mechanism (Hoist etc.) at Both Dams  Salient Features of each gate, valves with their hoists/operation.  Operation of Each gate (precondition ,lifting ,lowering ,other functions, operation from control panel ,prepare control panel, Details of push buttons , indicating lamps etc ,Manual operation )  Inspection & Maintenance of Each Gate with their hoist with schedule , Inspection of paints with schedule , Maintenance for Electrical works)  List of approved / recommended lubricants for each gate / hoist with schedule  Testing of gates with hoist.  Trouble shooting charts  Details & Make of bought out components  Storage of Equipment

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 Details of Instruments under HM works / gate position sensors if any.  List of spares to be available for each type of gates /hoist/valves  All reference drawings and circuit diagram with complete list  Catalogues of procured machine parts used for gates , hoists, valves , controls etc.

O&M manual shall also meet the requirement/recommendation of manufacturer of HM equipment provided in Dams.

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CHAPTER 5 - INSTRUMENTATION AND MONITORING

A dam‘s instrumentation furnishes data for deciding if the structure is functioning as intended and provides continuous monitoring to warn of any unsafe developments. Monitoring physical phenomena that can lead to a dam failure may draw information from a wide spectrum of instruments and procedures ranging from simple to complex. Any program of dam safety instrumentation has to be properly planned consistent with project components.

An instrumentation program should involve instruments and evaluation methods that areas simple and straight forward as the project will allow. The involvement of personnel with experience in the design, installation, regular monitoring, and evaluation of an instrumentation system is of prime importance to the success of the program.

Instruments installed at a dam can indicate occurrence of any anomalous or problematic behavior. They can show that whether the dam behavior is as per design or otherwise. Actual measurements of uplift pressure in a Gravity dam and comparison with the uplift pressure assumed in original designs is an example.

A wide variety of instruments and procedures are used to monitor dam behavior. The parameters often monitored by instruments include:

 Movements (horizontal, vertical, rotational and lateral)  Pore pressure and uplift pressures  Water level  Seepage flow  Water quality  Temperature  Crack width  Seismic activity  Weather and precipitation data  Stress and strains

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5.1 INSTRUMENTATION AT CHIMONI DAM The following instruments are installed at the dam and their status is as under:

SL.No Details of Instrument Number Status . 1 Standard Rain Gauge 1 Working 2 Thermo Meter wet and dry 1 Working 3 V- Notches 14 11 nos.Not working 4 Rectangular Notch 1 Working 7 Reservoir Gauging 1 Working 5.1.1 Parameters monitored

i) Water Level- Water level of the reservoir is measured in daily basis during non-monsoon period and on hourly basis on monsoon period. Staff gauges are being used for measuring water level

ii) Seepages in foundation gallery-nSeepage from foundation is measured with V- notches and rectangular notches

iii) Rain

Standard rain gauge installed in the campus area, and rain measured on daily basis. The instrument installed and maintained by Hydrology division of Irrigation department.

5.2 FREQUENCY OF MONITORING Reservoir level, seepage are monitored daily 5.2.1 Seepage assessment In Chimoni Dam, there are 131 nos. Porous drains and 145 Nos. Foundation Drain Holes. Monthly observations of these holes are being carried out. Total seepage is measured using V- notch fitted in the foundation gallery. Seepage details for the following previous years are tabulated below.

Year/date Reservoir water V Notch reading Discharge (Cm) (litre/min)

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5.3 DATA PROCESSING AND EVALUATION The steps required to process and evaluate data, whether collected manually or automatically, are the same. Instrument data should be processed and evaluated according to the procedures established by the monitoring program. Accumulation of instrument data by itself does not improve dam safety or protect the public. 5.3.1 Data Collection

Data collected manually should be recorded on the data sheets prepared as part of the monitoring program. Complementary data, such as air temperature, reservoir level, reservoir temperature, recent precipitation, and other information or observations that may be important in evaluating the instrumentation data should be noted on the data sheets.

Data collection for the dam is carried out on daily, fortnightly / monthly basis as the case may be. 5.3.2 Data Presentation

All data should be summarized in graphical form. All plots should include sufficient previous data to identify any long-term trends. Furthermore, the plots should be self-explanatory.

5.3.3 Data Interpretation

Data should be reviewed for reasonableness, evidence of incorrectly functioning instruments, and transposed data. Several checks for reasonableness can be made on all data. The magnitude of data should be near the range of previous data. Data that are significantly different may be incorrect. All data will have scatter from instrument error, human error, and from changes in natural phenomena such as temperature, wind, and humidity. The true accuracy of data will not be apparent until a significant number of readings have been taken under a variety of conditions. All data will follow trends, such as decreasing with time or depth, increasing with time or depth, seasonal fluctuation, direct variation with reservoir or tail water level, direct variation with temperature, or a combination of such trends.

Interpretation of data is carried out as per standard practice & on monthly / six monthly / yearly basis or as decided by design authorities for this dam.

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Interpretation of data, so collected, needs to be carried out judiciously. Help of experienced personnel from the concerned field from Institutes / manufacturers / instrument suppliers could prove to be useful. 5.3.4 Dam Performance Evaluation

The purpose of instrumentation and monitoring is to maintain and improve dam safety. The data should be used to evaluate whether the dam is performing as expected and whether it provides a warning of developing conditions that could endanger the safety of the dam. All data should be compared with expected behaviour based on the basic engineering concepts. Variations from expected behaviour may suggest development of conditions that should be evaluated. All data should be compared with design assumptions. If no unusual behaviour or evidence of problems is detected, the data should be filed for future reference. If data deviates from expected behaviour or design assumptions, action should be taken. The action to be taken depends on the nature of the problem, and should be determined on case-by-case basis. Possible actions include:

 Performing detailed visual inspection;  Repeating measurements to confirm behaviour;  Re-evaluating stability using new data;  Increasing frequency of measurements;  Installing additional instrumentation;  Designing and constructing remedial measures;  Operating the reservoir at a lower level; and  Emergency lowering of the reservoir.

5.3.5 Methods of Behavior Prediction Each dam is a unique structure and has its own special conditions of siting, design, construction and operation. Rigorous methods of prediction have been developed over the years. These methods apply the laws of physics to problems of slope stability, foundation stability and rock deformation. Modern solutions use finite element or finite difference models run on computers. Such numerical analyses are expensive and for that reason are generally used only for larger dams. Special analyses are made when investigations reveal weak materials or other anomalies.

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5.4 VISUAL OBSERVATIONS

Observations by on site personnel (dam owners/operators and maintenance personnel) may be the most important and effective means of monitoring the performance of a dam. An inspector, upon each visit to the dam site, should examine it visually – walking along the dam alignment and looking for any signs of distress or unusual conditions. Instrumentation Proposed under DRIP

SL.No Details of Instrument Proposed . Number 1 Automatic Water Level Sensor 1 2 Automatic Rain Gauge 1 3 Standard Rain Gauge 1 4 Thermo Meter 5 5 Tilt Meter 2 6 Joint Meter 5 7 Uplift Gauge 50 8 Settlement Plate/Survey Markers 50 9 Data Center at dam Site- Data logger etc, with monitoring software 1 10 Strong motion as Accelerograph 1

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CHAPTER 6 – REMEDIAL MEASURES TAKEN EARLIER Before DRIP, maintenance activities were limited to routine repair of electrical systems for hoisting system of Emergency gates of out let and valve operations; gallery drainage; routine mowing, vegetation removal, repair of dam top road and allied works etc. Apart from these routine maintenance activities, no major rehabilitation was carried before the involvement of DRIP. Under DRIP, following Rehabilitation Works have been carried out.

The rehabilitation works under DRIP include:

Strengthening of Masonry Dam by Cement grouting

Guniting the upstream face of Emergency shutter well of dam

Cleaning and painting of Masonry dam

Extension works to the profile of Earth dam and constructing parapet

Protection works to the Downstream Toe of Masonry Dam including Construction of Toe Drain

Security arrangements - Demarking boundaries and providing chain link fencing

Providing all weather access roads in the Campus area

Construction of Camp Office cum Watchman Cabin

Construction of Flat Type Quarters

Water Supply and Sanitary Arrangements to the Buildings

Mechanical works-Replacing the old rubber seals of the spillway shutter with new flat type at the bottom and angular seals at vertical edges, Providing new stainless steel guide roller assembly of spillway shutter and fixing with gun metal bush, SS shaft and other accessories, Painting all the exposed surfaces of the gate with two coats of epoxy coal tar black paint, Patch working the hoist platform of spillway shutter and fabricating new ladders for catwalk and hoist platform, Over hauling the operating mechanism, and providing new position indicator and manual operating mechanism and installing new wire rope and electrical equipments of spillway shutters, Providing diesel generator (100KVA), Painting the hoist unit, hand rails and platforms and its accessories by using 2 coats of Synthetic enamel paint over 1 coat of zinchromate primer, Testing the soldered socket and wire ropes

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in approved laboratory

Electrical works-Renewal of damaged fitting of dam top lighting and gallery lighting and providing Generator at Chimoni dam, Electrification of flat type quarters and camp office cum watchman cabin

Figure 5. 1 Masonry Dam parapet before painting

Figure 5. 2 Masonry Dam parapet after painting

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Figure 5. 3 Guniting Upstream face

Figure 5. 4 Camp Office cum Watchman Cabin

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Figure 5. 5 Access Road

Figure 5. 6 Earthen dam before parapet construction

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Figure 5. 7 Earthen dam parapet after construction

Figure 5. 8 Flat type Quarters

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CHAPTER 7 – UPDATING THE MANUAL

As features of the dam and appurtenant structures change occasionally, the O&M Manual must be edited and portions rewritten to reflect these changes. This important task is often ignored. Updating information in the O&M Manual should be done whenever major changes like construction of an additional spillway, construction of dam on the upstream etc. take place. Aspects to be considered when updating include:

 Increase/decrease in the frequency of an inspection or the maintenance routine 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 additional spillway etc.

All up-dates/revisions of the O&M Manual need to be sent to all the locations/addresses to whom the copies of the original O&M Manual had been sent earlier. It is recommended that O&M Manuals be reviewed/ updated after every 5-10 years by the respective Dam Owner

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ANNEXURE- A - BASIC DRAWINGS OF CHIMONI DAM

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Non over flow section

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Section of outlet

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Section of radial gate

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Section through spillway and stilling basin

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ANNEXURE B- HYDROLOGIC REVIEW REPORT

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ANNEXURE C- GATE MANUFACTURER’S OPERATION MANUAL

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ANNEXURE D- REPORT OF DAM SAFETY AUTHORITY DURING THE INSPECTION OF 27-10-06

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ANNEXURE –E- CHECK LIST FOR INSPECTION Composite Dam Checklist

SN Inspection Item Response Observations and Condition Recommendations, if ( any, of the authorized Unsatisfact inspecting officer ory/Poor/ Fair/ Satisfactor y Y N N A A-Reservoir A1.1 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 Are there people or livestock in and around reservoir? 1.1.6 Any other issues? B- Dam and Dam Reach (Embankment) B1.1 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? B1.2- Upstream Slope 1.2.1 Any signs of bulging or concavity (depressions)? if so, indicate their locations and extent(Checkup the cross – sections with tape and level at random locations, at least two) 1.2.2 Does the section of the dam and upstream slope appear

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structurally sound and stable

1.2.3 Presence of longitudinal or transverse cracks? 1.2.4 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 locations

1.2.8 Any other issues? B1.3 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

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heaving?

1.3.4 Does it provide an all- weather road surface?

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

1.3.7 Have the edges of the crest gotten 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?

B1.4 Downstream Slope

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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? 1.4.4 Any signs of distress to the stability of slopes? 1.4.5 Are of 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 Instability? 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 show 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 (turfing)? Indicate the general condition of downstream pitching/ turfing and rock toe.

1.4.10 Is the downstream area clear of debris and freely draining?

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1.4.11 Any other issues? B1.5 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.

1.5.4 Is the downstream area sufficiently clear and freely draining?

1.5.5 What is the depth of ground water table on the downstream as evident from the existing wells in the vicinity of the dam? To be checked up to 300 m downstream of toe

1.5.6 Does the water table show any marked variation in accordance with the variations in reservoir water level?

1.5.7 Are all the exposed drains working satisfactorily?

1.5.8 Toe drains and cross drains:

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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. Any other defects noticed in the drains?

1.5.9 Outfall Drain:

1.5.12 (a) Is the outfall drain in proper shape and grade and freely draining?

1.5.13 (b) Is the outfall drain properly cleaned and maintained?

1.5.14 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?

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

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rain cuts at any location?

1.6.5 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, explain if it has any relation to a certain reservoir level elevation.

1.7.3 Does the seepage show a turbid colour at any stage? Indicate if such a phenomenon has been 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:

i. On the day of present inspection

ii. Maximum since last June

iii. Minimum since last June

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?

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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?

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

1.8.5 Is the maintenance staff fully aware of the instructions related to operation of the beaching section and for reconstruction after the breach?

1.8.6 Ascertain and indicate the latest event of operation of breaching section and its performance.

1.8.7 Evidence of recent degradation?

1.8.8 Any other issues?

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please indicate the approximate rate and colour of the leakage and if it turns 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 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 wells properly surged and cleaned periodically?

1.10.3 Lease 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

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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 in the vicinity of 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?

1.7.3 Any evidence of erosion or slope instability? 1.7.4 Trees or profuse growth of weeds/bushes? 1.7.5 Any degradation to up/downstream slope protection (rip-rap, turfing)? 1.7.6 Any other issues? C Dam and Dam Block/Reach (Concrete/Masonry)

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 down- stream floodplain? 1.1.3 Any misalignment of poles, fencing or walls due to dam movement?

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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 (dis-placed/ 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 (dis-placed/ 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 down- stream curb wall? 1.3.6 Any other issues? C 1.4 Downstream Face 1.4.1 Evidence of surface defects (honey-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

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settlement (dis-placed/ 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 D1.1 General Condition 1.1.1 Slushy condition or water logging just downstream of dam? 1.1.2 Any evidence of boiling in vicinity of dam toe?

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)? 1.2.4 Evidence of surface defects (honeycombing, staining, stratification)?

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1.2.5 Excessive seepage/sweating at any location along gallery/shaft? 1.2.6 Significant leakage at any location along gallery/ shaft? 1.2.7 Are proper arrangements made for the measurement of seepage into the gallery?

1.2.8 Is the seepage measured separately from Porous pipes, Foundation drains and Monolith Joints?

1.2.9 Are the above arrangements satisfactory?

1.2.10 Has there been substantial progressive reduction in the seepage through the foundations? Indicate if it is due to choking of the drain holes and if so, indicate the number of choked holes.

1.2.11 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.

1.2.12 Is the seepage water and the deposit, if any, from the seepage being regularly examined for chemical composition? If so, indicate the result and the probable source of dissolved salts, if any.

1.2.13 Are any seepage water springs observed in the downstream area anywhere? If so, indicate the locations and state the physical nature of this seepage.

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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.

1.2.14 Is there any leachate deposition? If yes provide location

1.2.15 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 the dewatering pumping station fully operational?

1.3.4 Any problem inspecting the 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 the sump well clean and maintained?

1.3.8 Is the V-notch before sump well cleaned 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

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have unusual color (leachate)?

1.3.12 Any other issues?

D-1.4 Body Wall (Masonry/Concrete) of ‘NOF’ Dam

1.4.1 What is the total seepage into gallery from the porous pipes in the dam at lake full condition? Compare it with the seepage when the reservoir was first filled. (For the corresponding water level)

1.4.2 Has there 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)

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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?

E Spillway and Energy Dissipation Structure

E-1.1 Spillway

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,

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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 Waste Weir Bar and Tail Channel

1.2.1 Is the Concrete/masonry spillway bar in good condition? Indicate if there is 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?

1.2.2 Is the coping over the spillway bar in good condition?

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1.2.3 Does the upstream and downstream face of waste weir bar need pointing?

1.2.4 Is there any scouring on downstream side of the bar and/or EDA? If so what remedial measures are proposed/taken?

1.2.5 Are there any damages or undermining to guide walls, divide wall and other appurtenant? If so, indicate what remedial measures are proposed/taken.

E1.3 Structural performance of the ‘NOF’ and ‘OF’ Portions of Dam Foundations

1.3.1 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 in any part of the body wall or foundations

iii. Cracking and upheaval or settlement

iv. Excessive uplift)? v. Excessive seepage and leaching through the body of the dam and the foundation? 1.3.2 Conspicuous weathering of materials or components in any portion of the body wall or the foundations.

E-1.4 Water Conveyance Structure 1.4.1 Any problems inspecting energy dissipation structure?

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1.4.2 Any obstructions in or immediately downstream of dissipation structure?

1.4.3 Evidence of abrasion, cavitation or scour on dissipation structure?

1.4.4 Presence of displaced, offset or open joints?

1.4.5 Presence of cracking (structural, thermal, along joints)?

1.4.6 Evidence of surface defects (honeycombing, staining, stratification)?

1.4.7 Concrete/masonry deterioration (spalling, leaching, disintegration)?

1.4.8 Presence of vegetation (growth in joints between blocks)?

1.4.9 Evidence of any other damage to joints?

1.4.10 Any problems with under- drainage (blockage of open drain holes)?

1.4.11 Can the tail pond be drained easily for inspection of the stilling basin or bucket? If not, indicate the alternatives available for dewatering. Please ascertain and indicate the last event of inspection of stilling basin (or bucket).

1.4.12 From the examination of the levels and contour plans and reference marks in tail channel; is there progressive erosion and retrogression in the tail channel? If so, indicate the extent and location of such erosion with reference to the

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various components of dam, spillway, outlet, power house etc.

1.4.13 Is the concrete surface of the stilling basin and apron (or bucket) in good condition?

1.4.14 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.

1.4.15 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.

1.4.16 Is the under drainage of the stilling basin (or bucket) satisfactory? Are all the open drain holes clear and functioning well?

1.4.17 Any other issues?

G-1.5 Walls: Guide walls/Divide walls/Junction walls/Return walls/Spray walls etc. 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?

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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 End Weir

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

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 Hydraulic Performance of Energy Dissipation Arrangements

1.7.1 Do the flow conditions in the stilling basin (or bucket) have a tendency to draw material into the bucket and cause its churning and abrasion damage to the surface of buckets baffle blocks, apron and end sill?

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1.7.2 Is the hydraulic performance in agreement with the results of model studies? (wherever applicable)

1.7.3 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.

F-1.1 Intake/Outlet Structure water Conveyance 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, cavitations

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

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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)

1.1.1 Any problems inspecting gate/stop log/bulk head (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 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 track plates uniformly? Are the rollers well lubricated?

1.1.7 Are the embedded parts of spillway gates, emergency

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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 Are the following members and welded, bolted and riveted connections structurally sound? If not, please give details of any 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

(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 or wear caused to the seal plates? If so, indicate the nature of damage noticed.

1.1.11 Are any of the mechanical or structural components

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and fasteners or seals subjected to excessive wear? If so, please give details.

1.1.12 Is there any tendency for recurring damage to any particular component? If so, please give details.

1.1.13 Is sufficient stock of spares which need frequent replacement maintained at the site?

1.1.4 Any issues with storage of equipment (emergency stop logs, lifting beam and gate leaves)?

1.1.15 Any deterioration, corrosion, scaling, pitting or cracking of equipment (connecting bolts, welds)

1.1.16 Any obstructions preventing or impairing smooth operation?

1.1.17 Any problems with the rollers (not touching tracks, inadequate lubrication)?

1.1.18 Any debris, etc., in the gate grooves?

1.1.19 Any damages to Radial Gate trunnion pins, gate arms, lubrication? etc.?

1.1.20 Any damage to embedded parts above waterline, access structure?

1.1.21 Any damage to concrete grooves?

1.1.22 Is the staff posted at the site for maintenance and operation of gates, hoists, equipment and electrical

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installations, well experienced, fully trained and conversant with the job requirements and responsibilities?

1.1.23 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.

1.1.24 Are the trunnion hub and the brackets well maintained?

1.1.25 Are the trunnion 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.

1.1.26 Are all the nuts of connecting bolts and anchorages properly tightened?

1.1.27 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

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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 properly? 1.2.8 Any deterioration of equipment (connecting 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 sound and 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

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anchored to the piers? 1.3.9 Are the track rails for gantry cranes structurally sound and intact? G-1.4 Valves 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 Trash Racks 1.5.1 Is the trash rack fixed or movable? 1.5.2 What is the mode of cleaning? Is it manual or by TRCM? 1.5.3 Is the welding work on Trash Rack in sound health?

1.5.4 Any problems inspecting trash rack? 1.5.5 Problems of excessive debris and/or inadequate cleaning? 1.5.6 Any deterioration of trash rack (rust, corrosion, and damaged blades)? 1.5.7 Any other issues? G-1.6 Trash Rack Cleaning Machines 1.6.1 Any problems inspecting trash rack cleaning machine? 1.6.2 Missing or inadequate spare parts (particularly requiring regular replacement)? 1.6.3 Any deterioration of equipment (connecting bolts, welds, surface, paint work?) 1.6.4 Any wear or damage to wire cables and other moving parts? 1.6.5 Any obstructions preventing or impairing smooth operation? 1.6.6 Missing or inadequate provision of back- up/standby power supply?

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1.6.7 Any health and safety concerns (e.g. lack of "danger" sign during maintenance)? 1.6.8 Any other issues? G-1.7 Pumps 1.7.1 Any problems inspecting pump? 1.7.2 Any obstructions preventing or impairing smooth operation? 1.7.3 Any deterioration of pump and associated equipment? 1.7.4 Any other issues? G-1.8 Approach bridge, operation platform and cabin (for outlets): 1.8.1 Are the decking, girders and structural supports of approach bridge structurally sound? 1.8.2 Is the floor of the operating platform structurally sound and safe? 1.8.3 Is there satisfactory arrangement to prevent unauthorized entry into the control structures of the outlet? 1.8.4 Are the structural members and joints sound and free from corrosion? 1.8.5 When were the steel components painted last? 1.8.6 Is the surface of steel work and paint satisfactory? 1.8.7 Is the parapet or railing over the control tower, operating platform and approach bridge sound and safe? G-1.9 Outlet 1.9.1 1 Is the air vent periodically cleaned? 1.9.2 Are there any structural damages to the intake well? 1.9.3 Is there any leakage observed through the well proper and the conduit concrete or masonry? If so, 177

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give details of its location 1.9.4 Is there any damage noticed to the conduit concrete, breast wall and gate slots? 1.9.5 Is the bye-pass valve/filling- in-valve (wherever provided) operating satisfactory? Take operation trials of the following as provided and record 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. 1.9.6 Are there vibrations and noise noticed in operation of out- let gates at any time? If so, please indicate if periodical observations have been taken to ascertain their severity. 1.9.7 Is the energy dissipation arrangement working satisfactorily for all the discharges?

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1.9.8 Is there any structural damage to the energy dissipation structure? If so, give details of nature and extent of damage. 1.9.9 Is the conduit structurally sound and reasonably leak proof? If not, give details of nature and extent of the defects 1.9.10 Is there any seepage noticed around the conduit as ascertained from the observations of the downstream conditions? If so, please indicate if it is likely to cause erosion and piping (In case of earth dams). G-1.10 Outlet Gates 1.10.1 Is the surface of gates and the paint deteriorated? 1.10.2 Are the connecting bolts of rubber seals properly tightened or damaged? 1.10.3 Do the rubber seals show signs of weathering and damage and need replacements? 1.10.4 Are the rubber seals of sides and bottom touching the bearing surface uniformly? 1.10.5 Do all the rollers touch the track plates? 1.10.6 Are the rollers well lubricated? 1.10.7 Are the stem rods for lifting the gates perfectly straight? 1.10.8 Is the operation of outlet gates smooth? 1.10.9 Are the actual operations of lifting and lowering of the gates and hoist mechanisms adequate and smooth? 1.10.10 Are all the gears and hoist mechanisms well lubricated? 1.10.11 Is the storing arrangement for emergency gate leaves

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and the stop logs in satisfactory condition? 1.10.12 Are the seal plates/seats in sound condition? 1.10.13 Is the full length of wire rope (wherever applicable) of the hoist in serviceable condition and free from any broken strands? 1.10.14 Are all the nuts of connecting bolt and anchors properly tightened? 1.10.15 Are all the lifting beams in proper working order and in leveled condition? If not, ascertain the nature and extent of problems. 1.10.16 Do any of the mechanical or structural parts of the gate, fasteners of hoist show signs of excessive wear? If so, please give details. 1.10.17 Is there any tendency for recurring damage to any particular component or components? If so, please give details. 1.10.18 Is sufficient stock of spares, which need frequent replacement, maintained at the site? G-1.11 River Outlet/River Sluice 1.11.1 Is the overall condition of river outlet works/river sluices satisfactory? 1.11.2 Is the operation of the gate (Service/Emergency/S top- log) satisfactory as ascertained by taking operating trial? If not, indicate the defects noticed. 1.11.3 Are the trash racks (wherever provided) cleaned before monsoon? 1.11.4 Is there excessive silting on the upstream of the sluice? 1.11.5 When the gates were last opened for desilting, etc.?

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1.11.6 Please indicate the approximate quantity of the leakage through the gates, if any 1.11.7 Is there any seepage or leakage through the conduit surface? 1.11.8 Is there any damage to the upstream and downstream convergence of the conduit? 1.11.9 Is the condition of energy dissipation arrangement satisfactory? If not, indicate nature and extent of damage. 1.11.10 Is there any retrogression noticed in the downstream channel? If so, give details of 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 and well maintained all weather access road to the dam site? 1.1.3 What is the type of the pavement of the access road and its 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, audits 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 Are

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all the masonry 1.1.5 Are all the masonry structures on various access roads in good condition? 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)? 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 Any problems inspecting instrument (obstructed/unsafe access)? 1.1.2 Is the instrument vulnerable to damage or theft (inadequate protection)? 1.1.3 Any problems ensuring correct functioning of instrument (lighting, ventilation)? 1.1.4 Any evidence of degradation to condition of instrument (rusting, vandalism)? 1.1.5 Any evidence of instrument not working (decommissioned, broken)? 1.1.6 Any other issues? I-1 Instrumentation I-1.1 General Condition 1.1.1 Are all the instruments installed accessible? (Attach separate list).

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1.1.2 Are all the locations properly lighted, ventilated and adequately protected from possibilities of damage? 1.1.3 Any problems inspecting instrument (obstructed/unsafe access)? 1.1.4 Is the instrument vulnerable to damage Is the instrument vulnerable to damage 1.1.5 Any problems ensuring correct functioning of instrument (lighting, ventilation)? 1.1.6 Any evidence of degradation to condition of instrument (rusting, vandalism)? 1.1.7 Are all the instruments in working order? Ascertain the cases of instruments going out of order and indicate 1.1.8 Are all the registers of observations posted up-to- date? Please take test observations and initial the register. 1.1.9 Are all the plotting of the instrumentation data completed up-to date? 1.1.10 Are sufficient stocks of spares, gauges, master gauges, and stationary items etc., maintained at the site for uninterrupted data collection? 1.1.11 Operator or public safety issues? 1.1.12 Any other issues? I-1.2 Communication Facilities 1.2.1 Are following facilities available at dam site? (1) Wireless Telephone / mobile/Fax/Internet 1.2.2 Any other issue (please indicate part, location, etc., as necessary) K-1 Emergency Preparedness

K-1.1 Emergency Action Plan

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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? 1.1.10 Are adequate warning devices and facilities provided at the dam? 1.1.11 Are proper arrangements made for security of the dam and preventing cases of unauthorized trespass, vandalism and sabotage to the dam works? 1.1.12 Date of last annual stakeholder consultation meeting along with mock drill exercise conducted 1.1.13 Has the EAP been disseminated to all the concerned stakeholders? 1.1.14 Any other issues?

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K-1.2 Inspection of Records 1.2.1 Have the following Dam Safety Documents been prepared and approved by the competent authority? I. As Built Drawings II. EAP III. Completion Report

IV. Data Book

V. O and M 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 behavior. h) Reporting Procedures of emergency situations. (i) Emergency repairs

L-1.1 Inspection Photographs 1.1.1 Information to be furnished as per Annexure - II

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ANNEXURE F- PRE & POST MONSOON INSPECTION REPORT OF THE PROJECT Post monsoon inspection report – quarter January 2018 – March 2018

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Pre monsoon inspection report- Quarter April 2018 – June 2018

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ANNEXURE G – NOTIFICATION FOR STRENGTHENING OF ALARM AND WARNING SYSTEM FOR SAFETY OF PEOPLE FROM SUDDEN RELEASE OF WATER FROM DAMS ISSUED BY NATIONAL DISASTER MANAGEMENT AUTHORITY (OCTOBER 2015) Introduction

Dams are delivering enormous benefits to the nation through flood risk mitigation, navigation, irrigation, hydropower, water supply, fisheries, wildlife conservation and recreation. Dams store large amount of water; and an uncontrolled or excessive outflow of water from dam reservoir may pose unacceptable risks to the lives and property of people downstream of dam. Sometimes, unexpected release of even small quantum of water during day to day operation of dam reservoirs could also catch people unaware, and cause loss of lives - recent large dam incident (81 June, 2014) is the tragic example which resulted in drowning of 25 students in the river Beas in Himachal Pradesh. Strengthening of alarm and warning system linked with dam operations can go a long way in ensuring safety of people from sudden release of water through dam spillways.

Scope

This notification is intended to strengthen the alarm and warning system on India's dams for safety of people from sudden release of water through dam spillways/river sluices. It is also expected that the notification will sensitize and guide the dam operating staff in identifying, monitoring, and responding to emergency situation that may arise at any downstream stretch of the river due to sudden release of water from dam

Applicability

This notification is applicable for enforcement by all dam authorities in charge of operation of the dams. This is particularly applicable to barrages and independent outlet works which are directly discharging into the river.

Measures for Strengthening of Alarm and Warning System

1. Reservoir Operation Manual, prescribing standard operating procedures for the day to day as well as emergency operations of dam, shall be prepared by the concerned project authorities/ dam owners (State Governments, Public Sector Undertakings, other government or private agencies). The Operation Manual shall spell out all possible scenarios of operation of spillway gates and other outlet gates keeping in perspective the

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elevation-storage curve of the reservoir; the annual inflow pattern of the reservoir; the annual water demand pattern of the project; and in case of hydropower projects, the power demand and impact of load rejection on generating units.

2. The concerned project authorities shall carry out hydraulic routing studies for the downstream river reaches for different dam-outflow conditions in order to identify vulnerable areas in terms of depth/level and velocity of flows. In such vulnerable areas, project authorities shall mark danger levels at appropriate places and set up permanent warning posts (in English, Hindi and the local language) visible with naked eyes from reasonable distances. Movable barriers may be installed to prevent the entry of people and vehicles during passage of flood.

3. The purpose of a flood warning service is to detect and forecast threatening flood events so that the public can be alerted in advance and undertake appropriate responses to minimize the impact of flood. The components of a flood warning system can be aptly illustrated in figure below.

4. The vulnerable areas that pose very high risk levels (e.g. river reaches very c se to dam locations) shall be fenced to bar free access of people. Development of river front from the point-of- view of tourism shall be allowed only at safe places; and in all such places ample care shall be taken to prominently notify risks associated with sudden release of wafer from dam.

5. The concerned project authorities shall establish a Control Room to keep watch on probable water inflows so as to have advance information and sufficient lead time for protective measures. A proper coordinate ion regarding releases of water during both normal and emergent conditions shall be ensured with the immediate upstream and other cascading projects. The work of Control Room shall be entrusted to duly qualified persons.

6. A foolproof warning system to alert downstream habitants before release of water shall be put in place. The warning for release of water shall be given through Speakers, Sirens or Hooters adequately in advance of dam releases (minimum 15 minutes); and all such instruments shall be directly connected to the Control Room eliminating dependence on watch staff stationed at vulnerable areas. The warning system shall be backed up by alternate power sources in Control Room as well as vulnerable locations so as to avoid

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malfunctioning of system in case of power failures. The Sirens/ Hooters shall be distinguishable from other common sounds like VIP vehicles, fire brigades, ambulance etc. Regular Inspection shall be carried out to ensure all time functioning of sirens, and periodical mock drills shall also be planned for ensuring efficacy of the warning system.

7. Tourists entering the vulnerable zones shall be forewarned of dangers of sudden dam releases. A suitable mechanism shall be developed in consultation with pertinent telecom service providers to send SMSs to such tourists whenever they enter vulnerable zones. Attempts shall also be made to send SMSs related to extreme releases of water to all mobile phones operating in the downstream vicinity of the dam project.

8. For dealing with extreme weather and flood conditions, accurate and reliable hydro meteorological network, inflow forecasting and communication mechanism shall be established by the State Governments. Releases from the storage dams associated with irrigation and flood moderation shall be planned in advance with the help of telemetry data available on real time basis, and advance warnings shall be issued to the people. Such information related to flood estimates and planned releases from dams shall be made available on Project website and through other means of public dissemination.

9. The concerned project authorities shall develop appropriate mechanism to keep local administration informed about the extreme inflows, sudden release of water and any other exigency conditions. Directory of contact numbers of key persons of civil administration, police, ambulance, fire station etc. shall be available with the officials responsible for such communications, and a copy shall also be available in the Control Room. Regular revision/updating of the Directory shall be carried out for its meaningful intent.

10. Preparation of Emergency Action Plan (EAP) for each dam is crucial for minimizing the loss of life and property in the event of occurrence of any emergency situation. A typical EAP contains procedures and information to assist the dam owner in taking necessary actions in time to moderate or alleviate the problems, in addition to issuing early warning and notification messages to responsible authorities, viz., District Magistrate/Collector, Armed forces, Paramilitary forces, Project Authorities and other Central/State Agencies. It also contains inundation maps to identify critical areas for prioritization of relief and rescue actions in case of an emergency. Project Authorities shall ensure preparation and updation of the EAPs of their dams as per Central Water Commission's guidelines

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available on CWC website at http://www.cwc.gov.in/main/downloads/EAP chapter.pdf.

Detection

(Meteorological monitoring)

Forecasting

(Meteorological monitoring)

Thresholds

WARNING FLOOD (When to issue a warning)

Warning dissemination Preparedness (Issue warning to allocated (Emergency planning, public population) awareness etc.)

Response

(Contingency plans)

Recovery

(Repair and cleanup RESPONSE RESPONSE operations, care for victims)

Review

(Can the system be improved?)

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ANNEXURE- H- GLOSSARY

Dam any artificial barrier including appurtenant works constructed across rivers or tributaries thereof with a view to impound or divert water; includes barrage, weir and similar water impounding structures but does not include water conveyance structures such as canal, aqueduct and navigation channel and flow regulation structures such as flood embankments, dikes, and guide bunds.

Dam failure – failures in the structures or operation of a dam which may lead to the uncontrolled release of impounded water resulting in downstream flooding affecting the life and property of the people. Dam incident – all problems occurring to a dam that has not degraded into „dam failure‟and including the following: a) Structural damage to the dam and appurtenant works; b) Unusual readings of instruments in the dam; c) Unusual seepage or leakage through the dam body; d) Change in the seepage or leakage regime; e) Boiling or artesian conditions noticed below an earth dam; f) Stoppage or reduction in seepage or leakage from the foundation or body of the dam into any of the galleries, for dams with such galleries; g) Malfunctioning or inappropriate operation of gates; h) Occurrence of any flood, the peak of which exceeds the available flood discharge capacity or 70% of the approved design flood; i) Occurrence of a flood, which resulted in encroachment on the available freeboard, or the adopted design freeboard; j) Erosion in the near vicinity, up to five hundred meters, downstream of the spillway, waste weir, etc.; andk) Any other event that prudence suggests would have a significant unfavorable impact on dam safety. Dam inspection – on-site visual examination of all components of dam and its appurtenances by one or more persons trained in this respect and includes investigation of the non-overflow portion, spillways, abutments, stilling basin, piers, bridge, downstream toe, drainage galleries, operation of mechanical systems (including gates and its components, drive units, cranes), interior of outlet conduits, instrumentation records, and record-keeping arrangements.

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Dam owner – the Central Government or a State Government or public sector undertaking or local authority or company and any or all of such persons or organizations, who own, control, operate or maintain a specified dam. Dam safety –the practice of ensuring the integrity and viability of dams such that they do not present unacceptable risks to the public, property, and the environment. It requires the collective application of engineering principles and experience, and a philosophy of risk management that recognizes that a dam is a structure whose safe function is not explicitly determined by its original design and construction. It also includes all actions taken to identify or predict deficiencies and consequences related to failure and to document, publicize, and reduce, eliminate, or remediate to the extent reasonably possible, any unacceptable risks. Decommission― Taking a dam out of service in an environmentally sound and safe manner or converting it to another purpose. Design life― the intended period that the dam will function successfully with only routine maintenance; determined during design phase Distress condition – the occurrence or potential development of such conditions in the dam or appurtenance or its reservoir or reservoir rim, which if left unattended to, may impede the safe operation of dam for its intended benefits or may pose unacceptable risks to the life and property of people downstream. Documentation – all permanent records concerning investigation, design, construction, operation, performance, maintenance and safety of dams and includes design memorandum, construction drawings, geological reports, reports of specialized studies simulating structural and hydraulic response of the dam, changes made in design and drawings, quality control records, emergency action plan, operation and maintenance manual, instrumentation readings, inspection and testing reports, operational reports, and dam safety review reports; Emergency Action Plan(EAP)― a plan of action to be taken to reduce the potential for damage to property and loss of life in the area affected by failure of a dam or other potentially hazardous practice. Hazard Classification― a system that categorizes dams according to the degree of adverse incremental consequences of a failure or improper operation of the dam. CWC classifies dam hazards as “low”, “significant”, or “high”. Maintenance― the recurring activities necessary to retain or restore a dam in a safe and functioning condition, including the management of vegetation, the repair or replacement of failed components, the prevention or treatment of deterioration, and the repair of damages caused by flooding or vandalism. Operation― the administration, management, and performance of maintenance activities necessary to keep a dam safe and functioning as planned.

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Program ― any authorized activity used to implement and carry out goals, actions, and objectives contained within the authorizing legislation. Program Life― the period in a contract, conservation plan, or plan during which the conservation practice or conservation system shall be maintained and used for the intended purpose; determined by program requirements. Rehabilitation― the completion of all work necessary to extend the service life of the practice or component and meet applicable safety and performance standards. Repair― actions to restore deteriorated, damaged, or failed dam or its component to an acceptable by meeting functional condition. Replacement― the removal of a structure or component and installation of a similar, functional structure or component. Service Life― the actual period after construction of a dam, during which the practice functions adequately and safely with only routine maintenance; determined by on-site review Abutment―that part of a valley side against which a dam is constructed. Right and left abutments are those on respective sides of the of an observer looking downstream. Air-Vent Pipe―a pipe designed to provide air to the outlet conduit to reduce turbulence during release of water and safeguard against damages due to cavitation. Appurtenant Structures― ancillary features of a dam, such as the outlet, spillway, energy dissipation arrangement powerhouse, tunnels, etc. Arch Dam―a concrete or masonry dam that is curved to transmit the major part of the water pressure to the abutments. Backwater Curve―the longitudinal profile of the water surface in an open channel where the depth of flow has been increased by an obstruction, an increase in channel roughness, a decrease in channel width, or a flattening of the bed slope. Base Width (Base Thickness) - the maximum width or thickness of a dam measured horizontally between upstream and downstream faces and normal (perpendicular) to O&M Manual for Chimoni Dam, the axis of the dam but excluding projections for outlets, etc. Berm―a horizontal step or bench in the sloping profile of an embankment dam. Upstream Blanket―an impervious layer placed on the reservoir floor upstream of a dam. In case of an embankment dam, the blanket may be connected to the impermeable element in a dam. Buttress dam―a dam consisting of a watertight upstream face supported at intervals n the downstream side by a series of buttresses. Cofferdam―a temporary structure enclosing all or part of a construction area so that construction can proceed in a dry area.

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Concrete Lift―in concrete works the vertical distance between successive horizontal construction joints. Conduit Outlet Works―a closed conduit for conveying discharge through or under a dam for different project purposes. Consolidation Grouting (Blanket Grouting) ― the injection of grout to consolidate a layer of the foundation, resulting in greater impermeability, strength, or both. Construction Joint―the interface between two successive placing or pours of concrete where a bond, not permanent separation, is intended. Core Wall―a wall built of impervious material, usually concrete or asphaltic concrete, in the body of an embankment dam to prevent leakage. Crest Length―the length of the dam at its crest (dam top) top of a dam, including the length of the spillway, powerhouse, navigation lock, fish pass, etc., where these structures form part of the length of a dam. If detached from a dam, these structures should not be included. Crest of dam―Used to indicate the “top of dam”. To avoid confusion to indicate the crest of spillway and top of dam may be used. Culvert―a drain or waterway built under a road, railway, or embankment, usually consisting of a pipe or covered conduits Cutoff―an impervious construction or material which reduces seepage through the foundation material Cutoff trench―an excavation later to be filled with impervious material to form a cut off. Cutoff wall―a wall of impervious material (e.g., concrete, asphaltic concrete, steel-sheet piling) built into the foundation to reduce seepage under the dam. Dead storage―the storage that lies below the invert of the lowest outlet and that, therefore, cannot be withdrawn from the reservoir. Design flood―The maximum adopted flood occurs and that can be discharged through the spillway gates of a particular dam. Dike (Levee) ―a long low embankment whose height is usually less than 5 m and whose length is more than 10 times the maximum height. Usually applied to embankments or structures built to protect land from flooding. If built of concrete or masonry, the structure is usually referred to as a flood wall. Also, used to describe embankments that block areas on a reservoir rim that are lower than the top of the main dam and that are quite long. In the Mississippi River basin, where the old French word levee has survived, the term now applies to flood-protecting embankments whose height can average up to 15 m. Diversion channel, canal, or tunnel―a waterway used to divert water from its natural course. These terms are generally applied to temporary structures such as those designed to bypass water

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around a dam site during construction. “Channel‟ is normally used instead of “canal” when the waterway is short. Occasionally these terms are applied to permanent structures. Drainage area―an area that drains naturally to a point on a river. Drainage layer or blanket―a layer of permeable material in a dam to relieve pore pressure or to facilitate drainage of fill. Relief well―vertical wells or boreholes, constructed downstream of an embankment dam to relieve the pressure from confined pervious layers in foundation overlaid by an impervious layer to arrest boiling. Drawdown―the lowering of water surface level due to release of water from a reservoir. Earthen dam or earth filled dam―see embankment dam. Embankment dam (Fill dam)― any dam constructed of excavated natural materials. Earth dam (Earth fill dam)―An embankment dam in which more than 50 percent of the total volume is formed of compacted fine-grained material obtained from a borrow area. Homogeneous earth fill dam― an embankment dam constructed of similar earth material throughout, except internal drains or drainage blankets; distinguished from a zoned earth fill dam. Hydraulic fill dam―an embankment dam constructed of materials, often dredged, that are conveyed and placed by suspension in flowing water. Rock fill dam―an embankment dam in which more than 50 percent of the total volume comprises compacted or dumped pervious natural or crushed rock. Rolled fill dam―an embankment dam of earth or rock in which the material is placed in layers and compacted using rollers or rolling equipment. Zoned embankment dam―an embankment dam composed of zones of materials selected for different degrees of porosity, permeability and density Face―the external surface of a structure, e.g., the surface of a wall of a dam. Failure―the uncontrolled release of water from a dam. Filter (filter zone)―A band or zone of granular material that is incorporated into a dam and is graded (either naturally or by selection) to allow seepage to flow across or down the filter without causing the migration of material from zones adjacent to it. Flashboards―a length of timber, concrete, or steel placed on the crest of a spillway to raise the retention water level but that may be quickly removed in the event of a flood, either by a tripping device or by deliberately designed failure of the flashboard or its supports. Floodplain―an area adjoining a body of water or natural stream that has been, or may be, covered by flood water.

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Floodplain management―a management program to reduce the consequences of flooding, either by natural runoff or by dam failure, to existing and future properties in a floodplain. Flood routing―the determination of the attenuating effect of storage on a flood passing through a valley, channel, or reservoir. Flood surcharge―the volume or space in a reservoir between the controlled retention water level (Full Reservoir Level) and the maximum water level. Flood surcharge cannot be retained in the reservoir but will flow over the spillway until the controlled retention water level is reached. Flood wall―a concrete wall constructed adacent to a stream to prevent flooding of property on the landward side of the wall, normally constructed in lieu of or to supplement a levee where the land required for levee construction is expensive or not available. Foundation of dam―the natural material on which the dam structure is placed. Freeboard―the vertical distance between a stated reservoir level and the top of a dam. Normal freeboard is the vertical distance between Full Reservoir Level (FRL) and the top of the dam. Minimum freeboard is the vertical distance between the Maximum Water Level (MWL) and the top of the dam. Gallery― (a) a passageway within the body of a dam or abutment, hence the terms grouting gallery, inspection gallery and drainage gallery (b) a long and rather narrow hall, hence the following terms for a power plant viz. valve gallery, transformer gallery and bus bar gallery. Gate―a device in which a leaf or member is moved across the waterway from an external position to control or stop the flow. Bulkhead gate―a gate used either for temporary closure of a channel or conduit to empty it for inspection or maintenance or for closure against flowing water when the head difference is small, e.g., for diversion tunnel closure. Although a bulkhead gate is usually opened and closed under nearly balanced pressures, it nevertheless may be capable of withstanding a high pressure differential when in the closed position. Crest gate (spillway gate) ―a gate on the crest of a spillway to control overflow or\ reservoir water level. Emergency gate―a standby or reserve gate which is lowers only for repairing / servicing of the service gate. Fixed wheel gate (fixed-roller gate, fixed-axle gate) ―a gate having wheels or rollers mounted on the end posts of the gate. The wheels move against rails fixed in side grooves or gate guides. Flap gate―a gate hinged along one edge, usually either the top or bottom edge. Examples of bottom-hinged flap gates are tilting gates and belly gates, so called due to their shape in cross- section.

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Flood gate―a gate to control flood release from a reservoir. Guard gate (guard valve) ―a gate or valve that operates fully open or closed. It may function as a secondary device for shutting off the flow of water in case the primary closure device becomes inoperable but is usually operated under conditions of balanced pressure and no flow. Outlet gate―a gate controlling the outflow of water from a reservoir. Radial gate (Tainter gate) ―a gate with a curved upstream plate and radial arms hinged to piers or other supporting structures. Service/Regulating gate (regulating valve) ―a gate or valve that operates under full pressure and flow to throttle and vary the rate of discharge. Slide gate (sluice gate) ―a gate that can be opened or closed by sliding it in supporting guides. Gravity dam―a dam constructed of concrete, masonry, or both that relies on its weight for stability. Grout cap―a pad or wall constructed to facilitate pressure grouting of the grout curtain beneath it. Grout curtain (grout cutoff) ―a barrier produced by injecting grout into a vertical zone, usually narrow horizontally, in the foundation to reduce seepage under a dam. Height above lowest foundation―the maximum height from the lowest point of the general foundation to the top of the dam. Hydraulic height―the height to which water rises behind a dam and the difference between the lowest point in the original streambed at the axis of the dam and the maximum controllable water surface. Hydrograph―a graphic representation of discharge, stage, or other hydraulic property with respect to time for a point on a stream. (At times the term is applied to the phenomenon the graphic representation describes; hence a flood hydrograph is the passage of a flood discharge past the observation point.) Inclinometer―an instrument, usually consisting of a metal or plastic tube inserted in a drill hole and a sensitized monitor either lowered into the tube or fixed within it. The monitor measures at different points the tube’s inclination to the vertical. By integration, the lateral position at various levels of the tube may be found relative to a point, usually the top or bottom of the tube, assumed to be fixed. The system may be used to measure settlement. Intake―any structure in a reservoir, dam, or river through which water can be drawn into an aqueduct. Inundation map―a map delineating the area that would be inundated in case of a failure.

Leakage―Uncontrolled loss of water by flow through a hole or crack.

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Lining― a coating of asphaltic concrete, reinforced or unreinforced concrete, shotcrete, rubber or plastic on a canal, tunnel etc. to provide water tightness, prevent erosion, reduce friction, or support the periphery of structure. May also refer to lining, such as steel or concrete, of outlet pipe or conduit. Low-level outlet (bottom outlet) ―an opening at a low level from a reservoir generally used for emptying or for scouring sediment and sometimes for irrigation releases. Masonry dam―a dam constructed mainly of stone, brick, or concrete blocks that may or may not be joined with mortar. A dam having only a masonry facing should not be referred to as a masonry dam. Maximum cross-section of dam―a cross-section of a dam at the point of its maximum height. Maximum water level―the maximum water level, including flood surcharge, the dam is designed to withstand. Membrane (Diaphragm) ―a sheet or thin zone or facing made of a flexible material, sometimes referred to as a diaphragm wall or diaphragm. Minimum operating level―the lowest level to which the reservoir is drawn down under normal operating conditions. Full Reservoir Level (FRL)/Normal water level―for a reservoir with un-gated Spillway it is the spillway crest level. For a reservoir, whose outflow is controlled wholly or partly by movable gates, siphons or other means, it is the maximum level to which water can be stored under normal operating conditions, exclusive of any provision for flood surcharge One-Hundred Year (100-Year) Exceedance Interval― the flood magnitude expected to be equaled or exceeded on the average of once in 100 years. It may also be expressed as an exceedance frequency, i.e. a percent chance of being exceeded in any given year. Outlet―an opening through which water can be freely discharged from a reservoir. Overflow dam―a dam designed to be overtopped. Parapet Wall―a solid wall built along the top of a dam for ornament, for the safety of vehicles and pedestrians, or to prevent overtopping. Peak Flow―the maximum instantaneous discharge that occurs during a flood. It coincides with the peak of a flood hydrograph. Pervious Zone―a part of the cross-section of an embankment dam comprising material of high permeability. Phreatic Surface―the top most flow line in an embankment dam. Piezometer―an instrument for measuring pore water pressure within soil, rock, or concrete.

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Piping―the progressive development of internal erosion by seepage, appearing downstream as a hole or seam discharging water that contains soil particles. Pore Pressure―the interstitial pressure of water within a mass of soil, rock, or concrete. Pressure Cell―an instrument for measuring pressure within a mass of soil, rock, or concrete or at an interface between one and the other. Pressure Relief Pipes―Pipes used to relieve uplift or pore water pressure in a dam’s foundation or structure. Probable Maximum Flood (PMF) ―a flood that would result from the most severe combination of critical meteorological and hydrologic conditions possible in the region. Probable Maximum Precipitation (PMP)―the maximum amount and duration of precipitation that can be expected to occur on a drainage basin. Pumped storage reservoir―a reservoir filled entirely or mainly with water pumped from outside its natural drainage area. Regulating dam―a dam impounding a reservoir from which water is released to regulate. Reservoir area―the surface area of a reservoir when filled to controlled retention level. Reservoir routing―the computation by which the interrelated effects of the inflow hydrograph, reservoir storage, and discharge from the reservoir are evaluated. Reservoir surface―the surface of a reservoir at any level. Riprap―a layer of large stones, broken rock, or precast blocks placed randomly on the upstream slope of an embankment dam, on a reservoir shore, or on the sides of a channel as a protection against wave action. Large riprap is sometimes referred to as armoring. Risk assessment―as applied to dam safety, the process of identifying the likelihood and consequences of dam failure to provide the basis for informed decisions on a course of action. Roll Crete or Roller-Compacted Concrete A no-slump concrete that can be hauled in dump trucks, spread with a bulldozer or grader, and compacted with a vibratory roller. Seepage―the interstitial movement of water that may take place through a dam, its foundation, or its abutments. Sill― (a) A submerged structure across a river to control the water level upstream. (b) The crest of a spillway. (c) A horizontal gate seating, made of wood, stone, concrete or metal at the invert of any opening or gap in a structure, hence the expressions gate sill and stop log sill. Slope― (a) the side of a hill or mountain. (b) The inclined face of a cutting or canal or embankment. (c) Inclination from the horizontal. In the United States, it is measured as the ratio of the number of units of horizontal distance to the number of corresponding units of vertical distance. The term is used in English for any

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inclination and is expressed as a percentage when the slope is gentle, in which case the term gradient is also used. Slope Protection―the protection of a slope against wave action or erosion. Spillway―a structure over or through which flood flows are discharged. If the flow is controlled by gates, it is a controlled spillway; if the elevation of the spillway crest is the only control, it is an uncontrolled spillway. Auxiliary Spillway (Emergency Spillway) ―a secondary spillway designed to operate only during exceptionally large floods. Fuse-Plug Spillway―an auxiliary or emergency spillway comprising a low embankment or a natural saddle designed to be overtopped and eroded away during a rare and exceptionally large flood. Primary Spillway (Principal Spillway) ―the principal or first-used spillway during flood flows. Shaft Spillway (Morning Glory Spillway) ―a vertical or inclined shaft into which flood water spills and then is conducted through, under, or around a dam by means of a conduit or tunnel. If the upper part of the shaft is splayed out and terminates in a circular horizontal weir, it is termed a “bell mouth” or “morning glory” spillway. Side Channel Spillway―a spillway whose crest is roughly parallel to the channel immediately downstream of the spillway. Siphon Spillway―a spillway with one or more siphons built at crest level. This type of spillway is sometimes used for providing automatic surface-level regulation within narrow limits or when considerable discharge capacity is necessary within a short period. Spillway Channel (Spillway Tunnel) ―a channel or tunnel conveying water from the spillway to the river downstream. Stilling Basin―a basin constructed to dissipate the energy of fast-flowing water, e.g., from a spillway or bottom outlet, and to protect the riverbed from erosion. Stop logs―large logs or timber or steel beams placed on top of each other with their ends held in guides on each side of a channel or conduit providing a cheaper or easily handled temporary closure than a bulkhead gate. Storage―the retention of water or delay of runoff either by planned operation, as in a reservoir, or by temporary filling of overflow areas, as in the progression of a flood crest through a natural stream channel. Tail race―the tunnel, channel or conduit that conveys the discharge from the turbine to the river, hence the terms tailrace tunnel and tailrace canal. Tail water Level―the level of water in the tailrace at the nearest free surface to the turbine or in the discharge channel immediately downstream of the dam.

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August 2020 O&M Manual of Chimoni Dam

Toe of Dam―the junction of the downstream face of a dam with the ground surface, referred to as the downstream toe. For an embankment dam the junction of upstream face with ground surface is called the upstream toe. Top of Dam―the elevation of the uppermost surface of a dam, usually a road or walkway, excluding any parapet wall, railings, etc. Top Thickness (Top Width) ―the thickness or width of a dam at the level of the top of the dam. In general, “thickness” is used for gravity and arch dams, “width” for other dams. Transition Zone (Semi-pervious Zone) ―a part of the cross-section of a zoned embankment dam comprising material of intermediate size between that of an impervious zone and that of a permeable zone. Trash rack―a screen located at an intake to prevent the ingress of debris. Tunnel―a long underground excavation usually having a uniform cross-section. Types of tunnel include: headrace tunnel, pressure tunnel, collecting tunnel, diversion tunnel, power tunnel, tailrace tunnel, navigation tunnel, access tunnel, scour tunnel, draw-off tunnel, and spillway tunnel. Under seepage―the interstitial movement of water through a foundation. Uplift―the upward pressure in the pores of a material (interstitial pressure) or on the base of a structure. Valve―a device fitted to a pipeline or orifice in which the closure member is either rotated or moved transversely or longitudinally in the waterway to control or stop the flow. Water stop―a strip of metal, rubber or other material used to prevent leakage through joints between adjacent sections of concrete. Weir― (a) a low dam or wall built across a stream to raise the upstream water level, called fixed- crest weir when uncontrolled. (b)A structure built across a stream or channel for measuring flow, sometimes called a measuring weir or gauging weir. Types of weir include broad-crested weir, sharp- crested weir, drowned weir& submerged weir.

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