Operation and Maintenance
Manual for
Kallada Dam
(KL07HH0037) Kerala Water Resources Department State of Kerala
August 2020 O&M Manual of Kallada Dam
Operation and Maintenance
Manual for
Kallada Dam
(Prepared By)
KERALA WATER RESOURCES DEPARTMENT STATE OF KERALA
August 2020
1
August 2020 O&M Manual of Kallada Dam
Government of Kerala
Operation and Maintenance Manual
Kallada Dam
2
August 2020 O&M Manual of Kallada Dam
KERALA WATER RESOURCES DEPARTMENT
DISCLAIMER
This Operation and Maintenance Manual for Kallada 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]
i
August 2020 O&M Manual of Kallada 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
ii
August 2020 O&M Manual of Kallada Dam
PREFACE
Every dam requires an operation and maintenance manual for ensuring step
by step operation procedure for ensuring that the dam is safely operated frequently
and properly maintained. This manual also helps to avoid health deterioration and
extend service life of these assets. The O and M manual includes operation,
inspection, maintenance and repair of dam components, replacement of
equipments and appurtenant structure as required.
Kallada irrigation and Tree crop development scheme is the largest
irrigation project in the State of Kerala. . This project comprises of straight gravity
masonry dam across the Kallada river, at Parappar near Thenmala in Kollam
District at 8 057’ N Latitude and 77 0 04’ 20’’ E Longitude. It is situated 19 Km from
Punalur and 2 Km from Thenmala railway station. The aim of Kallada Irrigation
Project is to ensure water in the canals for irrigation and power generation.
The project was commissioned in 1986. At present designated ayacut
under Kallada Project is 53100 Ha. The project has now become an integral part of
the lives of the people of Kollam, Pathanamthitta and Allapuzha Districts and its
surroundings, since it is the main source of water for agricultural and drinking
purpose.
The main dam is a straight gravity masonry dam of 335m long. Height of
the dam above the deepest foundation is 85.35 m. The length of spillway is 42.06
m with 3 Nos of radial gates each having size of opening 12.19 X 9.14m. The
storage capacity of the reservoir is 487.92Mm3 at FRL with a design spill way
capacity of 1118.26 cumecs.
This manual is provided to assist the dam owner in management of Kallada
project in a safe and efficient manner. The Dam Safety Bill, 2010, introduced in the
Lok Sabha on August 30, 2010, and subsequently referred to the Parliamentary
Standing Committee on Water Resources for examination, prompted the need for
updated procedures for dam owners to follow during day to day, 24/7 operation of
iii
August 2020 O&M Manual of Kallada Dam
their respective dams. The draft Dam Safety Bill requires State Dam Safety
Organizations (SDSO) to keep perpetual vigilance, carry out inspections regularly,
and monitor the operation and maintenance of all dams in order to ensure their
safe functioning. Where a SDSO does not exist, the National Committee on Dam
Safety acting through the Central Dam Safety Organization is required to carry out
these activities.
This manual was prepared following the guidelines published by DRIP,
CWC.
iv
August 2020 O&M Manual of Kallada Dam
CONTENTS
Disclaimer ...... i
FOREWARD ...... ii
PREFACE ...... iii
LIST OF TABLES ...... vii
LIST OF FIGURES ...... vii
ABBREVIATIONS ...... ix
Chapter 1. General Information ...... 1
1.1 Purpose, Location, Description of Kallada Dam (Parappar Dam) ...... 1
1.2 Assignment of responsibility ...... 26
1.3 Collection & Reporting of Dam and Reservoir Data ...... 32
1.4 Public Utilities and Safety...... 33
1.5 Restricted Areas ...... 34
1.6 Staff position, Communication & Warning System ...... 36
1.7 Distribution of Operation & Maintenance Manuals ...... 42
1.8 Supporting Documents& Reference Material ...... 43
1.9 Typical Schedule of Duties ...... 43
CHAPTER 2. PROJECT OPERATION ...... 48
2.1 Operation Plan ...... 48
2.2 Normal Operations ...... 49
2.3 Emergency Operations ...... 72
2.4 Initial Filling of Reservoir ...... 74
2.5 Record Keeping ...... 74
CHAPTER 3.PROJECT INSPECTIONS ...... 76
3.1 Types of Inspections ...... 76
3.2 Informal Inspections ...... 76
3.3 Scheduled Inspections ...... 77
3.4 Special (Unscheduled) Inspections ...... 78
v
August 2020 O&M Manual of Kallada Dam
3.5 Comprehensive Evaluation Inspections ...... 79
CHAPTER 4.PROJECT MAINTENANCE ...... 85
4.1 Maintenance Plan ...... 85
4.2 Maintenance Priorities ...... 86
4.3 Maintenance Items ...... 88
4.4 Materials requirements for maintenance during monsoon period ...... 111
4.5 Establishment Requirements ...... 112
4.6 Preparation of O&M Budget ...... 112
4.7 Maintenance Records ...... 115
Chapter 5. INSTRUMENTATION AND MONITORING ...... 117
5.1 General Instrument types ...... 117
5.2 Instrumentation at Kallada Dam ...... 117
5.3 Frequency of Monitoring ...... 118
5.4 Data Processing and Evaluation ...... 119
5.5 Visual Observations ...... 120
Chapter 6. PREVIOUS REHABILITATION EFFORTS ...... 121
Chapter 7. UPDATING THE MANUAL ...... 133
Annexure – A (BASIC DRAWINGS) ...... 134
ANNEXURE –B -- Hydrology Review Report ...... 140
ANNEXURE – C --- Gate Manufacturer’s Manual – Not available ...... 155
ANNEXURE – D – Check List for Inspection ...... 155
Annexure – E -- Latest DSRP Report ...... 157
Annexure – F --- Inspection Report (Pre & Post Monsoon) ...... 158
ANNEXURE – G NOTIFICATION FOR STRENGTHENING OF ALARM AND
WARNING ...... 194
ANNEXURE H - GLOSSARY ...... 199
vi
August 2020 O&M Manual of Kallada Dam
LIST OF TABLES
Table 1. 1 Salient features of Dam ...... 20
Table 1. 2 Canal system: ...... 25
Table 1. 3 Example Proforma for recording flow data...... 33
Table 1. 4 Distribution of O&M Manual and Revisions ...... 42
Table 1. 5 Table showing Schedule of duties/inspections ...... 43
Table 2. 1 Discharge through spillway at different shutter opening and warning levels are shown below...... 56
Table 4. 1 O&M BUDGET COSTS (ANNUAL) ...... 113
LIST OF FIGURES
Figure 1. 1 Catchment area map ...... 5
Figure 1. 2 Location Map ...... 6
Figure 1. 3 Kallada Reservoir - left bank view ...... 7
Figure 1. 4 Kallada Reservoir ...... 8
Figure 1. 5 Stilling basin ...... 9
Figure 1. 6 Service Gate ...... 10
Figure 1. 7 Service Gate ...... 11
Figure 1. 8 Trash rack provided at the upstream side of penstock pipe ...... 12
Figure 1. 9 Disperser valve while in operation ...... 13
Figure 1. 10 Disperser valve in closed position...... 13
Figure 1. 11 Radial gates ...... 14
Figure 1. 12 Spillway bucket ...... 15
Figure 1. 13 Spillway bucket inside ...... 15
vii
August 2020 O&M Manual of Kallada Dam
Figure 1. 14 Energy Dissipaters (slotted roller bucket ) ...... 16
Figure 1. 15 Spillway U/s view ...... 16
Figure 1. 16 View of Auxiliary Spillway at FRL ...... 17
Figure 1. 17 Downstream side of saddle dam at Pallamvetty ...... 18
Figure 1. 18 Saddle Dam at Pallamvetty - U/s portion ...... 19
Figure 1. 19 Weir at Ottakkal ...... 20
Figure 2. 1 Rule Curve ...... 65
Figure 2. 2 Reservoir Storage Allocation Zones ...... 68
Figure 2. 3 Elevation - Capacity Curve ...... 69
Figure 2. 4 Elevation-Area Curve ...... 70
Figure 4. 1 Typical organisation setup chart ...... 116
Figure 5. 1 App.B- Before grouting Dam body ...... 125
Figure 5. 2 App. C – Damaged face drain holes ...... 125
Figure 5. 3 Appendix – K - Damaged wearing coat to roadway at top of Dam ...... 126
Figure 5. 4 App. F - Damaged ogee portion of spillway...... 127
Figure 5. 5 Appendix – I - Damaged drainage arrangements between the toe of dam, ...... 127
Figure 5. 6Appendix G- Right flank portion between reservoir and road near auxiliary spillway ...... 128
Figure 5. 7 Damaged road ...... 128
Figure 5. 8 App. A – Damaged Roads ...... 129
Figure 5. 9 Reservoir left view ...... 129
Figure 5. 10Dam top after DRIP 1 ...... 130
Figure 5. 11 Inked providing drainage arangement after drip. toe of dam ...... 130
Figure 5. 12 LB Head Regulator after rectification of pillars ...... 130
Figure 5. 13 Saddle dam after drip work ...... 131
Figure 5. 14 Side protection after DRIP work ...... 131
Figure 5. 15 Watch tower ...... 132
viii
August 2020 O&M Manual of Kallada Dam
ABBREVIATIONS
Acronyms used in this publication are as follows: 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 Global Positioning System (uses GPRS for data transmis- GPS sion 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 CE Chief Engineer SE Superintending Engineer EE Executive Engineer AEE Assistant Executive Engineer AE Assistant Engineer
ix
August 2020 O&M Manual of Kallada Dam
CHAPTER 1. GENERAL INFORMATION
This document represents a detailed Operation and Maintenance (O&M)
Manual for Kallada 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 staff and their supervisors who are assigned with 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.
1.1 Purpose, Location, Description of Kallada Dam (Parappar Dam)
Kallada irrigation and Tree crop development scheme is the largest irrigation project in the State of Kerala. The dam was commissioned on 1986. Our mission is to ensure water in the canals for irrigation and power generation, flood control and safety of the dam. This project comprises of straight gravity masonry dam across the
Kallada river, at Parappar near Thenmala in Kollam District at 80 57’ N Latitude and
77 0 04’ 20’’ E Longitude. It is situated 19 Km from Punalur and 2 Km from Thenmala railway station. The distance to nearest Airport from Dam is 115 km. The nearest boarder of Kerala- Tamil Nadu, is situated at 20 km away from the Dam. The
Northern and southern side of the dam are covered by thick forest.
The three major tributaries of Kallada River are Kalthuruthy river,
Chenthuruny river and Kulathuppuzha river. The dam is constructed in the downstream of the confluence of these tributaries. The catchment area of the
1
August 2020 O&M Manual of Kallada Dam reservoir at the dam site is 549 sqkm. The Head regulating structure ( weir ) is situated at Ottakkal, 5 km away from main Dam to divert water to the left bank and right bank canals.There is also an earthen saddle dam situated on the left side of main dam about 2 km away. The length of saddle dam is 225.7 m and the maximum height is 12.51 m.
The command area of this project is distributed over Kollam, Pathanamthitta and Alappuzha district and covers Punalur, Pathanapuram, Kottarakkara, Kollam,
Kunnathur, Karunagappally, Adoor, Konni, Mavelikkara and Karthikappally
Taluks.The Culturable Command Area (CCA) is 53100 Ha. Project has now become an integral part of the lives of the people of the above Taluks and its surroundings, since it is the main source of water for agricultural and drinking purpose.
The main dam is a straight gravity masonry dam of 335 m long. Height of the dam above the deepest foundation is 85.35 m. The length of spillway is 42.06 m with 3 No of radial gates each having size of opening 12.19 X 9.14 m.
Background Details of the Project
The Kallada River is a west flowing river which originates from the
Kulathuppuzha ranges. It flows through Pathanapuram, Kunnathur, Kottarakkara and Kollam Taluks of Kollam District, Kerala State for about 128 km before it falls into the Ashtamudi lake. The project area lies between Latitude 80 49’ north and 90
17’ north and Longitude 770 16’ east and 760 24’ east. It covers portions of
Pathanamthitta, Kollam and Alleppy Districts. It is bounded by the Achencoil River on the north, the backwaters on the west and the Ithikkara River in the south.
The eastern water shed boundary of the Kallada basin has an elevation varying from +853.44 m to +1524 m M.S.L. The main tributaries of the river are the
Kulathupuzha, Shendurni and Kalthuruthi rivers as mentioned above. The
Kulathupuzha river is formed by the confluence of the Pongumalai Aaru, which has
2
August 2020 O&M Manual of Kallada Dam its origin in Karimalai-Kadakal in Papanasom Range, at about +1524 m M.S.L, the
Sinikili Aaru which has its origin in Sinikili hills at about +1371.6 m M.S.L and the
Sankalipalam Aaru which has its origin in the Ponmudi Range at about +1066.8 m
.M.S.L. The Kulathupuzha river flows in a north – westerly direction till Moyalamod where it turns and continues to flow in a northern direction. It is joined by the
Shendurni Aaru at Kalamkunnu.
The Shendurni Aaru, originating from the Karimalai, Kadakar and Alwarkurichi peaks flows in a north-westerly direction till it joins the Kulathupuzha Aaru. This tributary has a catchment area of 306.54 sq. km. The Kalthuruthi Aaru joins the main river just above the Parappar bridge and is formed by several streams originating from the Periamuruthi Malai (+853.44 m) Padikattu Malai (+853.44 m) Kottavasal Teri (+792.48 m) Pillaiva Kovil Malai (+807.72 m) and Suvarnagiri Malai (+487.68 m). It follows a south westerly direction first and then a westerly course up to Thenmala, where it turns south and joins the main river at Parappar.
From Parappar the river flows north west under the name Punalu Aaru upto
Urukunnu and then Westwards up to Mukkadavu where it is joined by the Chit Aaru, a small stream originating from Kalamkunnu. From Mukkadavu upto Pathanapuram the river flows north west and at Pathanapuram, it again turns west and flows in that direction till Enathu, where after it takes a south-westerly course till it falls into the
Ashtamudi Lake backwaters. The Kundayathu Thodu, Pulamon Thodu and
Kadakkamon Thodu are some of its other important tributaries.
Heavy floods in Kallada river mostly occurs during the second monsoon. They correspond to the later part of the North East monsoon, when storm covers the whole basin and continues for two or three months. The most severe flood in this river basin known to have occurred was on the third week of July 1924. A flood of lesser magnitude had occurred on August 1947. On both these occasions, the
Kallada river banks had breached causing heavy damages. After the construction of
3
August 2020 O&M Manual of Kallada Dam dam, a severe flood and land slide occurred in the catchment of Kallada reservoir on the second week of October and November 1992.
Kallada Reservoir Planning
Catchment area 549 sqkm Average rain fall 305 cm Gross Storage at FRL (+115.82m) 504.92 Mm3 Live Storage at FRL 487.92 Mm3 MDDL + 70.25 m Storage at MDDL 17 Mm3 Crest level of spillway +106.68 m Water spread area 23 sq Km
Details of the various gates and outlets/weirs etc. Sl No Description No Height (M) Width Operating (M) Mechanism 1 Radial Gate 3 9.14 12.19 Electrical and Mechanical 2 Dispersal Valve 2 1M Dia Electrical and Mechanical 3 Emergency gate (Service 1 4.00 2.90 Electrical and Gate) Mechanical 4 Left bank Canal Gate at 2 2.60 3.55 Electrical and Ottakal weir Mechanical 5 Right Bank Canal Gate at 3 2.60 3.55 Electrical and Ottakkal weir Mechanical 6 River Sluice gate at 1 2.44 1.83 Electrical and Ottakkal weir Mechanical
4
August 2020 O&M Manual of Kallada Dam
Index Plan/Location Map
Figure 1. 1 Catchment area map
5
August 2020 O&M Manual of Kallada Dam
Location Map
Figure 1. 2 Location Map
6
August 2020 O&M Manual of Kallada Dam
Main Design Features and Components of Kallada Dam:
1. Components: - The total length of dam is 335 m and height from the deepest foundation is + 85.35 m. The dam was made up of 12 blocks, serially numbered from left to right. The total length of spillway is 42.06 m (which includes 3 Nos. gated ogee type spillway of size 12.19 m x 9.14 m). There are two non-overflow masonry sections dam on either side of the spillway. The non-overflow masonry dam on the left side is of length 130.87 m and on the right side is 162.07 m, including the power generation portion. A road way 7.62 m wide with parapets is provided.
Figure 1. 3 Kallada Reservoir - left bank view
7
August 2020 O&M Manual of Kallada Dam
Figure 1. 4 Kallada Reservoir
2. Masonry non-overflow section: - This portion is constructed in coursed rubble stone masonry in cement mortar. The dam (both spillway and non-overflow sections) was
made up of 12 blocks. Block numbers 1 to 4 and 8 to 12 are Non-overflow blocks. The
Block No. 6 completely comes under spillway portion and the Blocks 5 and 7 are partly comes under spillway portion. A drainage gallery of size 1.5 m x 2.1 m is provided from
block number 2 to 12. It is constructed with RCC of 1 m thick and is constructed at a
distance of 3 m from upstream body of the dam and at a height of 3 m from the foundation. 90 Numbers of Drainage holes (D holes) of 150 mm diameter at an interval
of 3 m c/c are provided in the gallery. In addition, 124 numbers of vertical drains connecting dam top to gallery at an interval of 3m c/c from left to right are provided. All
these vertical drains carry seepage water and it is collected in the sump well (in the 7th
block) in the gallery and from there it is pumped to stilling basin.
3. Power Dam Section: - Penstock is mounted in the 8th block of dam body, which is having a diameter of 3.75 m. The bottom level of the penstock is + 70.25 m. (MDDL).
8
August 2020 O&M Manual of Kallada Dam
The penstock pipe is bifurcated in to 4, two leads to power generation and other two
leads to irrigation conduits. These irrigation conduits are regulated with 1.50 m dia disperser valve. Total of 15 MW power is generated by KSEB. The tail race water from
the power house is used for irrigation purpose. The disperser valves are used for taking
water from the reservoir for irrigation purpose when the power generation is disturbed. No river sluice is provided in this dam. There is Penstock gallery of length 90m leads to
penstock block from audit 2 for inspecting purpose. A service gate is provided at the
upstream side of penstock pipe to regulate the flow of water through penstock pipe. A stop log gate is also provided at the upstream side just in front of service gate, which can
be used as an auxiliary regulating system as and when the service gate is unable to operate. A trash tack is also provided at the upstream side of the penstock for controlling
the entry of floating bodies in to the penstock pipe.
Figure 1. 5 Stilling basin
9
August 2020 O&M Manual of Kallada Dam
Figure 1. 6 Service Gate
10
August 2020 O&M Manual of Kallada Dam
Figure 1. 7 Service Gate
11
August 2020 O&M Manual of Kallada Dam
Figure 1. 8 Trash rack provided at the upstream side of penstock pipe
12
August 2020 O&M Manual of Kallada Dam
Figure 1. 9 Disperser valve while in operation
Figure 1. 10 Disperser valve in closed position.
4. Spillway section: -The total length of spillway is 42.06 m, which includes 3 numbers of
gated ogee type spillway, each of size 12.19 m x 9.14 m. The weight of each shutter is
13
August 2020 O&M Manual of Kallada Dam
40 tonnes. These shutters are fixed in Hoist Bridge. The operating system used for
operating the shutters is winch and rope. These shutters are operated mechanically or manually. All shutters can safely rise up to 3.657 m (12 feet). The spill way discharge
capacity (when spillway gate fully opened) at FRL is 1118.26 m3/sec. 22 Nos of Energy
dissipater of slotted roller type are provided in the spillway bucket. The tail water level is +67.70 m and top elevation of training wall is + 79.62 m. The length of stilling basin is
92.70 m and width is 42.06 m.
Figure 1. 11 Radial gates
14
August 2020 O&M Manual of Kallada Dam
Figure 1. 12 Spillway bucket
Figure 1. 13 Spillway bucket inside
15
August 2020 O&M Manual of Kallada Dam
Figure 1. 14 Energy Dissipaters (slotted roller bucket )
Figure 1. 15 Spillway U/s view
5. Auxiliary spillway: - An Auxiliary Spillway of Labyrinth type is constructed on the right bank of main dam. It is free flowing spillway without any control gate. The designed discharge of Auxiliary Spillway is 698 m3/sec. As and when the flood water rises above MWL (+116.73 M), flow will commence. The length of auxiliary spill way is 56 m. Crest level +116.73 m.
16
August 2020 O&M Manual of Kallada Dam
Figure 1. 16 View of Auxiliary Spillway at FRL
6. Earthen Dam across the Pallamvetty saddle: - The length of earthen dam is 225.7 m. and has a maximum height of 12.51m from the lowest foundation level. The lowest foundation level is +106.39 m and dam top level is + 118.90m. The type of saddle dam is impervious fill. Downstream slope of the embankment is 2:1 whereas for the upstream side, a slope of 2.50: 1 is provided. Rock toes on downstream are provided with graded filters at their base and embankment sides. A 45 cm thick rip rap over a filter layer of 15 cm is provided on the upstream side of the earthen embankment. i.e., on the water side. The top width is saddle dam is 4m. Two toe drain of 205 m long and 1m width is provided at the downstream side of the saddle dam. A V-notch is provided for measuring seepage from saddle dam at the lowest portion where both (Left & Right) toe drains are intersecting.
17
August 2020 O&M Manual of Kallada Dam
Figure 1. 17 Downstream side of saddle dam at Pallamvetty
18
August 2020 O&M Manual of Kallada Dam
Figure 1. 18 Saddle Dam at Pallamvetty - U/s portion
7. Head regulators: -A pick up weir having a capacity of 1.7 Mm3, 5 km downstream of
the dam is constructed at Ottakkal, on the right side of the Kollam –Shencottah road.
The main canals (Right bank canal and Left bank canal) take off from this weir. The tail race water from the power house is collected at weir and used for irrigation purpose. The
Right Bank Canal and its branches serve areas in Pathanamthitta, Pathanapuram,
Kunnathoor, Mavelikkara, Karunagappally and Karthikappally Taluks and the Left Bank Canal benefits areas in Punalur, Kottarakkara and Kollam Taluks. The total length of weir
is 120 m with 7 spans. Span between piers are 15.24 m. The thickness pier is 1.52 m.
The width of road way over the weir is 4.27m. One number river sluice gate of size 2.44 m x 1.83 m is provided. The crest level of the weir is +63.09 m and deepest bed level is + 57.50 m. The maximum upstream flood level is + 68.45m, maximum downstream flood
level + 65.84 m. 3 Nos of head regulators of 2.6 m x 3.55 m size screw type are provided for Right Bank Main Canal (RBMC) and 2 Nos head regulators of 2.6 m x 3.55
m size screw type are provided for Left Bank Main Canal (LBMC).
19
August 2020 O&M Manual of Kallada Dam
Figure 1. 19 Weir at Ottakkal
Table 1. 1 Salient features of Dam
A. General
1. Location of Dam Situated in Thenmala village of Punalur taluk at Kollam district at: Latitude 8°57'N Longitude 77°04’ 20 ‟ E 2. Means of Access 19 km from Punalur ,and 2 km from Thenmala railway station
B. Geophysical Features
1 Catchment area 549 sq km 2 Nature of catchment The catchment is fully occupied by forest area and contributed by three rivers, Kalthurity, Chenthuruni and Kulathupuzha The major area is of Kulathupuzha River. 3 Climate Moderate 4 Annual mean temperature 30°C
5 Mean annual precipitation 305 cm 6 Silt charge per year 4 cm
7 Geological features at dam Hard granite rock (Coarse-grained), laterite soil site.
20
August 2020 O&M Manual of Kallada Dam
C. Technical Details of Dam 1 Storage Capacity at FRL 487.92 Mm3 deducting dead storage 2 Dead Storage 17 Mm3
3 Lowest Foundation Level (El.) +46.94m
4 Lowest River Bed Level (El.) +57.50 m
5 Sill of Irrigation Sluice (El.) +70.25
6 Sill of River Sluice (El.) +57.50 (deepest bed level at weir)
7 Dead Storage Level at (El.) +70.25
8 Full Reservoir Level (FRL) (El.) +115.82
9 Maximum Water Level (MWL) +116.73 (El.) 10 Crest level (El.) +106.68
11 Top Level of Dam (El.) +118.87
12 Maximum area of water spread 23 sqkm D. Length of Dam
1 Length of spillway portion 42.06 m
2 Length of masonry Non- 292.94 m overflow including Power blocks 3 Masonry dam (Non- Overflow section) Left side 130.87 m Right side 162.07 m Earthen dam Nil Total length of dam 335 m E. Other 1 Maximum height of dam above +85.35 the lowest foundation level 2 Height of dam above the lowest +63.33m River Bed Level 3 Top width of dam 7.62m
21
August 2020 O&M Manual of Kallada Dam
4 Designed flood intensity 1118.26 m3/sec 5 No. & size of spillway crest 3 gates 12.19 m x 9.14 m gates 6 No. and dimensions of river No river sluice is at dam, river sluice only at 5km away sluice gates from weir 1 no. 2.44 m x 1.83 m 7 No. and dimensions of No irrigation sluice gate, one penstock pipe having 2 irrigation sluice gates dispersal valve of 1.5 m dia F. Details of submergence Total area of submergence 23 sqkm (Gross) Village submerged Part of Kulathupuzha Village
Population affected 1555
Road 6 km old Trivandrum- Schenkottai road and Kalamkunnu bridge submerged
22
August 2020 O&M Manual of Kallada Dam
23
August 2020 O&M Manual of Kallada Dam
24
August 2020 O&M Manual of Kallada Dam
Project Benefits
In addition to Irrigation, the project envisages generation of 15 MW power along with fish culture and other economic and social benefits.
The command area of this project is distributed over Kollam, Pathanamthitta and Alappuzha district and covers Punalur, Pathanapuram, Kottarakkara, Kollam, Kunnathur,
Karunagappally, Adoor, Konni, Mavelikkara and Karthikappally Taluks. Also, the canals pass through Kollam, Pathanamthitta and Mavelikkara Parliament constituencies. The scheme benefits a net cultivable command area of 53100 Ha in 92 villages.
The main canals (RBC and LBC) take off from the weir. The water consumed after power generation, is impounded at weir and is distributed through both canals during dry seasons. When there is no power generation, the irrigation valves are opened for water release to the weir.
Table 1. 2 Canal system:
Sl.No Name of canal Total Length (km) I .Main canal 1 Left Bank Main Canal 56.016
2 Right bank Main Canal 69.752
II.Branch canal 1 Oyoor Branch canal (LBC) 17.607 2 Kottiyam Branch canal(LBC) 22.360 3 Kulakkada Branch canal LBC 21.725 4 Sasthamcotta Branch canal (RBC) 25.511 5 Pandalam Branch canal(RBC) 15.482 6 Karunagapally Branch canal(RBC) 6.580 7 Distributaries and minors 676.856 Total 911.889
The water distribution through the canals usually started on the month January and ends at the month of May, through the completed canals and the same is irrigated through 48
25
August 2020 O&M Manual of Kallada Dam
Panchayaths and 5 Municipalities of the 3 districts. The recharging of water bodies including wells are also effected during water distribution period. Thus, irrigation and drinking water purpose can be met.
1.2 Assignment of responsibility
The Irrigation Department, Kerala is the owner, authority and is responsible 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 having responsibility for the following functions need to be identified by their designation.
Sl. No. Particulars Remarks
1 Implementing agency Kerala Irrigation Department
2 Project Administration Officer in Chief Engineer, Projects II, charge Thiruvananthapuram 3 Operations of equipment at the Assistant Engineer, KIP RB Section No dam 3/2, Thenmala. 4 Reservoir inflow and flood Chief Engineer, IDRB, forecasting Thiruvananthapuram 5 Authorising spillway flood release Executive Engineer, KIP RB Division No II, Kottarakkara. 6 Authorising releases for various Assistant Executive Engineer, KIP RB purposes irrigation, water supply Subdivision No II, Thenmala. etc
7 Recording reservoir data Assistant Engineer, KIP RB Section No 3/2, Thenmala 8 Routine inspection Executive Engineer, KIP RB Division No II, Kottarakkara 9 Maintenance Executive Engineer, KIP RB Division No II, Kottarakkara 10 Instrumentation Executive Engineer, KIP RB Division No II, Kottarakkara
26
August 2020 O&M Manual of Kallada Dam
1.2.1 General Roles and Responsibilities of the Executive Engineer
Coordinate routine inspections and Dam's Operations as per guidelines for safety
inspection of dams.
Conduct pre and post monsoon inspection of dams. Ensure effective transmission of hydro-metrological and stream flow data through
different means.
Ensure proper accessibility to all vulnerable points for constant monitoring during emergency situations
Identify primary and secondary communication systems, both internal (between persons at the dam) and external (between dam personnel and outside entities). Provide security measures at the dam (CCTV surveillance, security guards,
fencing).
Ensure the availability of adequate staff at dam site during holidays, nights and round the clock in weekdays.
Ensure that the EAP is functional and staffs are familiar with their responsibilities. Ensure that a signboard is installed and clearly visual in different locations at dam
site and operation room, with the most common evidence of distress and
corresponding levels of alert and remedial actions. Ensure all the equipment/means at dam site to response to an emergency are
easily accessible and well maintained (generators, vehicles, lanterns, radios,
heavy equipment, etc) Ensure the installation and proper maintenance of a warning system (sirens,
horns) in the critical areas within the floodplain (less than 2 hours of wave arrival
time) Ensure the current approved version of the EAP is available to all relevant
stakeholders (those who have a functional role in the emergency response)
1.2.2 General Roles and Responsibilities of the Assistant Executive Engineer and Assistant Engineers
27
August 2020 O&M Manual of Kallada Dam
Conduct routine inspections as per guidelines for safety inspection of dams and
follow up on the events, if any noticed Continuous monitor & surveillance of dam and appurtenant structures looking for evidence of distress as mentioned in Annexure 4 Conduct Pre and Post monsoon Inspections along with the Emergency Planning Manager
Inform the Emergency Planning Manager about any irregular/unusual condition at
dam site and keep him/her posted about any progression/change Operate dam's gates/under sluices, under the express direction of Chief Engineer /
Superintending Engineer / Executive Engineer Conduct routine dam maintenance
Collect instrumentation measurements, evaluate and report if found necessary.
Ensure that all the data are properly recorded. Ensure effective working conditions of the warning system (Sirens)
Participate in exercises for test/improvement of this EAP
Roles and Responsibilities of the AEE and AE for Kallada dam
General responsibilities of AE and AEE
1. Operation of Penstock as per the direction of higher officers.
2. Operation of Spillway shutters as per the direction of higher officers.
3. Daily reporting of Reservoir data as per the direction of higher officers.
Inspecting the gallery and shutter operation on daily basis and reporting any 4. irregularities to higher officers.
DURING FLOOD CONDITIONS
Maintain the reservoir water level register and to report the reservoir data in every 6 hrs. When the reservoir reaches 113.74 m, (First warning level) reporting of 1. reservoir data in every 2 hrs. when it reaches 114.81 m (Second warning level) and reporting data in every one hour
28
August 2020 O&M Manual of Kallada Dam
Giving timely warning, to District administration, District Police Chief, Tahsildar, (Kollam , Alappuzha, Pathanamthitta), Local Self Government Institutions, Media, and all higher officials of the Department, like providing first warning when the Kallada reservoir reaches +113.74 m, which is only 2.08m below FRL of +115.82 M
2. ”.”Shutters are likely to be opened”. Giving Second warning when the reservoir reaches +114.81 m “Kallada” reservoir level at +114.81 M, Shutters are likely to be opened soon.” Giving Third and final warning when the water level reaches +115.45 m “Kallada reservoir levels at +115.45m, shutters are being opened”.
When the reservoir level attains +113.74m, AE should closely watch the inflow rate
3. and levels. He should watch closely the downstream face of the Masonry dam, earthen dam, seepages through toe drains and drainage gallery.
Assist the EE/SE/CE to issue notification to the villagers downstream in 4. Newspapers, Radio, TV News channel to be alert regarding the flood situation
Assist the EE/SE/CE to coordinate with the Revenue authorities (District
5. Administration) to alert the downstream villagers to evacuate the flood zone to prevent loss of life and livestock
Assess the inflows in the reservoir as per the approved reservoir operation and to
6. prepare proforma 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.
Submit the inflow and releases from the reservoir details and status of the reservoir 7. twice in the day to the EE/SE/CE
8. Maintain the spillway crest gate operation log book
Operate the Spillway crest gates for flood mitigation as per the instructions of the 9. EE/SE/CE and to update the Gate operation log book
Maintain log books for the seepage and dewatering the sump well using pumps in 10. the drainage gallery as necessary and to submit to EE/SE/CE
Observe the gates and to see that the drain holes are not clogged and floating 11. debris is not deposited in the gate components
29
August 2020 O&M Manual of Kallada Dam
Monitor the condition of the generators, umbrellas, toolkits torches chain blocks
12. ropes ballies etc. on daily basis and to see that things are in place to handle any emergency situation Observe the Gates, hoists and handling equipment during operation for the smooth
13. movements and to immediately report any unwanted excessive sounds in the motors pumps or vibrations in the gate
Observe the dam top, embankment, catwalk, approach roads are well maintained 14. by housekeeping personnel
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 15. untoward incidents or malfunctioning of the gates of excessive seepages, leakages etc.
Assist EE/SE/CE to share the flow data and the reservoir storage details to the 16. Media on day to day basis
1.2.3 Roles and Responsibilities of the SE and EE
Coordinate with the Project Engineers of the State of Kerala& to get the information in email on the rainfall in the catchment and inflow status and to bring it to the notice
of the CE To issue notification to the villagers downstream in Newspapers, Radio, TV News
channel to be alert regarding the flood situation
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
Assist the CE to coordinate with the CWC flood monitoring authorities on the flood condition
Submit to the CE on the inflows and releases from the reservoir and status of the
reservoir twice in the day Operate the Spillway crest gates for flood mitigation as per the instructions of the CE
and to update the Gate operation Log book
30
August 2020 O&M Manual of Kallada Dam
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
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
Observe the dam top, embankment, approach roads are well maintained by house- keeping personnel
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
Assist CE to share the flow data and the reservoir storage details to the Media on day to day basis
Assist CE to coordinate with the Project Engineers of the State of Kerala and sharing
the details of the flood condition in the river and the reservoir releases.
1.2.4 Roles and Responsibilities of the Chief Engineer
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 Project Engineers of the State of Kerala, to the information on the rainfall in the catchment
and inflow status and also to Coordinate with the Revenue authorities (District
Administration) Coordinate with the CWC flood monitoring authorities on the flood condition
Issue necessary instructions to the engineers to Operate the reservoir based on the
inflows, rainfall data, releases from the upstream reservoirs and status of the reservoir
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
Coordinate with the downstream Dam Project Engineers
31
August 2020 O&M Manual of Kallada Dam
Conduct Pre and Post Monsoon inspections of the Dam
1.3 Collection & Reporting of Dam and Reservoir Data
A proforma 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
Records [Logbooks] of the following operations at Kallada Dam are maintained in a chronological manner for reference. 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 – 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.
32
August 2020 O&M Manual of Kallada Dam
• 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.
Table 1. 3 Example Proforma for recording flow data.
For the month of ...... Reservoir Outflow in cumec Reservoir Water Inflow capacity in Date Time Level in Mm3 (m) cumec RBMC LBMC Spillway Power Generation
Legend: RBMC -Right Bank Main Canal; LBMC-Left Bank Main Canal
1.4 Public Utilities and Safety
As safety of a dam is of prime concern, certain instructions & protection measures should be included in a supporting document and referenced in the Manual. Sign boards are provided at appropriate locations of dam for convenience of the public. This will include the flowing.
Toilet facility is provided on the way of dam top. Car parking area is available near
the main entrance of dam.
Public health centre is available for medical assistant at Thenmala which is 2 Km
away from the dam premise and Police station is also situated at Thenmala which is
also 2 Km away from dam premises.
Safety equipments yet to be arranged.
33
August 2020 O&M Manual of Kallada Dam
1.5 Restricted Areas
Restricted areas have been properly demarcated for the purpose of restricting people entering in to the area.
Dam top entering is well monitored by security arrangements.
Gallery, Spill way approach area, stilling basin, Canal sluice areas, and Reservoir
area etc are also restricted only to officers. Proper fencing arrangement has been
provided for any unauthorised entry in to the said places.
Certain areas of the dam and reservoir are restricted for entry by providing warning
boards. The purpose of restrictions is for security of the dam, public safety and
uninterrupted safe operation of the dam.
34
August 2020 O&M Manual of Kallada Dam
35
August 2020 O&M Manual of Kallada Dam
Details of the Security arrangements at Kallada Dam Site.
The security arrangements of Kallada Dam are entrusted to the Ex-military personnel engaged through KEXCON, with a total strength of 15 Security personnel. They are deployed at the main gate, Dam top, road to dam top, Saddle dam, Weir etc. Chain link fencing is provided around dam premises.
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.
The means of communications both in normal and emergency situations are identified in the Communication Directory found below. Available communication means including landline, mobile phones, wireless sets, at different locations on the dam. Security staff is provided with door frame and hand-held.
36
August 2020 O&M Manual of Kallada Dam
Organaisation Chart
Chief Engineer, Projects II, Thiruvananthapuram Land Line No.0471 e-mail ID: [email protected]
Superintending Engineer, KIP(RB) Circle, Kottarakkara Land line No.0474-2452635 E-mail ID: [email protected]
Executive Engineer, KIP(RB) Division No.II, Kottarakkara Land line No.0474 2452617 e-mail ID: [email protected]
Assistant Executive Engineer KIP(RB) Sub Division No.2, Assistant Executive Engineer Thenmala KIP Mechanical Sub Division, 0475 2344532 Thenmala E-mail 0475 2344097 ID:parappardam.thenmala E-mail @gmail.com A [email protected] s
s
i
s Assistant Engineer, Assistant Engineer, Section 3/2, Thenmala Mechanical Section, Thenmala E-mail ID: E-mail: [email protected] [email protected] 04752344532
37
August 2020 O&M Manual of Kallada Dam
Hydro-Mechanical Inspections / Checks
Special duties performed for H-M operating personnel works are given in this section.
Frequency of inspections / checks for hydro-mechanical components and necessary actions to be taken up during maintenance
1. Radial Crest Gates - 3 Nos.
a. Embedded Parts
Sl. Embedded Part Frequency No
1 Checking of seal beams. Seal Seats, Guide track & all Half Yearly other exposed embedded parts with respect to their alignment, distortion: if any due to continuous use, pitting and un-necessary cracks due to wear & carrying out requisite repairs, rectification by welding, grinding etc.
2 Removing debris & other foreign material deposited on Monthly embedded parts & cleaning the same
3 All cracks & defective weld joints to be ascertained& Half Yearly rectified.
4 All dirt, debris, grit, foreign material etc. to be removed Monthly from trunnion assemblies as well as trunnion chair and lubricate trunnion bearing & the sliding surface on trunnion chair with specified lubricant/ grade to ensure smooth sliding movement of trunnion.
5 All nut bolts connecting Trunnion Assembly & Trunnion Chair Monthly and Trunnion & Yoke, girder Trunnion pin lock plate to be checked& Tightened and replacement the same if found defective.
38
August 2020 O&M Manual of Kallada Dam
b. Gate Structure
Sl. Embedded Part Frequency No
1 Regular inspection of the gate along with the hoist Daily to be carried out daily to ensure that there is no unusual development/ observation 2 Check all welding for soundness & rectify defects Quarterly 3 Check welding between arms & horizontal girders Quarterly as well as arms & Trunnion with the help of magnifying glass for cracks/ defects and rectify the defects. 4 Clean all drain boles including those in end arms, Quarterly horizontal girders & Trunnion
5 Check all nuts & bolts provided and tighten them, Quarterly and replace the defective nuts & bolts
6 Check upstream face of Skin plate for pitting, Yearly scaling and corrosion. Scaling formation are to be removed. Pitting shall be filled with weld & ground. Corroded surface shall be cleaned & painted 7 Joints of side & bottom rubber seals to be checked Monthly for their proper alignment and fixing & to be rectified/ adjusted if there is leakage through joints 8 Nuts & bolts for rubber seal connection to be Quarterly tightened and damaged nuts and bolts to be replaced
9 The excessive or widespread leakages if any shall Quarterly be reported to the engineer in charge. If the seals are required to be replaced the same shall-be carried out after supply of rubber seal by the
39
August 2020 O&M Manual of Kallada Dam
department free of cost in case the change of rubber seals is more than once during total maintenance period of five years
2. Rope Drum Hoist 3 Sets
Sl. Description Frequency No.
1 Checking of oil level of gear box and pouring of make- Daily
up oil as & when required
2 Checking, adjustment & repairing of electric motor and Monthly & during
electromagnetic thrusters brake rainy season
3 Checking and adjustment of wire rope Monthly & during rainy season 4 Checking, cleaning, etc., of all filters, silica gel etc., & Weekly
their replacement and when required
5 Checking, repairing and replacement whenever Monthly
necessary of all plummer block
6 Checking, repairing & making good of all electrical Weekly
wirings & connections of local panels
7 Checking, repairing & making good and replacement of Monthly
all electrical contactors, timers, limit switches, fuses
etc. including setting of limit switches
40
August 2020 O&M Manual of Kallada Dam
8 Complete trouble shooting of the entire system as and Weekly
when necessary to maintain the same such that the
system can be put to operation at any point of time as
per requirement
9 Checking and ensuring perfect lubrication of the entire Monthly equipment with recommended lubricants & methods of the manufacturer 15 The maintenance of the equipment cleaning & shall As per include inspection, checking and ascertaining the deficiencies in the equipment for its smooth & trouble requirement free operation. The deficiencies noticed shall be
rectified by resorting to cleaning, adjustment, repairs, replacement of troubled/ damaged parts as per the requirement 16 Necessary maintenance records are to be prepared as Monthly a result of periodical inspection and submitted for deciding actions in respect of necessary repair/replacement of parts 3. Stop Logs Embedded parts (Emergency gate)
Sl. No. Description Frequency 1 Inspection, checking of sill beams, side seals, guide Half Yearly track and other ex-posed embedded parts with respect to their alignment cracks, distortion, pitting, uneven surface due to wear & tear and ascertaining defects. Carrying out requisite repair/rectification by welding, grinding etc. as per requirement 2 Removal of debris and other foreign material deposited Quarterly on the E.P. and cleaning the same
3 All cracks & defective weld joints of E. P. to be Quarterly ascertained & rectified by respective welding
41
August 2020 O&M Manual of Kallada Dam
1.7 Distribution of Operation & Maintenance Manuals
The list of unit officers to whom the O&M Manual is required to be distributed is shown in
the table below.
Table 1. 4 Distribution of O&M Manual and Revisions
Sl No Number of Manual Unit Officers Distribution Secretary to Govt, Water Resources Department, 3 Thiruvanathapuram Chief Engineer, (I&A), Thiruvanathapuram 1 Chief Engineer, P2, Thiruvanathapuram 1 Superintending Engineer, KIP RB Circle, Kottarakkara 1 Executive Engineer, KIP(RB) Division No 2, Kottarakkara 1 JD, IDRB, Thiruvanathapuram 1 TA to SE, KI P (RB) Circle Kottarakkara 1 Assistant Executive Engineer, (RB) Subdivision No 2, Thenmala 1 Assistant Executive Engineer, Mechanical Subdivision, Thenmala 1 Assistant Engineer, KIP(RB) Section No 1 /2, Thenmala 1 Assistant Egineer, KIP(RB) Section No 3/2, Thenmala 1 TA to EE, KIP(RB) Division No 2, Kottarakkara 1
District Collector, Kollam 1
District Collector, Pathanamthitta 1
District Collector, Alapuzha 1
State Dam Safety Organization 1
Central Dam Safety Organization 1
State Emergency Operation Center, Kerala Disaster 1
Management Authority
National Disaster Management Authority 1 Superintendent of Police, Kollam 1
42
August 2020 O&M Manual of Kallada Dam
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 (EAP)
1.9 Typical Schedule of Duties
Schedule of General Duties for Project Engineers: Schedules of duties being performed by the staff assigned to various locations and components of Kallada Dam are provided in this section. All activities are to be recorded daily in the Logbook and in site registers.
Table 1. 5 Table showing Schedule of duties/inspections
Sl. Component/ Duty Frequency Personnel
No.
1 Visual inspection of dam including Crest Daily Sub Engineer/Dam
of dam (Dam top), Upstream and operators on contract downstream faces, visible portions of
foundation and abutments, Galleries,
Spillway and its energy dissipation arrangements, sluices etc.
2 Record water surface elevation, Daily (Hourly Sub Engineer/Dam
reservoir inflow and spillway discharge. basis during operators on contract monsoon)
3 Record meteorological data, Record Daily Sub Engineer/Dam releases from canal sluices operators on contract
43
August 2020 O&M Manual of Kallada Dam
4 Check security and safety devices, Daily Assistant Engineer
Complete logbook / site register which include the above information.
5 Record seepage from drainage Weekly Sub Engineer/Dam
systems, Gallery drains etc. and record operators on contract
meteorological data.
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 dissipation
arrangements, canal sluices etc.
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
of dam (Dam top), Upstream and Engineer downstream faces, visible portions of
foundation and abutments, Galleries,
Spillway and its energy dissipation arrangements, canal sluices etc.
9 Check security and safety devices, log Fort nightly Assistant Executive
book and site register which include the Engineer 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, Engineer vegetation growth 12 Check Sign/Warning display boards Fort nightly Assistant Executive near vulnerable locations Engineer
44
August 2020 O&M Manual of Kallada Dam
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 dissipation arrangements, canal sluices etc. 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 Monthly Executive Engineer near 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 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.
45
August 2020 O&M Manual of Kallada Dam
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 Superintending Engineer hydromechanical components, Check (Pre and Post along with Executive paint on gates, Check lubrication of wire Monsoon) Engineer in charge of ropes etc. and application of cardamom 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 DSO, CWC and uploading into Engineer/Superintending DHARMA. Engineer 23 Comprehensive inspections Annually Dam Safety Authority along with Dam Owners
24 Inspect dam and gate structures, energy Five Yearly Chief dissipation arrangement, which normally Engineer/Superintending are under water (by dewatering or by Engineer divers).
Review Dam operation procedures and EAP and update as necessary. 25 Comprehensive inspection of Ten Yearly DSRP performance ofthe dam and gate structures and reservoirs, energy dissipation arrangement and allied structures including dam operating systems
1.10 Hydro-Mechanical Inspections / Checks
Frequent inspections/checks for hydro-mechanical components are to be conducted and necessary action to be taken up during maintenance. Routine
46
August 2020 O&M Manual of Kallada Dam
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
47
August 2020 O&M Manual of Kallada Dam
CHAPTER 2. PROJECT OPERATION
The operation of the dam will involve regulation of its reservoir as per project specific requirements, keeping records and ensuring public safety. Proper operation procedures are crucial for maintaining a safe structure. This chapter provides details on how various elements of a project are to be operated both during normal and emergency situations. Basic data enclosed in this chapter of O &M manual:
● Area capacity curve - Attached as ( 2.2.5.1)
● Data of historic flood - The most ruinous flood in the basin occurred in the third week of July 1924 as per project report. There was continuous heavy rain for 3 days throughout the area, 227 mm at Aryankavu on 17 July 1924. The river rose to unprecedented height causing heavy damages to property. The flood banks in the lower reaches cause the river breached for the first time and the low-lying areas remind submerged for nearly a week. Official records on the flood damages are not traceable.
Second sever flood was observed during the months of October and November 1992, when the dam got overtopped. Consequent to this an auxiliary spillway was constructed the crest level of which is +116.73 m, ie MWL of Dam.
● Latest design flood and flood routing study-Attach seperately
● Sequence of operation of spillway gates during monsoon – included in this manual
Discharge through spillway for different reservoir levels with different gate openings -Included in this manual.
2.1 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)
Operating procedures are to be developed for both normal operations and emergency operations.
48
August 2020 O&M Manual of Kallada Dam
2.2 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.
2.2.1 Instructions for Operating Control Mechanisms
The total length of spillway is 42.06 m, which includes 3 Nos. gated ogee type spillway of size 12.19m x 9.14m. The weight of each shutter is 40 tonne. These shutters are fixed in hoist bridge. The operating system used for operating the shutters is winch and rope.
These shutters are operated by mechanically or manually. All shutters can safely rise up to 3.657m (12 feet). Auxiliary Spillway is free flowing spillway without any control gate. A service gate is provided at the upstream side of penstock pipe to regulate the flow of water through penstock pipe. A stop log gate is also provided at the upstream side of penstock pipe which is presently not in a serviceable condition, which can be used as an auxiliary power system if repaired.
A back-up diesel-operated generator power system is provided for the, spillway gates , intake of the Penstock and other dam facilities even if all these are all electrically operated.
This system is mounted at levels higher than the extreme flood levels so that it can be accessed even during extreme events.
2.2.1.1 Recommended Gate Operation Procedures for Normal Flow Conditions
Under normal flow conditions, the reservoir is operated according to the rule curve elevations and direction from higher authorities, according to the prevailing conditions. According to the level of water to be maintained as per rule curve, additional water release can be made through power generation. This is can be done through penstock pipes.
2.2.1.2 Salient Features of Spillway
Number of gates : 3 Nos
49
August 2020 O&M Manual of Kallada Dam
Gate size : 12.19m x 9.14m
Full reservoir level : +115.82m
Max. Water level : +116.73 m
Top of gate : +115.97m
Clear width of opening : +12.19m
Top of spillway crest : +106.68m
2.2.1.3 Operation of Radial Crest Gates of Kallada Dam (Parappar Dam) Crest gates of Parappar Dam have been designed with spillway crest of +106.68m and FRL +15.82m. The basic principal of the design is that the water pressure is transferred to piers and abutments through skin plates, stiffeners horizontal girders, arms, trunion, tie flats and anchor girders. The skin plates between bottom and top horizontal girders are designed as supported on the girders. The portion below the bottom horizontal girder up to sill beam and above top horizontal girder and up to FRL is designed as cantilever.
There are 3nos of radial gates each having size of 12.19m x 9.14 m. 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 spill way gates will be opened and closed against full flow. When using the gate for control of the water level in the reservoir the gate may be in any position for prolonged periods of time between the fully closed and fully opened positions. With the gate fully open and the reservoir level at +115.82 m the discharge flow is 1118.26 m3/sec. Under these circumstances, the gate (in fully open position) and trunnions must be clear of the water surface. Discharge through spillway for different reservoir levels with different gate openings are shown below.
2.2.1.4 Radial Crest Gates – Technical Data
The Spillway radial gates will be used to regulate the flood in the reservoir when the water level rises above the predetermined level that is +115.82m (FRL) The gates will be designed for full water level of EI +115.82m and will be checked for MWL EL +116.73m in
50
August 2020 O&M Manual of Kallada Dam which case the stresses may be increased by 331/3 % of the normal stresses. The top of the gate will be at elevation +115.97m in closed position the spillway crest elevation +106.68m and the gate sill elevation +106.38m. The gate shall consist of a structural steel frame with steel skin plate forming the u/s surface.
The inside of skin plate shall have radius of 9.14m. The skin plates shall be supported by horizontal Stiffeners which are in supported by vertical stiffeners. The horizontal girders shall be supported on inclined arms. The trunnion girders shall be secured by anchor rods of suitable diameters. The side seals and seals at bottom shall bear on metal seal plates embedded in concretes. Each gate shall be provided with at least two guide rollers on each side.
Each gate shall be operated by means of individual motor driven hoists mechanically connected to each of the gates by means of a rope arrangement. The hoist and motor and the electric controls shall be located on a platform at the elevation. 20% reserve capacity should be provided in the design of hoists in addition to the required for the operation of the gates.
Design Considerations
The gate shall be designed for a static head of 9.436m (30.957’) corresponding to FRL ie + 115.82m. The effective thickness of the skin plate is taken as 1.5mm less than nominal size to aloe for corrosion. Notching in the main girders will not be permitted. The fully hydrostatic load on the upstream side of the gate when the water surface is at EL.380.00 ft(115.824m) with the gates closed. The total hydrostatic, hydrodynamic and frictional forces occurring when the gates are raised, lowered or maintained partially open with the upstream water surface at the any elevation between +106.38m and +115.82m awing load on the raised gate portion above water level. a) Radial Gates- General
The satisfactory operation of gate will depart from vertical plane by proper location and alignment of the holes for end arm bearings. b) Seals
51
August 2020 O&M Manual of Kallada Dam
Seals must be of an approved type carefully fitted and securely, fastened by suitable clamp bolts. c) Gate Guides and Anchorages
The bottom sill beam and wall plates are fabricated steel plates and structural shapes and are provided with anchorages for rigid connections to the spillway crest end to the piers. d)Trunnion Assembly
The trunnion bearing hubs are annealed cast steel and fitted with bronze bushings. If welded construction, it must be stress relieved. The bushing shall be of high tensile case bronze and shall be the standard product of an established manufacturer of such equipment. The trunnion pin will be such of dimension as to restrict the bearing stresses which shall not excess 175kg/cm2 if bronze bushing is used. e)Trunnion Bracket
The bracketed casting is rigidly fixed to anchorage or support girder. It will transfer the total load from the trunnion to the anchorage. f) Trunnion Girders
Trunnion girders are placed and held in proper inclination by proper adjustment of the erection plated provided at the bottom. The girder are designed for bending, shear and torsion caused by the mix, horizontal and vertical forces on trunnion pin.
g) Anchor Rods
The anchor rods are designed to withstand the total water load on the gate and transfer the load to piers and the abutments in bond as a bond stress between the anchors and the concrete h) Trunnion Tie
52
August 2020 O&M Manual of Kallada Dam
The trunnion tie is used to withstand the side thrust caused by the use of inclined arms. It shall span from one trunnion hub to the other.
2.2.1.5 Material Specification
Component parts Material
1. Skin Plate Structural Steel
2. Stiffeners, Horizontal Girder Structural Steel
3. Seals Natural and Synthetic rubber
4. Seal seat Stainless steel
5. Arms, bracing, Tie members, wall plate yoke girder Structural steel
6. Embedded Parts Structural Steel
7. Anchor bars Structural Steel
8. Pins Corrosion resisting steel
9. Bushing High tensile cast bronze or self
Lubricating bronze bushing or lubrite
10. Trunnion hub and bracket Cast steel structural steel
2.2.1.6 Checklist before Operation The following steps are to be taken before operation of the gates to ensure these eight critical functions are in good working condition.
Step 1 Seal Clamp The seal clamp fixing should be such as to ensure that the side seals are flexible enough Step 2 Limit Switch Limit Switches shall be checked for satisfactory operation (function) to stop the hoist automatically, when the gate reaches the fully opened or fully closed
53
August 2020 O&M Manual of Kallada Dam
position Step 3 Nut & Bolts All nuts, bolts and screws shall be checked for wear, tear and tightness Step 4 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 5 Trunnion Lubrication To check and apply the high pressure lubricating grease in trunnion bushing from the hole provided in trunnion hub Step 6 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. In case of any contact chatter, clean the magnet surface and try again. If the chattering continues, check the coil voltage and replace the contact / coil, if necessary
2.2.1.7 Rope Drum Hoisting Arrangements for Radial Crest Gates
Main components of hoists mechanism: 1) Hoist frame 2) Drive unit 3) Gear trains with wire rope drum. 4) Wire ropes and equalizer plate
Drum: The grooved drum is in such a size that normally there will not more than one
layer of rope on the drum when the rope is in its fully covered position unless specified. The layer of the drum shall be such that each lead off rope has minimum
two full turns on the drum when the gate is as its lowest position and one groove for
each lead off the drum when the gate is at its highest position. The drum is flanged at end. The flanges shall project to a height of not less than two rope diameters above
the rope. A spur gear secured to the drum may be regarded as forming one of the
flanges. Shaft: The shaft is designed for appropriate load/torque that is being transmitted.
Shafts have ample strength and rigidity and adequate bearing surfaces. They are
finished smoothly and if shouldered, shall be provided with fillets of large radius. Bearings: The entire running shaft is provided with bush bearings. Selection of
bearing shall be done on consideration of duty, load and speed of the shaft.
54
August 2020 O&M Manual of Kallada Dam
Wire rope drum: This is made of cast iron conforming to I.S. 210-1970 grade 20. The
drum has machined grooves on its periphery to guide the wire rope. Before clamping to wire rope on drum, it is adjusted in such a way that a minimum of two full turns
remain on the drum when the gate in its lowest position
Wire Ropes: The wire rope is made from improved plough steel, galvanized (if required) Lang’s lay and fibre core or normally of 6/36 and 44mm in diameter.
Equalizer Plate: The function of the plate is to equalize the tension in wire ropes. The
equalizer plates are rectangular in shape. A plate is provided at both suspension points of the gate.
Drive unit: It consists of electric motor (10HP), reduction gear box (gear ratio-70:1), electromagnetic brake, starter indicator and limit switches.
Electromagnetic Brake: The electromagnetic brake is of spring set, shoe type. It is
solenoid operated and continuously rated. The brake is effective in both directions of travel and capable of overcoming at least 150percent of the full load torque exerted
by the motor. The brake will set automatically when the current is cut off from the
motor and it will electrically release when the current is applied to the motor. The brake is equipped with a hand operated released lever. The manual operation is
provided if required for emergency operation in the event of electric supply failure. 2.2.2 Operation of the Reservoir
The general operation of the reservoir, including monitoring and regulation of inflow and outflow are included in this section. Inflow includes upstream dam release, flood water, etc. Out flow includes the releases from the dam for specific release and the date and duration of such releases. Gate operation sequence, maximum release that can be made, various reservoir levels, etc affect the operation of reservoir. Operation of reservoir should include reservoir capacities at different levels, monsoon yields, and proposed reservoir levels during monsoon months, release of surplus water, etc. With the experience and past records, the reservoir operation rules are formulated by the field officers so that reservoir levels are so maintained that the incoming flood water can be stored at FRL. The release pattern of flood water is made carefully by adopting prevailing standard operation procedures. The rainfall pattern is also considered while operating shutters. During flood season, reservoir level is watched by the dam site officers. When the level begins to raise up crest level, (+106.68m) the dam officers will be vigilant in dam
55
August 2020 O&M Manual of Kallada Dam
operation. Every day hourly rail fall will be reported to higher officers and the same will be monitored by Assistant Engineer and Assistant Executive in charges. When the water reaches first warning level, information is are passed to the Executive Engineer, KIP Division No II Kottarakkara for necessary steps to be taken depending on the intensity of the rainfall. The Executive Engineer will inform the dam officers to open the shutters if necessary. At the same time the information will be passed to the District Collector Kollam. Instructions for operating will be based on 1. Gate operation sequence including tables giving discharges for gate openings. 2. The discharge table is provided. The Executive Engineer, KIP RB Division No II, Kottarakkara uses his discretion and judgement to open shutters at various level depending on the inflow condition.
Table 2. 1 Discharge through spillway at different shutter opening and warning levels
are shown below.
KALLADA IRRIGATION PROJECT
DISCHARGE THROUGH SHUTTERS AT WARNING LEVELS
Water Left Discharge Centre Discharge Right Discharge Total Remarks Level In shutter through left shutter through left shutter through Discharge M opening shutter opening shutter opening right shutter Through in m in m in m Spillway Shutters in M3/sec
113.74 0.05 5.01 0.05 5.01 0.05 5.01 15.03 First warning level
113.74 0.10 10.01 0.10 10.01 0.10 10.01 30.02
113.74 0.15 14.98 0.15 14.98 0.15 14.98 44.95
113.74 0.20 19.94 0.20 19.94 0.20 19.94 59.83
113.74 0.25 24.88 0.25 24.88 0.25 24.88 74.65
113.74 0.30 29.81 0.30 29.81 0.30 29.81 89.42
56
August 2020 O&M Manual of Kallada Dam
113.74 0.35 34.71 0.35 34.71 0.35 34.71 104.13
113.74 0.40 39.60 0.40 39.60 0.40 39.60 118.79
113.74 0.45 44.46 0.45 44.46 0.45 44.46 133.39
113.74 0.50 49.31 0.50 49.31 0.50 49.31 147.94
113.74 0.55 54.14 0.55 54.14 0.55 54.14 162.43
113.74 0.60 58.96 0.60 58.96 0.60 58.96 176.87
113.74 0.65 63.75 0.65 63.75 0.65 63.75 191.25
113.74 0.70 68.53 0.70 68.53 0.70 68.53 205.58
113.74 0.75 73.28 0.75 73.28 0.75 73.28 219.84
113.74 0.80 78.02 0.80 78.02 0.80 78.02 234.06
113.74 0.85 82.74 0.85 82.74 0.85 82.74 248.21
113.74 0.90 87.44 0.90 87.44 0.90 87.44 262.31
113.74 0.95 92.12 0.95 92.12 0.95 92.12 276.36
113.74 1.00 96.78 1.00 96.78 1.00 96.78 290.34
113.74 1.05 101.42 1.05 101.42 1.05 101.42 304.27
113.74 1.10 106.05 1.10 106.05 1.10 106.05 318.14
113.74 1.15 110.65 1.15 110.65 1.15 110.65 331.95
113.74 1.20 115.23 1.20 115.23 1.20 115.23 345.70
113.74 1.25 119.80 1.25 119.80 1.25 119.80 359.40
113.74 1.30 124.34 1.30 124.34 1.30 124.34 373.03
113.74 1.35 128.87 1.35 128.87 1.35 128.87 386.61
113.74 1.40 133.38 1.40 133.38 1.40 133.38 400.13
113.74 1.45 137.86 1.45 137.86 1.45 137.86 413.59
113.74 1.50 142.33 1.50 142.33 1.50 142.33 426.98
113.74 1.55 146.77 1.55 146.77 1.55 146.77 440.32
113.74 1.60 151.20 1.60 151.20 1.60 151.20 453.60
113.74 1.65 155.61 1.65 155.61 1.65 155.61 466.82
113.74 1.70 159.99 1.70 159.99 1.70 159.99 479.97
113.74 1.75 164.36 1.75 164.36 1.75 164.36 493.07
113.74 1.80 168.70 1.80 168.70 1.80 168.70 506.10
113.74 1.85 173.02 1.85 173.02 1.85 173.02 519.07
113.74 1.90 177.33 1.90 177.33 1.90 177.33 531.98
113.74 1.95 181.61 1.95 181.61 1.95 181.61 544.83
57
August 2020 O&M Manual of Kallada Dam
113.74 2.00 185.87 2.00 185.87 2.00 185.87 557.61
113.74 2.05 190.11 2.05 190.11 2.05 190.11 570.33
113.74 2.10 194.33 2.10 194.33 2.10 194.33 582.99
113.74 2.15 198.53 2.15 198.53 2.15 198.53 595.59
113.74 2.20 202.71 2.20 202.71 2.20 202.71 608.12
113.74 2.25 206.86 2.25 206.86 2.25 206.86 620.58
113.74 2.30 210.99 2.30 210.99 2.30 210.99 632.98
113.74 2.35 215.11 2.35 215.11 2.35 215.11 645.32
113.74 2.40 219.20 2.40 219.20 2.40 219.20 657.59
113.74 2.45 223.27 2.45 223.27 2.45 223.27 669.80
113.74 2.50 227.31 2.50 227.31 2.50 227.31 681.94
113.74 2.55 231.34 2.55 231.34 2.55 231.34 694.01
113.74 2.60 235.34 2.60 235.34 2.60 235.34 706.02
113.74 2.65 239.32 2.65 239.32 2.65 239.32 717.95
113.74 2.70 243.28 2.70 243.28 2.70 243.28 729.83
113.74 2.75 247.21 2.75 247.21 2.75 247.21 741.63
113.74 2.80 251.12 2.80 251.12 2.80 251.12 753.37
113.74 2.85 255.01 2.85 255.01 2.85 255.01 765.03
113.74 2.90 258.88 2.90 258.88 2.90 258.88 776.63
113.74 2.95 262.72 2.95 262.72 2.95 262.72 788.16
113.74 3.00 266.54 3.00 266.54 3.00 266.54 799.62
113.74 3.05 270.34 3.05 270.34 3.05 270.34 811.01
113.74 3.10 274.11 3.10 274.11 3.10 274.11 822.32
113.74 3.15 277.86 3.15 277.86 3.15 277.86 833.57
113.74 3.20 281.58 3.20 281.58 3.20 281.58 844.74
113.74 3.25 285.28 3.25 285.28 3.25 285.28 855.85
113.74 3.30 288.96 3.30 288.96 3.30 288.96 866.88
113.74 3.35 292.61 3.35 292.61 3.35 292.61 877.83
113.74 3.40 296.24 3.40 296.24 3.40 296.24 888.72
113.74 3.45 299.84 3.45 299.84 3.45 299.84 899.52
113.74 3.50 303.42 3.50 303.42 3.50 303.42 910.26
113.74 3.55 306.97 3.55 306.97 3.55 306.97 920.92
113.74 3.60 310.50 3.60 310.50 3.60 310.50 931.50
58
August 2020 O&M Manual of Kallada Dam
113.74 3.65 314.00 3.65 314.00 3.65 314.00 942.01
114.81 0.05 5.38 0.05 5.38 0.05 5.38 16.14 Second warning level 114.81 0.10 10.74 0.10 10.74 0.10 10.74 32.23
114.81 0.15 16.09 0.15 16.09 0.15 16.09 48.27
114.81 0.20 21.42 0.20 21.42 0.20 21.42 64.26
114.81 0.25 26.73 0.25 26.73 0.25 26.73 80.20
114.81 0.30 32.03 0.30 32.03 0.30 32.03 96.09
114.81 0.35 37.31 0.35 37.31 0.35 37.31 111.93
114.81 0.40 42.57 0.40 42.57 0.40 42.57 127.72
114.81 0.45 47.82 0.45 47.82 0.45 47.82 143.45
114.81 0.50 53.05 0.50 53.05 0.50 53.05 159.14
114.81 0.55 58.26 0.55 58.26 0.55 58.26 174.77
114.81 0.60 63.45 0.60 63.45 0.60 63.45 190.36
114.81 0.65 68.63 0.65 68.63 0.65 68.63 205.89
114.81 0.70 73.79 0.70 73.79 0.70 73.79 221.37
114.81 0.75 78.93 0.75 78.93 0.75 78.93 236.79
114.81 0.80 84.06 0.80 84.06 0.80 84.06 252.17
114.81 0.85 89.16 0.85 89.16 0.85 89.16 267.49
114.81 0.90 94.25 0.90 94.25 0.90 94.25 282.76
114.81 0.95 99.33 0.95 99.33 0.95 99.33 297.98
114.81 1.00 104.38 1.00 104.38 1.00 104.38 313.15
114.81 1.05 109.42 1.05 109.42 1.05 109.42 328.26
114.81 1.10 114.44 1.10 114.44 1.10 114.44 343.32
114.81 1.15 119.44 1.15 119.44 1.15 119.44 358.32
114.81 1.20 124.42 1.20 124.42 1.20 124.42 373.27
114.81 1.25 129.39 1.25 129.39 1.25 129.39 388.17
114.81 1.30 134.34 1.30 134.34 1.30 134.34 403.01
114.81 1.35 139.27 1.35 139.27 1.35 139.27 417.80
114.81 1.40 144.18 1.40 144.18 1.40 144.18 432.54
114.81 1.45 149.07 1.45 149.07 1.45 149.07 447.22
114.81 1.50 153.95 1.50 153.95 1.50 153.95 461.84
114.81 1.55 158.80 1.55 158.80 1.55 158.80 476.41
59
August 2020 O&M Manual of Kallada Dam
114.81 1.60 163.64 1.60 163.64 1.60 163.64 490.93
114.81 1.65 168.46 1.65 168.46 1.65 168.46 505.39
114.81 1.70 173.26 1.70 173.26 1.70 173.26 519.79
114.81 1.75 178.05 1.75 178.05 1.75 178.05 534.14
114.81 1.80 182.81 1.80 182.81 1.80 182.81 548.43
114.81 1.85 187.56 1.85 187.56 1.85 187.56 562.67
114.81 1.90 192.28 1.90 192.28 1.90 192.28 576.85
114.81 1.95 196.99 1.95 196.99 1.95 196.99 590.97
114.81 2.00 201.68 2.00 201.68 2.00 201.68 605.03
114.81 2.05 206.35 2.05 206.35 2.05 206.35 619.04
114.81 2.10 211.00 2.10 211.00 2.10 211.00 632.99
114.81 2.15 215.63 2.15 215.63 2.15 215.63 646.88
114.81 2.20 220.24 2.20 220.24 2.20 220.24 660.72
114.81 2.25 224.83 2.25 224.83 2.25 224.83 674.49
114.81 2.30 229.40 2.30 229.40 2.30 229.40 688.21
114.81 2.35 233.96 2.35 233.96 2.35 233.96 701.87
114.81 2.40 238.49 2.40 238.49 2.40 238.49 715.47
114.81 2.45 243.00 2.45 243.00 2.45 243.00 729.01
114.81 2.50 247.50 2.50 247.50 2.50 247.50 742.50
114.81 2.55 251.97 2.55 251.97 2.55 251.97 755.92
114.81 2.60 256.43 2.60 256.43 2.60 256.43 769.28
114.81 2.65 260.86 2.65 260.86 2.65 260.86 782.58
114.81 2.70 265.27 2.70 265.27 2.70 265.27 795.82
114.81 2.75 269.67 2.75 269.67 2.75 269.67 809.00
114.81 2.80 274.04 2.80 274.04 2.80 274.04 822.12
114.81 2.85 278.39 2.85 278.39 2.85 278.39 835.18
114.81 2.90 282.73 2.90 282.73 2.90 282.73 848.18
114.81 2.95 287.04 2.95 287.04 2.95 287.04 861.11
114.81 3.00 291.33 3.00 291.33 3.00 291.33 873.98
114.81 3.05 295.60 3.05 295.60 3.05 295.60 886.79
114.81 3.10 299.85 3.10 299.85 3.10 299.85 899.54
114.81 3.15 304.07 3.15 304.07 3.15 304.07 912.22
114.81 3.20 308.28 3.20 308.28 3.20 308.28 924.84
60
August 2020 O&M Manual of Kallada Dam
114.81 3.25 312.47 3.25 312.47 3.25 312.47 937.40
114.81 3.30 316.63 3.30 316.63 3.30 316.63 949.89
114.81 3.35 320.77 3.35 320.77 3.35 320.77 962.32
114.81 3.40 324.89 3.40 324.89 3.40 324.89 974.68
114.81 3.45 328.99 3.45 328.99 3.45 328.99 986.98
114.81 3.50 333.07 3.50 333.07 3.50 333.07 999.21
114.81 3.55 337.12 3.55 337.12 3.55 337.12 1011.37
114.81 3.60 341.16 3.60 341.16 3.60 341.16 1023.47
114.81 3.65 345.17 3.65 345.17 3.65 345.17 1035.51
115.45 0.05 5.59 0.05 5.59 0.05 5.59 16.77 Third warning level 115.45 0.10 11.16 0.10 11.16 0.10 11.16 33.48
115.45 0.15 16.72 0.15 16.72 0.15 16.72 50.15
115.45 0.20 22.26 0.20 22.26 0.20 22.26 66.77
115.45 0.25 27.78 0.25 27.78 0.25 27.78 83.35
115.45 0.30 33.29 0.30 33.29 0.30 33.29 99.87
115.45 0.35 38.78 0.35 38.78 0.35 38.78 116.34
115.45 0.40 44.26 0.40 44.26 0.40 44.26 132.77
115.45 0.45 49.72 0.45 49.72 0.45 49.72 149.15
115.45 0.50 55.16 0.50 55.16 0.50 55.16 165.48
115.45 0.55 60.59 0.55 60.59 0.55 60.59 181.76
115.45 0.60 65.99 0.60 65.99 0.60 65.99 197.98
115.45 0.65 71.39 0.65 71.39 0.65 71.39 214.16
115.45 0.70 76.76 0.70 76.76 0.70 76.76 230.29
115.45 0.75 82.13 0.75 82.13 0.75 82.13 246.38
115.45 0.80 87.47 0.80 87.47 0.80 87.47 262.41
115.45 0.85 92.80 0.85 92.80 0.85 92.80 278.39
115.45 0.90 98.11 0.90 98.11 0.90 98.11 294.32
115.45 0.95 103.40 0.95 103.40 0.95 103.40 310.19
115.45 1.00 108.67 1.00 108.67 1.00 108.67 326.02
115.45 1.05 113.93 1.05 113.93 1.05 113.93 341.80
115.45 1.10 119.18 1.10 119.18 1.10 119.18 357.53
115.45 1.15 124.40 1.15 124.40 1.15 124.40 373.20
61
August 2020 O&M Manual of Kallada Dam
115.45 1.20 129.61 1.20 129.61 1.20 129.61 388.83
115.45 1.25 134.80 1.25 134.80 1.25 134.80 404.40
115.45 1.30 139.97 1.30 139.97 1.30 139.97 419.92
115.45 1.35 145.13 1.35 145.13 1.35 145.13 435.39
115.45 1.40 150.27 1.40 150.27 1.40 150.27 450.81
115.45 1.45 155.39 1.45 155.39 1.45 155.39 466.17
115.45 1.50 160.49 1.50 160.49 1.50 160.49 481.48
115.45 1.55 165.58 1.55 165.58 1.55 165.58 496.74
115.45 1.60 170.65 1.60 170.65 1.60 170.65 511.95
115.45 1.65 175.70 1.65 175.70 1.65 175.70 527.10
115.45 1.70 180.74 1.70 180.74 1.70 180.74 542.21
115.45 1.75 185.75 1.75 185.75 1.75 185.75 557.25
115.45 1.80 190.75 1.80 190.75 1.80 190.75 572.25
115.45 1.85 195.73 1.85 195.73 1.85 195.73 587.19
115.45 1.90 200.69 1.90 200.69 1.90 200.69 602.07
115.45 1.95 205.64 1.95 205.64 1.95 205.64 616.91
115.45 2.00 210.56 2.00 210.56 2.00 210.56 631.69
115.45 2.05 215.47 2.05 215.47 2.05 215.47 646.41
115.45 2.10 220.36 2.10 220.36 2.10 220.36 661.08
115.45 2.15 225.23 2.15 225.23 2.15 225.23 675.69
115.45 2.20 230.08 2.20 230.08 2.20 230.08 690.25
115.45 2.25 234.92 2.25 234.92 2.25 234.92 704.76
115.45 2.30 239.73 2.30 239.73 2.30 239.73 719.20
115.45 2.35 244.53 2.35 244.53 2.35 244.53 733.60
115.45 2.40 249.31 2.40 249.31 2.40 249.31 747.93
115.45 2.45 254.07 2.45 254.07 2.45 254.07 762.21
115.45 2.50 258.81 2.50 258.81 2.50 258.81 776.44
115.45 2.55 263.54 2.55 263.54 2.55 263.54 790.61
115.45 2.60 268.24 2.60 268.24 2.60 268.24 804.72
115.45 2.65 272.92 2.65 272.92 2.65 272.92 818.77
115.45 2.70 277.59 2.70 277.59 2.70 277.59 832.77
115.45 2.75 282.24 2.75 282.24 2.75 282.24 846.71
115.45 2.80 286.86 2.80 286.86 2.80 286.86 860.59
62
August 2020 O&M Manual of Kallada Dam
115.45 2.85 291.47 2.85 291.47 2.85 291.47 874.41
115.45 2.90 296.06 2.90 296.06 2.90 296.06 888.18
115.45 2.95 300.63 2.95 300.63 2.95 300.63 901.88
115.45 3.00 305.18 3.00 305.18 3.00 305.18 915.53
115.45 3.05 309.71 3.05 309.71 3.05 309.71 929.12
115.45 3.10 314.22 3.10 314.22 3.10 314.22 942.65
115.45 3.15 318.71 3.15 318.71 3.15 318.71 956.12
115.45 3.20 323.18 3.20 323.18 3.20 323.18 969.53
115.45 3.25 327.63 3.25 327.63 3.25 327.63 982.88
115.45 3.30 332.06 3.30 332.06 3.30 332.06 996.17
115.45 3.35 336.47 3.35 336.47 3.35 336.47 1009.40
115.45 3.40 340.85 3.40 340.85 3.40 340.85 1022.56
115.45 3.45 345.22 3.45 345.22 3.45 345.22 1035.67
115.45 3.50 349.57 3.50 349.57 3.50 349.57 1048.72
115.45 3.55 353.90 3.55 353.90 3.55 353.90 1061.70
115.45 3.60 358.21 3.60 358.21 3.60 358.21 1074.62
115.45 3.65 362.49 3.65 362.49 3.65 362.49 1087.48
115.82 3.657 372.75 3.657 372.75 3.657 372.75 1118.26 FRL
116.73 3.657 395.49 3.657 395.49 3.657 395.49 1186.47 MWL
PMF and Moderated Flood
The existing capacity of the main spillway is 2830 m3/s, and additional capacity of the additional spillway is reported to be 689 m3/s at original MWL. Therefore, the total spillway capacity is 3519 m3/s (2830 m3/s + 689 m3/s) at original MWL. The PMF arrived has been estimated as 5432 m3/s. As per Hydrological Review of Kallada Dam, carried out by CWC during December 2019, the estimated PMF comes to 5773cumecs. The Design Flood review study of Chimoni dam by CWC is attached as Annexure -B
Rule Curve
63
August 2020 O&M Manual of Kallada Dam
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 Kallada dam has been developed and is shown in Figure 2.1.
64
August 2020 O&M Manual of Kallada Dam
Figure 2. 1 Rule Curve
65
August 2020 O&M Manual of Kallada Dam
2.2.3 Safety Aspects
The public safety is of paramount importance at Kallada dam and reservoir. The general instructions in this regard are as under: Security arrangements are provided at Main gate, dam top and exit gate. Paid vehicle parking area is available near the main gate, which is being controlled by security staff. No vehicle will be allowed to dam top except official vehicles. Security surveillance is arranged in the dam premises, for restricting unauthorised entry. Visitors are allowed in the dam premises and dam top through paid entry pass. Tourists are directed to observe warring boards and restricted areas, which are being supervised by security and department staff. Inside the dam top and dam premises private vehicles are not allowed. Hence boards displaying speed limits are not provided. Only limited toilets are presently available in dam premises, which are maintained in good condition. No drinking water scheme is established in connection with dam. Safety hazards– Proper warning signs are provided wherever necessary in dam premises and dam top road as safety precaution to hazards. - Public access is not allowed to stilling basin and restricted dam area by security Arrangements. - Key locations and other restricted area are controlled by security staff, which is Supervised by deptl. Officers. - Adequate security arrangements have been provided by shift arrangements. Presently no sirens or hooters are provided. Emergency action plan has been prepared.
At the same time instructions regarding operations, inspection and maintenance need to be strictly followed for ensuring safe operation of the dam.
2.2.4. Flood Release Procedure of Kallada (Parappar) Dam For every dam it is necessary to ensure that all gates are in working condition. The flood releasing structures of Kallada dam are three spillways of size 3.656 m (ogee type) , having crest level of +106.68 m, a penstock pipe of 3.75 m dia, MDDL of which is +70.25 m, and an auxiliary spillway (labyrinth- having no gates) the crest level of which is +116.73m.
66
August 2020 O&M Manual of Kallada Dam
The auxiliary spillway functions during emergency condition to prevent overtopping of the dam.
Gate operation schedule for passing floods safely in Kallada dam is as follows. 1. The end gates shall normally be opened first to prevent cross flows striking against the walls and junctions. 2. At any time during the operation of different gates, the difference in gate opening of any two consecutive base should not exceed 0.50m. 3. After opening the end gates, the gates at centre will be opened and other gates should be opened in symmetrical manner starting from the centre towards the ends. 4. The gates shall be opened as per the directions of Executive Engineer and according to the quantity of inflow. 5. While closing the gates, the gate that was opened last will be closed first.
Reservoir Capacities The various important reservoir levels and corresponding capacities are given below:
Particulars RL. in meters Live Capacity in Mm3
Minimum draw down level +70.25 0
Crest level +106.68 296.60
Full Reservoir level +115.82 487.92
Maximum water level +116.73 507.30
First Warning Level +113.74 440.50
Second Warning Level +114.81 461.58
67
August 2020 O&M Manual of Kallada Dam
Third Warning Level +115.45 477.58
Figure 2. 2 Reservoir Storage Allocation Zones
Area Capacity curve The area capacity curves for Kallada Dam
Capacity, Mm3 Water Level, m 17 70 30 75 45 80 66 85 98 90 145 95 210 100 280 105
68
August 2020 O&M Manual of Kallada Dam
380 110 482 115 524.3 116.73
Figure 2. 3 Elevation - Capacity Curve
AREA, m2 water Level, m 1.6 65 2.2 70 2.9 76 3.8 80.5 4.9 85 7.9 90.5 11.2 96 13.8 100 18 106 20.5 110 21.5 115.83
69
August 2020 O&M Manual of Kallada Dam
Figure 2. 4 Elevation-Area Curve
Bathymetric Survey / Sedimentation Survey
Sedimentation study of Kallada Reservoir was conducted by KERI (Kerala Engineering
Research Institute, Peechi) on 2018 and the study shows the capacity of reservoir at the water level of +112.85m is reduced by 28.76 Mm3 in 32 years at the rate 0.899Mm3 per year. 2.2.6 Inflow Forecasting /calculation
Inflow into reservoirs is normally estimated by the reservoir gauging method (also called the rise and fall method or inflow-outflow method). Expressed as an equation, this will be.
Inflow (m3/s) = Rate of increase or decrease in Storage (m3/s) + Outflow (m3/s) Example for Inflow calculation
Inflow on 15/10/18
Storage on 14/10/18 6am = 405.09 Mm3 Storage on 15/10/18 6am = 404.90 Mm3
Storage Difference = 404.90 -405.09
= - 0.19 Mm3 ie, = -0.19 x 106/ 24*60*60
70
August 2020 O&M Manual of Kallada Dam
= -2.19906 m3/s
Out flow (By generation) = 19.89 m3/s Total inflow = Net inflow +Out flow
= (- )2.19906+19.89
= 17.690 m3/s Spillway discharge Calculation
F R L - 115.82 M
M W L - 116.73 M Storage at F R L - 504.92 Mm3
Number of shutters - 3 Type of Shutters - Radial shutters
Size of Shutters - 12.19 m X 9.14 m
Max. Opening of Shutters - 12 ‘(3.6576 m) Maximum Discharge through shutters at FRL
Q = 2/3 * cd*L* √2g (H13/2 – H2 3/2)
(Discharge for maximum opening of shutters i.e. 12’ (3.6576m) Cd - Constant = 0.7
L - Length of crest = 3 x 12.19
H1 - Head over crest level H2 - Head over the top of opening
Q= 2/3 x 0.7 x 3x12.19x√ (2x9.81) (115.82-106.68)3/2 – (115.82-
(106.68+3.6576))3/2 = 1118.26 m3/sec
71
August 2020 O&M Manual of Kallada Dam
2.3 Emergency Operations
Flood communication system:
The widely time-tested Communication to reach every corner of the flood affected zones have been radio, 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, network of mobile phones are available. Advantage of this facility can be taken into account. Mobile numbers of all staffs, who are to be contacted, are listed and made available to all the personnel who have been assigned duty of disaster management.
Apart from that, for ensuring smooth flood monitoring, meetings are conducted yearly within the state. Following liaising officers for flood co-ordination of Kallada Dam are as listed below:
Authority Name, Title, Phone
Name: Sri Sivasankarapillai Title : Assistant Engineer Mobile No: 7902205621 Office Ph: 0475-2344532 Email: [email protected]
Dam Operator/Site Name: Sri. Satheesan officials Title : Overseer
Mobile No. 9447993123 Office Ph: 0475-2344532 Email: [email protected]
Name: Smt. Litty Augustine Title :AssistantExecutive Engineer, KIP (RB) Sub division No.II, Thenmala.
72
August 2020 O&M Manual of Kallada Dam
Mobile No:9746676411 Office Ph: 0475-2344532 Email: [email protected]
Name: Sri Tessymon .K.K
Title : Executive Engineer, KIP (RB) Division
No.II, Kottarakkara Emergency Planning Mobile No: 9847524381 Manager Office Ph: 0474 2452617 Email: [email protected] Name: Sri. Alex Varghese
Title : Chief Engineer, Projects II, Tvpm
Mobile No: 9447739670 Kerala Water Office Ph: 0471 Resources Email: [email protected] Department Name: Sri .Vinod Mohan (full addl. Charge) Title : Superintending Engineer, KIP (RB) Circle, Kottarakkara. Mobile No: 9447023352 Office Ph: 0474 2452635 Email: [email protected] Name: Sri. K.A.Joshy Kerala Dam Safety Organisation Title : Chief Engineer, IDRB, Tvpm Mobile No: Office Ph: 0471-2306159, 0471- 2784001 Email: [email protected] Name: Sri. Biju .D Title: Director (Designs), IDRB, Tvm. Mobile No: 9446685757 Office Ph: 0471-2303972Email: [email protected]
2.3 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
73
August 2020 O&M Manual of Kallada Dam 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 lower level, 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/ land-slides 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.
2.4 Initial Filling of Reservoir
The prime consideration in deciding the rise of water should be to allow the dam to adjust to the forces it will experience as the water level behind it increases. Reservoir filling is governed by IS: 15472 – guidelines for planning and design of low-level outlets for evacuating storage reservoirs in which guidelines regarding initial filling of reservoirs have been described.
Kallada dam was commissioned on 1986. First filled on 01/06/1986, the water level was 84.43 m, Gross storage 62.58 Mm3 and Live storage 45.58Mm3.
2.5 Record Keeping
Rainfall and Reservoir Levels – On daily basis during non-monsoon and on hourly basis during monsoon. Release through outlet/sluices on daily basis for irrigation, hydropower etc. Outflows through spillway during monsoon on hourly basis and during non-monsoon on daily basis. Records of drawdown with reservoir levels, quantity of water released, draw down rates, reason for drawdown Water Audit register to be maintained on daily basis by accounting all the releases, incremental storage in the reservoir etc.
74
August 2020 O&M Manual of Kallada Dam
Security protocols to be in place along with operating protocols. Visitors register with complete details like name, address, designation, purpose etc. Other Procedures – Maintain a complete record of all operating procedures.
75
August 2020 O&M Manual of Kallada Dam
CHAPTER 3.PROJECT INSPECTIONS
The current practice of Inspection at Kallada dam envisages the Subdivision officers to carryout informal pre-monsoon and post-monsoon inspections. The checklist Performa included in this chapter is currently in use at Kallada Dam.
3.1 Types of Inspections
Four different types of dam safety inspections are being carried out at Kallada Dam. These include, but not limited, to the following: • Informal inspections
• Scheduled inspections (Pre & Post monsoon inspections & other scheduled
inspections) • Special (unscheduled) inspections
• Comprehensive evaluation 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). This comprehensive checklist allows for recording the status of each item being inspected and the overall condition of the equipment along with any consequential risks the condition may have on the health of the dam
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. Operators, maintenance crews, or other staff who are posted at Kallada 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
76
August 2020 O&M Manual of Kallada Dam 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, 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 authority. 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).
Scheduled inspections include the following four components as a minimum: • 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.
77
August 2020 O&M Manual of Kallada Dam
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 April - May out during Post-monsoon Inspection to be carried December - January out during 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
Submission of Pre-monsoon Inspection Report Before June 30th Submission of Post-monsoon Before January 15th Inspection Report
Checking and approval of report Deputy Chief Engineer, SPMU
Uploading corrected document in Executive Engineer DHARMA
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
78
August 2020 O&M Manual of Kallada Dam 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: • Review of relevant files or data,
• Visual inspection,
• 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. Further the following activities are also recommended to minimize the adverse impacts of an earthquake • Regular field drills at dam site to make the site officials aware of their roles and responsibilities during and after an earthquake event and thereby to upgrade the earthquake response system • Securing communication lines by having a redundancy in the system by way of availability of different types of telecommunication systems (viz. mobile phone, wireless, satellites, telephone etc.) at dam site. • Securing adequate fuel for at least 3 days (viz. petrol, diesel) for the emergency power generators and other essential supplies like food, water, fire wood etc. • Installation of seismometers in a dam and development of a data sharing system. 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
79
August 2020 O&M Manual of Kallada Dam 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 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.
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
80
August 2020 O&M Manual of Kallada Dam
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.
5. Slope stability issues along reservoir rim.
(d) Layout including Drawings 1. Dam
2. Spillway 3. Concrete/Masonry dams
4. River/Canal outlets
5. Instrumentation (e) Dam and Spillway
Geology
Special problems Foundation treatment including treatment of faults/shear zones/weak zones,
curtain/consolidation grouting, drainage provisions, any other special treatment, cut
off trench, diaphragm walls etc. Design criteria and result of stability analysis
Special studies (Finite element/Dynamic Analysis etc.)
Adequacy of design – from dam safety considerations Hydraulic design of Spillway and Energy Dissipation Arrangements including past
model study reports
Instrumentation – analysis and interpretation of instrumentation data including structural behaviour reports.
Pre-construction material testing reports including adequacy of field and laboratory
investigations, appropriateness of materials selected etc. Post-construction testing reports, if any.
Seismicity (Seismic Parameters approved by the National Committee for
Recommending Seismic Design Parameters for Dams)
81
August 2020 O&M Manual of Kallada Dam 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. 3.5.3 Field inspection- Observations and 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/sand 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
82
August 2020 O&M Manual of Kallada Dam
2. Outlet Gates, Hoists & Controls
3. Conduits / 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.
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 annexure. (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.
83
August 2020 O&M Manual of Kallada Dam
4. Education and training of the dam owner on the issues observed during dam
inspection, identification of potential dam failure modes & to carryout addition al 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. 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.
84
August 2020 O&M Manual of Kallada Dam
CHAPTER 4.PROJECT MAINTENANCE
A good maintenance program will protect Kallada Dam against accelerating deterioration, prolongs its life, and greatly reduce the chance of failure. Nearly all the components of Kallada 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.
4.1 Maintenance Plan
Timely 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/ cavitations/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.
85
August 2020 O&M Manual of Kallada Dam
4.2 Maintenance Priorities
For Kallada 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 spill-way 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. Emergency action plan (EAP) should be activated when any of the above conditions are noted.
4.2.2 Preventive Maintenance
This can be further classified as Condition based Maintenance and Routine Maintenance.
Condition Based Maintenance
The following maintenance should be completed as soon as possible after the defective condition is noted. These include 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.
86
August 2020 O&M Manual of Kallada Dam
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. 4.2.3 Routine Maintenance
Several tasks should be performed on a continuous basis. These may include but are not limited to Maintenance of all dam roads & access roads. Maintenance included in mowing grass, removing vegetation, bushes and trees, removing litter and other debris, sump well cleaning, gallery cleaning and access roads, etc. Maintenance and treatment of any cracks/joints/cavities in Concrete/Masonry dams and spillways based on the recommendations of experienced engineers/expert panels. Observation of any springs or seepage areas, comparing quantity and quality (clarity) with prior observation in embankment dam. Monitoring of development in the upstream watershed which would materially increase runoff and sediment from storms. Monitoring of downstream development which could have an impact on the dam and its hazard category.
87
August 2020 O&M Manual of Kallada Dam
Maintenance of Electrical & Hydro- Mechanical equipment and systems e. g. Servicing of spillway gates & stop logs, hoisting arrangements, gantry crane, gates/hoist of outlet works/sluices & stand by generator. Proper lighting at dam top, galleries in dams etc. Monitoring of seepage in galleries of concrete/masonry dams. Monitoring/cleaning & removal of leached deposits in porous concrete/formed drains in dam body & foundation drainage holes of Concrete/ Masonry dams. 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.
TASKFORCE - Vigilance work for inspecting unauthorized water diversion
Kallada (Parappar) Dam has a catchment area of 549 sq. km and the reservoir is formed by the confluence of three rivers viz. Kalthuruthi, Chenthuruni, and Kulathupuzha.
These rivers start from the Western Ghats with thick dense forest and wild life sanctuary. The state boundary at these areas passes through the dense forest and it is about 50 to 100
Km away from the office campus. To find out any kind of unauthorised water diversion from our catchment area, regular inspection is conducted by TASKFORCE on a monthly basis.
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 maintenance includes all maintenance and repair of issues/works identified during safety inspections and routine dam surveillance. 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
88
August 2020 O&M Manual of Kallada Dam 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 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. Identification of works /issues which may require periodic maintenance are summarized in Table
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 live-stock 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.
89
August 2020 O&M Manual of Kallada Dam
An important soil property affecting compaction is moisture content. Soils that are too dry or too wet do not compact well. One may test repair material by squeezing it into a tight ball. If the sample keeps its shape without cracking and falling apart (which means it is too dry), and without depositing excess water onto the hand (which means it is too wet), the moisture content is near the proper level. Before placement of earth, the repair area needs to be prepared by removing all inappropriate material. All vegetation, such as bushes, roots, and tree stumps, along with any large rocks or trash need to be removed. Also, unsuitable earth, such as organic or loose soils, should be removed, so that the work surface consists of exposed, firm, clean embankment material. Following clean-up, 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 centimetres thick
3. Compact to required density at optimum moisture content (OMC)
4. Scarify compacted layer 10 centimetres 5. Moisturize the layer before placement of soils
6. Compact
7. Continue process until lines and grades are accomplished. Overbuild can be trimmed back to design lines and grades
8. Seed of turf the fill to minimize erosion processes
9. 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
90
August 2020 O&M Manual of Kallada Dam 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 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 down 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 runup will also undermine the filter layer especially along the full reservoir level and over time wash out finer 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 a 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
91
August 2020 O&M Manual of Kallada Dam 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 the dam.
• Large trees can be uprooted by high wind or erosion and leave large voids that can lead to breaching of the dam.
• 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.
Further, it is desirable that there are no trees or bushes within 500 m of the toe drain on the downstream side of the dam.
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.
92
August 2020 O&M Manual of Kallada Dam
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, bentonite 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 tunnelling 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.
4.3.5 Controlling Ants and Termites (White Ants) Ants and termites have become one of the most serious pests for Embankment dams. They both need water to survive and have been found on most of the embankment dams in India. These insects can create problems in the dam itself and with any of its electrical components. In some habitats, ants and termites can move as much or more soil as earthworms, thereby reducing soil compaction. Nest galleries can penetrate in a V-shaped pattern below the nest, penetrating as much as more than one meter deep in the soil. These galleries can create pathways for surface water to penetrate in the dam, resulting in internal erosion and collapse of the surface.
Ants and termites left undisturbed can build mounds that can become quite large. These can create problems for mowing. However, frequent mowing can induce the colonies to migrate to neighbouring, undisturbed areas.
93
August 2020 O&M Manual of Kallada Dam
There are many options for managing ants and termites. Use only pesticides labelled 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 and sometimes even when sealed with flexible pavement, especially when the embankment is saturated and overweight trucks use the road. The ruts can then collect water and cause saturation and softening of the dam. Other ruts may be formed by tractors or other off-road vehicles such as motorbikes are allowed to drive up and down the embankment face; these can direct runoff resulting in severe erosion. Vehicles, except for maintenance, are restricted on the dam top and kept out by fences or barricades. Any ruts shall be repaired as soon as possible.
4.3.7. Masonry / Concrete Dams & Spillways Various issues/problems that may require maintenance/repairs on the
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 cavitations, abrasion, un-symmetrical flows, unfavourable 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.
94
August 2020 O&M Manual of Kallada Dam
For remedial measures of problems of special nature advice of experienced engineers
/Panel of Experts needs to be obtained
4.3.8 Outlet Works The outlet works of Kallada dam consist of one penstock (made of steel) which comes under low hydroelectric project and hence the 3.75m Diameter Penstock is of short length Penstock is divided into four conduits (each 1.5m Diameter), two conduits for irrigation purpose and two conduits for Power generation. Disperser valves are provided at the end of irrigation conduits. Penstock and conduits are fully covered in RCC only the disperser valves are exposed. There are three manholes, one in main penstock and two in irrigation conduits. Inspection, painting, greasing and oiling should be done on disperser valves periodically.
4.3.9 Trash Racks
Trash racks is provided in the u/s in front of penstock pipes. If it becomes clogged with debris or trash reduce their discharging capacity. The head losses through clogged trash racks also increase. Maintenance of trash racks includes periodic inspections for rusted and broken sections and repairs are made as needed.
4.3.10 Gates & Hoisting Equipment The safe and satisfactory operation of Kallada 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. 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.
95
August 2020 O&M Manual of Kallada Dam
Commonly used Gates and Hoists including their inspection / maintenance requirements are discussed below.
4.3.10.1 Vertical lift fixed wheel and Slide Gates These gates are provided in spillways, outlet works, sluices etc. for controlling/regulating the flow. The main components of these gates are as under; i). Embedded parts:
• Sill beam assembly
• Top and side seal seats • Roller track
• Side guide
• Dogging arrangement ii). Gate Parts:
• Skin plate Assembly
• End Verticals • Horizontal girders
• Vertical Stiffeners
• Roller assembly • Seal Assembly
• Side guide assembly
• Lifting Arrangement
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. 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.
96
August 2020 O&M Manual of Kallada Dam
Seals, if found damaged or found leaking excessively should be adjusted, repaired or
replaced as considered necessary. iii. 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.
iv. Hoisting connection of the gate leaf should be lubricated where necessary and
defects if any should be rectified. v. All nuts, bolts, check nuts and cotter pins of the lifting devices should be checked
periodically. vi. All components should be greased and lubricated. Recommended and approved oils
and grease only should be used.
vii. 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. viii. Where filling valves are provided as part of the gate structure, all the nuts, bolts,
check nuts etc. should be tightened. ix. 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. x. 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.
xi. The guide-assemblies, wheel-assemblies and sealing-assemblies shall be cleared off
grit, sand or any other foreign material. xii. The wheel pin shall be coated with corrosion resistant compound. xiii. All nuts and bolts shall be tightened.
4.3.10.2 Radial Gate
The main components of these gates are as under; a) Embedded Parts:
97
August 2020 O&M Manual of Kallada Dam
Common Anchorages (Bonded Anchorages)
• Sill beam Assembly • Wall plate Assembly
• Horizontal Anchor Rods
• Trunnion Girder • Trunnion girder chairs
• Vertical rods
• Thrust block (If tie between trunnion is not used) Independent Anchorages (Unbonded Anchorages)
• Sill beam assembly • Wall plate assembly
• Anchor girders
• Load Anchors / Tie flats • Yoke girders
• Rest plate
• Vertical rods etc. • Thrust block (If tie between trunnion is not used)
(b) Radial Gate Leaf:
Common Anchorages (Bonded Anchorages) • Skin plate
• Side guide and seal assembly
•Vertical stiffeners •Horizontal Girders
• Horizontal Girder Bracings
• Arm Assembly • Trunnion
•Trunnion pin
• Trunnion Bush • Trunnion Bracket • Tie between trunnion and thrust Block Independent Anchorages (Unbonded Anchorages)
98
August 2020 O&M Manual of Kallada Dam
• Lifting Bracket
• Skin plate • Side guide and seal assembly
• Vertical stiffeners
• Horizontal Girders • Horizontal Girder Bracings
• Arm Assembly
• Trunnion • Trunnion pin
• Trunnion Bush • Trunnion Bracket
• Tie between trunnion or Thrust block
The aspects to be inspected and maintained periodically for ensuring proper operation of these gates are as under:
i) Rubber Seals:
• Seals shall be inspected for leakages. Locations of excessive leakages shall
be recorded for taking remedial measures. Weeping or slight flow in localized area will not require immediate remedial measures. However, measures like
tightening of bolts are carried out. Further adjustment is carried out during
annual maintenance. • If leakage is excessive & immediate repair is considered necessary, the stop log gates shall be dropped and seals repaired or replace.
ii) Trunnion block assembly and its anchorages:
• All the nuts and bolts of Trunnion block assembly and its anchorages shall be checked for tightness.
• Check all the welds for soundness and rectify defects.
• Check whether the Yoke girder and thrust block is covered on not. If not, cover it with mild steel plates.
• Cover the trunnion pin with anticorrosive jelly
99
August 2020 O&M Manual of Kallada Dam
• 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 structure
• Check all the welding for soundness and rectify defects. • Check welding between arms and horizontal girders as well as between
latching bracket and skin plate with the help of magnifying glass for
cracks/defects and rectify the defects. • Clean all drain holes including those in end arms and horizontal girders.
• Check all the nuts and bolts and tighten them. Replace damaged ones. • Check upstream face of skin plate for pitting, scaling and corrosion. Scaling may be filled with weld and grinded. Corroded surface shall be cleaned and painted.
iv) Embedded Parts:
• All the sill beams and wall plates shall be inspected for crack, pitting etc. and
defects shall be rectified. • The guide roller pins shall be lubricated. v) General Maintenance:
• Defective welding should be chipped out and it should be re-welded duly following
the relevant codal provision (IS: 10096, Part-3). • Damaged nuts, bolts, rivets, screws etc. should be replaced.
• Any pitting should be filled up by welding and finished by grinding if necessary.
• The gate leaf, exposed embedded metal parts, hoists and hoist supporting structure etc., should be thoroughly cleaned and repainted when required keeping in view the
original painting system adopted and as per the guidelines contained in IS: 14177.
• Trunnion bearing should be greased as and when required. Keeping trunnion bearings in perfect working condition is very important. All other bolted connections
should also be checked up for proper tightness.
100
August 2020 O&M Manual of Kallada Dam
• Bolts and trunnion bearing housing should be tightened wherever required.
• The seals of the gate should be checked for wear and tear and deterioration. These should be adjusted/replaced as and when necessary.
• The wall plates, sill beams shall be checked and repaired if necessary.
• Wire ropes should be properly lubricated. • 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. • The stroke of the brake should be reset to compensate for lining wear. Worn out
brake linings should be replaced in time. • Flexible couplings should be adjusted if required.
• Repairs and replacements of all electrical relays and controls should be attended to.
• Maintenance of alternative sources of Power such as Diesel Generating sets and alter-native drives wherever provided should be carried out.
• The list of essential spare parts to be kept available should be reviewed and updated
periodically. The condition of spares should be checked periodically and protective coating given for use.
4.3.10.3 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;
101
August 2020 O&M Manual of Kallada Dam
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.
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
102
August 2020 O&M Manual of Kallada Dam
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 times (at least three to four) and
observe the following: - Check the limit switches and adjust for design limits.
- The effectiveness and slip of the breaks shall be checked by stopping the gate in
raising and lowering operations. The brakes shall be adjusted if needed. - When the gate is operated, there should not be any noise or chatter in the gears.
Adjust the rope tension of wires if unequal. Check for all gears and pinions for uneven wear and adjust for proper contact. Grease
the gears.
Repaint the hoist components, hoisting platform and its supporting structures as per requirement.
The periodic maintenance of commercial equipment like motors, brakes, thrusts etc.
shall be carried out as per manufacturers operation and maintenance manual.
4.3.10.3.1 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 any wear which may
have occurred during operation.
iv) If the contactor hums, the contact faces should be cleaned. 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.
103
August 2020 O&M Manual of Kallada Dam
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.
WARNING: The complete motor shall never be put in an oven for drying as that may melt the grease out of bearings.
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.
104
August 2020 O&M Manual of Kallada Dam
xxviii) Check air gap.
Solenoid 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.
4.3.10.4 Stop Logs, Lifting Beam and Gantry Crane a) Stop Logs for Spillway Radial Gate Not Applicable. There is no stoplogs, Lifting Beam and Gantry Crane for spillway in
the Kallada dam. b) Lifting Beam Not Applicable. c) Gantry Crane
Not Applicable. 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.
105
August 2020 O&M Manual of Kallada Dam 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: • 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
106
August 2020 O&M Manual of Kallada Dam
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 350 microns. b) Gates:
Primer Coat:
• Over the prepared surface 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 than 350 microns. v) Hoist and supporting structure: a) Structural components:
Primer coats of zinchromate primer shall be applied to give a dry film thickness of 40±5 microns. Final Coats: Two coats of synthetic enamel paint confirming to IS 2932 – 1974to 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 175 microns. b) Machinery: Except machined surfaces all sur-faces of machinery including gearing, housing, shafting, bearing pedestals etc., shall be given:
Primer coats: One coat of zinc chromate 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 consist of two coats of synthetic
107
August 2020 O&M Manual of Kallada Dam enamel paint confirming to IS 2932 – 1977 to give a dry film thickness of 25±5microns 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. 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.
Appendix A – Brushing of paint
Appendix B – Spraying of paint Appendix 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 have 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.
108
August 2020 O&M Manual of Kallada Dam vii) Removal of old paint for repainting:
Caution should be exercised while removing the old paint. The surfaces shall be de-rusted and decaled by either mechanically by one or more of the methods, namely:
a) Wire brushing, Scraping, and chipping. Sand papering or cleaning with steel
wool or abrasive paper b) Power tool cleaning
c) Sand blasting or shot blasting and
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
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 re-painted. d) New Works (Not previously painted): The following shall be decided by inspection: • The method of pre cleaning feasible or recommended;
• The intermediate protective treatments to be applied, if found necessary;
109
August 2020 O&M Manual of Kallada Dam
• 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 a 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 be checked for corrosion and mineral deposits. All necessary repairs should be carried out immediately and records of the 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 of the manufacturer 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
110
August 2020 O&M Manual of Kallada Dam surfaces to avoid binding. As rust is especially damaging to contact surfaces, existing rust is to be removed before periodic application of grease. 4.3.13 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. In Kallada dam, normally a 24x7 hour patrolling is carried out during monsoon period. The materials normally required to be stocked in sufficient quantity are: -
Gunny Bags Sand
Boulders/Wire crates
111
August 2020 O&M Manual of Kallada Dam
Bamboos/Balli‘s
Baskets Ropes
Petromax Lamps with Spares
Torches with spare cells Kerosene Oil
Match Boxes
Rain Coats Gum Boots
Warning sign indicator Danger zone lights
4.5 Establishment Requirements
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 Assistant Engineer level is given at Figure 4-1forguidance. 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 following personals are required for the Annual and Monsoon establishment: Driver with vehicle- 1 No Electrician - 1 No
Data Entry Operator – 1 No
Skilled Worker/ Lascar – 2 No Unskilled worker – 1 No
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).
112
August 2020 O&M Manual of Kallada Dam i) Establishment Cost of Work charged Staff - Salaries and allowances, Bonus, Medical
Reimbursement, LTC, Leave Encashment, Pension benefits, TA and DA, etc. (as applicable). ii) Establishment Cost of Daily wage Staff - Salaries and allowances, TA and DA etc.
(as applicable). iii) Office Expenses – Rent for office, Telephone/Mobile/any other Telecommunication
bills, Electricity bills, water bills, Office stationery, Day to day office requirements. iv) Motor Vehicles - Running and Maintenance cost of inspection vehicles, Cost of hiring of vehicles as required v) Maintenance of Colony - Maintenance of staff quarters, colony roads, Electricity, Sanitary and Water supply systems etc. vi) T&P - T&P requirements for offices, colony, works etc. as applicable. vii) 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)
CURRENT PREVIOUS YEAR SL.NO. BUDGET ITEM YEAR REMARKS BUDGET(YR COST(Rs) )(Rs)
A. ESTABLISHMENT
SALARY OF REGULAR 1
STAFFINCLUDING ALL OTHER BENEFITS
2 TRAVEL EXPENSES
113
August 2020 O&M Manual of Kallada Dam
3 OFFICE EXPENSES
4 MOTOR VEHICLE EXPENSES
5 MAINTENANCE OF OFFICE &COLONY
SUB-TOTAL - A
B. WORKS
1 CIVIL
1.1 CONCRETE / MASONRY DAM
1.2 EARTHEN DAM
INTAKE / OUTLETS INEARTHEN 1.3
DAMS
SLUICES IN CONCRETE / MASONRY 1.4
DAMS
APPROACH /INSPECTIONROADS 1.5 WITHIN DAMAREA
2 HYDRO-MECHANICAL
2.1 SPILLWAY GATES & HOISTS
SPILLWAY STOP-LOG &GANTRY 2.2
CRANE
OUTLETS 2.3 INEARTHENDAMSSERVICE/EME
RGENCY GATES& HOISTS SLUICES 2.4 INCONCRETE/MASONRYDA MS –SERVICE
/EMERGENCY GATES&HOISTS 3 ELECTRICAL
ELECTRICALFITTINGS, 3.1 MOTORS,CONTROLS FOR ALLGATE
HOISTS
3.2 POWER SUPPLY LINES
ELECTRICAL FITTINGS ON DAMTOP, 3.3
DAMGALLERIES,ETC.
STANDBY POWER /DIESEL 3.4
GENERATOR
REMOTE CONTROL/CCTV 3.5
INSTRUMENTATION 4
114
August 2020 O&M Manual of Kallada Dam
MISCELLANEOUS WORKS 5
SALARY OF WORKCHARGED 6 STAFFINCLUDING ALL BENEFITS
MATERIALS TO BESTORED 7 BEFOREMONSOON
SUB-TOTAL - B
CONTINGENCY (10%) ONSUB-TOTALOF 8 A & B
TOOLS & PLANTS 9
SUB-TOTAL- C
TOTAL ANNUAL COST 10
4.7 Maintenance Records
Maintenance records are of utmost importance. A record should be kept of all maintenance activities, both immediate and preventive maintenance works. Information that should be recorded includes the following as a minimum: date and time of maintenance,
weather conditions,
the type of maintenance, name of person or contractor performing maintenance,
description of work performed,
the length of time it took to complete the work with dates,
115
August 2020 O&M Manual of Kallada Dam
equipment and materials used, and before and after photographs
The data should be recorded by the person responsible for maintenance Organaisation Chart
Chief Engineer, IDRB, Thiruvananthapuram Land Line No. e-mail ID:[email protected]
Superintending Engineer, KIP(RB) Circle, Kottarakkara Land line No.0474-2452635 E-mail ID:[email protected]
Executive Engineer, KIP(RB) Division No.II, Kottarakkara Land line No.0474 2452617 e-mail ID: [email protected]
Assistant Executive Engineer KIP(RB) Sub Division No.2, Assistant Executive Engineer Thenmala KIPMechanical Sub Division, E-mail Thenmala ID:parappardam.thenmala E-mail @gmail.com [email protected] A s
s
i Assistant Engineer, Assistant Engineer, s Section 3/2, Thenmala Mechanical Section E-mail ID: ,Thenmala [email protected] E-mail ID
Figure 4. 1 Typical organisation setup chart
116
August 2020 O&M Manual of Kallada Dam
CHAPTER 5. INSTRUMENTATION AND MONITORING
Instrumentation, proper monitoring and evaluation are extremely valuable in determining the performance of a dam. Instrumentation designed for monitoring potential deficiencies at dams must consider the threat to life and property that the dam presents. Thus, the extent and nature of the instrumentation depends not only on the complexity of the dam and the size of the reservoir, but also on the potential for threat to life and property losses downstream. Continued monitoring is important to monitor the efficacy of the remedial works carried out. 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 behaviour. They can show that whether the dam behaviour 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.
5.1 General Instrument types
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; and stress and strains.
5.2 Instrumentation at Kallada Dam
The following instruments are installed at the dam and their status is as under:
117
August 2020 O&M Manual of Kallada Dam
Sl No Instruments Nos Remarks 1 Strain meter 18 (block no:8) Not in working condition
2 Stress meter 3 (block no:8) Not in working condition
3 Pore pressure 3 (block no:8) Not in working condition meters 4 Joint Meters 3 Not in working condition. Embedded in joints of block No. 7&8, 8&9 and 9&10.
5.2.1 Parameters monitored i) Uplift Pressure –No uplift pressure measuring instruments are installed at present ii) Water level –By reading from scale installed iii) Seepage in the foundation gallery by V-Notches provided iv) Any other parameter
5.3 Frequency of Monitoring
Seepage Assessment
In Kallada Dam, there are Porous drains and Foundation Drain Holes. Monthly observations of these holes are being carried out. Seepage is measured using V-notches installed in the foundation gallery.
Seepage details through the gallery as on date is tabulated as below.
Year / Date Reservoir V notch reading Discharge Water Level m (cm) (Litres/min) 07/05/2020 101.10 Audit 1 - 2.8 6.3056 Audit II- 3 7.492 Ch 740- 5 26.897 Ch 780 - 7.2 66.8604
118
August 2020 O&M Manual of Kallada Dam
Any other instrument Nil
5.4 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. Monthly reports are prepared for evaluation.
5.4.1 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 maybe 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.
5.4.2 Data Presentation All data should be summarised in graphical form. All plots should include sufficient previous data to identify any long-term trends. Furthermore, the plots should be self-explanatory.
5.4.3 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. 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.
119
August 2020 O&M Manual of Kallada Dam
5.4.4 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. 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 a 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
5.4.5 Methods of Behaviour Prediction Each dam is a unique structure and has its own special conditions of sitting, design, construction and operation. Rigorous methods of prediction have been developed over the years. These methods apply the laws of physics to solve 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.
5.5 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.
120
August 2020 O&M Manual of Kallada Dam
CHAPTER 6. PREVIOUS REHABILITATION EFFORTS
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 the routine maintenance activities, no other major rehabilitation works were carried before the involvement of DRIP. The following Rehabilitation Works had been carried out under DRIP Phase I
DRIP Phase I includes 11 appendices ie, Appendix A to K
App. A – Road work which includes rectification of different roads to dam top, and gallery etc. and allied works such as construction of drain, providing truffing and benchs, gates etc at dam premises.All works completed
App.B – Drilling and grouting the masonry dam in all blocks except 1,2 and 12
In Dam grouting process (Item No.120 of BOQ) as per detailed estimate and detailed specification, stage grouting was proposed and the re-drilling of drilled and grouted first depth of holes shall be executed after 15 minutes of grouting. The rate of re-drilling was calculated in detailed estimate as 1/3rd of original drilling. In BOQ specification, the word re- drilling was not mentioned but the quantity was included with re-drilling quantity. In 1st part bill, the contractor accepted the method adopted for measuring re drilled holes (1/3rd of original depth) and accepted all the measurements without protest and payment made to the contractor. But in 2nd part bill he had protested in the measurement of drilling. This matter was already reported to higher-ups and in the review meeting, it was decided to take up the matter with Chief Technical Examiner. Accordingly the contractor was directed to stop the drilling and grouting work until further orders. After that he had executed balance work as per the direction of Superintending Engineer.
As per agreement, total number of holes to be drilled and grouted was 139. Out of this, 125 numbers were completed as per the sanctioned estimate. Balance 14 number was
121
August 2020 O&M Manual of Kallada Dam to be completed and Superintending Engineer ordered to execute the balance 14 holes with alternate method. Moreover, work completed.
App. C – Reaming existing face drain holes and drilling new face drain holes from topof dam to drainage gallery. ( at block 3 to 11)
In this appendix, reaming clogged face drain holes are completed.
The consultant of DRIP, M/s. Egis directed to cancel the item for drilling new face drain holes from dam top to gallery vide No.129 of Appendix C. and drilling new face drain holes not executed. The matters were informed to the contractor accordingly.All balance works completed in this appendix.
App.D _ Rectification of Saddle dam at Pallamverry
This appendix includes the rectification of horizontal and vertical drains, damaged DR masonry, Chain link fencing around the dam, and dam top road and approach road to dam top.
All works except approach road to dam top was completed.
Reason for not executing the maintenance of approach roads are as follows.
The total length of the two approach roads to dam top is 235 m. 90% of this road is fully damaged. In the agreement, provision for 24 m3 of pothole filing and 3770m2 chipping carpet was given. Out of this, 24 m3 pothole filling and 1673 m2 chipping carpet were used for the maintenance of dam top road. Balance 2097 m2 chipping carpet is sufficient for the providing chipping carpet of approach road. However, there is no provision for filling potholes of approach roads in the agreement. Hence, the contractor not executed the chipping carpet of the approach roads.
App. F- Epoxy plastering to the ogee portion of spillway.
50 % work completed in this appendix.
The contractor had submitted the programme chart on 5/5/2016 and the Engineer approved it. According to that programme chart, the epoxy plastering over the ogee portion
122
August 2020 O&M Manual of Kallada Dam of the spillway should have been started by 8/8/2016 and should have been completed on
30/6/2017.
Meanwhile, the consultant of DRIP, M/s. Egis visited the site and directed to change the provision in Item No 163 of Appendix E and Item No170 of Appendix F for Epoxy plastering to Ogee portion of Spill way to UV resistant cementitious plastering. Hence direction given to the contractor to hold the execution of epoxy plastering on 29/11/2018, but he informed that he had purchased the material of epoxy plastering and change in material from Epoxy to UV resistant will lead to compensation event. The matter was discussed in the
DRIP review meeting on 09/01/2017 held by the Nodal officer of DRIP and SPMU Director at IDRB and it was directed to execute the Epoxy plastering work as per agreed schedule.
Communications send to the contractor on 11/01/2017. (One and a half month hold).
As per the daily water register, the water level of the reservoir was below the crest level of ogee portion from 22/4/2016 to 15/9/2017. (16.5 months). This time was very favorable to the contractor for executing and completing the epoxy plastering over the ogee portion of the spillway. As per programme chart time required to complete the work of epoxy plastering is 90 days.
Contractor had submitted a revised programme hart on 1/7/2016 and the same was approved by the Engineer. According to that revised programme chart, the epoxy plastering should have started by 2/2017 and should have been completed on 6/2017. Within 151 days. But he had completed only 50 % of this item.
But while spillway shutter opened during November- December 2017, it is seen that some portion of epoxy plastering from ogee portion of spillway was flacked out and become defective. Hence direction given to the contractor for rectifying the same. But the contractor had not rectify the same. Again while opening of dam shutters during August 2018, it is seen that more portion of epoxy plastering were flacked out from ogee portion of spillway.
Again direction given to the contractor for rectifying the same. But he had not rectified.
Appendix F- Rectification of head regulating structure –
123
August 2020 O&M Manual of Kallada Dam
This appendix includes rectification of Shutter supporting pillars, spill way buckets, and epoxy plastering to the ogee portion of spillway. All works completed.
But while spillway shutter opened during November- December 2017, it is seen that some portion of epoxy plastering from ogee portion of spillway was flacked out and become defective. Hence direction given to the contractor for rectifying the same. The contractor had rectified the same on 31/1/2018. Again, while opening of dam shutters during August 2018, it is seen that more portion of epoxy plastering were flacked out from ogee portion of spillway. Again direction given to the contractor for rectifying the same. But he had not rectified till date.
Appendix G- Right flank protection work between reservoir and road near auxiliary spillway for preventing seepage and piping failure.
This appendix includes the protection works to the right side of reservoir using
Gabion boxes. – All works completed.
Appendix H- Tightening security at KIP Campus Thenmala – This appendix includes, Providing fencing, Construction and maintenance of compound walls, gates, etc.- All works completed in this appendix.
Appendix – I - Providing drainage arrangements between the toe of dam, stilling basin and power house.- All works completed.
Appendix – J - Construction of watch- Tower - This appendix includes construction of watchtower and restricted pathway at Nadukanikkunnu at Dam top for watching dam area.
All works except construction of path way completed. Contractor had not executed the same.
Appendix – K - Providing wearing coat to roadway at top of Dam –
All works completed in this appendix.
124
August 2020 O&M Manual of Kallada Dam
PHOTOGRAPHS OF THE REHABILITATION WORKS (Before & After) Before rehabilitation works
Figure 5. 1 App.B- Before grouting Dam body
Figure 5. 2 App. C – Damaged face drain holes
125
August 2020 O&M Manual of Kallada Dam
Figure 5. 3 Appendix – K - Damaged wearing coat to roadway at top of Dam
126
August 2020 O&M Manual of Kallada Dam
Figure 5. 4 App. F - Damaged ogee portion of spillway.
Figure 5. 5 Appendix – I - Damaged drainage arrangements between the toe of
dam,
127
August 2020 O&M Manual of Kallada Dam
Figure 5. 6Appendix G- Right flank portion between reservoir and road near auxiliary
spillway
Figure 5. 7 Damaged road
128
August 2020 O&M Manual of Kallada Dam
Figure 5. 8 App. A – Damaged Roads
After Rehabilitation works
Figure 5. 9 Reservoir left view
129
August 2020 O&M Manual of Kallada Dam
Figure 5. 10Dam top after DRIP 1
Figure 5. 11 Inked providing drainage arangement after drip. toe of dam
Figure 5. 12 LB Head Regulator after rectification of pillars
130
August 2020 O&M Manual of Kallada Dam
Figure 5. 13 Saddle dam after drip work
Figure 5. 14 Side protection after DRIP work
131
August 2020 O&M Manual of Kallada Dam
Figure 5. 15 Watch tower
132
August 2020 O&M Manual of Kallada Dam
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 10 years by the respective Dam Owners.
133
August 2020 O&M Manual of Kallada Dam
ANNEXURE – A (BASIC DRAWINGS)
134
August 2020 O&M Manual of Kallada Dam
135
August 2020 O&M Manual of Kallada Dam
136
August 2020 O&M Manual of Kallada Dam
137
August 2020 O&M Manual of Kallada Dam
138
August 2020 O&M Manual of Kallada Dam
139
August 2020 O&M Manual of Kallada Dam
ANNEXURE –B -- HYDROLOGY REVIEW REPORT
140
August 2020 O&M Manual of Kallada Dam
141
August 2020 O&M Manual of Kallada Dam
142
August 2020 O&M Manual of Kallada Dam
143
August 2020 O&M Manual of Kallada Dam
144
August 2020 O&M Manual of Kallada Dam
145
August 2020 O&M Manual of Kallada Dam
146
August 2020 O&M Manual of Kallada Dam
147
August 2020 O&M Manual of Kallada Dam
148
August 2020 O&M Manual of Kallada Dam
149
August 2020 O&M Manual of Kallada Dam
150
August 2020 O&M Manual of Kallada Dam
151
August 2020 O&M Manual of Kallada Dam
152
August 2020 O&M Manual of Kallada Dam
153
August 2020 O&M Manual of Kallada Dam
154
August 2020 O&M Manual of Kallada Dam
ANNEXURE – C --- GATE MANUFACTURER’S MANUAL –
NOT AVAILABLE
ANNEXURE – D – CHECK LIST FOR INSPECTION
Authority Name, Title, Phone
Name: Sri Sivasankarapillai Title : Assistant Engineer Mobile No: 7902205621 Office Ph: 0475-2344532 Email: [email protected]
Name: Sri. Satheesan Title : Overseer Dam Operator/Site Mobile No. 9447993123 officials Office Ph: 0475-2344532
Email: [email protected]
Name: Smt. Litty Augustine Title :AssistantExecutive Engineer, KIP (RB) Sub division No.II, Thenmala. Mobile No:9746676411 Office Ph: 0475-2344532 Email: [email protected] [email protected] Name: Sri Tessymon .K.K
Title : Executive Engineer, KIP (RB) Division
No.II, Kottarakkara Emergency Planning Mobile No: 9847524381 Manager Office Ph: 0474 2452617 Email: [email protected]
155
August 2020 O&M Manual of Kallada Dam
Name: Sri.Alex Varghese
Title : Chief Engineer, Projects II, Tvpm
Mobile No: 9447739670 Kerala Water Office Ph: 0471 Resources Email: [email protected] Department Name: Sri Vinod Mohan(full addl. Charge) Title : Superintending Engineer, KIP (RB) Circle, Kottarakkara. Mobile No: 9447023352 Office Ph: 0474 2452635 Email: [email protected] Name: Sri. Joshy K.A. Kerala Dam Safety Organisation Title : Chief Engineer, IDRB, Tvpm Mobile No: Office Ph: 0471-2306159, 0471- 2784001 Email: [email protected] Name: Sri.Biju .D Title: Director (Designs), IDRB, Tvm. Mobile No: Office Ph: 0471-2303972Email: [email protected]
156
August 2020 O&M Manual of Kallada Dam
ANNEXURE – E -- LATEST DSRP REPORT
157
August 2020 O&M Manual of Kallada Dam
ANNEXURE – F --- INSPECTION REPORT (PRE & POST
MONSOON)
KALLADA IRRIGATION PROJECT PRE - MONSOON REPORT Inspection date :07/05/2020, Water level -+101. 10m , Live storage- 204.40Mm3
Concrete/Masonry Dam Checklist
Response Observations and Sl Recommendati Condition N Inspection Item ons, if any, of (Unsatisfactory/Poor/Fair/S o the authorized atisfactory) inspecting Y N NA officer
A-Reservoir
A-1.1 General Condition
Is the reservoir water 1.1.1 level unusually high or N low?
Are there signs of decline 1.1.2 in water quality? N
While opening disperser valve Are there signs of recent 1.1.3 after flood, sediment deposition? Y presence of silt are seen.
Floating bodies are seen in the U/s of 1.1.4 Is floating debris present? Y reservoir and are removed.
158
August 2020 O&M Manual of Kallada Dam
Any indications of major active or inactive landslide 1.1.5 area in the reservoir rim? N If so, indicate their locations and extent.
Are there people or 1.1.6 livestock in and around N reservoir?
1.1.7 Any other issues? N
B2 Dam and Dam Block/Reach (Concrete/Masonry)
B2.1 General Condition
Any major alterations or 2.1.1 changes to the dam since N the last inspection?
Is there any new nearby 2.1.2 development in the N downstream floodplain?
Any misalignment of 2.1.3 poles, fencing or walls N due to dam movement?
B2.2 Upstream Face
Evidence of surface 2.2.1 defects (honeycombing, N staining, stratification)?
Concrete/masonry 2.2.2 deterioration (spalling, N leaching, disintegration)?
Is cracking present 2.2.3 (structural, thermal, along N joints)?
Evidence of differential settlement 2.2.4 (displaced/offset/open N joints)?
Presence of vegetation 2.2.5 (growth in joints between N blocks)?
159
August 2020 O&M Manual of Kallada Dam
Evidence of any other 2.2.6 damage to joints and/or N water stops?
2.2.7 Any other issues? N
B2.3 Crest of Dam Evidence of differential settlement 2.3.1 (displaced/offset/open N joints)? Presence of cracking Cracks are found 2.3.2 (structural, thermal, along Y in U/s of crests joints)?
Profuse growth of 2.3.3 weeds/grass/plants at any N location?
Any degradation to access 2.3.4 road? N
Any degradation to 2.3.5 upstream parapet or N downstream curb wall?
2.3.6 Any other issues? N
B2.4 Downstream Face
Rectification to the damaged pointing Evidence of surface and cement 2.4.1 defects (honey-combing, Y washing is staining, stratification)? proposed in phase II
Concrete/masonry 2.4.2 deterioration (spalling, N leaching, disintegration)?
Presence of cracking 2.4.3 (structural, thermal, along N joints)? Evidence of differential settlement 2.4.4 N (displaced/offset/open joints)?
Presence of vegetation Being removed 2.4.5 (growth in joints between N periodically blocks)?
Evidence of any other 2.4.6 damage to joints and/or N water stops?
160
August 2020 O&M Manual of Kallada Dam
Excessive seepage/sweating at any 2.4.7 N location on downstream face? Significant leakage at any 2.4.8 location on downstream N face?
2.4.9 Any other issues? N
B2.5 Abutment Contacts
Any presence of leaks, 2.5.1 springs or wet spots in N vicinity of abutment?
Any presence of cracking 2.5.2 N or settlement?
Profuse growth of 2.5.3 weeds/grass/plants at any N location?
2.5.4 Any other issues? N
D Gallery/Shaft and Drainage
D-1.1 General Condition
Slushy condition or water 1.1.1 logging immediately downstream of dam? N
Any evidence of boiling 1.1.2 in vicinity of dam toe? N D-1.2 Gallery/Shaft Condition
Any problems accessing 1.2.1 or inspecting gallery/shaft N (obstruction)?
Any safety issues 1.2.2 (inadequate handrails, lighting or ventilation)? N
Problems of inadequate drainage (slippery stairs, 1.2.3 water logging of gallery, clogged porous or foundation drains)? N
161
August 2020 O&M Manual of Kallada Dam
Evidence of differential settlement 1.2.4 (displaced/offset/open joints)? N Excessive seepage/sweating at any 1.2.5 location along gallery/shaft? N
Significant or excessive leakage at any location 1.2.6 along gallery/shaft / porous drain? If yes, provide location(s). N
Are proper arrangements made for the 1.2.7 V notches are measurement of seepage provided Audit 1 into the gallery? &2, Ch. 740m and Y 780m
Is the seepage measured separately from Porous 1.2.8 pipes, Foundation drains and Monolith Joints? N
Are the above 1.2.9. arrangements satisfactory? Y
Has there been substantial 18 No Vertical progressive reduction in drains fully the seepage through the chocked and 72 foundations? Indicate if it 1.2.10. is due to choking of the Y Nos partially drain holes and if so, chocked. indicate the number of Proposed in phase choked holes. II
Are all the foundation and porous holes periodically cleaned with During 2009 ( reaming tool and air water New estimate jetting? Indicate the last submitted to Dam 1.2.11. N date of such cleaning and safety) Reaming is extent of variation proposed in phase observed in the seepage II discharge before and after the cleaning.
162
August 2020 O&M Manual of Kallada Dam
Is the seepage water and the deposit, if any, from the seepage being regularly examined for 1.2.12 N chemical composition? If so, indicate the result and the probable source of dissolved salts, if any.
Are any seepage water springs observed in the downstream area any where? If so, indicate the locations and state the physical nature of this seepage. Look out for 1.2.13. N such seepage spots particularly near the dykes, fault zone etc. Ascertain if chemical testings are made of water samples from such springs for dissolved salts.
Is there any leachate found in 1.2.14 deposition? If yes provide Y foundation gallery location of Block 8
1.2.15 Any other issues? N D-1.3 Drain Condition
Is the flow in the drain 1.3.1 N unusually high or low?
Presence of calcium or 1.3.2 other deposits in drain? Y work tendered Is the dewatering 1.3.3 pumping station fully Y operational?
Any problem inspecting 1.3.4 the pump? N
Any obstruction 1.3.5 preventing or impairing smooth operation? N
163
August 2020 O&M Manual of Kallada Dam
Any deterioration of 1.3.6 pump and associated equipment? N
Is the sump well clean 1.3.7 and maintained? Y Is the V-notch before 1.3.8 sump well cleaned and maintained? Y
Any other evidence of the drain being 1.3.9 blocked/having reduced section? N
Is the flow in the drain 1.3.10 noticeably sporadic/irregular? N Does the drainage water 1.3.11 have unusual color (leachate)? N
1.3.12 Any other issues? N D-1.4 Body Wall (Masonry/Concrete) of ‘NOF’ Dam
What is the total seepage into gallery from the porous pipes in the dam at lake full condition? 1.4.1 Compare it with the seepage when the The seepage reservoir was first filled. during lake full (For the corresponding condition on water level) 17/8/2018, is 136.38 lit/m.
Drip work was executed prior to 17/8/2018. Has there been substantial Seepage before reduction in this seepage? grouting at water 1.4.2 Ascertain and indicate the Y probable reasons level +114.70m is therefore. 621.75lit/m and after grouting at same level is 137.11 lit/m
164
August 2020 O&M Manual of Kallada Dam
Has there been a tendency for gradual reduction of drainage through pipes and 1.4.3 N progressive appearance of sweating on the downstream face of the dam?
Has there been considerable leaching from the seepage water 1.4.4 and deposition of lime N near the seepage exit spots?
Are the samples of the seepage water and reservoir water being 1.4.5 regularly tested for N reactive and corrosive properties?
Is there excessive seepage, sweating at any locations on the downstream face of the 1.4.6 dam? ( Examine the N monolith or construction joints for such seepage and leaching and indicate the findings)
Is there any swelling or cracking observed on the downstream face especially near the points of concentration of 1.4.7 stresses like the toe or N locations of abrupt change in geometry of the face of the opening? If so, indicate the details of observations.
165
August 2020 O&M Manual of Kallada Dam
Is the pointing on upstream face of the dam 1.4.8 in good condition? If not, Y indicate the nature and extent of deficiency.
Are the registers and graphs showing the periodical measurements of seepage discharge from Registers and 1.4.9 the porous drains in the graphs are gallery and from the maintaining downstream face at various lake levels maintained at site?
Y
E Spillway and Energy Dissipation Structure
E 1.1 Spillway
Any problems inspecting 1.1.1 spillway (obstructed Y Hand rails are not access, damaged catwalk)? provided in catwalk bridge
Any obstructions in or 1.1.2 immediately downstream Y of the spillway? Work arranged for epoxy plastering
Evidence of abrasion, cavitation or scour on 1.1.3 glacis (e.g. exposed reinforcement)? N
Presence of displaced, 1.1.4 offset or open joints? N Presence of cracking 1.1.5 (structural, thermal, along joints)? N
Evidence of surface 1.1.6 defects (honeycombing, staining, stratification)? Y
166
August 2020 O&M Manual of Kallada Dam
Concrete/masonry 1.1.7 deterioration (spalling, leaching, disintegration)? N Presence of vegetation 1.1.8 (growth in joints between blocks)? N Evidence of any other 1.1.9 damage to joints and/or waterstops? N Excessive seepage/sweating at any 1.1.10 location on spillway glacis? N Significant leakage at any 1.1.11 location on spillway glacis? N 1.1.12 Any other issues? N
E 1.2 Waste Weir Bar and Tail Channel
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 1.2.1 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?
NA Is the coping over the 1.2.2 spillway bar in good condition? NA
Does the upstream and 1.2.3 downstream face of waste weir bar need pointing? NA
167
August 2020 O&M Manual of Kallada Dam
Is there any scouring on downstream side of the 1.2.4 bar and/or EDA? If so what remedial measures are proposed/taken?
NA
Are there any damages or undermining to guide walls, divide wall and 1.2.5 other appurtenants? If so, indicate what remedial measures are proposed/taken. NA
Structural performance of the ‘NOF’ and ‘OF’ Portions of E 1.3 Dam Foundations
Are there any signs of structural distress noticed 1.3.1 in the dam spillway and foundations in the form of-
i. Excessive deflection with respect to
permissible deflection at the time of design N ii. Tendency of gradual
sliding N
iii. Cracking and upheaval or settlement in
any part of the body wall or foundations, N iv. Excessive uplift, N v. Excessive seepage and leaching through the body
of the dam and the foundation. N
Conspicuous weathering of materials or 1.3.2 components in any portion of the body wall or the foundations. N
168
August 2020 O&M Manual of Kallada Dam
E-1.4 Energy Dissipation Structure
Any problems inspecting 1.4.1 energy dissipation structure? N
Any obstructions in or 1.4.2 immediately downstream of dissipation structure? N
Evidence of abrasion, 1.4.3 cavitation or scour on dissipation structure? N
Presence of displaced, 1.4.4 offset or open joints? N
Presence of cracking 1.4.5 (structural, thermal, along joints)? N
Evidence of surface 1.4.6 defects (honeycombing, staining, stratification)?
N
Concrete/masonry 1.4.7 deterioration (spalling, leaching, disintegration)? N Presence of vegetation 1.4.8 (growth in joints between blocks)? N
Evidence of any other 1.4.9 damage to joints? N
Any problems with 1.4.10 under-drainage (blockage of open drain holes)? N
169
August 2020 O&M Manual of Kallada Dam
Can the tail pond be drained easily for inspection of the stilling basin or bucket? If not, Last de-watering indicate the alternatives 1.4.11 available for dewatering. N done during Please ascertain and 5/2015 indicate the last event of inspection of stilling basin (or bucket).
From the examination of the levels and contour plans and reference marks in tail channel; is there progressive erosion and retrogression in the tail 1.4.12 channel? If so, indicate the extent and location of such erosion with reference to the various components of dam, spillway, outlet, power house etc.
N
Is the concrete surface of the stilling basin and 1.4.13 apron (or bucket) in good condition? Y
Are there any indications of pitting, cracking, spalling or wearing of the 1.4.14 surface of bedding concrete? If so, please give details of the nature and extent of the damage. N
170
August 2020 O&M Manual of Kallada Dam
Is there any indication of abrasion and cavitation damage (pitting of concrete) especially at friction blocks , chute blocks and 1.4.15 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.
N
Is the under drainage of the stilling basin (or bucket) satisfactory? Are 1.4.16 all the open drain holes Y clear and functioning well?
1.4.17 Any other issues? N
Walls: Guide walls/Divide walls/Junction walls/Return G-1.5 walls/Spray walls etc.
Are all the locations of such wall accessible for 1.5.1 inspection, maintenance and repairs? Y
Is the drainage of back sides of the walls (wherever applicable) 1.5.2 from the weep holes satisfactory? If not, indicate the nature of deficiencies. Y
Is there any tendency for 1.5.3 the water to undercut the ends of the walls? N
Is there any foundation erosion or scour noticed in the vicinity of such 1.5.4 walls? If so, give the details of nature and extent of such damage. N
171
August 2020 O&M Manual of Kallada Dam
Is there any surface erosion/damage caused, 1.5.5 to face or body of such walls? N
Do any of the walls show symptoms of unusual settlement, developments 1.5.6 of cracks and tilting? If so, give details of the defects noticed.
N
Is there any damage to 1.5.7 guide bunds? If so, give details of the damage. N G-1.6 End Weir
1.6.1 Is it accessible? NA
Is there any erosion, pitting or spalling of 1.6.2 the concrete or masonry surface? If so, give details NA
Is there any scour noticed on the immediate downstream of such weir? 1.6.3 If so, give details of location and extent of such damage. NA
G-1.7 Hydraulic Performance of Energy Dissipation Arrangements
Do the flow conditions in the stilling basin (or bucket) have a tendency to draw material into the 1.7.1 bucket and cause its churning and abrasion damage to the surface of buckets baffle blocks, apron and end sill?
N
172
August 2020 O&M Manual of Kallada Dam
Is the hydraulic performance in agreement 1.7.2 with the results of model studies? (wherever applicable) Y
Ascertain the performance from observed tail water rating curves and deficient observation, if any, such 1.7.3 as sweep outs and excessive erosion under plunge pools and locations of secondary rollers and retrogression.
N F Intake/Outlet and Water Conveyance Structure
F-1.1 Intake/Outlet Structure
Any problems inspecting intake/outlet structure 1.1.1 (obstructed/unsafe access)? N
Any obstructions in, 1.1.2 upstream or downstream of intake/outlet structure? N
Evidence of abrasion, 1.1.3 cavitation or scour on intake/outlet structure? N
Any evidence of structural distress 1.1.4 (displaced/offset/open joints, cracking)? N Any evidence of surface defects and/or 1.1.5 concrete/masonry deterioration? N 1.1.6 Any other issues? N F-1.2 Water Conveyance Structure
173
August 2020 O&M Manual of Kallada Dam
Any problems inspecting intake/outlet structure 1.2.1 (obstructed/unsafe access)? N
Any obstructions in, upstream or downstream 1.2.2 of water conveyance structure? N Evidence of abrasion, 1.2.3 cavitation or scour on structure? N
Any evidence of structural distress 1.2.4 (displaced/offset/open joints, cracking)? N
Any evidence of surface 1.2.5 defects and/or material deterioration? N
Any evidence of seepage 1.2.6 or leakage from water conveyance structure? N
1.2.7 Any other issues? N G-1 Hydro-Mechanical Component and Pump
Spillway Gates (Radial gates, Vertical lift gates, Automatic G-1.1 gates)
Any problems inspecting gate/Stop-logs 1.1.1 (obstructed/unsafe access)? Stop logs non- Y operational
Is the condition of the steel surface and the 1.1.2 surface paint U/s surface of deteriorated? radial gate Y corroided
Are any connection bolts of rubber seals loosened 1.1.3 or damaged? If so, indicate the details of defects. N
174
August 2020 O&M Manual of Kallada Dam
Do any of the rubber seals show signs of 1.1.4 weathering, hardening, cracking or tearing and damage? N
Are the rubber seals of side and bottom touching 1.1.5 uniformly all along the sealing surface? Y
Do the rollers (wherever applicable) touch the 1.1.6 track plates uniformly? Are the rollers well lubricated? Y
Are the embeded parts of spillway gates, emergency gates and stop-logs in sound condition and free from corrosion, uneven 1.1.7 wear, cracking, chipping and dents? If not, state the nature of defects or deficiencies and observation, if any, regarding such defects.
Y
Are the following members and welded, bolted and riveted connections structually sound? If not, please give 1.1.8 details of any uneven wear, uneven bearing, cracking, chipping and dents and indicate the findings:
(1) Gate leaf and
stiffeners Y
(2) End arms Y (3) Trunnion
girders / Yoke girder Y
(4) Stop logs NA Non- operational
(5) Lifting beams NA
(6) Gantry cranes NA
175
August 2020 O&M Manual of Kallada Dam
(7) Tracks Y (8) Trunnion
bracket Y (9) Chains/ wire
ropes Y
(10) Bridge structure Y
Are the trunnion bearings 1.1.9 of radial gates properly lubricated? Y
Is there any damage or wear caused to the seal 1.1.10 plates? If so, indicate the nature of damage noticed.
N
Are any of the mechanical or structural components and fastners or seals 1.1.11 subjected to excessive wear? If so, please give details. N
Is there any tendency for recurring damage to any 1.1.12 particular component? If so, please give details. N
Is sufficient stock of spares which need 1.1.13 frequent replacement maintained at the site? N
Any issues with storage of equipment (emergency 1.1.14 stop logs, lifting beam and gate leaves)? Stop logs Non- NA operational
Any deterioration, corrosion? scaling? 1.1.15 pitting? or cracking? of equipment (connecting bolts, welds?) N
Any obstructions 1.1.16 preventing or impairing smooth operation? N
176
August 2020 O&M Manual of Kallada Dam
Any problems with the rollers (not touching 1.1.17 tracks, inadequate lubrification)? N
Any debris, etc., in the 1.1.18 gate grooves? N
Any damages to Radial 1.1.19 Gate trunion pins? gate arms? lubrication? etc.? N
Any damage to embedded 1.1.20 parts above waterline? access structure? N Any damage to concrete 1.1.21 grooves? N
Is the staff posted at the site for maintenance and operation of gates, hoists, equipments and electrical 1.1.22 installations, well Y experienced, fully trained and conversant with the job requirements and responsibilities?
Are the following documents maintained at 1.1.23 the respective location of all the units?
(1) Maintenance schedules specifying each operation, its frequency and ‘due’ and’ done’ dates. N
(2) Operating instructions with ‘dos’
and ‘don’t’ for all operational units. N
177
August 2020 O&M Manual of Kallada Dam
Are the trunnion hub and 1.1.24 the brackets well maintained? Y
Are the trunnions likely to get submerged during actual working of the spillway? if so, ascertain 1.1.25 the causes for the same and specify. Please enquire for occurrence of such events, if any.
N Are all the nuts of connecting bolts and 1.1.26 anchorages properly tightened? Y
1.1.27 Any other issues? N G-1.2 Hoists, Cranes and Operating Mechanisms
Are the hoists working 1.2.1 satisfactorily? Y
Any problems inspecting 1.2.2 hoist/crane/operating mechanism? N
Is sufficient stock of spares which need 1.2.3 frequent replacement maintained at the site? N
Is the full length of the chains or wire rope of the 1.2.4 hoist in sound condition and free from broken strands? N
Is the electrical wiring in 1.2.5 sound condition? N
Is the alternative power 1.2.6 system for gate operation working properly? Y
178
August 2020 O&M Manual of Kallada Dam
Is the alternate hand 1.2.7 operation system of hoist working properly? Y
Any deterioration of equipment (connecting 1.2.8 bolts, welds, surface, paint work?) N Any wear or damage to 1.2.9 wire cables and other Wire cables moving parts? Y deteriorated
Any obstructions 1.2.10 preventing or impairing smooth operation? N
Any health and safety concerns (e.g. lack of 1.2.11 "danger" sign during maintenance)? N
1.2.12 Any other issues? N Spillway Bridge, Hoist Bridge, Trunnion Level Bridge G 1.3. Catwalks
Are the decking, girders and structural supports of spillway bridge, hoist 1.3.1 bridge, trunnion level bridge and catwalks structurally sound? Y
Is the chequered platform 1.3.2 of the bridge structurally sound and safe? Y
Is there satisfactory arrangement to prevent 1.3.3 unauthorized entry into the control structures and bridges? Y
Are the structural members and joints 1.3.4 sound and free from corrosion? Y
179
August 2020 O&M Manual of Kallada Dam
When were the steel 1.3.5 components painted last? During 2017 Is the surface of steel 1.3.6 work and paints satisfactory? Y
Is the parapet or railing 1.3.7 over the bridges sound, safe and painted? Y
Is the walkway properly 1.3.8 anchored to the piers? Y Are the track rails for 1.3.9 gantry cranes structurally sound and intact? NA
G-1.4 Valves
Any problems inspecting 1.4.1 valve? N Any obstructions 1.4.2 preventing or impairing smooth operation? N
Any deterioration of valve 1.4.3 and associated equipment? N
1.4.4 Any other issues? N G-1.8 Trash Racks
Is the trash rack fixed or 1.5.1 movable? Fixed What is the mode of 1.5.2 cleaning? Is it manual or by TRCM? Not manual Is the welding work on 1.5.3 Trash Rack in sound health? N
Any problems inspecting 1.5.4 trash rack? N
180
August 2020 O&M Manual of Kallada Dam
Problems of excessive 1.5.5 debris and/or inadequate cleaning? Y Excessive Debris
Any deterioration of trash 1.5.6 rack (rust, corrosion, and damaged blades)? y Partially corroded
1.5.7 Any other issues? N G-1.9 Trash Rack Cleaning Machines
Any problems inspecting 1.6.1 trash rack cleaning machine? NA
Missing or inadequate spare parts (particularly 1.6.2 requiring regular replacement)? NA
Any deterioration of equipment (wheel trolleys, gantry structures, 1.6.3 operating mechanism, connecting bolts, welds, surface, paint work?) NA
Any wear or damage to 1.6.4 wire cables and other moving parts? NA Any obstructions 1.6.5 preventing or impairing smooth operation? NA
Missing or inadequate provision of back- 1.6.6 up/standby power supply? NA
Any health and safety concerns (e.g. lack of 1.6.7 "danger" sign during maintenance)? NA 1.6.8 Any other issues? NA G-1.10 Pumps Any problems inspecting 1.7.1 pump? N
181
August 2020 O&M Manual of Kallada Dam
Any obstructions 1.7.2 preventing or impairing smooth operation? N
Any deterioration of 1.7.3 pump and associated equipment? N 1.7.4 Any other issues? N G-1.11 Approach bridge, operation platform and cabin (for outlets):
Are the decking, girders and structural supports of 1.8.1 approach bridge structurally sound? Y
Is the floor of the operating platform 1.8.2 Supporting structurally sound and concrete pillars safe? are structurly not N so safe
Is there satisfactory arrangement to prevent 1.8.3 unauthorized entry into the control structures of the outlet? Y
Are the structural members and joints 1.8.4 sound and free from corrosion? Y
When were the steel 1.8.5 components painted last? Y 2017
Is the surface of steel 1.8.6 work and paint satisfactory? Y
Is the parapet or railing over the control tower, 1.8.7 operating platform and approach bridge sound and safe? Y G-1.12 Outlet
Is the air vent periodically 1.9.1 cleaned? Y
182
August 2020 O&M Manual of Kallada Dam
Are there any structural 1.9.2 damages to the intake well? NA
Is there any leakage observed through the well proper and the conduit 1.9.3 concrete or masonry? If so, give details of its location and extent. NA
Is there any damage noticed to the conduit 1.9.4 concrete, breast wall and gate slots? NA
Is the bye-pass valve/filling-in-valve 1.9.5 (wherever provided) operating satisfactory? NA
Take operation trials of the following as provided and record the observations and defects noticed, if any.
(1) Service gate(s). Y (2) Emergency gate(s). Y (3) Stop-log gate(s). NA (4) Sluice valves. Y Note-
183
August 2020 O&M Manual of Kallada Dam
(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.
Are there vibrations and noise noticed in operation of out- let gates at any 1.9.6 time? If so, please indicate if periodical observations have been taken to ascertain their severity.
N
Is the energy dissipation arrangement working 1.9.7 satisfactorily for all the discharges? Y
Is there any structural damage to the energy 1.9.8 dissipation structure? If so, give details of nature and extent of damage. N
184
August 2020 O&M Manual of Kallada Dam
Is the conduit structurally sound and reasonably leak 1.9.9 proof? If not, give details of nature and extent of the defects. N
Is there any seepage noticed around the conduit as ascertained from the observations of 1.9.10 the downstream conditions? If so, please indicate if it is likely to cause erosion and piping (In case of earth dams).
N G-1.13 Outlet Gates
Is the surface of gates and 1.10.1 U/s surface of the paint deteriorated? radial gate Y corroded
Are the connecting bolts 1.10.2 of rubber seals properly tightened or damaged? Y
Do the rubber seals show signs of weathering and 1.10.3 damage and need replacements? N
Are the rubber seals of sides and bottom 1.10.4 touching the bearing surface uniformly? Y
Do all the rollers touch 1.10.5 the track plates? NA No rollers Are the rollers well 1.10.6 lubricated? NA Are the stem rods for 1.10.7 lifting the gates perfectly straight? NA
Is the operation of outlet 1.10.8 gates smooth? Y
185
August 2020 O&M Manual of Kallada Dam
Are the actual operations of lifting and lowering of 1.10.9 the gates and hoist mechanisms adequate and smooth? Y Are all the gears and hoist 1.10.10 mechanisms well lubricated? Y
Is the storing arrangement for 1.10.11 emergency gate leaves and the stop logs in satisfactory condition? N
Are the seal plates/seats 1.10.12 in sound condition? Y
Is the full length of wire rope (wherever applicable) of the hoist in 1.10.13 serviceable condition and free from any broken strands? Y
Are all the nuts of connecting bolt and 1.10.14 anchors properly tightened? Y
Are all the lifting beams in proper working order and in levelled condition? 1.10.15 If not, ascertain the nature and extent of problems. NA
Do any of the mechanical or structural parts of the gate, fasteners of hoist 1.10.16 show signs of excessive wear? If so, please give details.
N
Is there any tendency for recurring damage to any 1.10.17 particular component or components? If so, please Cover plate of give details. rubber seal and Y bottom will rise
186
August 2020 O&M Manual of Kallada Dam
Is sufficient stock of spares, which need 1.10.18 frequent replacement, maintained at the site? N
G-1.14 River Outlet/River Sluice
Is the overall condition of 1.11.1 river outlet works/river sluices satisfactory? NA
Is the operation of the gate (Service/Emergency/Sto p-log) satisfactory as 1.11.2 ascertained by taking operating trial? If not, indicate the defects noticed. Operation is not smooth
Are the trash racks (wherever provided) 1.11.3 cleaned before monsoon?
Is there excessive silting 1.11.4 on the upstream of the sluice?
When were the gates last 1.11.5 opened for desilting, etc.?
Please indicate the approximate quantity of 1.11.6 the leakage through the gates, if any. N Is there any seepage or 1.11.7 leakage through the conduit surface? N
Is there any damage to the upstream and 1.11.8 downstream convergence of the conduit? N
187
August 2020 O&M Manual of Kallada Dam
Is the condition of energy dissipation arrangement 1.11.9 satisfactory? If not, indicate nature and extent of damage. N
Is there any retrogression noticed in the 1.11.10 downstream channel? If so, give details of nature and extent of damage.
H-1 Access Road
H-1.1 General Condition
Any problems ensuring security of dam site 1.1.1 (including gates and fencing)? N Is there a properly constructed and well 1.1.2 maintained all weather Y access road to the dam site?
What is the type of the 1.1.3 pavement of the access Bitumen , Good road and its condition? condition
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 Approach road to arrangement Drainage Saddle dam is 1.1.4 gallery, adits and exits damaged . Work Bridge structure arranged Downstream stilling basin Junction and abutments Outet control tower Outlet gates Toe of earth dam, downstream drainage arrangements and berms. All saddle dams.
Y
188
August 2020 O&M Manual of Kallada Dam
Are all the masonry structures on various 1.1.5 access roads in good condition? Y Are all the structures on the access roads adequately safe for 1.1.6 allowing passage of plant machinery for emergent repairs? Y
Any obstructions along or 1.1.7 at entrance to access road (temporary or long-term)? N Any slope stability issues 1.1.8 (road embankment or adjacent slopes)? N Profuse growth of 1.1.9 weeds/grass on or in vicinity of access road? N
Any drainage problems 1.1.10 (standing water on or adjacent to road)? N Any other degradation to road surface (ruts, 1.1.11 potholes, cavities, cracking)? N
1.1.12 Any other issues? N I-1 Instrumentation
I-1.1 General Condition
Are all the instruments 1.1.1 installed accessible? (Attach separate list). N
Are all the locations properly lighted, 1.1.2 ventilated and adequately protected from possibilities of damage? N
189
August 2020 O&M Manual of Kallada Dam
Any problems inspecting instrument 1.1.3 (obstructed/unsafe access)? N
Is the instrument vulnerable to damage or 1.1.4 theft (inadequate protection)? N
Any problems ensuring correct functioning of 1.1.5 instrument (lighting, ventilation)? NA
Any evidence of degradation to condition 1.1.6 of instrument (rusting, vandalism)? N
Are all the instruments in working order? Ascertain 1.1.7 the cases of instruments going out of order and indicate. NA
Are all the registers of observations posted up- 1.1.8 to-date? Please take test observations and initial the register. NA
Are all the plotting of the 1.1.9 instrumentation data completed up-to-date? NA
Are sufficient stocks of spares, gauges, master gauges, stationary items 1.1.10 etc., maintained at the site for uninterrupted data collection? NA Operator or public safety 1.1.11 issues? 1.1.12 Any other issues? N I-1.2 Communication Facilities
190
August 2020 O&M Manual of Kallada Dam
Are following facilities Satellite phone is available at dam site? provided and in 1.2.1 (1) Wireless good working Telephone / condition. mobile/Fax/Internet Wireless set N unserviceable Any other issue (please 1.2.2 indicate part, location, etc., as necessary) y K-1 Emergency Preparedness
K-1.1. Emergency Action Plan
Is the Emergency Action Plan (EAP) prepared for the dam as per the 1.1.1 national guidelines? If not, the expected date of preparation of guidelines Y When EAP was last 1.1.2 updated?
If not, are any dam staff 1.1.3 unaware or insufficiently conversant with the EAP? N Any concerned authorities unaware or 1.1.4 insufficiently conversant with the EAP? N
Are communication directories/contact details 1.1.5 and other dynamic information are being updated annually?
NA
Any problems accessing or operating the 1.1.6 communication/ warning system? NA Are inundation maps 1.1.7 updated and available to EAP recently concerned authorities? submitted
191
August 2020 O&M Manual of Kallada Dam
Are the concerned authorities informed 1.1.8 about the system of emergency reporting procedures and warning? EAP recently submitted
Are available safety spots on the downstream of the 1.1.9 dam identified and made known to the concerned authorities? EAP recently submitted
Are adequate warning 1.1.10 devices and facilities provided at the dam? EAP recently submitted
Are proper arrangements made for security of the dam and preventing cases 1.1.11 of unauthorized trespass, vandalism and sabotage to the dam works? EAP recently submitted
Date of last annual stakeholder consultation 1.1.12 meeting along with mock drill exercise conducted
Has the EAP been 1.1.13 disseminated to all the concerned stakeholders? N 1.1.14 Any other issues? N K-1.2 Inspection of Records
Have the following Dam Safety Documents been 1.2.1 prepared and approved by the competent authority?
I. As Built
Drawings N II. EAP Y III. Completion
Report N IV. Data Book N
192
August 2020 O&M Manual of Kallada Dam
V. O and M manual Y submitted Are the relevant documents reviewed and 1.2.2 updated from time to time? NA
Are all the members of the maintenance staff adequately trained and 1.2.3 fully conversant with their responsibilities concerning.
(a) Designer’s
Operation Criteria. Y (b)Standing Operating
Procedures. Y (c) Maintenance and Vigilance Procedures of the dam. Y (d) Maintenance and operation of all control equipments. Y
(e) Reservoir Operation Schedules, Gate Operation Schedule Y (f) Maintenance and Operation of all instruments. Y (g) Identification of signs of deficient behavior. Y (h) Reporting Procedures of emergency situations. Y (i) Emergency repairs Y L-1.1 Inspection Photographs
Communication 1.1.1 Facilities
193
August 2020 O&M Manual of Kallada Dam
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 Larji dam incident (8 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
194
August 2020 O&M Manual of Kallada Dam of spillway gates and other outlet gates keeping in perspective the 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 close 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 fool proof 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 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.
195
August 2020 O&M Manual of Kallada Dam
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 intime 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 up- dation of the EAPs of their dams as per Central Water Commission's guidelines available on CWC website at http://www.cwc.gov.in/main/downloads/EAP chapter.pdf.
196
August 2020 O&M Manual of Kallada Dam
Figure 0.1Warning Scheme
197
August 2020 O&M Manual of Kallada Dam
198
August 2020 O&M Manual of Kallada Dam
ANNEXURE H - GLOSSARY
Abutment ― that part of a valley side against which a dam is constructed. Right and left abutments are those on respective sides 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 safe guard 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 hat is curved to transmit the major part of the water pressure to the abutments. Auxiliary Spillway (Emergency Spillway) ― a secondary spillway designed to operate only during exceptionally large floods. 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 the axis of the dam but excluding projections or outlets, etc. Berm ― a horizontal step or bench in the sloping profile of an embankment dam. 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. Buttress dam ― a dam consisting of a watertight upstream face supported at intervals on 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. 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 consolidated 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.
199
August 2020 O&M Manual of Kallada Dam
Core Wall ― a wall built of impervious material, usually concrete or asphaltic concrete, in the body of an embankment dam to prevent leakage. Crest gate (spillway gate) ― a gate on the crest of a spillway to control overflow or reservoir water level. 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 Cut off― an impervious construction or material which reduces seepage through the foundation material. Cut off trench ― an excavation later to be filled with impervious material to form a cut off. Cut off wall ― a wall of impervious material (e.g., concrete, asphaltic concrete, steel-sheet piling) built into the foundation to reduce seepage under the dam. 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 in appropriate 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;
200
August 2020 O&M Manual of Kallada Dam i) Occurrence of a flood, which resulted in encroachment on the available free board, or the adopted design freeboard; j) Erosion in the near vicinity, up to five hundred meters, downstream of the spillway, waste weir, etc.; and k) Any other event that prudence suggests would have a significant unfavourable 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. 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. Dead storage ― the storage that lies below the invert of the lowest outlet and that, therefore, cannot be withdrawn from the reservoir. Decommission ― Taking a dam out of service in an environmentally sound and safe manner, or converting it to another purpose. Design flood ― see spillway design flood. Design life ― the intended period that the dam will function successfully with only routine maintenance; determined during design phase. Diaphragm ― see membrane. 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 at block areas on a reservoir rim that are lower than the top of the main dam and that are quite long. In the
201
August 2020 O&M Manual of Kallada Dam
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. 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. Diversion channel, canal, or tunnel ― a water way used to divert water from its natural course. These terms are generally applied to temporary structures such as those designed to bypass water 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. 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; 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. Drawdown ― the lowering of water surface level due to release of water from a reservoir. 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. Earthen dam or earth fill dam ― see embankment dam. Embankment dam (Fill dam) ― any dam constructed of excavated natural materials. 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. Emergency gate ― a standby or reserve gate which is lowers only for repairing/ servicing of the service gate. Emergency spillway ― see spillway. 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.
202
August 2020 O&M Manual of Kallada 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. 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 inside 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. 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 flash board or its supports. Flood gate ― a gate to control flood release from a reservoir. 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 retain in the reservoir but will flow over the spillway until the controlled retention water level is reached. Flood wall ― a concrete wall constructed adjacent to a stream to prevent flooding of property on the landward side of the wall, normally constructed in lieu of or to supplemental levee where the land required for levee construction is expensive or not available. Floodplain ― an area adjoining a body of water or natural stream that has been, or may be, covered by flood water. 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. 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. 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.
203
August 2020 O&M Manual of Kallada Dam
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. 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. 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 cut off) ― a barrier produced by injecting grout into a vertical zone, usually narrow horizontally, in the foundation to reduce seepage under a dam. 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. 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. Height above lowest foundation ― the maximum height from the lowest point of the general foundation to the top of the dam. 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. 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.)
204
August 2020 O&M Manual of Kallada Dam
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. Internal Erosion ― see piping. 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. 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. 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. 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 ― across-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. Morning glory spillway ― see spillway. One-Hundred Year (100-Year) Exceedance Interval ― the flood magnitude expected to be equal 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.
205
August 2020 O&M Manual of Kallada Dam
Operation ― the administration, management, and performance of maintenance activities necessary to keep a dam safe and functioning as planned. Outlet ― an opening through which water can be freely discharged from a reservoir. Outlet gate ― a gate controlling the outflow of water 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. 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. Primary Spillway (Principal Spillway) ― the principal or first-used spillway during flood flows. 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. 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. Pumped storage reservoir ― a reservoir filled entirely or mainly with water pumped from outside its natural drainage area. Radial gate (Tainted gate) ― a gate with a curved upstream plate and radial arms hinged to piers or other supporting structures. Regulating dam ― a dam impounding a reservoir from which water is released to regulate
206
August 2020 O&M Manual of Kallada Dam
Rehabilitation ― the completion of all work necessary to extend the service life of the practice or component and meet applicable safety and performance standards. 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. 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. 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 armouring. 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. 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. Rock fill Dam ― see embankment dam. 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. 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. Seepage ― the interstitial movement of water that may take place through a dam, its foundation, or its abutments. 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. Service/Regulating gate (regulating valve) ― a gate or valve that operates under full pressure and flow to throttle and vary the rate of discharge. 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
207
August 2020 O&M Manual of Kallada Dam 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. 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. 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. Slide gate (sluice gate) ― a gate that can be opened or closed by sliding it in supporting guides. 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 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. Sluiceway ― see low-level outlet. 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. 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 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.
208
August 2020 O&M Manual of Kallada Dam
Tailrace ― the tunnel, channel or conduit that conveys the discharge from the turbine to the river, hence the terms tailrace tunnel and tailrace canal. 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 zone 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. 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. Upstream Blanket ― see blanket. 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, and submerged weir. Zoned embankment dam ― an embankment dam composed of zones of materials selected for different degrees of porosity, permeability and density.
209