project rehabilitation report of krishnarajasagara (krs) dam,

Project Rehabilitation Report of KRS Dam

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Project Rehabilitation Report of

Krishnarajasagara (KRS) Dam,

Karnataka Water Resources Department

Doc. No.: CDSO_DSR_PRR_ KA06HH0020_KaWRD_v1.0

July, 2020

Central Water Commission

Ministry of Jal Shakti

Department of Water Resources,

River Development & Ganga Rejuvenation

Government of India


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Quality Control:

Version Date Writers/Contributors Checked by

1 31/07/2020 Dr. Hadush S Hagos (HSH) Hemant Joshi (HJ)

Rajiv Kumar Sawarn

Issued/Copied to:

I/C Date Name Organization

Issued 31/07/2020 Shri. Pramod Narayan Central Water Commission


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Abbreviations

DRIP Dam Rehabilitation & Improvement Project

CWC Central Water Commission

CPMU Central Project Management Unit

CSV Construction Site Visit

SPMU State Project Management Unit

IA Implementation Agency

PIC Project Identification Code

DSRP Dam Safety Review Panel

PST Project Screening Template

DFR Design Flood Review

MSL Mean Sea Level

FRL Full Reservoir Level

MWL Maximum Water Level

TBL Top Bund Level (Top Level of Dam)

MDDL Maximum Draw Down Level

LSL Lowest Sill Level

DSL Dead Storage Level

U/S Upstream

D/S Downstream

El. Elevation

L/B Left Bank

R/B Right Bank

PMF Probable Maximum Flood

SPF Standard Project Flood

CD Works Cross Drainage Works

VRB Village Road Bridge

WBM Water Bound Macadam

NDT Non Destructive Testing

DHARMA Dam Health And Rehabilitation Monitoring Application

O & M Operation and Maintenance

EAP Emergency Action Plan


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ESMF Environmental and Social Management Framework

E & S specialists Environmental and Social Specialists

HM Works Hydro-Mechanical Works

EM Works Electro-Mechanical Works

SCADA Supervisory Control and Data Acquisition System

DG Set Diesel Generator Set

MW Mega Watt

MU Million units

Ha Hectare

MCM Million Cubic Metre

Deg. Degree

Min. Minute

Sec. Second

CM Construction management

QC Quality control

m meter

m3 Cubic meter

m3/sec Cubic meter per second

Km2 Square kilometre

MCM Million cubic meter

TNWRD Tamil Nadu Water Resource Department

TANGEDCO Tamil Nadu Generation and Distribution Corporation

KWRD Kerala Water Resource Department

KSEB Kerala State Electricity Board

MPWRD Madhya Pradesh Water Resource Department

UJVNL Uttarakhand Jal Vidyut Nigam Limited

DVC Damodar Valley Corporation


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DRIP Component Wise Project Cost

KaWRD Initial/Revised Projects & Cost

BACKGROUND

In April 2012, the Central Water Commission

(CWC) with assistance from the World Bank,

embarked upon a six year Dam

Rehabilitation and Improvement Project

(DRIP) at a preliminarily estimated initial cost

of Rs.2100 Crore targeting rehabilitation and

improvement of about 250 dams initially of

six, later of nine implementing agencies -

namely: MPWRD, OWRD, TNWRD,

TANGEDCO, KWRD, KSEB, KaWRD,

UJVNL and DVC.

In June 2018, the project was extended by

two years, until June 2020. The current

revised cost for DRIP is Rs.3466 Crore out of which Rs. 2920.5 Crore is allocated for

Component 1 (Rehabilitation and Improvement of Dams and Associated Appurtenances),

Rs.232.5 Crore for Component 2 (Dam Safety Institutional Strengthening), and Rs.313 Crore

for Component 3 (Project Management). Appropriate assistance is also provided under

DRIP to develop O & M Manuals and Emergency Action Plans (EAP) for these dams. The

project also promotes new technologies and improves institutional capacities for dam safety

evaluation and implementation at the Central and State levels as well as in some identified

premier academic and research institutes in the country. The actual total number of dams

under DRIP stands at 223.

The Implementing Agencies for DRIP are the Water Resources Departments and State

Electricity Boards in the participating States and Damodar Valley Corporation (DVC) with

Central Water Commission at Central Level. State Implementing Agencies are responsible

for implementation of works of dams under their charge. Co-ordination and management of

such works within a State rests with the

concerned State Project Management

Unit (SPMU). Overall project oversight

and coordination is carried out by Central

Project Management Unit (CPMU) headed

by the Project Director with assistance of

an Engineering and Management

Consultant.

Karnataka Water Resource Department

(KaWRD) joined DRIP in August 2014

with initial number of dams totalling 31.

Later, KaWRD dropped 9 dams and

continuing in DRIP with 22 dams.

Preliminarily estimated initial DRIP project

cost for KaWRD was Rs.276.1 Crore and

the revised actual current project cost is

Rs.581.2 Crore.


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Table of Contents

1. EXECUTIVE SUMMARY .................................................................................. 1

2. PROJECT DETAILS ......................................................................................... 2

2.1 Project Description .......................................................................................................... 2

2.2 Project Location ............................................................................................................... 2

2.3 Project Benefits ................................................................................................................ 2

2.4 Dam and Reservoir Features (Before rehabilitation under DRIP) ............................... 3

2.5 Any Emergency Spillway, Fuse Plug etc. ...................................................................... 4

2.6 Details of previous dam incidents, if any ...................................................................... 4

2.7 PST Details ....................................................................................................................... 4

2.8 DSRP, CPMU and World Bank Recommendations and Compliance ......................... 5

2.9 Scope of Rehabilitation Works as per PST ................................................................... 5

2.10 Drawings ......................................................................................................................... 19

3. DAM VISITS (PST STAGE) ............................................................................ 26

3.1 Dam Inspections ............................................................................................................ 26

3.2 Summary of observations made by CPMU ................................................................. 26

4. DESIGN FLOOD REVIEW (DFR) ................................................................... 26

4.1 DFR Outcome ................................................................................................................. 26

4.2 Brief Summary of Review.............................................................................................. 26

4.3 Recommendations ......................................................................................................... 26

5. REHABILITATION WORKS CARRIED OUT ................................................. 26

5.1 Summary of Investigations ........................................................................................... 26

5.2 Main Dam Works ............................................................................................................ 27

5.3 Basic facilities ................................................................................................................ 27

6. INSTRUMENTATION ..................................................................................... 27

6.1 List of existing instruments installed in dam and their condition ............................ 27

6.2 Details of new instruments installed ........................................................................... 28

6.3 CPMU Recommendations ............................................................................................. 28

7. PROCUREMENT OF WORKS ....................................................................... 29

7.1 Package wise details ..................................................................................................... 29

7.2 Details of bidding process ............................................................................................ 31

7.3 Reason for Variation, if any .......................................................................................... 31

7.4 Litigation / Arbitration, If Any ....................................................................................... 31

8. THIRD PARTY CONSTRUCTION SUPERVISION VISITS BY CPMU ........... 31

8.1 Summary of Visits undertaken ..................................................................................... 31

8.2 Summary of Third Party Material Testing .................................................................... 31

8.3 Summary of Major Recommendations ........................................................................ 31


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8.4 Summary of Compliance by SPMU .............................................................................. 37

8.5 Summary of any Special Visits made by CWC/World Bank/Expert Committee ...... 37

8.6 Summary of Technical Assistance provided by CPMU ............................................. 37

9. ENVIRONMENTAL AND SOCIAL MANAGEMENT FRAMEWORK (ESMF) 37

9.1 Basic Details ................................................................................................................... 37

9.2 Summary of Observations ............................................................................................ 37

9.3 Details of ESMF/EIA study (if any) ............................................................................... 37

10. OTHER NON-STRUCTURAL INTERVENTIONS ........................................... 37

10.1 Basic Details ................................................................................................................... 37

10.2 Summary of Observations ............................................................................................ 38

11. PENDING REHABILITATION WORKS .......................................................... 38

11.1 Details of pending works .............................................................................................. 38

11.2 Further course of action................................................................................................ 38

12. REFERENCES ............................................................................................... 38

LIST OF FIGURES

Figure 2-1: Bird’s eye View of KRS Dam ......................................................................... 19 Figure 2-2: Google Map of KRS Dam ............................................................................... 20 Figure 2-3: Water Catchment Map of KRS Dam .............................................................. 21 Figure 2-4: Index Map KRS Dam ...................................................................................... 22 Figure 2-5: Plan of KRS Dam and Brindavan Ganden .................................................... 23 Figure 2-6: Site Plan and Longitudinal Section of KRS Dam ......................................... 24 Figure 2-7: Cross-section of non-overflow section ........................................................ 25

Annex A: PST Approval Letter .............................................................................. 39

Annex B: Drawings issued for Rehabilitation measures .................................... 43

Annex C: Completion Certificate .......................................................................... 51

Annex D: Photographs Before and After Rehabilitation Works ......................... 57

Annex E: Compliance as Received from Project Authorities ............................. 69

Annex F: DBA and Inundation Maps .................................................................... 93


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1. EXECUTIVE SUMMARY

This Project Rehabilitation Report (PRR) is for KRS Dam, which is one of the 22

dams under DRIP in Karnataka. The Dam Safety Review Panel (DSRP) inspected

the dam in May 2014 and recommended both structural & non-structural measures to

be taken up by the dam authorities.

DSRP main recommendations included arresting leakage/seepage through the dam

body by deep racking of the joints and filling with epoxy mortar, as well as covering

the treated portion of the dam with shortcreting (8 to 10 cm thick) over steel mesh

which should be fixed to the upstream face; rectification of damaged sections of the

right side guide wall of scouring sluice at +50 levels; repair/covering all prominent

scour depression noticed in the chute spillway channel at 34.30 m and 81.30 m

downstream of the dam axis with apron concrete on the top surface; replacement of

all broken and cracked gates by new gates having indigenous Teflon cladded seals.

Non-structural measures included checking profile of the dam for full uplift conditions

as well as seismic conditions of loading as stipulated in relevant IS code; assessing

Probable Maximum Flood (PMF) discharge at the dam after obtaining updated Hydro

meteorological data from IMD; preparation of Emergency Action Plan including

suitable communication system of flood forewarning as well as continuation of

bathymetric survey being carried out by KERS at ever 5 to 10 years interval.

The existing surplus flood release sluices were designed for a flood release capacity

of 9911 cumec. The revised design flood (PMF) under DRIP worked out to be 17010

cumec. Flood routing study carried by the SPMU as part of the Dam Breach Analysis

(DBA) indicates that the revised MWL is at EL 754.88 m. The Top level of dam (TBL)

is at EL 754.08 m. Hence the available freeboard is not sufficient for the revised

design flood as per IS 6512. Therefore, structural and non-structural measures are

needed to accommodate the revised design flood for dam safety.

Following DSRP recommendations, rehabilitation works carried out under DRIP

included:

i) Racking and pointing of upstream face with UV resistant, high strength, non-

shrink Poly Ironite Ceramic Cementitious (PICC) mortar.

ii) Drilling and grouting of dam body.

iii) Steel Fibre Reinforcement Shotcrete (SFRS) treatment to U/S above FRL in

view of severe wave splashing impact.

iv) Conducting videography in drilled 150 mm diameter core holes.

v) Carryout the water percolation/permeability test in investigation hole and test

holes.

The rehabilitation works were executed under 1 package at a total completion cost of

Rs. 6661 Lakhs including a variation of Rs. 2999 Lakhs. The other package of

replacement of 136 gates at a Contract Amount of 58.46 Crore is currently under

progress. Hence, this PRR needs to be updated in the future after the 136 gates

replacement work is completed.

SPMU carried out dam break analysis and prepared inundation maps, which were

reviewed and approved by CPMU. Based on this, the SPMU prepared Emergency

Action Plan (EAP), which was reviewed by CPMU and being finalized by SPMU. The

SPMU also prepared Operation and Maintenance (O&M) manual as per CWC/DRIP

guidelines, which was reviewed by CPMU and published.


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2. PROJECT DETAILS

The Krishnarajasagara Dam is located across Cauvery River near Krishnarajasagara village, Sriranagapatna taluk and Mandya district of Karnataka state, at Latitude of 12º 25’00” N and Longitude of 76º 33’ 30” E. It was completed in the year 1932 and the project consists of a masonry gravity dam constructed of surki mortar of 2621 m long, maximum height of 44.66 m and 4.12 m dam crest width. It has a total of 152 surplus sluices at different elevations (excluding 8 sluices at lowest level permanently plugged) with a design flood discharge capacity of 9911 cumec.

The TBL, FRL, and original MWL are at EL 754.32 m, 752.489 m, and 752.489 m, respectively. The surplus flood sluices are at RL +12 FT (8 Nos. all plugged), RL +80 FT (16 Nos.), RL +103 FT (48 Nos.), RL +106 FT (40 Nos.), and RL +114 FT (48 Nos.). The gross storage at FRL is 1400.32 MCM (or 49.452 TMC).

2.1 Project Description

Sl. No.

Item Details

a. Project Identification Code (PIC) KA06HH0020

b. Project Name Krishnarajasagara Dam

c. River Basin Cauvery

d. Sub River Basin Cauvery

e. River/Stream Cauvery

f. Catchment area (km2) 10619

g. Year of commencement of project 1911

h. Year of completion of project 1932

2.2 Project Location

Sl. No.

Item Details

a. State Karnataka

b. District Mandya

c. Earthquake Zone II

d. Survey of India Map Ref No’s 57D/11

e. Nearest City Mysore

f. Nearest Airport Mysore

g. Nearest Railhead KRS Railway Station

h. Name of Immediate U/S Project Hemavathy and Harangi

i. Name of Immediate D/S Project Mettur

j. Latitude in Deg., Min, Sec. (North) 12º 25’00”

k. Longitude in Deg., Min, Sec. (East) 76º 33’ 30”

2.3 Project Benefits

Sl. No. Item Details


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Sl. No. Item Details

a. Type of Project Multipurpose

b. Irrigation –

Gross Command Area (Ha.) 111681

c. Irrigation –

Colourable Command Area (Ha.) 111681

d. Irrigation –

Annual Irrigation Potential in (Ha). 111681

e. Hydropower –

Installed Capacity (MW) 16

f. Hydropower –

Firm Power (MW) 12+4

g. Hydropower –

Average Annual Generation (MU) 72

h. Domestic/Municipal/Industrial Water –

Annual Quantum (MCM) Nil

i. Domestic/Municipal/Industrial Water –

Area and Population Benefitted Nil

j. Flood Protection –

Flood Protected Area (Ha) Nil

k. Flood Protection –

Details of Area Benefitted Nil

l. Details of Tourism/Recreational Facilities Nil

2.4 Dam and Reservoir Features (Before rehabilitation under DRIP)

Sl. No.

Item Details

a. Full Reservoir Level (m) 752.489

b. Original Maximum Water Level (m) 752.489

c. Gross Reservoir Storage Capacity at FRL (Mm3 )

1400.32

d. Live Storage Capacity (Mm3 ) 1275.38

e. Revised Live Storage Capacity, if any

(Mm3 )

NA

f. Date of bathymetric survey, if any NA

g. Dam Type

h.

Length of Dam at Top (m)

i) Total length of the main dam

ii) Length of embankment dam

iii) Length of masonry/concrete dam

2621

NA

2621

i. Number and length of dykes (No. & m)


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Sl. No.

Item Details

j. Top of dam (El. in m.) 754.32

k. Top Level of Upstream Parapet Wall of main dam (El. in m.)

l.

Height of Dam (m)

i) Embankment dam – above river bed level (up to dam top without camber)

ii) Concrete/Masonry dam – above deepest foundation level (up to dam top)

NA

44.66

m Top width of main dam (m) 4.12

n.

Details of Surplus Release Sluice Gates

Sluice Level Height

(m) Width (m) Nos. REMARKS

+12 FT -- -- 08 Permanently plugged since May 2007

+80 FT 3.00 6.00 16 All gates are replaced recently under state grants.

+103 FT 2.44 3.00 48 Proposed to replace under DRIP (Work in Progress)



o.

Outlet/Sluice details

i) Turbine Sluices +53’ – 4 Gates (Since inception it is not Operated)

ii) Irrigation Sluices +60’ – 6 Gates

Note: All elevations are above MSL

2.5 Any Emergency Spillway, Fuse Plug etc.

Nil

2.6 Details of previous dam incidents, if any

Nil

2.7 PST Details

Sl.

No. Item Date/Cost Remarks

a. PST first received from SPMU May 2015

b. Proposed PST Cost (INR in Lakhs) 5958

c. First review by CPMU 28.08.2015

d. Second Version of PST January 2016

e. Proposed PST Cost (INR in Lakhs) 6781

g. Second review by CPMU 22.04.2016


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h. Final Version of PST May 2016

i. Proposed PST Cost (INR in Lakhs) 6633.00

j. Final review by CPMU 21.06.2016

n. World Bank Approval 16.08.2015 Via e-mail

o.. Approved PST Cost (INR in Lakhs) 5958.00

2.8 DSRP, CPMU and World Bank Recommendations and Compliance

2.8.1 DSRP Recommendations and Compliance

Compliance to DSRP recommendations as obtained from dam authorities as part of

SPMU draft PRR is shown on pages 7 to 17 below.

2.8.2 CPMU/World Bank Recommendations and Compliance

Compliance to World Bank observations during PST review stage is attached in

Annexure E.

2.9 Scope of Rehabilitation Works as per PST

(a) Remedial measures

Rehabilitation & improvements to 100 years old Krishna Raja Sagara dam

under DRIP by conducting detailed investigations, carrying out treatment to

upstream face by pointing with UV resistant and anti-shrink materials like

cements using crystalline technology(CT) or Poly Ironite Ceramic

Cementitious(PICC) or equivalent materials (where required) conforming to

BIS/EN-1504-3, ClassR4(2014) standard, steel fibre reinforced shotcrete

above FRL in view of severe splashing /impact of water, extraction of cores,

videography of boreholes and water loss testing as directed, dam body

grouting(where required) to arrest the seepage & to improve the structural

strength of the dam. (Package-I)”

Providing and supplying 2 Nos. Scorpio vehicles to K.R.S. Dam.

Replacing flood Gates of +103 feet Sluice Gates covering +114 & +103 vents

and Replacement of +106 Ft Sluice gates at KRS Dam.

Consultancy services for CWPRS, Pune or any reputed institution for

construction and control supervision of the works relating to the treatment of

the upstream face of masonry dam.

Consultancy services for, engaging a grouting specialist / reputed agency well

versed in drilling & grouting to supervise grouting operations on a continuing

basis.

Conducting Test Pre and Post Grouting Non-Destructive Surface Geophysical

Investigations using Electrical Resistivity Imaging, Seismic Refraction and

Refraction Micro-Tremor (ReMi) for a section length of 750m at dam crest to

determine electrical resistivity distribution, P wave velocities and S wave

velocities”

Consultancy services including inspection & supervision of each and every

activity covering quality assurance plan, procurement of materials, fabrication,

erection, testing and commissioning of gates for Replacing flood Gates of

+114, +103 & +106 feet Sluice Gates at KRS Dam.


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Consultancy services for Review of Operation and maintenance manual of

gates, Stability analysis of KRS Dam, Preparation of inundation maps, Setting

up of warning system, Flood routing study, Preparation of PSTs.,

Providing and fixing of Echo Sounder-Model: Bathy 500 dual frequency,

DGBS Beacon-cum-heading receiver-Model SPS 461, Single Beam Software

for Data logging and processing-Model NAVISUITE, Panasonic/equivalent

tough book,

Supplying and installing wire piezo meter / pore pressure meter, wire uplift

pressure system unit, Surface settlement units, automatic non-contact Radar

based water level monitoring system, Mechanical Type Crack Meter,

Automatic Weather Station, Wind speed and Direction, Tipping Bucket Rain

gauge, Relative humidity, Solar panel, with Telemetry & Sonic Tomography

Video Ray/equivalent ROV including voyager submersible, control box,

Turbidity sensor system and real time video enhancement for the ROV

system.


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2.10 Drawings

Figure 2-1: Bird’s eye View of KRS Dam


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Figure 2-2: Google Map of KRS Dam


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Figure 2-3: Water Catchment Map of KRS Dam


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Figure 2-4: Index Map KRS Dam


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Figure 2-5: Plan of KRS Dam and Brindavan Ganden


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Figure 2-6: Site Plan and Longitudinal Section of KRS Dam


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Figure 2-7: Cross-section of non-overflow section


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3. DAM VISITS (PST STAGE)

3.1 Dam Inspections

Sl. No.

Item Date of visit Remarks

a. Dam Safety Review Panel (DSRP) May 2014

b. Site Visit made by CPMU experts August 2015

3.2 Summary of observations made by CPMU

All the observation along with compliance is attached as Annex. - E.

4. DESIGN FLOOD REVIEW (DFR)

4.1 DFR Outcome

Sl. No. Item Original

Value

Revised

Value Remarks

a. Inflow Design Flood (m3/s) 9911 17010

b. Spillway Capacity / Routed Outflow (m3/s) 9911 --

c. Maximum Water Level (m) 754.32 754.88* TBL-754.08 m

*Based on results of flood routing carried out as part of DBA study.

4.2 Brief Summary of Review

The existing surplus flood release sluices were designed for a flood release capacity of 9911 cumec. The revised design flood (PMF) under DRIP worked out to be 17010 cumec. Flood routing study carried by the SPMU as part of the Dam Breach Analysis (DBA) indicates that the revised MWL is at EL 754.88 m. The Top level of dam (TBL) is at EL 754.08 m. Hence the available freeboard is not sufficient for the revised design flood as per IS 6512. Therefore, structural and non-structural measures are needed to accommodate the revised design flood for dam safety.

4.3 Recommendations

Structural measures – detailed flood routing study to be carried out and come up

with structural measure to accommodate the revised design flood.

Non-structural measures – modifying rule curve, EAP.

5. REHABILITATION WORKS CARRIED OUT

5.1 Summary of Investigations

Sl. No.

Item Details Remarks

a. Geo-Physical Investigations Borehole videography of

150 mm dia. Holes predrilled up to 40 m depth

b. Geo-Technical Investigations Nil

c. Hydraulic Model Studies Nil


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5.2 Main Dam Works

Sl. No.

Item Details Remarks

a.

Works because of Seepage / leakage issues in Gravity dams / spillways (u/s face treatment, grouting of dam body etc.)

Providing and applying PICC pointing and grouting to the body of dam

Drilling and grouting of dam body as well as nipple grouting of leaked areas

Completed

b. Any other works

Steel Fibre Reinforcement Shotcrete (SFRS) treatment to U/S face above FRL in view of severe wave splashing impact.

Drilling 150 mm diameter core hole fore bore hole videography.

Conducting Bore hole videography in drilled 150 mm diameter core hole.

Drilling of 76 mm diameter hole for investigation.

Carryout water percolation/permeability test in investigation holes.

Drilling 51-57 diameter core holes and re-drilling 51-57 mm diameter core holes.

Providing upheaval gauge in dam body.

Completed

c. Hydro-mechanical works

i. Main spillway gates & hoists Replacement of 136 gates for surplus flood release Work in

Progress

To be incorporated in

to this PRR after completion

ii. Outlet gates & hoists

5.3 Basic facilities

S/N Item Details Status

a. Lighting Nil

b. Roads Nil

c. Security Nil

6. INSTRUMENTATION

6.1 List of existing instruments installed in dam and their condition

Digital Water Level Recorder Automatic Water Level Recorder Radar River Gauging System

All of the above instruments are not in working condition.


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6.2 Details of new instruments installed

Nil

6.3 CPMU Recommendations

The following instruments have been recommended under DRIP and are currently in the process of

procurement

No. INSTRUMENTS

1 Automatic Water Level Recorder

2 AUTOMATIC WEATHER STATION

3 Automatic pendulum

4 Normal Plumb line device

5 Resistance type Temperature sensor

6 vibrating wire/ MEMS biaxial type Tilt meter

7 vibrating wire type Joint meter / Crack meter

8 vibrating wire type Uplift pressure meter

9 V-Notch weir

10 Settlement Plate/ Survey markers.

11 Data Collection Unit and Transmission equipment

12 Piezometer

13 Electronic Total Station


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7. PROCUREMENT OF WORKS

7.1 Package wise details

Work Package No.

Name of Works

Estimated Cost

(INR in Lakhs)

Procurement

Method

Invitation for bids / NIT

Issue date

Pre-Bid Meeting date

Bid Opening date

Contract Agreement

No.

Contract Agreement date

Contractor’s Name &

Address

Scheduled

Duration (Months)

Scheduled

Completion date

Actual Date of

Completion

Contract / Award Value

(INR in Lakhs)

Completion Cost (INR in Lakhs)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

1

Rehabilitation and

improvements to 100 years

old KRS DAM under DRIP by

conducting detailed

investigations, carrying out treatment to

upstream face by pointing with

UV resistant and anti-shrink materials like

cements using crystalline

technology(CT) or poly ironite

ceramic cementitious

(PICC0 or eqivalent materials (where

reqired)conforming to BIS/ EN-1504-3,class

R4(2014)

3864.20

NCB 11.01.

16 10.12.

15 11.01.

16

Original Agreement

No. 127/2016-17 Dated

21.07.2016

Supplementary

Agreement No. No.

1/2018-19 Dated

27.12.2018

Supplementary

Agreement No. No.

2/2019-20 Dated

31.10.2019

21.07.16 (Original

)

M/s Ferro Concrete

(India) Private

Limited, #42 Bhagirath Pura Main

Road Rafeli, Bhagirathpura, Indore, Madhya Pradesh

24 20.07.18 26.06.19

Initial 3662

Amendment (2 no)

2999

6661


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Work Package No.

Name of Works

Estimated Cost

(INR in Lakhs)

Procurement

Method

Invitation for bids / NIT

Issue date

Pre-Bid Meeting date

Bid Opening date

Contract Agreement

No.

Contract Agreement date

Contractor’s Name &

Address

Scheduled

Duration (Months)

Scheduled

Completion date

Actual Date of

Completion

Contract / Award Value

(INR in Lakhs)

Completion Cost (INR in Lakhs)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

standard, steel fibre reinforced

shotcrete above FRL in

view of servere splashing/impa

ct of water, extraction of

cores, videography of boreholes and

water loss testing as

directed, dam body

grouting(where required) to arrest the

seepage & to improve the

structural strength of the

dam works

6661 6661


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7.2 Details of bidding process

As per details in the above table.

7.3 Reason for Variation, if any

Increase in actually required quantities more than in the BoQ quantities tendered

awarded initially.

7.4 Litigation / Arbitration, If Any

Nil

8. THIRD PARTY CONSTRUCTION SUPERVISION VISITS BY

CPMU

8.1 Summary of Visits undertaken

Sl. No. Date of visit Transmittal details of CSV

Report

a. 29.07.2016 3592/12.08.2016

b. 15.12.2016 4040/30.12.2016

c. 15.12.2016 & 02.02.2017 7672/06.06.2017

d. 07.06.2017 4728 /28.06.2017

e. 08.09.2017 5264/20.11.2017

8.2 Summary of Third Party Material Testing

Nil

8.3 Summary of Major Recommendations

1st Construction Site Visit Report

Observations & Recommendations:

Low quality of Safety Standards. Masonry wall treatment was performed using inadequate scaffold.

Insufficient length of the bracket: The platform could not reach properly the wall surface for the presence of a masonry wedge

The platform itself did not have adequate handrail. Adequate PPE were not distributed to the labors (Safety Shoes).

Recommendations

The Contractor is recommended to address aforementioned observations at the earliest.

Lab test needs to be set up.

2nd Construction Site Visit Report

Observations and Quality Control issues:

Site visit and discussions:

This was the first such visit to KRS dam, when there was no water in the u/s part of the dam and the embedded parts & u/s dam was fully accessible and could be closely seen. The majority of the cast iron tracks and side angles were


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found in very good condition. The grooves were found in very sound masonry not requiring any special treatment, if used as such.

On detailed inspection and site discussions, it transpired that it will be preferable not to disturb the existing masonry structure as well as the embedded parts which may endanger the structure itself which is approximately 80 years old. It was considered prudent to utilize these cast iron embedded parts by undertaking suitable modifications by use of special welding technology between cast iron and structural steel or corrosion resistant stainless steel materials for modifying the tracks and seal seats, guides etc. as per the requirements of the IS 4622, as similar modification earlier got carried by the Project on + 80’ gates were intimated to be serving well and were found satisfactory by the Project.

It was noticed that no steel liner exists at any location for these three gates, although the technical specifications had mentioned provision of steel liners.

It was also observed that all the piers are not alike & the project was advised for a detailed survey to provide the detailed dimensions of civil structure as well as the existing embedment, for all the three locations namely +103, + 106 and +114covering each of the 136 number individual spans of these gates with reference to the center line of each span. This shall cover the civil structure shapes, dimensions in elevations and plan views with requisite X-sections.

During the site visit it was jointly decided that the work is required to be accomplished with least disturbance to the masonry structure keeping in view safety aspect of structure, utilizing the existing embedment and anchors etc.

Project authority was advised to carry out the revision in PST and Bid documents, and in the specification drawings accordingly.

Project site data to be supplied:

Project authority was also advised to simultaneously submit the following basic site data after

thorough survey and site measurements of the existing arrangement to CPMU:

Exact details and dimensioning of the existing piers, gate grooves, existing embedded parts, from the center line of each bay to be marked on drawings for all gates.

As Flood Routing Study for standard conditions has been done by KRSE, Mysore, wherein there an increase of 0.83 m water level has been reported above MWL It is advised to submit this studies to CWC Officially and team of KRSE along with all relevant records, input data and reports may be deputed to CWC so that official discussion may be held and final MWL may be firmed up. The MWL to be estimated with all gates operative and with 10% of gates considered as inoperative. It is suggested that design of all new gates shall be done for this revised MWL so that safety of gates under critical hydraulic conditions may be ensured.

Hydraulic Model studies to be got conducted for sluices with gates at RL +103’, + 114’ and + 106’ gates in parallel. Discharging capacity at revised MWL to be checked. Need for aeration at the d/s to be looked in to in the sectional models. Pressures in the sluices to be measured. This work could be carried out as a parallel activity.

Detailed construction planning and schedule of completion to be made part of bid document.

Reservoir Operation/regulation frame work/ Rule curve, and revised rule curve may also be required to be generated for the revised MWL in case MWL is incrased beyond the present MWL in order to ensure structural safety.

Technical specifications and detailed technical specification drawings, scope and estimate for associated civil works.


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Detailed design of gates to be based on head up to FRL, and checking for MWL (with 10% gates inoperative) with 33% increased stresses.

At site the pier details, especially the face of pier was found to be at variance with details available with C.P.M.U. The pier details of all the gates namely +103, + 106 need to be provided as per actual measurements. Similarly the details of bell mouth curves at various levels in the civil structure need to be shown for guidance to the bidders.

A suitable condition needs to be made part of bid document for installation of get 2 gates of each type in beginning along with their dry testing prior to proceeding for installation of balance gates .

Other Observations:

To provide stainless steel side guide wheels in place of side guides to be designed for side thrust of 10% of the gate weight, especially in view of the historical side bumping experienced on gates under partial operation due to skew alignment between the two parts of the dam in this reach.

The groove liners earlier proposed in the technical specification drawings without stiffeners were not found desirable and Project authority was advised to utilize the existing track with provision of 30 cr13, stainless steel track plates of suitable size through welding after filling the cavity existing in the cast iron track through specialized welding technology (TIG welding) as used on + 80 gates. This process shall need to be elaborated in the technical specifications.

The existing track in respect of gates at RL +103’ & + 106’ gates was found very near to the edge of the masonry structure but had endured the stresses without causing any shear, it was advised to provide eight number stainless steel wheels, four in each of the two units of each gate to be spliced together with fit bolts, the wheels with a provision of crown was felt more appropriate to provide contact stresses at the center of existing track to keep the loading pattern on masonry to be in line with the earlier loading pattern.

There were no embedded parts in the deeper face of the block outs for provision of embedded guides. This may require a modified approach to utilize existing anchors available in the groove area to provide an alternative guiding arrangement. (To be supported on available anchor provisions in the groove area). It was further decided to use the through bolts for fixing of first stage plates for guides / any other component as required.

Sill beam for + 103’ and + 106 gates shall be of Minimum ISMB 250 with provision of S.S. seal seat welded at top and to be flush with surrounding concrete.

For + 114’ gates, the earlier proposed arrangement vide transmittal 3970 dated 08.12.2016 requires to be modified as per the revised sketch attached to meet the actual site conditions. The sill beams proposed for these gates is also shown in the revised sketch (attached).

Bid documents need complete review based on the past observations already transmitted as well as the updating based on the recent site visit and discussions held at site on 15th December 2016. The irrelevant parts like provision of single gate for +103’ & + 114’ gates need to be removed. The PST may be updated accordingly based on firmed up drawings and other details.

KRS project expert committee in its meeting dated 06.05.2016 had cleared the provision of independent hoists on trestles, based on CPMU recommendations for provision of skid mounted compact wire hoists conforming to IS 3938. The specification drawings submitted are not in line with it and are showing common hoists with clutch arrangement which already stand again discussed and not accepted during this visit. It was agreed to revise the documents and drawings accordingly as it even contravenes the requirement of remote control system.


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The sample GTS made available to SPMU be reviewed to incorporate the relevant aspects as per the now agreed provisions.

Provision of AMC for a period of 5 years for Remote control system, compact hoists, and electrical control and measuring system needs to be included in the scope of work.

Provision of steel liners introduced in the specifications needs to be deleted as it was not existing as noted during the recent site visit.

The weights of gates, capacities of compact hoists need not be mentioned as done in recent revision of bid & PST documents. May like to provide that “the hoist capacity shall not be less than -----T capacity”

The PST does not include the works to be identified for + 50’ & + 60’ gates etc. as per the site visit report as per transmittal 3593 dated 16.08.2016.

Provision of “ monorails” in place of compact hoists is still being mentioned at few locations in PST & Bid Document, needs to be deleted.

Observations already sent vide M.O.M 3671 dated 06.09.2016 and 3970 dated 08th December, 2016, need to be taken care of.

Elevations for FRL, MWL, and MDDL etc. need to be mentioned in documents and drawings.

The masonry grooves face if required shall be deepened and extended or levelled by grinding. The chipping etc. needs to be avoided.

Miscellaneous provisions, like water repellent paintings of all existing cast iron gate grooves along with its fitting, RCC provision for floor d/s of sill beam etc. may also be made part of work

The cost estimate needs to be reviewed to make it realistic covering all proposed and agreed changes as per past and recent review meeting at site on 15.12.2016.

The Concluding Remarks By Director, DRIP:

The Director DRIP mentioned that the submission of revised Bid document had already

been delayed and that the World Bank in the last 16th TC . meeting held in December

2016 has given a clear cut deadline of February 2017 for the award of this work, failing

which the Project is not likely to be considered under DRIP. He advised that the Project/

SPMU need to modify the documents in accordance with the decisions taken on these

works in the past with modifications to the extent agreed during this visit and meeting at

KRS to meet the deadline set by the World Bank.

SPMU, site Engineers and the Project consultants who attended this meeting were

fully apprised on the basic important agreed aspects requiring proper incorporation in

the Revised PST and Bid documents in detail.

Important Past Observations:

The Edge distance of track needs to be checked for shear strength of masonry as per

IS 1905 (1987) especially for 103’ & 106’gates.

Technical specifications for + 103 and + 114’ gates need to be made separately instead

of common one.

Connected Civil works are required to be fully included both in in BOQ.

Use of independent compact hoists as per IS3938 were agreed for all the three type of

gates. Drawings details need to be made as per the agreement.

The project expert committee in its meeting dated 06.05.2016 had cleared the provision

of independent hoists on trestles for all 136 gates including replacement of existing

embedded parts by stainless steel embedded parts. Provision in documents needs to

be made accordingly.

The cost estimate is varying at different locations in PST as Rs 24.5 Cr, Rs 26.63

crores. This needs to be revised considering all civil works to be included.


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The sample General Technical Specifications (GTS) provided by CPMU were to be

reviewed to exclude all non-applicable aspects before appending into the document.

Item 13 on page 252 envisages steel liners. There were no liners seen during site visit.

This needs to be reviewed.

All the gates need to be lifted during design flood above revised MWL. Planning needs

to be carried out accordingly.

Cross section of dam is required showing Gates at both +114’ & 103’ levels.

The track of all the gates should extend above the revised MWL.

The specification drawings need to be revised as per site visit report and discussions,

including earlier communicated observations.

3rd Construction Site Visit Report.

Observations:

CPMU monitored various on-going works including water loss testing and mixing of

grout. The Contractor is conducting his work using best construction practices and

scheduling of activities including multiple drilling operations which are being carried out

on a night shift.

An inspection of the upstream face revealed that a set of masonry steps has pulled

away from the dam body and needs to be thoroughly inspected and a design developed

to mitigate possible collapse of the stairway and potential damage to the dam body.

This needs to be accomplished on an accelerated schedule to ensure the large

exposed surface area of the dam body behind the stairs in treated in a timely manner. Upstream face treatment including raking and pointing of masonry using PICC

cementitious cement and nipple grouting of cavities. Status report from Contractor on

file. Documents available for review.

Works are well-documented with OK card systems in place to ensure all steps are

taken during implementation of the various scopes of work.

Justifications for increase in scope and costs are in order and technically correct.

ESMF and HSE/PPE OK system tracking mitigation requirements outlined in proposal.

4th Construction Site Visit Report.

Observations:

Upstream face treatment including raking and pointing of masonry using PICC

cementitious cement and nipple grouting of cavities was inspected. Work has been

implemented as per contract. Status report from Contractor on file. Documents

available for review. Extension of pier grouting is being taken up to extend depth of

grouting from the current limit of the gates to 3 to 4 meters downstream to complete

filling of voids noted during previous inspections.

Works are well-documented with OK card systems in place to ensure all steps are

taken during implementation of the various scopes of work.

Justifications for increase in scope and costs are in order and technically correct.

CPMU recommends the additional items in the variation order are taken up to ensure

addressing all the structural enhancements necessary to successfully implement the

project

ESMF and HSE/PPE OK system tracking mitigation requirements outlined in proposal.

5th Construction Site Visit Report

Observations:

Two points are brought out emphasizing additional work that CPMU recommends being taken

up as schedule and budget allow:

Completed between CH +760 to CH 2+100 m from levels +70 to +125 and above level

+125 in place of shotcreted. Submitted EFI proposal for approval of excess quantity

already pointed and balance area to be done.


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Primary holes at 12 m c/c at 1.30 m d/s of u/s face, secondary holes at 12 m c/c

(staggered to primary holes) at 1.50 m d/s of primary holes and tertiary holes in row

between primary & secondary holes at 6.00 m c/c (staggered to primary & secondary

holes) completed. EFI proposal submitted for excess quantity executed and quantity to

be executed for extended tertiary holes at 1.50 m c/c as Lugeon values are not in

permissible limit even after three rows of grouting. Also proposed for grouting between

CH +600 m and +750 m and between CH 2+100 m & CH 2+540 m.

No work is carried out after last site inspection made on 7.6.2017 and the status of works

is the same as it was on 7.6.17.

The contract provides for PICC mortar pointing to u/s dam face between CH +750 to CH

+2100, for full area from levels +50 to +80, 35% area from levels +80 to +125 and for full

area from levels +125 to 130. During execution of works, it was noticed that most of the

surkhi mortar joints between levels +80 and +125 are in dilapidated condition or have

developed cracks or peeled off. Hence full area is pointed from levels +70 to +125 and

above FRL level instead of shotcreting. Total quantity of pointing executed as of to date is

40,265 sqm. against BoQ quantity of 26,800 sqm., which is 50% more than BOQ quantity.

Provision is made for dam body grouting by drilling primary holes at 12 m c/c and

secondary holes at 6 m c/c & 40% of primary & secondary holes for tertiary holes. The

permeability values before grouting were ranging from 1.86 Lugeons in rock to 29.83

Lugeons in masonry. After grouting 106 primary holes, 108 secondary holes and 220

tertiary holes at 3 m c/s, the Lugeon values in the three test holes ranged from 4.85 to

19.33.

The average grout intake in primary holes is 171.77 kg/m, in secondary holes 143.08

kg/m and in tertiary holes it is 81.25 kg/m. The overall average grout intake is 121.88

kg/m.

Sl. No.

Observation / Deficiency 15.12.2016 Remarks

1

Masonry stairway attached to upstream face of dam body has a failed foundation. Stones and mortar may be pulled out from dam body

Design for stabilization / removal of stairs and repair of dam body face.

2 Rubble from construction is stockpiled to the upstream face of the dam

Rubble needs to be removed to accommodate raking and pointing of upstream face

3 Contract requires underwater raking and pointing. No method provided

it is ascertained that the present contract does not provide for under water pointing item. Planning to include pointing of the area below water level up to Level +12 level in DRIP-2 works.

4

Upstream face not completely covered in scope for raking and pointing. Only 60% of face under contract. lA requesting an additional 261% financial increase to cover all the upstream face including underwater works.

Requires WB approval


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8.4 Summary of Compliance by SPMU

Compliance letter received from SPMU against the CPMU experts’ comments during

construction site visits is attached in Annex E.

8.5 Summary of any Special Visits made by CWC/World Bank/Expert

Committee

Observations/recommendations and compliance of Design Team from Gates

(E&NE), CWC during the inspection of Krishnarajasagar (KRS) dam, Karnataka on

02.07.2015 are attached at Annex E.

8.6 Summary of Technical Assistance provided by CPMU

Review of PST. Review of design flood.

Review of Dam Break Analysis and Inundation maps prepared by SPMU.

Provided technical guidance on maintaining quality of works as per design, contract agreement technical specification and best engineering practices.

9. ENVIRONMENTAL AND SOCIAL MANAGEMENT

FRAMEWORK (ESMF)

9.1 Basic Details

Sl. No.

Item Yes / No Remarks

a. ESMF Issue Identified in PST Yes

b. Mitigation Measures Proposed Yes

c. Any Rehabilitation and Resettlement involved No

d. Site Visit Date of CPMU E&S Specialists -

e. Site Visit Report of CPMU E&S Specialists -

9.2 Summary of Observations

ESMF management during implementation was generally satisfactory but site photo

records show that PPE was sometimes not used during construction.

9.3 Details of ESMF/EIA study (if any)

Nil.

10. OTHER NON-STRUCTURAL INTERVENTIONS

10.1 Basic Details

Sl. No.


a

Emergency Action Plan (EAP)

(i) EAP Available at Site

(ii) EAP Prepared under DRIP

(iii) EAP Published

No

Yes

No

Inundation map prepared by SPMU was reviewed by CPMU.

Draft EAP is also Prepared by SPMU and reviewed by CPMU


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Sl. No.


(iv) Stake holder consultations

No

the comments of CPMU sent to SPMU via Transmittal Reference No. 8242 / 21-04-2020 for finalization and publication.

b. O&M Manual availability Yes O&M manual was prepared by SPMU as per DRIP guidelines, reviewed by CPMU and published.

c. Inflow Forecasting No

d. DHARMA Implementation Yes In progress

e. Siren No Needs to be installed

10.2 Summary of Observations

Nil

11. PENDING REHABILITATION WORKS

11.1 Details of pending works

i. Finalization of EAP.

ii. Completion of data entry into DHARMA.

iii. Completion of on-going work for replacement of 136 gates.

iv. Carrying out detailed flood routing and come up with structural and non-

structural measures to accommodate the revised design flood under DRIP II.

11.2 Further course of action

Pending action stated above should be completed.

12. REFERENCES

i. PST

ii. DSRP report

iii. Construction site visit report.

iv. Information received from SPMU from time to time

v. Completion Certificate.

vi. World Bank approval

vii. Compliance against various Observations/Comments from SPMU.


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Annex A: PST Approval Letter


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Annex B: Drawings issued for

Rehabilitation measures


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Annex C: Completion Certificate


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Annex D: Photographs Before and

After Rehabilitation Works


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Few Photographs of Ongoing HM works (Replacemnt of 136 surplus release sluice gates)


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Annex E: Compliance as Received

from Project Authorities


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COMPLIANCE TO OBSERVATIONS / RECOMMENDATIONS MADE BY SRI.R.K MALHOTRA,

BANK CONSULTANT, WORLD BANK DURING THE MEETING HELD DELHION 15TH& 16TH

JUNE 2015

Sl.

No.

OBSERVATIONS /

RECOMMENDATIONS

COMPLIANCE BY PROJECT

AUTHORITIES

A

(i)

DSRP Recommendations vide Page 64,

Item No. 17:“ Series of inclined holes of

at least 150 mm dia spaced at 20 m

centre to centre be drilled from

downstream face through the body of the

dam and up to the foundation to provide

means of drainage”. There being no

foundation gallery in this dam, provision

of the DSRP’s suggested drainage holes

is considered essential to release the

uplift pressure.

Inclined Bore holes from the downstream

face of the dam are suggested by the DSRP

and the project authorities of KRS dam

have expressed their apprehensions before

the Technical Committee (T.C) during their

visit with respect to stability if we have

inclined bore holes in 100 years old dam.

The T.C opined that there is no necessity of

inclined bore holes as the authorities have

not experienced the effect of uplift pressure

ever since. Hence this item is dropped.

(ii) DSRP Recommendations vide Page 64,

Item xv. “Undertaking drilling of core

holes in the body of the dam up to few

metres into the foundation to assess the

in situ properties of the masonry and the

mortar including masonry permeability

and uplift pressure etc”. This provision

should be made, being essential to

assess the condition of the dam body.

This will also help in the assessment of

the discontinuities / voids/ cracks/ cavities

in the dam body besides appropriate

assessment of grout intake in the various

sections of the dam body. In this

context,provision of 6 bore holes of 150

mm dia between 750 m to 2100m is

considered to be adequate. Cores from

these bore holes shall provide the

needed guidance. Also, it is suggested to

make provision for the ‘bore hole video-

graphy’ for ensuring realistic situation of

the dam body with respect to the

information provided by the cores.

The provision for drilling of 6 core holes of

150 mm dia between 750 m to 2100m

including bore hole video-graphy has been

now made in the estimate. In the mean

time the EGIS is recommended an another

bore hole at Ch: 2120 m. where

downstream springs erupt when RWL

reaches El.744m and accordingly total 7

core holes are included in the proposed

PST.

(iii) DSRP Recommendations vide Page 71,

Item No.12. The Dam Safety Review

Panel has

recommended that in addition to the

treatment of the upstream face through

raking and pointing of masonry joints in

the reaches proposed to be treated, the

treated portions should be covered with

shot creting (8 to 10 cm thick) over steel

mesh fixed to the upstream face of the

dam. The project authority has not made

any provision of shot creting. The PST

envisages treatment of the upstream face

from El +70 ft to + 80 ft (associated with

wide opening of joints and occurrence of

cavities) and from El +125 ft to +130 ft ,

As recommended, the provision for

providing “Fibre Shot Crete” (8cm thick)has

been made

in the estimate. The cost of this item is

worked out based on the data rate. The

cost of this item is included in the Sub

Estimate NO.1 at Item No 11.


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OBSERVATIONS /

RECOMMENDATIONS


AUTHORITIES

being associated with opening of joints

due to splashing of water. It is suggested

that shot crete be provided at least over

the treated reach from El +125 ft to +130

ft since this reach is reported to be in the

zone of severe splashing of water. Also

that, “fibre shot crete” (8 cm thick) be

provided instead of the DSRP’s

suggested plain shotcrete with steel

mesh. The fibre shot crete has several

advantages over the plain shot crete with

steel mesh. Design mix of the fibre shot

crete has been provided to Mr. Gowda,

Executive Engineer

B Treatment of upstream Face. The PST

envisages treatment of the upstream face

only at 2 levels ( from + 70 ft to + 80 ft;

and from +125 ft to +130 ft) and no

treatment has been proposed in the

intervening levels / reach. To the specific

query, Mr. Gowda, Executive Engineer

intimated to the Bank Consultant that the

intervening reach is also associated with

open masonry joints and cavities though

the extent of such open joints & cavities

was somewhat less than those in the

reaches + 70 ft to +80 ft / +125 ft to +130

ft. Now that the reservoir level is around

77 ft, the extent of the open joints/

cavities existing in the intervening reach

above + 80 ft level should be realistically

examined by Mr. Gowda, Executive

Engineer and the provision for treatment

to the extent required in the intervening

reach should be made in the PST.

The upstream face of the dam is inspected

by the team of Project Officers and

observed many number of openings/cavities

on the upstream face of the dam after

inspection of higher authorities it is

concluded to include the entire area from

+50' to +70' between chainages 750 to

2100 m & 35% of the remaining exposed

area of on the exposed area of the dam ,

accordingly the area between +50' to +70'

from Ch. 750 to Ch 2100 works out to 8100

sqm & 35% of the remaining exposed area

of 30350.07 sqm works out to 10623 sqm

(say 10600 sqm) is considered for

horizontal grouting & included in the PST.

The cost of treatment of both horizontal

grouting and pointing are included in the

Sub Estimate NO.1 at Item No 1,2&3.

C Drilling and Grouting. In the Estimate

submitted earlier at Sub-Estimate No. 1,

Pages 109 – 110 indicates the following:

(i) Item No. 4-A &4-B. Drilling of 47 mm

(Bx) core holes is envisaged. The correct

nomenclature should be 51 mm(Ax). It is

also noted that no mention is made for

“washing and conducting water loss

tests” in the holes. These being important

activities should be appropriately

included.

As suggested nomenclature from 47 mm

(Bx) (As per WRD SR 8.11.2, Page-150) is

changed to 51-57mm (Ax). Also washing

bore holes and conducting water loss tests

are included in the detailed specification.


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OBSERVATIONS /

RECOMMENDATIONS


AUTHORITIES

(ii) Item No. 5 It is noted that grouting is

envisaged to be done through primary

holes spaced at 6 m centres. No

provision is made for secondary holes.

Secondary holes may also be required for

completion of grouting to achieve the

requisite acceptance level of

impermeability in terms of lugeon values.

In this context, it shall be appropriate to

include the provision of drilling secondary

holes in between the primary holes and

undertaking grouting through these holes.

Accordingly, provision for about 33 %

secondary holes may be made for

estimation purposes.

As suggested, provision for drilling of

secondary holes to an extent of 33% of the

primary holes to access the Lugeon values,

has been made in the estimate. Also the

provision for grouting to these secondary

holes has been made in the estimate. The

cost of drilling secondary bore holes is

worked out based on the WRDO SR 2014-

15 vide Item No.8.11.2 Page No.150.

However, the cost of grouting is worked out

based on the data rate due to non-

availability of any scheduled rates. The

costs of these two items are included in

revised Sub Estimate NO.1 at Item No.

4(A), 4(B)&6.

(iii) Supply & Installation of Upheaval

Gauges. It is essential to install upheaval

gauges prior to the commencement of

pressure washing and grouting of any

hole within about 150 m to monitor

movement, if any, of the dam masonry /

rock mass. This dam being about 100

years old, it is of paramount importance

that the masonry does not get disturbed

during the pressure washing and

pressure grouting operations. Provision

for 9 upheaval gauges should be made in

the PST. An illustrative sketch depicting

an ‘upheaval gauge’ was provided to

MrGowda, Executive Engineer.

The provision for installation of upheaval

gauges prior to the commencement of

pressure washing and grouting of any hole

within about 150 m to monitor movement, if

any, of the dam masonry / rock mass has

been included in the estimate. The cost of

upheaval gauges is worked out based on

the WRDO SR 2014-15 vide Item No.2.9.3

Page No.33. The cost of these items is

included in the revised Sub Estimate NO.1

at Item No.5.

(iv) Test Holes. No provision is presently

made for checking the ‘efficacy of

grouting operations’’. It is essential to do

so. In this context, provision for about 7-

10 % test holes of Nx size be made in the

PST to cover drilling to the specified

depths, water loss tests, and finally

grouting of these holes.

As suggested, provision for drilling of 16

Nos. test holes which forms about 7% of the

primary holes to access the efficacy of

grouting operations has been made in the

estimate. Also the provision for grouting to

these test holes has been made in the

estimate. The cost of drilling test holes is

worked out based on the WRDO SR 2014-

15 vide Item No.8.11.2 Page No.150.

However, the cost of grouting is worked out

based on the data rate due to non-

availability of any scheduled rates. The

cost of these two items are included in

revised Sub Estimate NO.1 at Item No. 6, 7

& 8.

D Consultancy for Supervision of Drilling &

Grouting Operations. Drilling and

Grouting operations are specialized jobs

A provision of about ₹25.00 lakhs be made

for engaging a grouting specialist / reputed

agency well versed in drilling & grouting to


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OBSERVATIONS /

RECOMMENDATIONS


AUTHORITIES

requiring specialized skill and practical

knowledge. These operations require

constant attention. In this context, it is

suggested that a provision of about Rs 15

lakhs be made for engaging a grouting

specialist / reputed agency well versed in

drilling & grouting to supervise these

operations on a continuing basis.

supervise these operations on a continuing

basis till the satisfactory completion of the

work.

E Gates. The PST envisages replacement

of all 48 flood gates at Level +103 ft and

all 40 flood gates at +106 ft as well as all

the 48 automatic flood gates at +114 ft

level. It is noted that the Committee

formed by the Managing Director, CNNL

has recommended for replacement of all

these 136 gates with new gates and the

project authority has decided for

independent hoisting arrangement of

these gates to be operated through

remote-control system including the

provision for new embedded parts. This is

acceptable from considerations of overall

operational efficiency.

The Project Authorities while preparing

estimate earlier, it was proposed to replace

all 136 gates (40 gates @ + 106’, 48 gates

@ + 103’ and 48 gates @ + 114’) based on

the committee recommendations headed by

Chief Engineer, Irrigation (South), Mysore.

However, a team of Senior Officers from

CWC headed by Sri.Harkesh Kumar,

Director (Gates), CWC, New Delhi, has

conducted a detailed inspection of all gates

and recommended for replacement of gate

@ + 103’ & + 114’ by a single gate and

replacement of gates @ + 106’ level if the

skin plate is corroded by more-than 25% in

thickness by conducting UT test.

Repair/Replacement of embedded parts in

all gates. As recommended/suggested by

the Gates Expert Committee of CWC,

necessary changes have been made in the

estimate and detailed in Sub Estimate

NO.2. However, CPMU has deputed two

experts Sri. Ajit kumar Sachdev, Hydro-

mechanical expert & Sri.Zika Smilkovic,

Dam Design expert, to assist assessment

and recommendations of the current gates

and hoist arrangements. Both experts

visited the dam on 20/08/2015 and awaiting

their reports for finalizing the design of

hydro-mechanical equipments. The final

cost will be arrived after getting the

clearance from the CWC with respect to

design of hydro mechanical equipments.

F Third Party Inspection Agency. It is

suggested that a reputed inspection

agency should be engaged to supervise

each and every activity covering quality

assurance plan, fabrication, erection,

testing, and commissioning of gates.

Accordingly, a provision of Rs 15.00

lakhs should be made in the PST.

A provision of ₹25.00 Lakhs towards

appointing a reputed inspection agency to

supervise each and every activity covering

quality assurance plan, fabrication, erection,

testing, and commissioning of gates has

been made in the revised estimate.


75 | P a g e

COMPLIANCE TO OBSERVATIONS/RECOMMENDATIONS OF DESIGN TEAM FROM GATES

(E&NE), CWC DURING THE INSPECTION OF KRISHNARAJASAGAR (KRS) DAM, KARNATAKA

ON 02.07.2015

Sl.

No.

Inspection Note of design team from

Gates (E&NE), CWC on its visit to

KrishnarajaSagar (KRS) Dam,

Observations & Recommendations


AUTHORITIES

1

+106 level gates:

The skin plate of almost all gates has

developed uniform rusting with general

pitting & scaling. The downstream

components of gate are in good condition

and do not appear to have deteriorated

much in last eight decades (since cast

iron does not rust easily and generally

last longer). Overall, the gates did not

seem to be in severe distress. The skin

plate thickness is 1" as against design

requirement of ½". 1948-handbook states

that that additional ½" thick plate riveted

onto I-joists on rear had been provided in

front of original skin plate to improve gate

strength and overall weight. (Few gates

which had failed during initial years were

replaced with extensively ribbed CI gate

like the one provided in bay no.1 in

1938). Therefore, it is suggested that

ultrasonic thickness testing be performed

on skin plate and in case thickness has

reduced by more than 25%, entire gate

shall be replaced with new gate as the

repair works on cast iron may not yield

desired results. Otherwise, the existing

gates shall be sand blasted and painted

as per existing Standards.

The project Authorities have made

enquiries with 3 agencies who are in this

line of executing UT test. They have

agreed to carry out ultra sound thickness

test on skin plate even under water and

required about 25 to 30 days for completing

the work for 40 gates. Further, project

Authority need about 25 to 30 days to

finalise the agency.

As such we have assumed 50% of gates

that is about 20 gates in which thickness of

skin plate has reduced by more than 25% of

the original thickness of skin plate in view

of long age of gate, heavy rust formation on

upstream of skin plate etc.,

Accordingly, replacement of 20 gates &

refirbification of 20 gates is considered for

estimation purpose. The exact number of

gates to be replaced can be known only

after UT test. In the mean time the project

authority will find agency to conduct UT test

& actual number of gates replaced/

refirbificated will be considered before

placing the proposal for technical sanctions.

If the number of gates to be replaced is

more than 50% based on UT test, the

excess number of gates exceeding 20

gates will be considered out of State

Government Grants.

The cost of replacement of gates is worked

out based on WRD S.R 2014-15. The cost

of refirbification is worked out by assuming

that 30% of cost replacement of these gates

based on WRD S.R 2014-15.

The cost of the above is considered under

Sub Estimate No.2

2 Sealing against water leakage is

achieved by means of staunching

arrangement which provides two brass

surfaces to come in contact once the gate

The project Authority will make clear in the

tender schedule about providing suitable

sealing arrangement (Seals on gate shall

be fitted to L or Z-shaped plate bolted to


76 | P a g e

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AUTHORITIES

is fully closed. However, the action is not

automatic and in the present case the

gate plates are pushed forward using

screw jacks to abut against embedments.

The metallic seals are never expected to

give water tight joint (design

shortcoming) and it seems water

tightness was not imperative all these

years as there

are numerous anicuts on downstream.

But the situation has been aggravated

due to

Damage/loss of brass beading; both on

staunching plates & embedments leading

to profuse leakages. Divers are normally

deployed to pack the gaps between

staunching plates and embedments with

jute/gunny bags to minimize leakage but

are temporary measure. Further, the

operating mechanism by means of screw

jacks is not user friendly Page 4 of 18 in a

sense that the top plate merely tenoned

to side plates was expected to move

along with side plates when screw jack is

operated. In actual practice, simultaneous

operation of screw jacks is never

achieved and has been further

accentuated by rusting of staunching

plates. Therefore, it is recommended that

the sealing shall be replaced with rubber

seals. To achieve the same, additional

embedment’s with seal seats of AISI 304

(min.width of SS plate 150mm) including

concreting etc. shall be provided on

upstream to suit the site condition. The

seals on gate shall be fitted to L or Z-

shaped plate bolted to gate in place of

staunching plates. Choice of L-shaped

plate with music note type seals OR Z-

shaped plate with angle type seals is left

to discretion of designer. However, it is

felt that angle shaped seals may be more

suitable due to greater pre-compression

available considering varying degree of

corrosion of wheel & its track (if at all

present). Standard engineering practice

of providing suitable taper on top seal

seat with adequate recess in adjoining

concrete shall be ensured during

erection.

gate) on U/s & taper on top seal seat with

adequate recess in adjoining concrete.

The project Authority is requesting the CWC

for providing available drawings if any with

them so has to enable us to enclose the

same in the tender document.

The cost of the above all items is worked

out by assuming that 30% of cost

replacement of this entire sealing

arrangements of gates based on WRD S.R

2014-15.

The cost of the above is considered under

Sub Estimate No.2


77 | P a g e

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No.






AUTHORITIES

3 It was informed that the gates sway

during operation against load beyond full

opening.

This is very much expected due to

absence of guide/restraints above top of

vent opening as well as due to single

point gate suspension. The provision of

guiding mechanism on upstream may be

formulated along with new seal

embedments (as explained at sl. no ii) up

to top of vent opening. FromEL118.0' to

EL131.0', the guide anchorages could be

Hilti type expansion anchors. The guide

shoe shall be fitted to new plate meant for

rubber seals.

The project Authority will incorporate in the

tender about providing suitable

*guiding mechanism on upstream up to top

of vent opening. FromEL118.0' to EL131.0'

* guide anchorages

The project Authority request for sending

available drawing with CWC to examine of

providing same in our +106 gate groove &

gate.

The cost is considered under Sub estimate

no 2

4 Leakages were noticed through masonry

behind wheel track in few bays. It is

suggested that the masonry around

wheel track shall be treated with suitable

material (preferably epoxy based) having

excellent bonding properties with

masonry. Wheel track in one of the bay

has developed crack. The same shall be

repaired using metal stitching technique

as field welding of cast iron parts are

difficult.


tender about treatment with suitable

material (preferably epoxy based) having

excellent bonding properties with masonry

behind wheel trackrepairing of wheel track

wherever required using metal stitching

technique (as field welding of cast iron parts

are difficult)

The cost is considered under Sub estimate-

No.2

5 The cantilevered cast iron wheels are

mounted on brass bush & mild steel

shaft. The broken wheels on a couple of

gates as well severely worn-out wheels

shall be replaced


tender about replacement of wheels

wherever broken, worn out etc.The cost is

considered under Sub estimate- No.2

6 One of the gate was operated to assess

the hoisting mechanism and the

functioning of

gantry crane was found to be smooth. PA

(Project Authority) informed that no

problems have been reported w.r.t.

gantry in past

The project Authority will utilze the Gantry

for operation of two gates at a time.

7 Though no failures have been reported of

suspension chain in past and may not

occur with periodical examination. But it

is felt that additional wire ropes may be

provided on gate as a precautionary

measure to prevent accidental dropping

of gate due to chain snapping or any

other reasons. OR it is advised that these

gates shall not be used for regulating the

flow (i.e. no partial opening of gate, only

open/shut condition) and shall be latched


tender about providing Additional wire rope

as suggested.

The cost is considered under Sub estimate-

No.2


78 | P a g e

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No.






AUTHORITIES

at top deck level by providing suitable

latching arrangement after full opening

8 Multiple screw jacks were missing or

bent. No action needs to be taken for

replacement of missing/damaged screw

jacks

The project Authority will not taken action

but material will be considered as Scrap.

The cost is considered under Sub estimate

No.2

9 +114 level gates:

These gates are presently inoperative

due to non-functioning of float system.

The automatic hoisting arrangement is in

dilapidated state and it seems that no

efforts have been made in the past to

make them functional. It was informed

that these gates have not been operated

for last many years. The restoration of

automatic float system is not

recommended as its functional reliability

cannot be ensured.

The project Authority had decided for non-

restoration of these gates. As same has

been recommended by CWC, no work will

be under taken.

10 It was informed that the gates are

subjected to severe hammering action

due to wave effect; also resulting in

lateral shift of gate. This is expected as

there is absence of guiding mechanism

and is design deficiency

Noted

11 The gates have developed general

rusting but do not appear to be severely

distressed.

However, there is profuse leakage

through metallic seals on account of

design Deficiency (as elaborated under

sub-heading A), damaged/worn-out brass

beads. Considering the fact that these

gates are required for flood disposal and

doubtful reliability of any restorative

measures if implemented on gate & float,

it is recommended that these gates shall

be combined with +103 level sluice gates

and a single gate of size 10.0' x 21.0' with

appropriate freeboard shall be installed.

The gate shall be regulating type with

upstream sealing (no top seal required)

and skin plate. The gate shall be

fabricated in minimum three pieces (to

keep the wheel load under 6T to suit

existing masonry) and designed as per

latest codes in a manner to preclude

These gates will be combined with +103

level sluice gates and a single gate of size

10.0' x 21.0' with appropriate freeboard will

be provided.

We will incorporate technical specifications

as suggested under +106 & +114 heads in

the tender document. The cost is

considered under Sub estimate No.2


79 | P a g e

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AUTHORITIES

vibrations. Independent electrical rope

drum hoist mounted on trestle shall be

provided for operating the new gates.

However, the hoist capacity & self-

closure property of gate shall be

evaluated considering coefficient of

friction for seals as min. 1.0 even if PTFE

cladded seals are preferred (μ value for

rubber on stainless steel varies between

0.65- 1.5). The corrosion resistant wheel

track shall be provided upto EL133.0'

(existing track), but the guide shall be

extended to EL141.75' (top of deck). All

other appurtenants required for gate

including latching/dogging shall be

provided as per standard practices and to

suit existing civil structure.

12 The Gantry crane for +103 level gates

was operated to assess its functioning.

The operation was smooth and no

problems have been reported in past as

well. Therefore, it is suggested that this

gantry crane shall be shifted and used for

operating +106 gates as it is identical in

capacity, make & other parameters to the

crane already provided for +106 gates.

However, it may be noted that the C/C

distance of +103 gate is 13.5' while for

+106 gate, it is 12.0'. If any modification

is required for simultaneous handling of 2

alternate +106 level gates with the shifted

crane, it shall be carried out provided it is

feasible. Otherwise the shifted crane shall

be used to handle one gate at a time.

The gantry crane will be shifted and used

for operating +106 gates as suggested.

Modification for lifting two gates at a time

will be examined

General

13 Since there is absence of maintenance

gates for sluices, the painting system for

gates shall be such that it is durable with

long life cycle. In this context, it is advised

that Page 7 of 18 international codes (like

EN ISO-12944) shall also be referred

along with BIS codes. Whichever gives

better durability & longevity shall be

adopted for painting.

Painting system as per international codes

(like EN ISO-12944) as suggested will be

examined at the time of tender

At present for estimation purpose standard

practice and as per WRD Specification

Painting system is considered.

14 The scrap comprising discarded gates

including chains, hoisting arrangement for

Automatic gates, inlet pipe arrangements

to float well, screw jacks (including for

+106 level gates) etc. shall be made part

Considered & Included in Sub-Estimate NO

2


80 | P a g e

Sl.

No.






AUTHORITIES

of Tender. The bidders shall be asked to

quote price for scrap in their bids.

However, the embedments for +114 level

gates shall not be removed. Further, the

inlet conduits provided in dam feeding

water to float well on rear shall be

plugged suitably after removal of inlet

piping arrangement.

15 Remote operation (like ARMAC, SCADA

based control systems) for proposed new

gates and + 80 level gates shall be made

Considered & Included in Sub-Estimate NO

2

As suggested by the Senior Officers(Gates) of the CWC, provision for replacement/refurbication of

gates is made in the PST. However, CPMU CPMU has deputed two experts Sri. Ajit kumar Sachdev,

Hydro-mechanical expert & Sri.Zika Smilkovic, Dam Design expert, to assist assessment and

recommendations of the current gates and hoist arrangements. Both experts visited the dam on

20/08/2015 and awaiting their reports for finalizing the design of hydro-mechanical equipments. The

provision for gates as per the clearance by the CWC with respect to design hydro mechanic

equipments will be made in the PST.


81 | P a g e

COMPLIANCE TO THE OBSERVATIONS / RECOMMENDATIONS MADE BY EGIS,

CONSULTANTS TO CWC, WITH RESPECT TO CIVIL WORKS SUB-ESTIMATE -1 OF PST,

DATED 28 AUG 2015

Sl.

No. Observations Compliance

1. Any structural measure required to augment

the discharging capacity to safely pass the

revised design flood should be planned and

taken up in the next phase.

Noted. structural measures for safe

discharge of revived design flood will be

planned and taken up in the next phase

since the revised design flood reviewed and

approved by CWC is 17,010 cumecs.

2. The WB has recommended a series of

boreholes in the masonry structure between

Ch. 800 to 2100 m. be conducted to

understand the existing seepage and

leakage conditions of the masonry structure

and foundation. CPMU recommends an

additional borehole be placed at Ch. 2120

where downstream springs erupt when RWL

reaches El.744m.

As recommended by World Bank, 6 core

holes with bore hole video-graphy in

between Ch. 750 to 2100 m. are provided in

the revised PST. Now an additional core

hole with borehole video-graphy at

chainage 2120 m. where downstream

springs erupt when RWL reaches El.744m

is included in the project and accordingly

the estimated cost is revised.

3. The methodology suggested by CWPRS

may be followed and conformity of the repair

materials i.e.PICC or equivalent UV resistant

materials to BIS and international standards

may be ensured from the manufacturer/

supplier.

The methodology suggested by CWPRS

will be followed meticulously and conformity

of the repair materials i.e., PICC or

equivalent UV resistant materials to BIS and

international standards will be ensured from

the manufacturer/supplier. Accordingly

necessary tests required to ensure the

above is included in the NCB.

4. Extensive investigations including drilling for

Geological and Geotechnical investigations,

testing forassessing the in-situ properties of

masonry, regular chemical analysis of water,

preparation of hydraulic model for energy

dissipation arrangements, Geodetic survey

of the dam, Stability analysis of dam have

been suggested by DSRP and agreed by the

Department. Provision of all these

investigations in the estimate may be

confirmed. These investigations should

precede actual execution of remedial

measures proposed. The results of these

investigations may suggest a need for

additional remedial measures. Provision for

the same may also be made in the estimate.

The grouting material has been identified by

CWPRS after extensive testing. However,

quantities may change depending on the

results of above investigations.

Provision for conducting the extensive

investigations, including drilling for


testing for assessing the in-situ properties of

masonry, regular chemical analysis of

water, preparation of hydraulic model for

energy dissipation arrangements, Geodetic

survey of the dam, Stability analysis of dam

as suggested by DSRP is made in the

estimate. An additional 10% of the cost of

the grouting, is included in the project cost

to meet the cost of additional remedial

measures, if required based on the above

tests. However, the actual quantity of

grouting required for the proposed project

will be considered at the time of execution.

5. Other essential points to consider during final design and preparation of tender documents

include:


82 | P a g e

Sl.

No. Observations Compliance

6. It is recommended that the SPMU

incorporate the identified mitigation

measures as a part of the tender document

to ensure that environmental mitigation

measures are actually implemented during

construction.

In the PST Page No.222 & 223, it is clearly

mentioned that the proposed DRIP project

is in safe zone & it is free from

environmental & social impact. Hence, no

need of ESMF compliance. However, a

condition to mitigate the impacts at the time

of execution with respect to environmental

& social hazards will be included in the

NCB.

7. At maximum section of the dam, a small

pond (350 meters long by 200 meters wide

and between 3 to 5meters deep) has been

constructed and drainage from the under

sluices is directed into the pond. CPMU

recommends that an underwater camera-

mounted remote operated vehicle (ROV)

investigation of the pond be conducted to

map the basin and any disturbances or

visible areas of turbid water where noted.

This mapping can be used as a baseline for

periodic efforts to monitor dam health and

safety concerns

Provision for procuring ROV with camera

mounted for conducting periodical

underwater investigations of the pond is

made in the PST and the cost of the

equipment is around ₹42.00 lakhs which is

ascertained through internet. This value is

considered only for estimate purpose.


83 | P a g e

COMPLIANCE TO THE COMMENTS / RECOMMENDATIONS MADE BY THE CPMU OF C.W.C

NEW DELHI, FOR KRS REVISED PST & SITE VISITS

Sl.

No. OBSERVATIONS/

RECOMMENDATIONS


AUTHORITIES

1 The water level corresponding to the

spillway discharge capacity of 9912 m³/s

has been mentioned as 24.38 m (page 7 of

the PST), without any mention of reference

point.

It is understood from the PST that this is

perhaps with reference to the deepest river

bed level. This may please be clarified in

the PST so that this aspect is clear. The

reference level may also be indicated. In

the same light, reference to gate sills

should be in Elevation above MSL to avert

misunderstandings. Mixing of feet and

meters in any combination can lead to

misinterpretations and worse.

Further it appears that the same correction

is also to be applied to various invert/crest

levels in respect of sluice gates. This may

also be looked into and clarified.

The water level corresponding to the

spillway discharge capacity of 9912 m³/s is

754.32m above MSL. Necessary correction

has been effected in the PST. All levels of

structures are mentioned with reference to

MSL.

2 Both the live and gross storage of the

reservoir have been mentioned as 1369

Mm³. It should be corrected considering

the dead storage.

The live storage capacity of the reservoir is

1275.38Mm3 and gross storage capacity of

the reservoir is 1400 Mm3, .Necessary

correction has been effected in the PST.

3 The drawings enclosed are not readable.

Bigger size (minimum A3) and readable

drawings may be enclosed.

Drawing for Sluice sections may also be

enclosed.

Bigger size readable drawings (from size A4

to A2) are enclosed.

Sluice sections drawings are also enclosed.

4 From the dam specific details in Form II, it

is seen that the top level of the dam, FRL

and MWL are all the same, i.e. El.752.25m

(pages 7 and 9 of PST). On page 73 of the

May 2014 DSRP report the crest of the

dam is stated as El. 754.08 meters; this

may be looked into and corrected.

The FRL is at 752.48m above MSL & the

MWL is at754.32m above MSL.

Corresponding data are corrected in the

PST.

5 Hydrology

In the revised design flood study, based on

PMP values received from IMD, a peak

flood of 8539 m³/s has been estimated.

Since this was found to be less than the

original design flood of 9911 m³/s, the

original design flood was retained.

As per the studies conducted by KERS, the

PMF value is 9683m3/s without considering

the effect of interceptions in the estimating

the flood and PMF value is 8539 M3/s

considering the effect of interceptions in

estimating the flood. Both values are much

less than the existing designed spillway


84 | P a g e

Sl.

No. OBSERVATIONS/

RECOMMENDATIONS


AUTHORITIES

Subsequently it has been learnt from CWC

that they have carried out a storm study for

the project and obtained PMP values of

17.7 cm for 1-day and 28.6 cm for 2 days.

Estimation of probable maximum flood

hydrographs from the sub-catchments

followed by routing through the channel

reaches and Hemavathy Reservoir carried

out based on these new values by CWC

yielded a peak magnitude of PMF of 16057

m³/s.

capacity of 9911m3/s. However, structural

measures for safe discharge of revived

design flood will be planned and taken up in

the next phase since the revised design

flood reviewed and approved by CWC is

17,010 cumecs.

6

As the revised design flood increases

significantly from the current spillway

capacity (6686 m³/s), reservoir routing

studies should be carried out to establish

the adequacy of freeboard during

passage of the flood peak Consequently,

any Structural measure required to

augment Discharging capacity to safely

pass the revised design flood may be

planned and taken up in the next phase.

The spillway capacity by considering the

operative spillway gates is 6686m3/s (less

than the designed due to defunct of certain

spillway gates) and the same will be

reached to 9794m3/s after implementation

of this DRIP project. However, Structural

measures for safe discharge of revived

design flood will be planned and taken up in

the next phase.

7 Downstream springs are occurring at Ch.

2120m whenever the RWL reaches El.

744.7m. The WB has recommended

provision for borehole videography

between Ch. 750m to 2100m. CPMU

recommends an additional similarly

spaced borehole placed at Ch. 2120 to

better understand the existing condition of

the masonry structure and foundation

where these springs have been observed.

.As recommended by World Bank, 6 core

holes with bore hole video-graphy in

between Ch. 750 to 2100 m. are provided in

the revised PST. Now, an additional core

hole with borehole video-graphy at chainage

2120 m. where downstream springs erupt

when RWL reaches El.744m is included in

the project and accordingly the estimated

cost is revised.

8 It is proposed to carry out re-pointing of

masonry joints on the u/s face of the

Masonry dam above low water level where

ever the pointing has peeled off/come out

using PICC or equivalent as per the

recommendations of CWPRS.

The methodology suggested by CWPRS

may be followed and conformity of the

repair materials i.e. PICC or equivalent UV

resistant materials to BIS and international

standards may be ensured from the

manufacturer/supplier.

It is recommended that CWPRS may be

associated during construction.

Further the type of cement proposed to be

used in grouting of the dam from dam top

The methodology suggested by CWPRS will

be followed meticulously and conformity of

the repair materials i.e. PICC or equivalent

UV resistant materials to BIS and

international standards will be ensured from

the manufacturer/supplier. Accordingly

necessary tests required to ensure the

above is included in the NCB.

It is proposed to appoint CWPRS as

grouting consultants.

53 grade ordinary Portland cement is

proposed for grouting from top of the dam

and necessary corrections have been

incorporated in the PST.


85 | P a g e

Sl.

No. OBSERVATIONS/

RECOMMENDATIONS


AUTHORITIES

also needs to be indicated.

All precautions as recommended by the

World Bank with regard to pressures to be

applied and monitoring of movements

using upheaval gauges need to be

followed.

All precautions as recommended by the

World Bank with regard to pressures to be

applied and monitoring of movements using

upheaval gauges will be followed

meticulously.

9 It is seen that as the dam does not have

any foundation/drainage gallery, a series

of inclined holes of at least 150mm dia.

spaced at 20m centre to centre are

proposed to be drilled from the d/s face up

to the foundation for drainage.

In this regard it is felt that the above

drainage holes may not be very useful as

any such drainage holes from the d/s face

are normally not very effective in reducing

uplift pressures and also as the proposed

spacing of drainage holes is too large

(normal spacing is 3m centre to centre). It

is felt that these holes may not be

necessary

The stability of the masonry dam may be

checked as per IS 6512 and IS 1893

assuming extreme uplift in the locations of

normal uplift using the parameters

obtained from proposed investigations/

testing

If required then strengthening of the dam

by addition of buttresses/continuous

concrete lamina on the d/s face could be

considered later.

Inclined Bore holes from the downstream

face of the dam are suggested by the DSRP

and the project authorities of KRS dam have

expressed their apprehensions before the

Technical Committee (T.C) during their visit

with respect to stability if we have inclined

bore holes in 100 years old dam. The T.C

opined that there is no necessity of inclined

bore holes as the authorities have not

experienced the effect of uplift pressure ever

since. Hence this item is dropped.

It is proposed to conduct stability analysis of

the Dam as per IS 6512 and IS 1893 and

strengthening of the Dam by addition of

buttresses/continuous concrete lamina on

the d/s face will be considered in the next

phase if required.

10 The nomenclature of item no.1 of Sub-

Estimate 1 at page 105 of the PST may be

modified and elaborated to cover all the

items proposed to be carried out for clarity

The nomenclature of item no.1 of Sub-

Estimate 1 at page 105 of the PST is

modified and elaborated to cover all the

items proposed to be carried out.

11 Similarly the nomenclature of item no.3 of

Sub-Estimate 2 on Sluice Gates at page

105 of the PST is not clear .The

gates/vents at +103 ft. are seen to be

occurring twice in the nomenclature. The

nomenclature needs to be clearly worded

for the sake of clarity. It is presumed that

the recommendations of the CWC expert

team on gates and the Committee under

Managing Director, CNNL have been duly

CPMU has deputed two experts Sri. Ajit

kumar Sachdev, Hydro-mechanical expert &

Sri.Zika Smilkovic, Dam Design expert, to

assist assessment and recommendations of

the current gates and hoist arrangements.

Both experts visited the dam on 20/08/2015

and awaiting their reports for finalizing the

design of hydro-mechanical equipments.


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RECOMMENDATIONS


AUTHORITIES

considered

The details/type of the new gates and

their hoists as planned may be indicated

Provision for embedded parts and

implications on civil works need to be

appropriately considered.

12

Again, some confusion as sill elevations

based on the foot distance above deepest

river bed elevation is confusing.

Recommend all sill elevations are

referenced in meters above MSL to avert

misinterpretations by reviewers and

contractors.

All sill elevations are corrected to meters

with reference to MSL and are incorporated

in the PST

13 The provision of energy dissipation

arrangements for the waste weir sluices

has been suggested.

However, no provision for its study by

Hydraulic model and subsequent

execution of the energy dissipation

arrangements works has been made

The energy dissipation arrangements for the

waste weir sluices are already proposed in

the state budget.

14 Extensive investigations (Para 2.5.1.1)

including drilling for Geological and

Geotechnical preparation of hydraulic

model for energy dissipation

arrangements, Geodetic survey of the

dam, Stability analysis of dam have been

suggested by DSRP and agreed by the

Department. Provision of all these

investigations (proposed to be outsourced)

in the estimate may be confirmed.

Investigations, testing for assessing the in-

situ properties of masonry, regular

chemical analysis of water These

investigations should precede the actual

execution of remedial measures work. The

results of these investigations may suggest

the need for additional remedial measures.

Provision for the same may also be made

in the Estimates. The grouting material has

been identified by CWPRS after extensive

testing. However, the quantities may

change depending on the results of

investigations.

Provision for conducting the extensive

investigations, including drilling for


testing for assessing the in-situ properties of

masonry, regular chemical analysis of water,

preparation of hydraulic model for energy

dissipation arrangements, Geodetic survey

of the dam, Stability analysis of dam as

suggested by DSRP is made in the

estimate. An additional 10% of the cost of

the grouting, is included in the project cost

to meet the cost of additional remedial

measures, if required based on the above

tests. However, the actual quantity of

grouting required for the proposed project

will be considered at the time of execution.

15 Additional works may be needed in case

the dam is found to be unstable under

various loading conditions as per IS Codes

especially due to change (increase) in

design seismic parameters.

Additional works, if needed due to change

in design seismic parameters will be

proposed under state budget.

16 A boat pond lies at the downstream toe of

the dam and measures approximately 200

Provision for procuring ROV with camera

mounted for conducting periodical


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meters by 350 meters. The estimated

depth of the pond is about 3 to 5 meters.

There has been no investigation as to the

foundation condition of the pond. CPMU

recommends an underwater camera-

mounted ROV investigation of the pond be

conducted to understand the current

condition. CPMU recommends mapping of

the bed of the pond be conducted and

areas and or locations of turbidity,

turbulence of the water and or the current

floor condition be done to form a baseline

for future monitoring of dam behaviour.

underwater investigations of the pond is

made in the PST and the cost of the

equipment is around ₹ 42.00 lakhs which

is ascertained through internet. This value

is considered only for estimate purpose.

17 Instrumentation

There is no drainage and Foundation

Gallery in the body of the dam and

hence limited instrumentation has been

suggested by DSRP (DSRP of 1996, 97,

98 and 2014). However, no provision has

been made in the estimate submitted.

Provision of automatic Reservoir Water

Level Gauge, uplift gauges, V notches for

measurement of quantity of seeping water

at various places, automatic weather

station, etc., may be made.

Provision for providing and fixing Echo

Sounder, DGPS beacon-cum-heading

receiver along with single beam software for

data logging and processing, automatic

Reservoir Water Level Gauge, uplift gauges,

automatic weather station has been made in

the sub estimate-4 under instrumentation.

18 Hydro-Mechanical

Most of the gates need replacement and or

extensive repair. Some of these gates

have already been replaced and the

balance of the gates to be replaced now

has been studied by a committee

constituted by the department. The

provision for the same has been made in

the Estimate

CPMU recommends a more detailed

review of the existing gates and

appurtenant structures be conducted and,

in that light, CPMU will dispatch two

experts in hydro-mechanical and dam

design respectively, to assist assessment

and recommendations of the current gate

and hoist arrangement.

CPMU has deputed two experts Sri. Ajit

kumar Sachdev, Hydro-mechanical expert &

Sri.Zika Smilkovic, Dam Design expert, to

assist assessment and recommendations of

the current gates and hoist arrangements.

Both experts visited the dam on 20/08/2015

and awaiting their reports for finalizing the

design of hydro-mechanical equipments.

19 Environmental

The Attachment 1- Abstract Screening for

ESMF Activities and Categorization is

given but the identification of impacts and

the mitigation measures not provided. The

In the PST Page No.222 & 223, it is clearly

mentioned that the proposed DRIP project is

in safe zone & it is free from environmental

& social impact. Hence, no need of ESMF

compliance. However, a condition to


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proposed activities will have impacts on

environmental components to a certain

extent and it is recommended to be

addressed appropriately in the PST

covering all the individual screening forms

of the ESMF.

mitigate the impacts at the time of execution

with respect to environmental & social

hazards will be included in the NCB

20 Other

EAP has already been prepared (Para

2.3.6). However, provision has been kept

in the Estimate submitted for its review

through outsourcing. Please clarify

EAP has already prepared and this item is

removed from the estimate.


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Compliance for the EGIS/CWC - Meeting with project to firm up the proposal of sluice gates at

KRS Dam on December 8th 2015

Sl. No.

EGIS / CWC- RECOMMENDATION PROJECT COMPLIANCE

+114 Gates and Hoist System

1

Replacing the existing battery of gates by a new set of gates designed & fabricated out of stainless steel material as per IS 4622 ( fixed wheel gates ), provision of corrosion resistant material wheels with self- lubricating Lubrite or equivalent bearings, for making these almost maintenance free.

Provided New set of structural steel with self lubrite or equivalent , as gates will be hardly in water for 3-4 months

However SS materials same will be considered looking into the financial implication for implementing SS materials .

2

Providing fabricated guides on both sides & supporting sill (removable) at the bottom by suitably designed channel shaped frames of stainless steel material to be anchored to the civil structure by chemical bonded anchors to properly guide the gate removable supporting sill at the bottom of the gate.

Provided Side guides & Supporting Sill at the bottom of Structural Steel materials by anchoring to civil structure However SS of C section will be adopted

3

Dispensing the original system of pulleys & chains, removing & disposing the unutilised removable components, while leaving pulleys etc. as such as their removal is likely to damage & disfigure the masonry structure.(The removal & replacement of old age pulley system would have required un-necessary disturbing the masonry unique look.)

The components which are embedded in

civil work ( pulleys& chains ) will not be disturbed.

4

Removal of additional gate supporting slings provided for safety of hanging gates against failure of pulling sling resulting in free fall of gates in the reservoir, for their disposal.

The removal and replacement of SUPPORTING

SLINGS will be removed for disposal.

5

Abandoning the use of float, float well Counter weight, & float-well system by isolating the same by delinking of connecting chain sling system. The existing structure to be retained & preserved as Heritage structure & marvel of age old engineering.

The system of Float well Counter weight, & float-well by isolating same by delinking conecting chain sling system will be abandond. The Civil structure will be retained and preserved Heritage structure & marvel of old age engineering.

6

Providing actuation to gate systems through an individual lightweight & compact skid mounted, electrical rope drum hoist conforming to IS 3938 for lifting & lowering the gates. The proposal remained deferred for some additional studies on how to support the hoisting system appropriately on the old & heritage masonry structure to cause the least damaging impact on the aesthetics & outlook of the structure. With this objective another site visit on 19.11.15 was conducted & detailed meetings were held with Director, DRIP to evolve the structural support system on the masonary dam to support the independent hoist systems for individual fixed wheel gates Detailed deliberations led to: v An innovative approach to provide for the load bearing concrete.

We have examined the proposal of laying the RCC beam beneath the existing track and extend the same RCC beam on the Upstream to accommodate the hoist arrangement for both the +103’ and +114’ and to free the gate from hoist arrangement during non -usage and for maintenance by a portal structure provided over the existing rail system for handling the gate for maintenance .

a

Beam structures over the existing piers to be cast & anchored to the existing pier with cantilever projection on u/s to support the

As per the site condition the RCC beam will be provided at 141.75 ‘level and will be projected beyond the face of the dam. Then


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Sl. No.


compact hoist systems. This would require removal of one stone support from each side of the pier from under the stone beams supporting the crane rails for casting concrete beam with overhang on u/s side for supporting the rope drum hoists.

the gate cannot be lifted above the newly casted beam and approach for the gate maintenance is constrained. Further the portal provided should be capable of taking the gate from EL141.75 ‘and turn by 180 degree and store at 124 ‘ level as there is no space at EL 141.75’. In view of the above constrain it is proposed to provide hoist on the common Hoist bridge mounted on the columns. In this proposal the columns will be proposed by casting RCC foundation in the existing recess of the +103’ gate groove on piers without disturbing the existing stone masonry. With this arrangement gate can be lifted above the pier for maintenance and can be dogged within the groove during long non- use and this arrangement is in line with the present +80’ vents. Under the circumstances explained above we request to examine this proposal for adoption. This will least damage the masonry structure .The aesthetics and outlook will not change and will be in line with the +80’ vent which are recently innovated.

b

Suitable dogging arrangements shall be provided under this hoist supporting structure for facilitating freeing the gate from the hoist during long periods of non-usage & also for facilitating removal & lifting of the hoists from its base for any intended maintenance

requirements on the gates.

Suitable dogging arrangement shall be provided

under hoist supporting structure for faacilating

the gate from hoist.

c

For facilitating this a portal structure crane shall be provided over the existing rail system for handling the removal of hoist & gates for maintenance as & when required. Moreover the ropes & rope drums for +114 gates shall be such as will allow these gates to be lowered to the sluice + 103 ground level for any maintenance jobs as & when essential during the lean periods.

A Portal crane will be provided for handling hoists & gates for maintainance of +114 gates The rope & rope drums for +103 gates shall be placed on similar way.

d

Considering the age of the Surkhi mortar structure, the most challenging work shall be to handle the work of installation/ modification work of gate grooves & provision of embedment in the civil structure for the proposed new gates without affecting the integrity of the civil structure.

Work of installation / modification of gate and hoist will be handled without affecting the integrity of the masonry structure considering age of dam for the proposed New gates . Precautionary method will be adopted and methodology /experience gained during execution of +80’ vents will be given as guidelines for the executing agency

e

The proposed methodology for the civil structure has been broadly discussed & envisaged & the project has been advised to prepare the detailed methodology based on their past experience gained on earlier modified gate installations at + 80 & other locations as a guideline for the executing agency for preparation of bid document and submission to

Work of installation / modification of gate and hoist will be handled without affecting the integrity of the masonry structure considering age of dam for the proposed New gates . Precautionary method will be adopted and methodology /experience gained during execution of +80’ vents will be given as guidelines for the executing


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CPMU for review. agency

103 &106 Gates & Hoists

1

The scheme of the proposed replacement of cast iron gates & embedded parts for +103 & +106 gates by structural steel wheeled gates as per IS 4622 along with their embedded parts has already been cleared.

The Embedded parts and wheeled gate for 103 & +106 gates ( Structural steel ) will designed as per IS 4622.

2

Project had all along been requesting for provision of independent rope drum hoists over trestles for all the gates. Keeping in view the requirement for independent hoist driven gates at these locations, the same was also agreed to with a centralised control room for

operation of all the gates on these sluices with the exception that hoist light weight, compact, skid mounted electric wire rope hoists conforming to IS 3938-1983 to be adopted for +114, +103 gates & also

for +106 gates at the top of dam structures (without use of trestles) to be mounted on the same pattern as for the +114 gates.

The rollers will be out of cast steel with anti-friction bearing and will be replaced as per the proposal.

The Independent rope drum hoist will be mounted on pier and designed for a IS 6938 and is operated by central control remote system for +114, +103 & +106 gates

3938 -1983.

Maintenance provision:

For facilitating this a portal structure crane shall be provided over the existing rail system for handling the removal of hoists & gates for maintenance of gates & hoists at +103 & +114 gate installations along with a similar separate portal structure for maintenance of

+106 gate installations. Moreover the ropes & rope drums for +114 gates shall be such as will allow these gates to be lowered to the sluice + 103 ground level for any maintenance jobs as & when essential during the lean periods, if so required.

A Portal structure crane shall be provided for existing rail system for handling for maintenance of +103 , +114 and also for +106 hoists & gates. With this portal the hoist is to be freed from the gate and gate is to be lifted above the pier for maintenance. Only one gate at a time can be taken up for maintenance. It is empathized the time required for maintenance of 48 gates may be high. If the hoist is on the individual hoist bridge then the maintenance will be quicker and easier as the hoist and gate need not be freed to take out gate from the vent. We request to examine to adopt hoist and hoist bridge mounted on the column. This will not affect aesthetes and outlook of the dam. Further we will have similar look from +106’ to end of dam i.e. including recently renovated vent +80’. Illumination to the hoist will be further attractive.


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