project rehabilitation report of votehole dam,

Project Rehabilitation Report of Votehole Dam

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Project Rehabilitation Report

of Votehole Dam, Karnataka Water Resources Department

Doc. No.: CDSO_DSR_PRR_ KA06HH0154_KaWRD_v1.0

July 2019

Central Water Commission

Ministry of Jal Shakti

Department of Water Resources,

River Development & Ganga Rejuvenation

Government of India


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THIS PAGE IS LEFT BLANK INTENTIONALLY


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Quality Control:

Version Date Writers/Contributors Checked by

1 31/07/2019 Dr. Hadush S Hagos (HSH) Pankaj Kumar Awasthi (PKA Anil Kumar Verma (AKV)

Rajiv Kumar Sawarn

Issued/Copied to:

I/C Date Name Organisation

Issued 31/07/2019 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

ESMF Environmental and Social Management Framework


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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 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 ......................................................................................................................... 11

3. DAM VISITS (PST STAGE) ............................................................................ 17

3.1 Dam Inspections ............................................................................................................ 17

3.2 Summary of observations made by CPMU ................................................................. 17

4. DESIGN FLOOD REVIEW (DFR) ................................................................... 17

4.1 DFR Outcome ................................................................................................................. 17

4.2 Brief Summary of Review.............................................................................................. 17

4.3 Recommendations ......................................................................................................... 17

5. REHABILITATION WORKS CARRIED OUT ................................................. 17

5.1 Summary of Investigations ........................................................................................... 17

5.2 Main Dam Works ............................................................................................................ 18

5.3 Basic facilities ................................................................................................................ 18

6. INSTRUMENTATION ..................................................................................... 18

6.1 List of existing instruments installed in dam and their condition ............................ 18

6.2 Details of new instruments installed ........................................................................... 18

6.3 CPMU Recommendations ............................................................................................. 18

7. PROCUREMENT OF WORKS ....................................................................... 19

7.1 Package wise details ..................................................................................................... 19

7.2 Details of bidding process ............................................................................................ 20

7.3 Reason for Variation, if any .......................................................................................... 20

7.4 Litigation / Arbitration, If Any ....................................................................................... 20

8. THIRD PARTY CONSTRUCTION SUPERVISION VISITS BY CPMU ........... 20

8.1 Summary of Visits undertaken ..................................................................................... 20


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8.2 Summary of Third Party Material Testing .................................................................... 20

8.3 Summary of Major Recommendations ........................................................................ 20

8.4 Summary of Compliance by SPMU .............................................................................. 24

8.5 Summary Special Visits made by CWC/World Bank/Expert Committee .................. 24

8.6 Summary of Technical Assistance provided by CPMU ............................................. 24

9. ENVIRONMENTAL AND SOCIAL MANAGEMENT FRAMEWORK (ESMF) 24

9.1 Basic Details ................................................................................................................... 24

9.2 Summary of Observations ............................................................................................ 24

9.3 Details of ESMF/EIA study (if any) ............................................................................... 24

10. OTHER NON-STRUCTURAL INTERVENTIONS ........................................... 24

10.1 Basic Details ................................................................................................................... 24

10.2 Summary of Observations ............................................................................................ 25

11. PENDING REHABILITATION WORKS .......................................................... 25

11.1 Details of pending works .............................................................................................. 25

11.2 Further course of action................................................................................................ 25

12. REFERENCES ............................................................................................... 25

Annex A: PST Approval Letter .............................................................................. 27

Annex B: Drawings issued for Rehabilitation measures .................................... 31

Annex C: Completion Certificate .......................................................................... 41

Annex D: Photographs Before and After Rehabilitation Works ......................... 51

Annex F: DBA and Inundation Maps .................................................................... 63

LIST OF FIGURES

Figure 2-1: Index Map of Votehole Dam. ........................................................................................... 11

Figure 2-2: Google Map of Votehole Dam. ........................................................................................ 12

Figure 2-3: Layout Map of Votehole Dam. ........................................................................................ 13

Figure 2-4: Longitudinal Section of Votehole Dam. ....................................................................... 14

Figure 2-5: Typical Cross Section of Votehole Earth Dam. ............................................................ 15

Figure 2-6: Masonry Dam & Spillway Cross-section of Votehole Dam. ........................................ 16


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1. EXECUTIVE SUMMARY

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

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

inspected the dam in May 2015 and recommended both structural & non-structural

measures to be taken up by the dam authorities.

DSRP main recommendations included arresting leakage on left bank along a

pipeline under non-overflow section of masonry dam; providing drainage for the dam

top roadway by providing cross slope towards downstream; providing longitudinal

and cross drains on downstream slope of dam; install an automatic water level

recorder; examine condition of existing piezometers and if needed provide new ones;

clear all vegetative growths noticed on the spillway; non-overflow dam sections and

training walls; provide trash racks at the entry of sluice vents; and investigation of

spillway stilling basin. Non-structural measures included review of design flood,

reservoir siltation surveys; preparation of EAP and O&M manual.

The original design flood for Votehole dam was 531.07 m3/sec with corresponding

MWL of 966.05 m. The revised design flood (SPF) under DRIP worked out to be

1606 m3/sec. Flood routing study carried out by the SPMU indicates that the revised

MWL is at EL 967.84 m. The Top Bund Level (TBL) is at 968.48 m. Hence, the

available freeboard above the revised MWL is only 0.64 m, which is less than the

recommended 1.5 m freeboard for embankment dams as per IS 10635. Compliance

to freeboard requirements for the revised design flood is pending.

Following DSRP recommendations, rehabilitation works carried out under DRIP

included:

Package 1 (Civil):

Providing longitudinal and cross drains for the downstream slope of earthen

dam.

Providing semi dense bituminous concrete on road way of dam.

Arresting leakage on the left bank.

Providing trash racks for Irrigation sluices.

Providing barbed wire fencing.

Package 2 (Instrumentation):

Providing and installation of piezometer and Automatic water level recorder.

The rehabilitation works were executed under 2 contracts at a total completion cost

of Rs. 163.73 Lakhs.

Existing vibrating wire piezometers were repaired and made functional. Hence,

installation of piezometer in package 2 was omitted. Automatic water level recorder

was installed.

CPMU carried out dam break analysis and prepared inundation maps. Based on this,

Emergency Action Plan (EAP) was prepared by dam authorities, reviewed by CPMU

and has been published for stakeholders dissemination.

Operation and Maintenance (O&M) manual is currently under preparation as per

CWC guidelines published under DRIP.


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2. PROJECT DETAILS

The Votehole dam is located across Votehole River in Hassan district, Karnataka

state at Latitude of 13º03’30” N and Longitude of 75º55’00” E. It was completed in

the year 1984. The project consists of an earthen dam 1,075 m long and 5.49 m dam

crest width. It has 32 m long spillway with 3 nos. of radial gates having discharge

capacity of 531.07 cumec.

The TBL, FRL, original MWL and Spillway Crest level are at EL 968.48 m, 966.05 m,

966.05 m and 961.476 m, respectively. The gross storage at FRL is 42.75 MCM (or

1.51 TMC).

2.1 Project Description

Sl. No.

Item Details

a. Project Identification Code (PIC) KA06HH0154

b. Project Name Votehole Dam

c. River Basin Cauvery

d. Sub River Basin Votehole

e. River/Stream Votehole

f. Catchment area (km2) 110

g. Year of commencement of project 12/01/1975

h. Year of completion of project 05/01/1984

2.2 Project Location

Sl. No.

Item Details

a. State Karnataka

b. District Hassan

c. Earthquake Zone II

d. Survey of India Map Ref No’s 48-o/16

e. Nearest City Hassan

f. Nearest Airport Bangalore

g. Nearest Railhead Hassan

h. Name of Immediate U/S Project No

i. Name of Immediate D/S Project Hemavathy Dam

j. Latitude in Deg., Min, Sec. (North) 13º03’30”

k. Longitude in Deg., Min, Sec. (East) 75º55’00”

2.3 Project Benefits

Sl. No. Item Details

a. Type of Project Irrigation

b. Gross Command Area (Ha) 9108


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Sl. No. Item Details

c. Culturable Command Area (Ha) 7489

d. Annual Irrigation Potential (Ha) 7489

e. Hydropower –

Installed Capacity (MW) Nil

f. Hydropower –

Firm Power (MW) Nil

g. Hydropower –

Average Annual Generation (MU) Nil

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) 966.05

b. Original Maximum Water Level (m) 966.05

c. Gross Reservoir Storage Capacity at FRL (Mm

3 )

42.75

d. Live Storage Capacity (Mm3 ) 38.7

e. Revised Live Storage Capacity, if any

(Mm3 )

38.7

f. Date of bathymetric survey, if any Nil

g. Dam Type Earth fill Cum Masonry Dam

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

1,075

912

163

i. Number and length of dykes (No. & m) 1, 175

j. Top of dam (El. in m.) 968.48

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

28.19


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Sl. No.

Item Details

top) 44.48

m Top width of main dam (m) 5.49

n. Spillway details

i) Location Middle

ii) Type of spillway Ogee

iii) Length of spillway (m) 32

iv) Spillway crest level (m) 961.476

v) Type of Gate Radial

vi) Number and size of gates (no. and

m. x m.) 3, 9.14 X 4.57

vii) Number and thickness of piers (no.

and m. x m.) 2, 2.286

o.

Outlet/Sluice details

i) In Embankment dam

Number

Size (Width (m). x Height (m).)

Location

Invert level El. (m)

Discharging capacity (m3/s)

ii) In Concrete/Masonry dam

Number

Size (m. x m.)

Location

Invert level El. (m)

Discharging capacity (m3/s)

2, LBC and RBC

1.524 X 0.90 and 1.828 X 1.676

CH +185 and CH +750

955.00 and 953.235

0.358 and 3.88

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 27/06/15

b. Proposed PST Cost (INR in Lakhs) 215.0

c. First review by CPMU -

d. Final review by CPMU 19/08/15

e. World Bank Approval 24/08/15 E- mail dated 24/08/2015

f. Approved PST Cost (INR in Lakhs) 215.0


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2.8 DSRP, CPMU and World Bank Recommendations and Compliance

2.8.1 DSRP Recommendations and Compliance

Compliance to DSRP recommendations as submitted by SPMU/dam authorities is

shown on pages 6 to 10 below.

2.8.2 CPMU/World Bank Recommendations and Compliance

Majority of CPMU/WB Comments are in line with DSRP comments. Additional

recommendations raised by CPMU/WB included dam stability analysis and ensuring

the impervious core is above the revised MWL. These recommendations are yet to

be taken up by the SPMU.

2.9 Scope of Rehabilitation Works as per PST

(a) Remedial Measures (Structural)

i. Providing longitudinal and cross drain for the downstream slope and longitudinal drain for saddle portion of left bank

ii. Arresting leakage on the pipe line provided in the left bank portion

iii. Providing trash racks for right bank sluice and left bank sluice.

(b) Non-structural Measures

iv. Providing and installation of Piezometers and automatic water level recorder.

(c) Basic Facilities

v. Providing and installation of Piezometers and automatic water level recorder.


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2.10 Drawings

Figure 2-1: Index Map of Votehole Dam.


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Figure 2-2: Google Map of Votehole Dam.


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Figure 2-3: Layout Map of Votehole Dam.


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Figure 2-4: Longitudinal Section of Votehole Dam.


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Figure 2-5: Typical Cross Section of Votehole Earth Dam.


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Figure 2-6: Masonry Dam & Spillway Cross-section of Votehole Dam.


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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) 20 August 2014

b. Site Visit made by CPMU experts 21 August 2015

3.2 Summary of observations made by CPMU

CPMU observation and recommendation focused mainly on arresting leakage

through a pipeline on the left bank under the non-overflow masonry dam section.

This was taken in the works Contract and an attempt was made to arrest the leakage

from the downstream side but it was not successful.

4. DESIGN FLOOD REVIEW (DFR)

4.1 DFR Outcome

Sl. No.

Item Original

Value

Revised

Value Remarks

a. Inflow Design Flood (m3/s) 531.07 1,606 SPF

b. Spillway Capacity / Routed Outflow (m

3/s)

- 937.45 Flood routing study by SPMU

c. Maximum Water Level (m) 966.05 967.84 TBL = 968.48

4.2 Brief Summary of Review

The original design flood for Votehole dam was 531.07 m3/sec with corresponding original MWL of 966.05 m. The revised design flood (SPF) under DRIP worked out to be 1606 m3/sec. Flood routing study carried out by the SPMU indicates that the revised MWL is at EL 967.84 m. The Top Bund Level (TBL) is at 968.48 m. Hence, the available freeboard above the revised MWL is only 0.64 m, which is less than the recommended 1.5 m freeboard for embankment dams as per IS 10635.

4.3 Recommendations

Structural measures – a 1 m high parapet wall shall be considered to be

considered to accommodate the revised deign flood.

Non-structural measures - EAP.

5. REHABILITATION WORKS CARRIED OUT

5.1 Summary of Investigations

Sl. No.

Item Details Remarks

a. Geo-Physical Investigations NA

b. Reservoir Bathymetric Study Not Carried Out


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Sl. No.


c. Hydraulic Model Studies NA

d. Underwater investigation of spillway flip bucket

NA

5.2 Main Dam Works

Sl. No.


a. Works from hydrological angle

Design flood review Completed.

b. Repairs to d/s toe drains, provision of V-Notches for seepage measurements

Providing longitudinal and

cross drains for the

downstream slopes of earthen

dam

Completed.

c. Works because of Seepage / leakage issues in embankment dams

Arresting leakage on left bank

Work carried out but

not successful in

arresting leakage.

d. Hydro-mechanical works

i. Outlet gates & hoists

Providing trash racks for Irrigation sluices

Completed.

5.3 Basic facilities

S/N Item Details Remarks

a. Roads Providing semi dense bituminous concrete on road way of dam

Completed.

b. Fencing / security provisions Providing barbed wire fencing Completed.

c. Others Providing and installation of piezometer and Automatic water level recorder.

Completed.

6. INSTRUMENTATION

6.1 List of existing instruments installed in dam and their condition

Digital water level recorder.

Vibrator wire piezometers.

6.2 Details of new instruments installed

Nil.

6.3 CPMU Recommendations

Nil


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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 Completio

n date

Contract /

Award Value

(INR in Lakhs)

Completion Cost (INR in Lakhs)

Actual Date of

Completion

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

1

Providing longitudinal and

cross drains for the downstream slopes

of earthen dam: Semi dense

bituminous concrete on road way of dam, Arresting leakage on left

bank, Trash racks for Irrigation sluices, Barbed wire fencing

to Votehole dam under Votehole

reservoir project.

149.7 NCB 05/12/15 - 16/11/15 No.: 07/2016-

17 20/04/2016

S.NARAYANAR:EDDY, CLASS-I

CONTRACTOR,

NAGASAMUDRA ROAD

CHANNARAYAPATTANA.

HASSAN DIST.

6 01/11/16 160.08 158.23 18/08/17

2

Providing and installation of

piezometer and Automatic water level recorder to Votehole dam

21.7 NCB 05/12/15 - 16/11/15 No. 08 /2016-

17 02/05/2016

SRI. ABDUL ADIL,

CONTRACTOR AIMJL LTD, NAGASANDR

A OUTER RING ROAD

,BANGALORE .

6 01/1116 20.31 5.5 29/10/18


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7.2 Details of bidding process

As per details in the above table.

7.3 Reason for Variation, if any

No variation of cost increase was registered. As the existing piezometer was repaired

and functional, there was no need to install new piezometers. Hence only 27.1% of

package 2 contract amount was used for installation of automatic water level

recorder and repair of existing piezometers.

7.4 Litigation / Arbitration, If Any

No litigation.

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. 27-07-2016 3585/11.08.2016

b. 13-12-2016 4038/29.12.2016

c. 21-06-2017 4765/11-07-2017

d. 22-09-2017 5817/29.11.2017

e. 17-01-2018 5589/22.02.2018

8.2 Summary of Third Party Material Testing

Nil.

8.3 Summary of Major Recommendations

1st Construction Site Visit Report

Key observations:

Welding works (Providing of trash racks) normally require Welding

Procedures and Certified Welders. In this case the welding works regard

normal steel grating panel, nonetheless it is recommended to use very high

skill labours.

Significant documentations need to be completed and submitted.

Recommendations:

PPE supplying to be improved (Safety Shoes).

The Contractor has demonstrated good attitude and knowledge for

performing the scheduled works, nevertheless Method Statement represents

a crucial document in case any corrective action might be required.


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2nd Construction Site Visit Report

Observations and Recommendations:

The overall quality of works reviewed is considered as satisfactory; however,

significant documentation including the environmental management plan,

HSE manual and method statements need to be completed and submitted at

the earliest.

Closure of an underground leak on near the toe of the embankment wrap-

around is still in progress. The Contractor has excavated to a depth of 3 to 4

meters to cap the leak in an old water line that is no longer in use. Closure of

the line is important to ensure erosion potential is stopped. The leaking pipe

has been a long-term problem at the dam and is now under remedial works

as part of the DRIP works.

Package II – Instrumentation is yet to be taken up. This package has been

awarded with a contract value of Rs. 0.20 Crore and includes installation of

piezometers for use in monitoring performance of the embankment. Notice to

proceed has not been granted at the time of the site visit.

No. Deficiency or Observation Remarks

1 Housekeeping chores needed attending to.

Contractor has cleared debris. Minor excavated material around concrete work needs to be removed and or spread out and compacted.

2 Bare areas adjacent to drains and kerb wall need to be turfed. Not in contract

CPMU recommends these areas be turfed or seeded to minimize erosion.

3 Contract for Instrumentation works not yet taken up.

Award is awaited.

4 Grass emerging through fresh asphalt

Contractor to apply environmentally-friendly herbicide to check weed growth on all pavements.

3rd Construction Site Visit Report Observations:

Observations and recommendations

DSRP’s recommendations for the left downstream non-overflow section river

sluice pipe leakage included finding the source of the leaks and plugging as

necessary. However, during excavation upstream of the shutoff valve and slightly

downstream of the masonry section, it became evident that this activity could not

be implemented and plugging the pipe downstream was not feasible.

CPMU recommends that the BOQ line items in the contract be tasked to conduct

geophysical scanning to first locate position of intake pipe alignment and

secondary to locate seepage/leakages along pipe. Once the information and

drawings are prepared, a solution for controlling the seepage may be entertained.

The porous and foundation drains are thoroughly calcinated and or plugged with

calcareous materials. CPMU recommends these items as well as upstream face

treatment be carried out during the second phase of DRIP and or as time and

budget allow.

No. Deficiency or Observation Remarks

1 Bare areas adjacent to drains and kerb wall needs to be turfed. Not in contract

CPMU recommends these areas be turfed or seeded to minimize erosion


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2 Contract for Instrumentation works not yet taken up.

Requires MD approval

3 Grass emerging through fresh asphalt

Contractor to apply environmentally-friendly herbicide to check weed growth on all pavements

4 Seepage under left NOF section

Efforts to close the River Sluice pipe have not been accomplished. CPMU recommends a magnetometer scan of the reservoir be constructed using contract line items for consultancies to locate and recommend repair of the old MS pipe.

4th Construction Site Visit Report Observations:

Observations and recommendations:

Most of the porous holes in the body of the dam are clogged and very little or no

flow of water from the drainage holes in the foundation gallery. Reaming/re-

drilling of both the porous drains and foundation drains are required to be taken

up.

The older piezometers have been repaired and appear to be in good working

condition. CPMU recommends the data be recorded and monitored for any

changes.

For arresting leakage on the left bank, the IA has recommended the Contractor

sink another 10-feet of well to reach the pipe location and deploy higher capacity

dewatering pump to complete the well sinking. The problem is that there are no

plan drawings indicating the exact position and actual size of the conduit.

Possibility of real piping erosion along the existing pipe could occur and a

sinkhole could develop on the upstream side of this very short non-overflow

section. Loss of the wrap-around and potential erosion of the non-overflow block

could seriously compromise the stability of the dam. CPMU strongly

recommends stoppage of additional sinking of the well works immediately.

Further, CPMU urges that the IA develops a methodology and plan for repairing

the pipe and control mechanism to ensure the dam remains stable and the

undersluice can be used without endangering the dam. Below is an example of

necessary steps to assist the IA in developing a thorough program to fix the pipe

without endangering the safety of the dam:

Immediately backfill the downstream excavation with graded crushed

aggregate 19-mm (-minus).

Locate the existing pipe on the upstream side of the where it enters the non-

overflow block.

Excavate the upstream side of the wraparound to the pipe level.

Sleeve the mild steel 30-cm-diameter pipe through the masonry section

Install new HR valve on the upstream side.

Backfill the upstream wrap-around with impervious material allowing for an

inspection well around new valve.

Remove all downstream existing pipes and replace with new pipe either

steel or Hume pipe, backfill and compact using best engineering practices.


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No Observation / Deficiency Remarks

1

Mortar layer of concrete at D/s face of glacis got eroded/peeled off at many locations and aggregate surface is exposed. (Fig-9 & 10)

Damage caused is not critical at present. Depending on frequency and duration of letting out of water through gates may cause further deterioration of glacis and lead to major damages. It is recommended for abrasive protective coat,

2 Providing and installation of piezometers under packge-2

During the inspection of CE, WRDO & Nodal Officer DRIP, it was noticed that the piezometers already embedded are in working condition and displaying the readings. Hence instructed there is no need of providing new piezometers. During my inspection also it is observed that the piezometer gauges are displaying the readings.

3 Installation of water level recorder under package-2

Contractor not mobilised to carry out the work.

5th Construction Site Visit Report Observations:

Observations and recommendations:

The Contractor was not successful in arresting the leakage along the pipeline on

left flank masonry. Attempts made by excavating at the d/s toe of the dam were

not acceptable for the safety of the dam and in the last CSV report, the

Contractor was instructed to immediately backfill the excavated section with

sand-gravel material However, backfill was not done until the current site visit and

CPMU again gave the same instruction during this inspection. One month later,

the Contractor has carried out the backfill and sent photographs on 16 February

2018.

As previously recommended by CPMU, any attempt to plug the leakage shall be

done from u/s side.

On the capacity of the spillway, a flood routing report dated 9 Nov 2015 indicates

that the MWL for the revised design flood is at EL 967.84 m. The dam crest level

is at 968.48 m (3177.42 ft). Hence, the available freeboard above MWL is only

0.64 m. CPMU recommends construction of a 1-meter-high wave deflection wall

to meet minimum freeboard requirements be taken up as budget and schedule

allow. DSRP & PST also recommended to prepare EAP including a suitable

communication system for flood warning.

SPMU informed that the leakage along the pipeline under left masonry NOF

section has been continuing for over 25 years (since 1992). The leakage amount

ranges from 2 to 2.5 l/s. SPMU also informed that the pipeline is about 8 m below

the hand wheel of the valve at the toe of the dam. Based on this and geological

borehole log information near the pipeline obtained from old design drawings, the

pipeline may be in a rock foundation. But SPMU is recommended to further verify

and confirm.

No. Deficiency / Observation Remarks

1 Excavation at the toe of the dam to locate source of leakage along pipe. This is not acceptable in terms of safety of the dam.

Contractor stopped excavation and backfilled.

2 Some corrosion of installed trash racks at left and right bank canal intakes

Contractor agreed to paint the trashracks with suitable anti-corrosion epoxy.


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8.4 Summary of Compliance by SPMU

The main compliance issue was related to arresting leakage on left bank under NOF

section of the dam. However, as explained above, this activity could not be

implemented successfully and plugging the pipe downstream was not feasible.

SPMU compliance of the same is also given on page 9, in No. 9 of compliance to

DSRP recommendations.

8.5 Summary Special Visits made by CWC/World Bank/Expert Committee

Nil.

8.6 Summary of Technical Assistance provided by CPMU

Review of PST. Review of design flood.

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

Carrying out dam break analysis and preparation of inundation maps.

Review of Emergency Action Plan (EAP).

9. ENVIRONMENTAL AND SOCIAL MANAGEMENT

FRAMEWORK (ESMF)

9.1 Basic Details

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 CPMU

construction site visit reports indicate PPE was hardly provided during construction.

9.3 Details of ESMF/EIA study (if any)

Nil.

10. OTHER NON-STRUCTURAL INTERVENTIONS

10.1 Basic Details

Sl. No.

Item Yes / No Remarks

a

Emergency Action Plan (EAP)

(i) EAP Available at Site

(ii) EAP Prepared under DRIP

(iii) EAP Published

No

Yes

No

Inundation maps prepared by CPMU and based on this the SPMU prepared EAP, which was reviewed and approved by CPMU for


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Sl. No.

Item Yes / No Remarks

(iv) Stake holder consultations No stakeholders’ dissemination.

b. O&M Manual availability Yes O&M manual is under preparation as per DRIP guideline.

c. Inflow Forecasting No

d. DHARMA Implementation Yes In progress. Most data uploaded.

e. Siren Yes Yes

10.2 Summary of Observations

Nil

11. PENDING REHABILITATION WORKS

11.1 Details of pending works

i. Compliance to freeboard requirements for the revised design flood as per IS

10635.

ii. Preparation of O&M manual.

iii. Completion of data entry in DHARMA.

iv. Address noted incompliances to DSRP recommendations.

11.2 Further course of action

All pending actions stated above should be completed before December 2019.

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 letters from SPMU.

viii. Inundation report and maps.


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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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Providing longitudinal and cross drains for the downstream slope - Before

Providing longitudinal and cross drains for the downstream slope - During


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Providing longitudinal and cross drains for the downstream slope – During



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Providing longitudinal and cross drains for the downstream slope – After


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Arresting Leakage on Left Bank – During



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Arresting Leakage on Left Bank – During and After Backfiling at toe of dam


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Providing Trash Rack for Irrigation Sluice


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Providing Barbed Wire Fencing - During

Providing Barbed Wire Fencing - During


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Providing Barbed Wire Fencing – After


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Installed Automatic Water Level Recorder


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Repaired Vibrating Wire Piezometer – Functionlal

Completed Asphalt Road on Dam Crest


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Annex F: DBA and Inundation Maps


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project rehabilitation report of votehole dam,

Documents