project rehabilitation report of amarja dam,

Project Rehabilitation Report of Amarja Dam

Project Rehabilitation Report

of Amarja Dam, Karnataka Water Resources Department

Doc. No.: CDSO_DSR_PRR_ KA06HH0199_KaWRD_v1.0

July 2019

Central Water Commission

Ministry of Water Resources,

River Development & Ganga Rejuvenation

Government of India


THIS PAGE IS LEFT BLANK INTENTIONALLY


Quality Control:

Version Date Writers/Contributors Checked by

1 31/06/2019 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 08/07/2019 Shri. Pramod Narayan Central Water Commission


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

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


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.



Table of Contents

Abbreviations ........................................................................................................... 5

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

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

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

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

2.3 Project Benefits ................................................................................................................ 3

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 ....................................................................................................................... 5

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

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

2.10 Drawings ......................................................................................................................... 14

3. DAM VISITS (PST STAGE) ............................................................................ 21

3.1 Dam Inspections ............................................................................................................ 21

3.2 Summary of observations made by CPMU ................................................................. 21

4. DESIGN FLOOD REVIEW (DFR) ................................................................... 21

4.1 DFR Outcome ................................................................................................................. 21

4.2 Brief Summary of Review.............................................................................................. 21

4.3 Recommendations ......................................................................................................... 22

5. REHABILITATION WORKS CARRIED OUT ................................................. 22

5.1 Summary of Investigations ........................................................................................... 22

5.2 Main Dam Works ............................................................................................................ 22

5.3 Basic facilities ................................................................................................................ 23

6. INSTRUMENTATION ..................................................................................... 23

6.1 List of existing instruments installed in dam and their condition ............................ 23

6.2 Details of new instruments installed ........................................................................... 23

6.3 CPMU Recommendations ............................................................................................. 23

7. PROCUREMENT OF WORKS ....................................................................... 24

7.1 Package wise details ..................................................................................................... 24

7.2 Details of Bidding Process ........................................................................................... 25

7.3 Reason for Variation, if any .......................................................................................... 25

7.4 Litigation / Arbitration, If Any ....................................................................................... 25

8. THIRD PARTY CONSTRUCTION SUPERVISION VISITS BY CPMU ........... 25


8.1. Summary of Visits undertaken .................................................................... 25

8.2. Summary of Third Party Material Testing ................................................... 25

8.3. Summary of Major Recommendations ........................................................ 25

8.4. Summary of Compliance by SPMU ............................................................. 29

8.5. Special Visits made by CWC/World Bank/Expert Committee ................... 29

8.6. Summary of Technical Assistance provided by CPMU ............................. 29

9. ENVIRONMENTAL AND SOCIAL MANAGEMENT FRAMEWORK (ESMF) 29

9.1 Basic Details ................................................................................................................... 29

9.2 Summary of Observations ............................................................................................ 30

9.3 Details of ESMF/EIA study (if any) ............................................................................... 30

10. OTHER NON-STRUCTURAL INTERVENTIONS ........................................... 30

10.1 Basic Details ................................................................................................................... 30

10.2 Summary of Observations ............................................................................................ 30

11. PENDING REHABILITATION WORKS .......................................................... 30

11.1 Details of pending works .............................................................................................. 30

11.2 Further course of action................................................................................................ 30

12. REFERENCES ............................................................................................... 31

Annex A: PST Approval Letter .............................................................................. 33

Annex B: Drawings issued for Rehabilitation measures .................................... 39

Annex C: Completion Certificate .......................................................................... 45

Annex D: Third Party QC Tests ............................................................................. 53

Annex E: ESMF OK Card ....................................................................................... 61

Annex F: Photographs Before and After Rehabilitation Works ......................... 65

Annex G: DBA and Inundation Maps .................................................................... 77

LIST OF FIGURES

Figure 2-1: Index Map of Amarja Dam. ............................................................................... 14

Figure 2-2: Google Map of Amarja Dam. ............................................................................. 15

Figure 2-3: Water Catchment Map of Amarja Dam. ............................................................. 16

Figure 2-4: Layout Map of Amarja Dam............................................................................... 17

Figure 2-5: Longitudinal Section of Amarja Dam. ................................................................ 18

Figure 2-6: Typical Cross Section of Amarja Earth Dam. .................................................... 19

Figure 2-7: Spillway Cross-section of Amarja Dam. ............................................................ 20


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1. EXECUTIVE SUMMARY

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

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

the dam on 7th April 2015 and recommended both structural & non-structural

measures to be taken up by the dam authorities.

DSRP main recommendations included reaming of porous and foundation drains

inside the gallery; concrete dam body grouting; concrete dam foundation curtain

grouting; provision of horizontal collector drain on dam crest and chute drains on dam

d/s slope; repair of disturbed riprap in selected sections; installation of V-notch weir;

renovation of spillway and sluice gates and hoisting mechanism including painting,

oiling, greasing and replacement of rubber seals. Non-structural measures included

review of design flood, dam stability analysis, preparation of EAP and O&M manual.

The original design flood was 2,832 cumec and the revised design flood (PMF) under

DRIP worked out to be 3,704 cumec. The MWL for the original design flood was at

EL 461.5 m. Flood routing study carried out by CPMU indicates that the MWL for the

revised design flood is at 461.52 m, which is only 0.02 m above the original MWL.

The TBL is at 464.5 m. The freeboard above the revised MWL is 2.98 m and fulfils

the minimum recommended 1.50 m for embankment dams as per IS 10635.

Following DSRP recommendations, rehabilitation works carried out under DRIP

included:

Improvements to Earthen Dam and Rough Stone Revetment

Construction of MSS Road on Top of Dam Bund

Construction of Surface Drains on Earthen Bund of D/s slope

Reaming of Porous and Drainage Holes

Grouting Treatment to Spillway of U/s and D/s, Stilling Basin

Providing Painting to Radial Crest Gates, Stop Log Gates and Overhauling

and Maintenance of Radial Crest Gates, Stop Log Gates and Gantry crane

Restoration of RBC Sluice Gate

Providing and Fixing Ladder to Crest Gates on D/s Side including Hand

Railing and to Catwalk, Drain Holes, Platform, Trash Rack for Sluices, and

Gauge Board Writing.

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

Rs. 254.37 Lakhs. SPMU reported Rs. 70.19 Lakhs savings due to change in scope

of work during construction.

Following DSRP recommendations, dam body grouting was carried out on non-

overflow section of the concrete dam. However, no grouting was carried out in the

overflow section and heavy leakage still continues inside the gallery (see section 8.3

for details).

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

were reviewed by CPMU. Draft O&M manual prepared by SPMU as per guideline

published by CWC under DRIP has also been reviewed by CPMU. EAP is currently

under preparation by the SPMU.


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2. PROJECT DETAILS

The Amarja dam is located across Amarja River in Gulbarga district, Karnataka state

at Latitude of 17º29’6.74” N and Longitude of 76º33’7.55” E. It was completed in the

year 1999.

The project consists of an earthen dam 827 m long and 5.0 m dam crest width. It has

77 m long spillway with 5 nos. radial gates having discharge capacity of 2,832

cumec.

The TBL, FRL, original MWL and Spillway Crest level are at EL 464.5 m, 461.5 m,

461.5 m and 452.5 m, respectively. The gross storage at FRL is 44.01 MCM (or 1.55

TMC).

2.1 Project Description

Sl. No.

Item Details

a. Project Identification Code (PIC) KA06HH0199

b. Project Name Amarja Dam

c. River Basin Krishina

d. Sub River Basin Manjra

e. River/Stream Bhima

f. Catchment area (km2) 530.85

g. Year of commencement of project 1973

h. Year of completion of project 1999

2.2 Project Location

Sl. No.

Item Details

a. State Karnataka

b. District Gulbarga

c. Earthquake Zone II

d. Survey of India Map Ref No’s 56C/11 & 56C/10

e. Nearest City Gulbarga

f. Nearest Airport Hyderabad

g. Nearest Railhead Ghanagapur

h. Name of Immediate U/S Project Nil

i. Name of Immediate D/S Project Nil

j. Latitude in Deg., Min, Sec. (North) 17º29’6.74”

k. Longitude in Deg., Min, Sec. (East) 76º33’7.55”


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2.3 Project Benefits

Sl. No. Item Details

a. Type of Project Irrigation

b. Gross Command Area (Ha) 14959

c. Culturable Command Area (Ha) 8903

d. Annual Irrigation Potential (Ha) 8903

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) 3.51

i. Domestic/Municipal/Industrial Water –

Area and Population Benefitted 10.5 KM² and 422,366

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) 461.5

b. Original Maximum Water Level (m) 461.5

c. Gross Reservoir Storage Capacity at FRL (Mm

3 )

44.01

d. Live Storage Capacity (Mm3 ) 40.07

e. Revised Live Storage Capacity, if any

(Mm3 )

-

f. Date of bathymetric survey, if any -

g. Dam Type Earthen embankment

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

960

827

133 (central masonry dam/spillway)

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

j. Top of dam (El. in m.) 464.5

k. Top Level of Upstream Parapet Wall of -


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Sl. No.

Item Details

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)

24

18.5

m Top width of main dam (m) 5.0

n. Spillway details

i) Location Middle (CH 842 m to 919 m)

ii) Type of spillway Ogee

iii) Length of spillway (m) 77

iv) Spillway crest level (m) 452.5

v) Type of Gate Radial

vi) Number and size of gates (no. and

m. x m.) 5, 13 x 9

vii) Number and thickness of piers (no.

and m. x m.) 4

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, RBC)

0.8 m x 2.2 m

CH 435 m, CH 975 m

449 m

2.27, 1.82

Nil

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


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2.7 PST Details

Sl.

No. Item Date/Cost Remarks

a. PST first received from SPMU 14/05/15

b. Proposed PST Cost (INR in Lakhs) 400

c. First review by CPMU 17/06/15

d. Final review by CPMU 02/09/15

e. World Bank Approval 23/09/15 E- mail dated 23/09/2015

f. Approved PST Cost (INR in Lakhs) 330

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 15 to 22 below.

2.8.2 CPMU/World Bank Recommendations and Compliance

WB Comments are in line with DSRP comments specially related to dam stability

analysis, foundation curtain grouting, and provision of sufficient pumps inside gallery.

The SPMU compliance to this comment is as given in item 2.9.1 of the compliance to

DSRP comments (see pages 17, 20 and 21).

2.9 Scope of Rehabilitation Works as per PST

(a) Remedial Measures (Structural)

i. Improvement to Earthen dam

ii. Construction of toe drain with chambers

iii. Construction of surface drain on D/s

iv. Repairs & Grouting of drainage gallery

v. Grouting treatment to observed seepage in the spillway

vi. Drilling of weep holes at right and left side training wall

vii. Restoration of RBC sluice gate

viii. Providing and fixing ladder to crest gates on d/s side including hand railing and to catwalk, drain holes, platform, gauge board writing.

(b) Non-structural

i. Removal of obstruction at stilling basin and river training works

ii. Providing painting to radial crest gates & allied works

iii. Providing instrumentation system

(c) Basic Facilities

i. Construction of CC Road on Dam bund

ii. Providing & installing of CCTV camera.

iii. Providing and supplying vehicle - Bolero Jeep.


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2.10 Drawings

Figure 2-1: Index Map of Amarja Dam.


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Figure 2-2: Google Map of Amarja Dam.


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Figure 2-3: Water Catchment Map of Amarja Dam.


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Figure 2-4: Layout Map of Amarja Dam.


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Figure 2-5: Longitudinal Section of Amarja Dam.


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Figure 2-6: Typical Cross Section of Amarja Earth Dam.


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Figure 2-7: Spillway Cross-section of Amarja 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) April 2015

b. Site Visit made by CPMU experts 9 Oct 2015

3.2 Summary of observations made by CPMU

The following points were recommended for immediate consideration for

development of a final design and preparation of all tender documents:

Since the revised design flood magnitude (3704 m³/s) has increased by about

30% from its original magnitude (2832 m³/s), flood routing studies are

recommended to be carried out and the adequacy of the freeboard checked

as per IS 10635 for the revised design flood.

In the DSRP report, the drainage gallery in the concrete dam/spillway could

not be inspected due to standing water. During this site visit, the same

condition was experienced. Scheduled arrangements for automatic pumping

of seepage water collected in sump well needs to be attended to with

additional or standby automated pumps sited in a sump well that would be

located near the gallery entrance. Frequent, and regular, monitoring of

seepage is recommended to be carried out, all the choked drainage holes in

the dam body and foundations reamed/re-drilled to make them functional and

the gallery maintained in a dry condition. Provisions for these works are

recommended to be made in the estimate.

4. DESIGN FLOOD REVIEW (DFR)

4.1 DFR Outcome

Sl. No.

Item Original

Value

Revised

Value Remarks

a. Inflow Design Flood (m3/s) 2,832 3,704 PMF

b. Spillway Capacity / Routed Outflow (m

3/s)

- 3,612.80 Flood routing

study by CPMU

c. Maximum Water Level (m) 461.5 461.52 TBL = 464.5

4.2 Brief Summary of Review

The original design flood was 2,832 cumec and the revised design flood (PMF) under DRIP worked out to be 3,704 cumec. The MWL for the original design flood was at EL 461.5 m. Flood routing study carried out by CPMU indicates that the MWL for the revised design flood is at 461.52 m, which is only 0.02 m above the original MWL. The TBL is at 464.5 m. The freeboard above the revised MWL is 2.98 m and fulfils the minimum recommended 1.50 m for embankment dams as per IS 10635.


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4.3 Recommendations

Structural measures - Nil.

Non-structural measures - EAP.

5. REHABILITATION WORKS CARRIED OUT

5.1 Summary of Investigations

Sl. No.

Item Details Remarks

a. Geo-Physical Investigations Not carried out

b. Geo-Technical Investigations Done

c. Hydraulic Model Studies NA

d. Under-Water Scanning NA

5.2 Main Dam Works

Sl. No.


a. Works from hydrological angle Design flood review Design flood Completed.

b. Resetting of disturbed upstream pitching (rip-rap)

Improvements to Earthen Dam and Rough Stone

Revetment Completed

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

Construction of Surface Drains on Earthen Bund of

D/s slope Completed

d. Repairs / provision of d/s rock toe

e. Provision for d/s turfing

f. Re-drilling / Reaming of drainage holes in the dam body and in the foundations

Reaming of porous and

foundation drains inside

gallery

Partially Done (not

completed due to heavy leakage in

drain holes)

g. Works because of Seepage / leakage issues

Grouting Treatment to

Concrete dam

Completed (in non-flow section only)

h. Hydro-mechanical works

i. Main spillway gates & hoists

Providing Painting to Radial

Crest Gates, Stop Log Gates

and Overhauling and

Maintenance of Radial Crest

Gates, Stop Log

Gates and Gantry crane

Completed

ii. Outlet gates & hoists Restoration of RBC Sluice

Gate Completed

i. Other miscellaneous works d/s of embankment dam

Providing and Fixing Ladder to Crest Gates on Dis Side

including Hand Railing and to Catwalk, Drain Holes,

Platform, Trash Rack for

Completed


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Sl. No.


Sluices, Gauge Board Writing

5.3 Basic facilities

S/N Item Details Status

a. b. Roads

Construction of MSS Road on Dam Bund Top

Completed

6. INSTRUMENTATION

6.1 List of existing instruments installed in dam and their condition

Automatic water level recorder (gauge reading instrument) is fixed near RBC Sluice Gate. Other instruments such as piezometers, v-notch weir, etc., are yet to be installed.

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

Rehabilitation and Improvement

works to Amarja Dam under World Bank Aided DRIP

Programme

330.00 NCB 17/10/19 27/10/16 19/01/17 99/ 2016-17 20/03/17

Sri B.S.Loni, Class-I

Contractor, Basava Nagar, Gokak

12 19/03/18 262.77 254.37 31/07/18

*SPMU reported there was a saving of 70.2 Lakh from the original Contract Amount.


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7.2 Details of Bidding Process

As per details in the above table.

7.3 Reason for Variation, if any

SPMU reported Rs. 70.19 Lakhs savings due to change in scope of work during

construction.

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. 13-07-2017 4805 / 24-07-2017

b. 28-09-2017 5402/01-01-2018

c. 12-10-2017

d. 23-03-19 5781 / 13-04-2018

e. 26-07-19 6489 / 25.10.2018

8.2. Summary of Third Party Material Testing

Third party quality control tests were performed on M15 concrete for dam d/s slope

chute drains, as well as on M10 concrete for dam top drain and upstream riprap

templates using non-destructive Schmidt hammer test (NDT). For chute drains, the

tests gave unsatisfactory results and were recommended for rectification by CPMU.

For dam top drain and riprap templates, the tests gave satisfactory results. Detailed

test report is attached as Annexure D.

8.3. Summary of Major Recommendations

1st Construction Site Visit Report

Dam Safety: The DSRP in their comprehensive review of the health of the dam and

their recommendations that followed, include multiple pre-construction details to

ensure successful implementation of the approved rehabilitation measures. Many of

these recommendations have not been incorporated into the work plan. CPMU

recommends that the SPMU ensure all rehabilitation measures in the contract are

carefully followed and documented for the record.

Major Observations:

• Drilling and grouting of the NOF portion of the dam is in progress and the field data indicates that the pre-grout permeability is greater than (>) 150 Lugeon.

• The DSRP in their report and with concurrence from CPMU recommended a geophysical scan be conducted to determine the points of inflows and that the


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grouting scheme be based on directional grouting instead of blanket or “blind” grouting.

• A full galley inspection was not possible due to 1-meter-deep flooding at the starting point of the overflow section. CPMU recommends larger pumps are employed to maintain a dry gallery to enable a thorough inspection.

• CPMU observed that the porous drains are packed from the bottom by using wooden pegs and bags. As per the advice of SPMU consultants 3 to 4 porous drain holes are cleared of the blockage insertions made at the bottom. Heavy seepage is observed in one porous hole of NOF portion and one porous hole of Overflow portion. The seepage in one NOF porous drain was observed by CPMU at over 30-litres-minute but another porous drain in the overflow section could not be approached due to depth of flooding. (Fig-8)

• Other package items are in various stages of completion and the WBM has been satisfactory completed.

Project Management: Implementing this project will require strong oversight by the

EIC to ensure all works are qualitatively carried out. This includes ensuring all

methodologies and material detail are fully documented. A detailed OK card system

for all major works is recommended to be incorporated to help in this effort. The

quality of the works is dependent on these procedures, measure and pay purposes,

and award of a work completion certificate.

2nd and 3rd Construction Site Visit Report

Major Observation on 28.09.2017:

Water loss test results after tertiary grouting of NOF section on the right bank exceeds minimum requirements of < 5 Lu.

Honeycombing on all lift joints along OF and NOF sections, piers, gallery walls. Uplift pressure from foundation drains exceeds 3kg/cm2. Discovery of limestone in the near-surface of the foundation materials Grout overflow in gallery gutter that needs to be cleaned by Contractor

Major Observations on 12.10.2017:

Drilling and grouting of first row holes located at 2.00 m d/s of the u/s dam face in the NOF section are completed. Drilling and grouting of second row holes located at 1.50 m d/s of the first row is in progress. 3 Nos of primary holes are drilled and grouted as on 12.10.17.

Drain works at the d/s slope of earthen dam are completed. It is observed that the some of the porous drains appear to be plugged with

concrete and some with wooden pegs and bags. Underwater videography depicts significant honeycombs & cavities on the u/s

face of the dam. These honeycombs and cavities most likely causing heavy seepage in the opened porous drains, in spillway piers & d/s face of the dam. There is no provision for taking up under water treatment in the present contract.

No Observation / Deficiency

Status Remarks

Observation during visit on 13.7.17

1

Out of cleared 3 to 4 porous drain holes, heavy seepage is coming in two. Because of this, water is heading up in the drainage gallery. Dewatering is being carried out using 7.50 HP pump, which is

Open

The seepage in one porous drain is 30 litres per minute. The seepage in another porous drain measured during visit on12.10.17 is about 80 litres per minute. The cause for the heavy seepage may be due to existence of some suction points at u/s face of the dam. Blind grouting of the dam body and inside the gallery may not control the seepage of this magnitude. The leakage points are to be


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No Observation / Deficiency

Status Remarks

not sufficient. If the blockages in all the porous blocks are removed it is not known what may be the amount of seepage.

identified by deploying divers and they should be plugged first before taking up the grouting.

2

The pre-grout water loss of >150 Lu observed seems to be very high. Maybe because of testing is being conducted without saturation of holes.

Closed Following the proper procedure to conduct the water loss test. However, Lugeon values must be reduced to less than or equal to 5.

3 Grouting is stopped at thick mix

Open

It is conveyed that they are stopping the grout at thin mix now. But not recorded in the register. It is advised to record the same in the register.

4 Vigilant observation is required during grouting

Open

As there is heavy seepage in the gallery vigilant observation is required during grouting, as there are chances of leakage of grout from the porous hoes and from the u/s face of the dam.

Observation during this visit on 12.10.17

5

Some of the porous drains appeared to be plugged with concrete and some with wooden pegs and plastic bags.

Open

Reaming of porous drains to be done after taking up the treatment to u/s face to plug the water ingress points and treating the honeycomb formations.

6

Even after completion of drilling & grouting of 1st row of holes at NOF portion of the dam, seepage is observed at the d/s face of the dam.

Open

Observation is to be made after completion of drilling & grouting of 2nd row of holes. If seepage persists even after completion of grouting of 2nd row of grout holes, alternative remedial measures like treatment to u/s face of dam has to be thought of.

7 Seepage is observed at left & right abutment piers.

Open

Grouting to the piers or treatment to the u/s face of piers and its adjacent areas may have to be taken up to stop the seepage. But there is no provision in the contract to take up this work

4th Construction Site Visit Report Observations:

Key observations and recommendations:

Amarja gravity dam section is highly permeable and leakage is observed in several sections. After grouting of the NOF section, Lugeon values have reduced but remain high (40 to 127 Lugeon) exceeding allowable limits. No grouting has been carried out in the OF section to date. Previously recommended foundation curtain grouting to minimize uplift pressure is also yet to be taken up.

Very heavy leakage is observed in two porous holes inside the gallery under the OF section. Heavy leakage is also observed in the foundation drains (see photos below).

A few trial holes (0.75 m deep) were recently drilled for radial grouting from the gallery (see photo 10). The Contractor will mobilize another longer drill bit capable of drilling at least 1.5 m deep.


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Heavy Leakage in Porous and Foundation Drains inside Gallery

Considering the heavy leakage observed in several sections of the highly pervious concrete dam, and the challenge of dam body grouting in the OF section u/s of the gallery, SPMU is recommended to consider u/s face treatment as budget and schedule allow but only after a successful bathymetric study in the reservoir. Possible options include geomembrane, cementitious material, block joint hydrophilic, and nipple grouting treatments.

During the site inspection, the LBC service gate was inoperative and lowering the stop log gate was not possible due to high reservoir water level. This has resulted in uncontrolled flow in the LBC, which is undesirable in terms of downstream flooding and dam safety risk due to possible erosion at the toe of the embankment dam. The attempt made to stop the flow by dumping debris into the gate grooves is unacceptable. SPMU is recommended to quickly remove the debris and put the gate back in order.

Embankment dam d/s slope cross drains are completed. However, 3rd party NDT test results on M15 concrete indicate unsatisfactory quality and needs to be rectified. Rock toe protection is required at the d/s end of the cross drains. No longitudinal drains are provided at the berm.

Noted construction deficiencies and dam safety observations:

No. Deficiency / Observation Status Remarks

1.

Very heavy leakage from porous and drain holes inside the gallery under the OF section

Open As budget and time allow, SPMU to consider bathymetric survey and underwater u/s face treatment.

2. Lugeon values still high after grouting of NOF section

Open

3. LBC gate not operational and water flowing uncontrolled

Open Remove debris inside gate groove and repair gate as quickly as possible.

4.

Unsatisfactory results in some sections from 3rd party NDT test on M15 concrete cross drain on embankment d/s slope

Open To be rectified.

5. Rock toe protection is required at the d/s end of the cross drains

Open To be rectified. No provision in Contract.

6. No longitudinal drains provided at d/s slope berm of embankment dam.

Open No provision in contract. To be considered as budget and schedule allow.

7. No provision for renovation and painting spillway stop logs.

Open No provision in contract. To be considered as budget and schedule allow.


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4th Construction Site Visit Report Observations:

Key observations and recommendations:

There was not much progress in this site since last visit. The only activity on-going during this inspection was construction of dam top longitudinal drain using M10 concrete. 3rd party NDT test carried out following this inspection on part of the completed drain gave satisfactory results based on IS 13311 (part 2): 1992, clause 8.1 of ± 25% accuracy.

As previously reported, after grouting of the NOF section, Lugeon values significantly reduced but remain high (40 to 127 Lugeon) exceeding allowable limits. No grouting has been carried out in the OF section to date. Previously recommended radial grouting from gallery and foundation curtain grouting to minimize uplift pressure is also yet to be taken up.

Very heavy leakage was observed in two porous holes inside the gallery under the OF section. Heavy leakage was also observed in the foundation drains.

Considering the heavy leakage observed in several sections of the highly pervious concrete dam, and the challenge of dam body grouting in the OF section u/s of the gallery, SPMU is recommended to consider u/s face treatment as budget and schedule allow but only after a successful bathymetric study in the reservoir. Possible options include geomembrane, cementitious material, block joint hydrophilic, and nipple grouting treatments.

During the previous inspection, the LBC service gate was inoperative. The same has been repaired and is now functional.

8.4. Summary of Compliance by SPMU

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

construction site visits is attached in Appendix E.

8.5. 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 and flood routing.

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

Third party quality control tests.

Review of dam break analysis and inundation maps.

Review of O&M manual.

9. ENVIRONMENTAL AND SOCIAL MANAGEMENT

FRAMEWORK (ESMF)

9.1 Basic Details

Sl. No.

Item Yes / No Remarks

a. ESMF Issue Identified in PST Yes


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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 PPE was

hardly used during construction. ESMF OK Card is attached in Annexure F.

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

(iv) Stake holder consultations

No

Yes

No

No

Draft Inundation maps reviewed by CPMU on 11/10/2018, revised version received from SPMU on 22/05/2019 is under review by CPMU.

b. O&M Manual availability Yes

Draft O&M manual revised from SPMU on 14/05/19 as per guidelines issued by Central Water Commission (CWC) was reviewed by CPMU and comments sent to CPMU on 17/06/2019.

c. Inflow Forecasting No

d. DHARMA Implementation Yes In progress. So far 91% data uploaded.

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 O&M manual.

ii. Finalization of DBA and Preparation of EAP.

iii. Completion of data entry in DHARMA.

iv. Taking action on compliance issues to DSRP recommendations.

11.2 Further course of action

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


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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. Third party testing.

viii. Compliance letters from SPMU.

ix. ESMF OK Card

x. DBA and Inundation 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: Third Party QC Tests


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Annex E: ESMF OK Card


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Annex F: Photographs Before and

After Rehabilitation Works


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Annex G: DBA and Inundation Maps


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Dam Break Analysis and

Inundation Maps for

Amarja Dam

KA06HH0199

Water Resources Department

State of Karnataka.

Advanced Centre for Integrated Water Resources Management

Water Resources Department, Govt. of Karnataka

No. 1/1, 1st Floor, K.S.F.C Bhawan, Thimmaiah Road Bengaluru – 560052

Phone No: 080-22262042/43/44 Fax No: 080-22262045

Dam Break Analysis Report &

Maps for Amarja Dam,

Karnataka

Project ID Code: KA06HH0199

Doc. No: KaWRD_MAP_AMARJA_01




Phone No: 080-22262042/43/44 Fax No: 080-22262045

Dam Break Analysis Report & Maps for Amarja

Dam, Karnataka

Project ID Code: KA06HH0199

Prepared By:

Siddaraj H P

Assistant Engineer


Water Resources Department,

Government of Karnataka

GIS Support By:

Asra Kubra Khan

GIS Specialist, ACIWRM

Amarja -Flood Inundation Maps, Karnataka

Advanced Center for Integrated Water Resources Management (ACIWRM), GoK i

ABSTRACT

Amarja dam (Project id KA06HH0199) s classified as intermediate dam as per IS 11223-1985, the

potential risk factor in case of dam breach is also higher. The Dam Break Analysis for Amarja

Dam is carried out using HEC-RAS 5.0.3. The ALOS Global Digital Surface Model (DSM)

“ALOS World 3D-30m” (AW3D30) DSM is used for the terrain. The embankment portion of the

composite dam was breached for assessment of flood inundation downstream of the dam. The dam

failure was assessed for the scenarios such as overtopping failure and non-flood failure (piping

failure). Inundation due to large controlled releases from the dam was also considered in the study.

The inundation maps for the critical parameters such as water surface elevation, depth of water,

velocity of flow and flood wave arrival time are prepared for all the three flood scenarios. The

villages which are likely to be inundated in case of Amarja dam breach were identified using

Google map. The population affected due to inundation was obtained from the 2011 census data

hosted on data.gov.in website. Open source road and rail layers were also used in the map

preparation.

The peak discharge obtained for overtopping failure and non-flood failure (piping) are 10,546.36

m3/s and 8248.88 m3/s respectively. However, for large controlled releases, the peak flood is the

design discharge capacity of the spillways. The reasonableness of the peak discharge was

ascertained by evaluating the velocity through the breach which has to be less than 3m/s for breach

in embankment portion. The discharge at the end of the downstream boundary is 1600.68 m3/s

and 799.34 m3/s for overtopping failure and non-flood failure respectively.

Around 32 villages will be affected due to the dam break flood especially in case of overtopping

failure. The villages which are very close to the dam are the most vulnerable as the flood wave

arrival time is less than 12 minutes in case of overtopping failure and sufficient time for evacuation

may not be available. As such the villages which are located within 1 km downstream from the

dam needs quick response from the disaster management team in case of Amarja dam breach.


Advanced Center for Integrated Water Resources Management (ACIWRM), GoK ii

TABLE OF CONTENTS

Contents Page No.

Abstract i

Table of Contents ii

List of Tables iv

List of Figures v

1.0 Introduction

1.1 Preface 1

1.2 General 1

1.2.1 Overtopping Failure 1 & 2

1.2.2 Piping Failure 2

1.2.3 Large controlled Release 2 & 3

1.3 Objectives 3

1.4 Scope 3

2.0 Description of Amarja Dam 4 - 9

3.0 Dam Breach Analysis

3.1 Model Selection 10

3.2 Dam Breach and Flood Inundation Scenarios 10 – 11

3.3 Study Area Boundaries 11

3.4 Data Inputs for Hydraulic Model 11

3.4.1 Elevation Data 11

3.4.2 Land Use Land Cover Data 12

3.4.3 Population Data 12

3.4.4 Hydraulic Data 13

3.4.5 Hydrologic Data 13

3.4.5.1 Inflow Design Flood 13 - 14


Advanced Center for Integrated Water Resources Management (ACIWRM), GoK iii

4. Model Development

4.1 Grid/ Mesh Resolution 15

4.2 Roughness Co-efficient 15

4.3 Flow and Boundary Conditions 15-16

4.4 Dam Breach Parameters 16-22

4.5 Calibration and Sensitivity Analysis 22

4.5.1 Computational Aspects 22

4.6 Peak Discharge Reasonableness 27

4.7 Results 27

4.8 Output Hydrograph 28-32

4.9 Flood Vulnerability 32-33

4.10 Flood Hazard Reference Values/Population at Risk 33

5.0 Flood Inundation Mapping 37

6.0 Conclusion 38

References 39

Annexure-1 Inundation Maps (soft copy in DVD) vi


Advanced Center for Integrated Water Resources Management (ACIWRM), GoK iv

LIST OF TABLES

Tables Page No.

2.1 Salient features of Amarja Reservoir Project

4 & 5

3.1 Existing dam classification for inflow design flood selection

13

4.1 The land use land cover downstream of Amarja dam and its Manning’s N

values

15

4.2 Dam breach parameters and expected peak outflow for Overtopping failure

20

4.3 Dam breach parameters and expected peak outflow for Non- Flood failure

(Piping)

21

4.4 Trapezoidal dam breach model parameters and obtained dam breach flood

peak discharges

22

4.5 Classification limits for vulnerability thresholds of combined hazard curves 33

4.6 Showing the Potential loss of Life based on percentage area of Inundation for

the Projected Population from 2012-2021

34

4.7 Flood hazard reference values

35-36


Advanced Center for Integrated Water Resources Management (ACIWRM), GoK v

LIST OF FIGURES

Figures Page

No.

Fig 2.1 Plan of Amarja Dam 6

Fig 2.2 CS of spillway portion of Amarja Dam 7

Fig 2.3 Typical cross section of embankment and LS Amarja Dam 8-9

Fig 3.1 DEM of the study area 11

Fig 3.2 LULC map of study area 12

Fig 3.5: SPF @ Amarja Irrigation Project 22

Fig 4.1: Reservoir Routing showing Inflow and Outflow Discharge 16

Fig 4.2 Overtopping failure computation log file 23

Fig 4.3 Non-flood failure computation log file 24

Fig 4.4 Large controlled releases computation log file 25

Fig 4.5 Runtime message for overtopping failure 26

Fig 4.6 Runtime message for piping failure 26

Fig 4.7 Runtime message for large controlled releases 27

Fig 4.8 Overtopping failure dam breach flood hydrograph 28

Fig 4.9: Flood hydrograph at the boundary line (BC-1) for overtopping failure 28

Fig 4.10: Flood hydrograph at the boundary line (BC-2) for overtopping failure 29

Fig 4.11: Non-Flood Failure (Piping) dam breach flood hydrograph 29

Fig 4.12: Flood hydrograph at the boundary line (BC-1) for piping failure 30

Fig 4.13: Flood hydrograph at the boundary line (BC-2) for piping failure 30

Fig 4.14: Flood hydrograph for large controlled releases 31

Fig 4.15: Flood hydrograph at the boundary line (BC-1) for large controlled releases 31

Fig 4.16: Flood hydrograph at the boundary line (BC-2) for large controlled releases

32


Advanced Center for Integrated Water Resources Management (ACIWRM), GoK vi

ANNEXURE-1 – FLOOD INUNDATION MAPS

The data used to carry out dam break studies of three scenarios using HECRAS software and the

maps are included in the DVD files and DVD is organized in folders as shown below:

➢ Dam Name – state

• Common data

• Model data

▪ Overtopping failure

▪ Piping Failure

▪ Large Controlled release

• Output maps

▪ Overtopping failure

▪ Piping Failure

▪ Large Controlled release

The common data folder contains information related to three flood simulations including digital terrain models and land use / land cover data and other data required to carry dam breach study. The inundation maps for the three failure scenarios (Overtopping, Piping, Large Control release) showing - Depth (max.) in m, Velocity (max) in m/s, Water surface elevation (max), flood arrival time in hrs. flood vulnerability maps are attached in this report as Annexure-1.


Advanced Center for Integrated Water Resources Management (ACIWRM), GoK 1

1. INTRODUCTION:

1.1 Preface:

Advanced Center for Integrated Water Resources management (ACIWRM) is a think tank to the

government’s Water resources Department (WRD). It engages in policy analysis, research,

planning, capacity building and develop the knowledge base to gear up the department up for its

future vision. ACIWRM was entrusted with the dam break analysis and preparation of inundation

maps for emergency action plan for Amarja Dam by Project Authorities.

The necessary training and inputs for dam break modelling have been provided by CWC under

DRIP. The required information and details of the Amarja dam have been provided by the project

Authorities.

1.2 General:

Based on the type of dam and conditions of the dam site, a dam may fail due to multiple causes.

The most common causes of dam failure are flood or dam overtopping. The next common cause

is piping or seepage. The structural failure occurs on influence of various factors and its third most

common category. Sometimes dam may even fail due to the failure of spillway gate, earthquake

or even poor design/construction. Depending on the nature / type of dam the failure of dam varies.

Concrete gravity dams may suffer a partial breach with failure of one or more monolith sections.

Concrete arch dams may fail suddenly and completely within a few minutes. Embankment dams

do not fail completely or suddenly as their concrete counterparts. Breaching action in an earthen

dam continues to the point where the reservoir is deleted completely or to the point where the

breached materials resist erosion.

1.2.1 Overtopping Failure:

Overtopping due to large inflow flood is the most common failure mode for embankment dams. It

occurs when the water surface elevation in the reservoir exceeds the height of the dam. The flow

of water over the crest of the dam, an abutment, or a low point in the reservoir rim follows as a

consequence. The foundation and abutments of a concrete dam may also be eroded due to

overtopping, leading to loss of support and failure due to sliding or overturning. For embankment

dams, the failure begins at a downstream location, with head cutting progressing upwards

gradually. As it reaches the dam top, the width of the dam crest is eroded fast, before the reduction



in height starts taking place. This proceeds at a fast rate and may include the phase of maximum

outflow for a reservoir with capacity small compared to its height. In this phase, the earthen dam

without a core behaves mostly like a sharp crested weir.

The opening created by erosion expands gradually, almost in the shape of a trapezoid. As the height

is reduced to the foundation level, outflow may continue for a long time if the reservoir is of

sufficiently large capacity. For such cases, the peak rate of outflow is also expected to occur during

this phase. The flow mostly resembles the overflow pattern observed over a broad crested weir

with long crest.

1.2.2 Piping Failure:

Piping occurs when concentrated seepage paths develop within an embankment dam. The seepage

slowly continues to erode the dam embankment or foundation, leaving behind large voids in the

soil. Piping begins near the downstream toe of the dam and works its way towards the reservoir

upstream. Erosion proceeds at a more rapid rate as the voids become larger and larger. As the

erosion reaches the reservoir upstream, it may enlarge and cause total failure of the dam. The

process of internal erosion and piping may be broken up into four phases: initiation of erosion,

continuation of erosion, progression to form a pipe and ultimately, the formation of a breach.

Piping failures occur in earthen dams only. Once such a pipe connection is formed, it is almost

impossible to save the dam from failure.

1.2.3 Large Controlled Releases:

Flood risks at locations downstream of the dam may also arise without any failure of the dam and

its components. After construction of a dam, the safe carrying capacity of the river channel

normally keeps on decreasing, due to the diversion of water as well as flood moderation by the

reservoir. Consequently, after many years of dam construction, the river channel downstream of a

dam loses its capacity to carry the peak flood magnitudes. So, extensive bank overflows become

associated with flood discharges. The situation gets further aggravated due to developmental

activities taking place in the floodplain because of reduced frequency of inundation.

In the event of a severe flood in the dam catchment having a magnitude of peak discharge near to

the design flood of the dam, the priority of dam operation will shift to saving the dam. Otherwise,

a dam breach may endanger the lives of many more persons residing in the downstream area. With



the passage of flood flows near to the spillway capacity, severe floods causing huge inundation

may occur. It may even lead to loss of lives which has to be minimized through implementation

of strict floodplain regulatory management plans and flood warning.

1.3 Objectives:

• The main purpose of the study is to find out the areas downstream of Amarja Dam which

will be inundated due dam breach scenarios such as overtopping and non-flood failure

(piping) and to find out the inundation scenario in case of large controlled release.

• To estimate the number of villages and people at risk due to dam failure and large

controlled release.

• To assess the submergence of infrastructure facilities such as roads and railways.

• To prepare the inundation maps for the breach scenarios such as overtopping and piping

and for controlled large release.

1.4 Scope:

• The scope of the study is restricted to failure of the dam due to overtopping and piping

only. However, inundation maps are prepared for both the cases of failure and for large

controlled releases. No other failure scenarios such as landslide, earthquake, malfunction

of gates and planned removal are considered in this study because the HEC-RAS software

cannot simulate these conditions.

• A tier-2 approach to dam breach and inundation mapping are followed which is an

intermediate level of analysis using medium resolution terrain data. A tier 3 approach to

dam breach analysis could be carried out using high resolution LIDAR data.



2. DESCRIPTION OF AMARJA DAM

The Amarja is a river flows in Kalaburagi District, Karnataka, India. Born at Koralli and flows up

to 50–60 kilometers and will merge into Bhima river at Sangam Kshetra Ganagapura village in

Kalaburagi District. The water of these rivers, especially at their confluence, called Sangam, are

considered extremely holy. There is a temple in Sangam in which Shree Narasimha Saraswathi

Swamy (The second incarnation of Lord Dattatreya)

Amarja Dam is located in Aland town near the city of Kalaburagi in the Kalaburagi district of

Karnataka. The Dam is built across the river Amarja that flows through the Krishna basin in the

Southern part of India. The dam was constructed in the year 1998, this is a multi-purpose dam.

The reservoir is used for irrigation of the surrounding areas, for providing water supply and for

solving the problem of drinking water in the area. The dam is 960-meter-long and 31.85-meter-

high from the foundation. It covers a catchment area of 53.095 Thousand ha. The design flood of

the dam is 2837 Cumecs. The dam has Ogee type of spillway and 5 spillway gates. The maximum

water level of the dam is 461.5 meters. The type of Dam is Earthen + Gravity and gross capacity

of the reservoir is 1.554 TMC.

Table:2.1 Salient features of the Amarja dam

Name of the Project Amarja Reservoir Project

Type of Project Multi-Purpose Project

Name of the Dam Amarja Dam

Location of Dam Across Amarja River about 1.5 km D/S of

Sangolgi Village Taluk. Aland District

Gulbarga

Name of the River Basin location Krishna Basin

River Tributary Amarja

Latitude 17° 92 '

Longitude 76° 33'

Catchment Area 530.95 Sq.kms

Gross Storage Capacity 1.554 TMC



Live Storage 1.415 TMC

Dead Storage 0.139 TMC

Lowest River Bed Level (m) RL 436.655

Crest Level (m) RL 452.5

Full Reservoir Level (m) RL 461.5

Maximum Water Level (m) RL 461.5

Top of the Dam RL 465

Maximum water spread area at FRL 640.20 ha

Type of Dam Earthen dam with zonal section with gated

ogee spillway at gorge

Length of the Dam (m) 960

Height of the dam above the Lowest River bed

level (m)

28.345

Top width of road way (m) 8.0

Designed flood intensity (Cumecs) 2837

Discharging length of spillway (m) 77

Spillway crest Ogee Section

Crest gates 5 nos. Radial gates of size 13 m x 9 m



FIGURE 2.1 PLAN OF AMARJA DAM



FIGURE 2.2 C/S OF SPILLWAY PORTION OF AMARJA DAM



FIGURE 2.3 TYPICAL CROSS SECTION OF EMBANKMENT OF AMARJA DAM



FIGURE 2.4 LONGITUDINAL SECTION OF AMARJA DAM



3. DAM BREACH ANALYSIS

3.1 Model Selection:

HEC-RAS software is used for the dam breach analysis of Amarja Dam. 2D modeling approach

was adopted because of its simplicity when compared to 1D modeling and the advantages of 2D

modeling with 1D modeling is enumerated below;

• 2D modeling can perform 1D, 2D and combined 1D and 2D modeling. In the present study

2D flow areas were created which were directly connected to 1D storage with a hydraulic

structure.

• There is also an option of choosing either Saint Venant or diffusion wave equations.

• The 2D flow area can start completely dry and handle sudden rush of water into the area.

• The algorithm can handle subcritical, supercritical and mixed flow regimes.

• The computational meshes can be both unstructured and structured.

• The detailed hydraulic table properties for 2D computational cells and cell faces are

computed.

• Detailed flood mapping and flood animations are obtained.

The limitations to the 2D modeling approach are less flexibility in adding internal hydraulic

structures; cannot perform sediment transport erosion/ deposition; cannot perform water quality

modeling and cannot connect pump stations to 2D flow area.

3.2 Dam Breach and Flood inundation Scenarios:

The following three dam breach scenarios are considered in the study;

1. A dam failure caused by overtopping from the inflow design flood leading to breaching

and uncontrolled flow of impounded water.

2. A dam failure caused by internal erosion (piping) with the reservoir at FRL leading to

breaching and uncontrolled flow of impounded water.

3. A large controlled-release flood with IDF and without dam failure.



The hazard potential will be at its maximum when there is a dam breach failure due to overtopping,

downstream hazards due to a dam failure because of piping or even passage of high discharge

(design spillway capacity) through the spillway gates may sometimes be hazardous. The sudden

release of water of even lesser magnitude from a dam without proper warning may also cause loss

of life and property.

3.3 Study Area Boundaries

The study area boundaries are limited to an extent of 53 km downstream of the Amarja dam where

in the flow gets restricted to the natural channel i.e., the total outflow in the downstream end of

the model is within the channel carrying capacity of the main stream.

3.4 Data Inputs for the Hydraulic Model

3.4.1 Elevation Data

“ALOS World 3D-30m” (AW3D30) dataset, the global digital surface model (DSM) dataset with

a horizontal resolution of approximately 30-meter mesh (1 arcsec. latitude and longitude)

generated from 5m resolution DSM and provides open distribution of this high-resolution global

data set through JAXA website. The elevation data is in Georeferenced Tagged Image File Format

(GeoTIFF) which is a TIFF file with embedded geographic information. This dataset is highly

expected to be used in scientific research and geospatial information application services.

Fig 3.1 DEM OF THE STUDY AREA



3.4.2 Land Use Land Cover Data

LISS 4 image extracted to a scale of 1:10000 and a spatial resolution 5.8 m is used as the input to land

cover data. The land cover map was provided by Karnataka State Remote Sensing Application Center

(KSRSAC).

Fig 3.2 LULC MAP OF STUDY AREA

3.4.3 Population Data

The estimated population for each settlement as per 2011 census was obtained from data.gov.in

portal. However, the present population in each of these settlements needs to be ascertained. The

village-wise population data hosted in the site is having all the demographic information as per the

2011 census



3.4.4 Hydraulic Data

The Amarja Dam has five radial gates of size 9m x 13 m with ogee spillway. The crest level of the

gate is 452.5 m. The weir width considered is 8.0 m with an elevation of 452.5 m. The length of

the weir 960 m. The discharge co-efficient for weir is taken as 1.44 considering it as broad crested

weir whereas for the ogee weir the weir co-efficient is taken as 2.2. The radial gate flow parameters

considered are radial discharge co-efficient as 0.6, trunnion exponent as 0, opening exponent as

1.0, head exponent as 0.5 and trunnion height as 0.0 m

3.4.5 Hydrologic Data

The dam classification system in India depends on the static head and gross storage capacity of the

reservoir. The Amarja dam is classified as Intermediate dam as per IS: 11223 (1985) “Guidelines

for Fixing Spillway Capacity”.

Table 3.1: Existing dam classification for inflow design flood selection (IS:11223 - 1985)

Class

Gross storage capacity

(Mm3)

Static head (m)

Inflow Design Flood

(IDF)

Small

0.5 to 10

7.5 to 12

100-year flood

Intermediate

10 to 60

12 to 30

Standard Project

Flood (SPF)

Large

> 60

> 30

Probable Maximum

Flood (PMF)

3.4.5.1 Inflow Design Flood

Inflow Design Flood was carried out by Hydrology Unit, WRDO. The spillway capacity is

originally designed for 2832 Cumecs (1,00,000 cusecs). The dam comes under the classification

of “Intermediate dams” as the gross storage and the height of earthen dam is 28.345m and 44.01

Mcum respectively.



In absence of closed interval gauge data for developing a unit hydrograph, recourse has been made

for computing the maximum design flood discharge from the Synthetic unit graph by making use

of the flood Estimation Report for Krishna & Pennar Basins (Sub Zone-3(h)” prepared and

published by Directorate of Hydrology (small catchments), Central Water Commission, New

Delhi, which involves a method based on Unit Hydrograph principle.

As the storage of the dam is more than 10 Mcum, and height of the dam is more than 12 m and

less than 30 m, dam has been classified as intermediate dam is hence SPS needs to be considered.

As per Generalized PMO ATLAS of CWC of Krishna Basin Prepared during the Feb-2007, The

1-day PMP value has been reduced to 1-day SPS value by dividing the 1-day PMP value with

Moisture maximum Factor (MMF) of 1.23, as per table 16, vide page no.105 of the said ATLAS.

Thus, the Design Flood has been calculated by adopting the SPS, which works out to 130811

cusecs say 1.31 lakh cusecs.

As per the above classification and based upon the study carried out by Hydrology Unit, WRDO

with KERS the dam was classified as Intermediate dam and probable maximum flood was

considered as 3704.16 m3/s for the present study.



4. MODEL DEVELOPMENT

4.1: Grid/Mesh Resolution:

The two-dimensional depth averaged model was used in the study. The grid resolution of

90mx90m was selected and the total cells were 30724. Break lines are not used in the model.

4.2: Roughness Co-efficient:

The roughness co-efficient was selected based on the land use land cover of the study area, which

was obtained from Karnataka State Remote Sensing Application Center (KSRSAC).

Table 4.1: Land use and Land Cover downstream of Amarja Dam and its Manning’s N Value

Sl.no. Land Use and Land Cover type Manning’s ‘N’ Value

1 Agriculture land 0.034

2 Water body 0.04

3 Waste land 0.035

4 Buildup 0.4

5 Forest 0.05

4.3: Flow and Boundary Conditions:

The initial condition assumed for overtopping failure is the top of embankment dam F.R.L level

461.50 m (critical depth for overtopping failure). For Overtopping failure F.R.L level is considered

as the critical depth because reservoir routing shows (Figure 4.1) the peak discharge 3704.16 m3/s

occurs at elevation 460.07 which is below the level of F.R.L for piping failure the storage elevation

at FRL i.e., 461.50 m of the reservoir and for large controlled release the crest level i.e.,652.50 m

of spillway is considered. The boundary conditions (BC-1 & BC-2 were considered on the

downstream as the flow joins the river Bhima @ downstream) for overtopping failure are lateral

inflow hydrograph for the reservoir, elevation-controlled gates (gates are fully opened) for the

storage area connection i.e., dam and normal depth of 0.001 is assumed for the 2D flow area.

However, for the piping failure, only normal depth and elevation-controlled gates (gates are fully

closed) are used as the boundary condition. For controlled large releases, IDF as lateral inflow,



gates opening at a rate of 0.1m/min and the normal depth of 0.001 is considered. The breach

progression is modeled as sine wave progression where, breach grows very slowly at the beginning

and end of development and rapidly in between.

Figure 4.1: Reservoir Routing showing Inflow and Outflow Discharge in Cumecs

4.4: Dam Breach Parameters:

The key parameters for arriving at a dam breach hydrograph are the breach parameters related to

the geometry and timing of the breach formation (e.g., width, depth, shape, and time of failure).

The selection of breach parameters for modelling dam breaches contain the greatest uncertainty of

all aspects of dam failure analysis and therefore a careful evaluation and understanding of the

associated breach parameters is necessary.

174.20 229.85

0.00

300.00

600.00

900.00

1200.00

1500.00

1800.00

2100.00

2400.00

2700.00

3000.00

3300.00

3600.00

3900.00

8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 28.0 30.0 32.0 34.0 36.0 38.0 40.0

INFL

OW

/OU

TFLO

W (

CU

MEC

)

TIME (HRS)

Inflow (Cumec) Outflow (Cumec)



Breaching begins when the reservoir water surface elevation reaches the failure elevation (above

the datum). The formulae for the embankment breach parameters are

𝐵𝑎𝑣𝑔 = 0.23 𝑋 𝑘𝑀 𝑋 𝑉𝑤

1

3

Where,

𝑘𝑀 = {1.5 𝑓𝑜𝑟 𝑂𝑣𝑒𝑟𝑡𝑜𝑝𝑝𝑖𝑛𝑔 𝑓𝑎𝑖𝑙𝑢𝑟𝑒𝑠1.0 𝑜𝑡ℎ𝑒𝑟 𝑓𝑎𝑖𝑙𝑢𝑟𝑒 𝑚𝑜𝑑𝑒𝑠

𝑚 = {1.0 𝑓𝑜𝑟 𝑂𝑣𝑒𝑟𝑡𝑜𝑝𝑝𝑖𝑛𝑔 𝑓𝑎𝑖𝑙𝑢𝑟𝑒𝑠0.7 𝑜𝑡ℎ𝑒𝑟 𝑓𝑎𝑖𝑙𝑢𝑟𝑒 𝑚𝑜𝑑𝑒𝑠

𝑡𝑓 = 60 𝑋 √𝑉𝑤

𝑔𝐻𝑏2

(Froehlich, 2017a)

The formulae for the masonry/ concrete breach parameters are

(Froehlich, 2017 b)

Two mathematical models are presented for predicting peak discharge from gradually breached

embankment dams. The first model is an empirical formula based on previously developed

statistical relations using measures of embankment and reservoir properties as predictors. The

second model is a semi theoretical which reduces the maximum possible discharge from an

instantaneous reservoir breach having prescribed dimensions.



Expected outflow (empirical);

𝑄�̂� = 0.0175 𝑋 𝑘𝑀 𝑋 𝑘𝐻 𝑋 √ 𝑔𝑉𝑤 𝐻𝑤𝐻𝑏

2

𝑊𝑎𝑣𝑔

Where,

𝑘𝑀 = {1.0 𝑓𝑜𝑟 𝑛𝑜𝑛 − 𝑂𝑣𝑒𝑟𝑡𝑜𝑝𝑝𝑖𝑛𝑔 𝑓𝑎𝑖𝑙𝑢𝑟𝑒 𝑚𝑜𝑑𝑒𝑠1.85 𝑓𝑜𝑟 𝑜𝑣𝑒𝑟𝑡𝑜𝑝𝑝𝑖𝑛𝑔 𝑓𝑎𝑖𝑙𝑢𝑟𝑒 𝑚𝑜𝑑𝑒𝑠

𝑘𝑀 = {

1: 𝑓𝑜𝑟 𝐻𝑏 ≤ 𝐻𝑠

(𝐻𝑏

𝐻𝑠)

1

8∶ 𝑓𝑜𝑟 𝐻𝑏 > 𝐻𝑠

𝐻𝑠 = {6.1 𝑚 (𝑓𝑜𝑟 𝑆𝐼 𝑢𝑛𝑖𝑡𝑠)20 𝑓𝑡 (𝑓𝑜𝑟 𝑈. 𝑆. 𝑐𝑢𝑠𝑡𝑜𝑚𝑎𝑟𝑦 𝑢𝑛𝑖𝑡𝑠)

(Froehlich,2016)

Maximum outflow for instantaneous breach;

(Froehlich,2016)

Expected outflow (semi-theoretical)

(Froehlich,2016)



Where;

Bavg = expected value of average breach width in meters

Tf = breach formation time in seconds

Qp is the peak discharge in m3/s

KM is the factor that accounts for failure mode

KH is the factor that accounts for embankment height

g is acceleration due to gravity in m/s2

Vw is the volume of water above breach bottom in m3

Hw is the height of water above breach bottom in m

Hb is the height of breach in m

Hs is height of small embankment in m

Wavg is the average embankment width in m

m is the average side slope ratio (horizontal: vertical) of trapezoidal opening

The top level of the dam is taken as 461.50 m and the breach bottom level as the river bed level.

The reservoir volume for overtopping is considered to be 44.21 M Cum at 461.50 m (F.R.L level

of the dam) and for the piping the capacity at FRL is considered i.e., 44.21 Mcum. The center

station considered for the breach is 700 m from the chainage “0” measured from the left end of the

earthen dam. It is assumed that the left earthen embankment is more vulnerable for breach in the

study. The breach parameters and expected outflow as obtained from the above equations are given

below.



TABLE 4.2: THE DAM BREACH PARAMETERS AND EXPECTED PEAK OUTFLOW

FOR OVERTOPPING FAILURE



TABLE 4.3: DAM BREACH PARAMETERS AND EXPECTED PEAK OUTFLOW FOR

NON-FLOOD FAILURE (PIPING)



Table 4.4: Trapezoidal Dam Breach Model Parameters and obtained Dam Breach Flood

Peak Discharges

Breach Parameters Units Dam Failure Mode

Overtopping Piping

Height m 24 24

Bottom Width m 117 103

Average Side Slope (horz: vert) -- 1:1 0.7:1

Formation time hrs. 2.18 2.09

Obtained Peak Discharge m3/s 10546.36 8248.88

4.5: Calibration and Sensitivity Analysis:

Calibration and sensitivity analysis were not carried out. However, the breach parameters were

finalized by conducting trials and verifying the breach velocity for embankment breach to be less

than 3 m/s. The velocity threshold was monitored just after the breach formation time and was

established based on the construction material of the dam.

4.5.1: Computational Aspects:

Full momentum equation is used for the analysis and the computation interval or the time step

adopted is 1 sec, Hydrograph output interval 1 minute, mapping Output interval 5 min and detailed

output interval 5 min for Overtopping, Piping & large Control release simulation.

The percent volume accounting error for the storage and 2D flow area for overtopping failure

simulation and for non-flood failure simulation for embankment breach are 0.5822 & 0.08433 and

1.364 & 0.1683 respectively. There is no convergence error in both the simulations. In case of

large controlled releases, the percent volume accounting error for the storage and 2D flow area are

0.01999 and 0.02049 respectively. There was no runtime error.



Figure 4.2: Overtopping Failure Computation Log File



Figure 4.3: Piping Failure Computation Log File



Figure 4.4: Large Control Release Failure Computation Log File



Figure 4.5: Runtime Message for Overtopping Failure

Figure 4.6: Runtime Message for Piping Failure



Figure 4.7: Runtime Message for Large Controlled Releases

4.6: PEAK DISCHARGE REASONABLENESS:

The reasonableness of the peak discharge downstream of the dam breach is ascertained by expected

peak outflow (gradual breach- semi theoretical and empirical equations) as given by Froehlich,

2016.

4.7: RESULTS:

The simulation results show that for embankment breach, the breach velocity for overtopping

failure is 2.70 m/s whereas for piping failure it is 2.24 m/s at the time of breach. The peak discharge

obtained for overtopping failure is 10546.36 m3/s and for piping failure it is 8248.88 m3/s. The

discharge at the end of the downstream boundary is 1600.68 m3/s and 799.24 m3/s for overtopping

failure and non-flood failure respectively



4.8: OUTFLOW HYDROGRAPH:

The output hydrograph as obtained after simulation in HEC RAS for overtopping and non-flood failure

are given below;

Figure 4.8: Overtopping Failure Dam Breach Flood Hydrograph

Figure 4.9: Flood Hydrograph at the Boundary Line (BC Line-1) for Overtopping Failure



Figure 4.10: Flood Hydrograph at the Boundary Line (BC Line-2) for Overtopping Failure

Figure 4.11: Non-Flood Failure (Piping) Dam Breach Flood Hydrograph



Figure 4.12: Flood Hydrograph at the Boundary Line (BC Line-1) for Non-Flood (Piping) Failure

Figure 4.13: Flood Hydrograph at the Boundary Line (BC Line-2) for Non-Flood (Piping) Failure



Figure 4.14: Flood Hydrograph for Large Controlled Releases

Figure 4.15: Flood Hydrograph at the Boundary Line (BC Line-1) for Large Controlled Releases



Figure 4.16: Flood Hydrograph at the Boundary Line (BC Line-2) for Large Controlled Releases

4.9 Flood Vulnerability

The vulnerability by Smith et al. (2014), of the community and its assets can be described by using

thresholds related to the stability of people as they walk or drive through floodwaters, or take

shelter in a building during a flood. The vulnerability to hazard will also be influenced by whether

the primary consideration is strategic land use planning aimed at ensuring that the land use is

compatible with the flood risk or assessing development proposals or emergency management

planning aimed at addressing residual flood risks.



Table 4.5: Classification limits for vulnerability thresholds of combined hazard curves.

Hazard

Vulnerability

Classification

Description Classification

Limit (D and

V in

combination,

m2s-1

Limiting Still

Water Depth

(d, m)

Limiting

Velocity

(V, m s-1)

H1 Generally safe for vehicles, people and

buildings.

D x V ≤ 0.3 0.3 2.0

H2 Unsafe for small vehicles D x V ≤ 0.6 0.5 2.0

H3 Unsafe for vehicles, children and the elderly D x V ≤ 0.6 1.2 2.0

H4 Unsafe for vehicles and people D x V ≤ 1.0 2.0 2.0

H5 Unsafe for vehicles and people. All buildings

vulnerable to structural damage. Some less

robust building subject to failure.

D x V ≤ 4.0 4.0 4.0

H6 Unsafe for vehicles and people. All building

types considered vulnerable to failure.

D x V ≤ 4.0 - -

4.10 FLOOD HAZARD REFERENCE VALUES/ POPULATION AT RISK (PAR) /

POTENTIAL LOSS OF LIFE (PLL):

Flood hazard reference values consisting of maximum water depth, maximum depth-averaged

velocity, and flood wave arrival time at various locations downstream of Amarja Dam, Population

at risk as per the 2011 census data and potential loss of life are presented in Table 4.6. The potential

loss of life is approximately estimated based on the settled area inundated to the total settlement

area and then multiplied with the total population and actual population data provided by the

Amarja Dam Engineer. The Reference values were determined close to the identified positions

and represent the degree of danger that would be created by the flood. The settlements along the

downstream of the Amarja Dam were identified using Google earth.



Sl.no. Location Name Area in Sq.km

Area Intersected in

Sq.km

Percentage of

Intersection

Population as

per 2011

census

Projected Population at

17.13 % as per

Karnataka statics dept

report from 2012-2021. Potential Loss of

Life

1 Auradi 0.128 0.000 0.077 1102 1290.77 1.0

2 Badanhalli 0.062 0.003 4.229 461 539.97 22.8

3 Busnur 0.445 0.056 12.590 5190 6079.05 765.3

4 Chaudapur 0.433 0.021 4.924 4142 4851.52 238.9

5 Chaudapur Tanda 0.164 0.002 1.421 400 468.52 6.7

6 D.Ghangapur Sangama 0.038 0.006 17.113 3900 4568.07 781.7

7 D.Ghangapur Sangama 0.098 0.011 11.641 3960 4638.35 540.0

8 Dangapur 0.241 0.006 2.677 2340 2740.84 73.4

9 Dannur 0.027 0.014 50.956 500 585.65 298.4

10 Diksangi 0.042 0.011 25.394 1516 1775.69 450.9

11 Gangapur 0.804 0.002 0.270 1200 1405.56 3.8

12 Gaudgaon 0.101 0.002 1.721 1615 1891.65 32.6

13 Harnala 0.036 0.000 0.022 550 644.22 0.1

14 Hittal Sirur 0.297 0.016 5.248 3136 3673.20 192.8

15 Ingalgi 0.085 0.001 1.492 188 220.20 3.3

16 Itagi 0.232 0.000 0.015 1589 1861.20 0.3

17 Jawali 0.079 0.021 26.962 1673 1959.58 528.3

18 Karabosga 0.028 0.003 12.066 602 705.12 85.1

19 Karalli 0.065 0.021 33.006 2477 2901.31 957.6

20 Koganur 0.169 0.001 0.431 1350 1581.26 6.8

21 Koganur Cross 0.011 0.005 46.227 300 351.39 162.4

22 Koganur Cross Extn 0.034 0.001 4.378 100 117.13 5.1

23 Kudaki 0.058 0.001 1.475 1304 1527.38 22.5

24 Madra Buzurg 0.149 0.004 2.529 711 832.79 21.1

25 Madra Khurd 0.047 0.004 9.614 2076 2431.62 233.8

26 Place 2 near Korahalli 0.050 0.004 8.838 500 585.65 51.8

27 Tellur 0.158 0.000 0.148 2105 2465.59 3.6

Table 4.6: showing the Potential loss of Life based on percentage area of Inundation for the Projected Population from 2012-2021



TABLE 4.7: FLOOD HAZARD REFERENCE VALUES

Sl.

no

Location Name Dist_

km

Populati

on at

risk as

per

2011

census

Projecte

d

Populati

on at

17.13 %

as per

Karnata

ka

statics

dept

report

from

2012-

2021.

Potential

Loss of

life

(considerin

g the area

of

inundation

%age)

Overtopping Failure Non-Flood Failure Large Control

Releases

Max

Depth

(m)

Max

Velocity

(m/s)

Flood

wave

arrival

time(hrs)

Max

Depth

(m)

Max

Velocity

(m/s)

Flood

wave

arrival

time(hrs)

Max

Depth

(m)

Max

Velocity

(m/s)

1 Badanhalli 26.80 461.00 539.97 23 5.65 1.41 4.30 4.21 1.24 5.03 4.66 1.15

2 Busnur 3.12 5190.00 6079.05 766 4.53 2.08 0.60 3.65 1.74 1.12 1.82 0.94

3 Chaudapur 28.06 4142.00 4851.52 239 2.89 0.39 4.75 1.43 0.33 5.63 1.93 0.24

4 Chaudapur Tanda 27.67 400.00 468.52 7 0.89 0.26 5.32 0.00 0.00 0.00 0.00 0.00

5 D.Ghangapur

Sangama 34.81 3900.00 4568.07 782 5.69 1.31 6.65 3.79 0.71 7.67 6.10 1.13

6 D.Ghangapur

Sangama 35.21 3960.00 4638.35 540 5.69 1.31 6.65 3.79 0.71 7.67 6.10 1.13

7 Dangapur 6.94 2340.00 2740.84 74 4.48 1.67 1.40 3.74 1.43 1.85 2.55 0.86

8 Dannur 25.03 500.00 585.65 299 5.63 3.05 3.90 4.36 2.37 4.58 4.60 2.30

9 Dannur 24.76 419.00 490.77 0.00 5.63 3.05 3.90 4.36 2.37 4.58 4.60 2.30

10 Diksangi 21.60 1516.00 1775.69 451 4.43 3.20 3.55 2.76 1.94 4.23 2.75 1.90

11 Gangapur 33.73 1200.00 1405.56 4 0.36 0.09 9.63 0.00 0.00 0.00 0.82 0.07

12 Gaudgaon 17.95 1615.00 1891.65 33 2.77 0.93 3.05 1.42 0.72 3.70 1.05 0.59

13 Harnala 37.05 550.00 644.22 1 0.59 0.08 8.82 0.00 0.00 0.00 0.95 0.08

14 Hittal Sirur 11.73 3136.00 3673.20 193 3.69 1.74 2.00 2.88 1.49 2.48 2.10 1.23

15 Ingalgi 29.15 188.00 220.20 4 1.02 0.31 5.97 0.00 0.00 0.00 0.31 0.03

16 Itagi 34.72 1589.00 1861.20 1 0.03 0.05 10.85 0.00 0.00 0.00 0.48 0.05

17 Jawali 7.04 1673.00 1959.58 529 2.85 1.67 1.27 2.20 1.58 1.72 1.31 0.99

18 Karabosga 19.96 602.00 705.12 86 3.43 1.46 3.42 1.85 1.16 4.10 1.82 1.05



19 Karalli 1.70 2477.00 2901.31 958 4.68 1.34 0.20 3.76 1.24 0.75 1.23 0.49

20 Karbhosga 20.31 600.00 702.78 0.00 2.00 0.06 3.80 0.38 0.02 4.78 0.37 0.01

21 Kerakanahalli 35.30 1162.00 1361.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

22 Koganur 16.64 1350.00 1581.26 7 0.40 0.18 3.47 0.00 0.00 0.00 0.00 0.00

23 Koganur Cross 17.40 300.00 351.39 163 2.17 1.27 3.03 0.83 1.00 3.75 0.46 0.80

24 Koganur Cross

Extn 17.71 100.00 117.13 6 1.56 0.89 3.18 0.31 0.29 4.03 0.00 0.00

25 Kudaki 15.39 1304.00 1527.38 23 1.13 0.64 2.83 0.12 0.66 3.62 0.00 0.00

26 Madra Buzurg 24.53 711.00 832.79 22 1.05 1.04 4.45 0.00 0.00 0.00 0.00 0.00

27 Madra Khurd 21.80 2076.00 2431.62 234 5.27 2.51 3.53 3.56 2.26 4.18 3.56 2.12

28 Place 2 near

Korahalli 1.76 500.00 585.65 52 1.62 0.95 0.75 0.69 0.70 1.20 0.00 0.00

29 Tellur 33.31 2105.00 2465.59 4 1.56 1.13 6.58 0.00 0.00 0.00 1.57 0.94



5. FLOOD INUNDATION MAPPING

An Emergency Action Plan (EAP) is a formal document that identifies potential emergency

conditions at a dam and specifies pre planned actions which are required to be followed for

minimizing damage to proper-ties and loss of life. The EAP specifies actions for the dam owner,

in coordination with emergency management authorities, to be taken while responding to incidents

or emergencies related to the dam. It presents procedures and information for assisting the dam

owner in issuing warnings and notification messages to responsible downstream emergency

management authorities. The EAP includes inundation maps for assisting the dam owner and

emergency management authorities in identifying critical infrastructure and sites with huge

population at risk, which may require protective measures and warning as well as evacuation

planning.

Inundation maps showing

1) Maximum water depth in m

2) Maximum water velocity in m/s

3) Maximum water-surface elevation in m-MSL and

4) Flood wave arrival time are prepared for each of the three flood scenarios considered.

Flood inundation maps for the parameters mentioned above were prepared using Arc GIS software.

The Scale of the map is 1:25,000. The total length of the inundation downstream of Amarja Dam

is about 53 km has 17 tiles per scenario. The projection type is WGS-84 UTM zone 43 N. The

settlement layer is obtained by distinguishing the settlement boundary from google earth.



6. CONCLUSIONS:

❖ The Amarja dam break analysis is carried out for tier 2 approach using medium resolution

terrain data.

❖ About 29 villages are found to be affected in case of Amarja dam breach.

❖ The people living in villages within 1 km downstream of Amarja dam are most vulnerable

as the flood wave arrival time is less.

❖ The peak breach flow obtained is 10,546.36 m3/s and 8248.88 m3/s for overtopping and

piping failure respectively.

❖ The breach velocity at the time of failure is 2.70 m/s and 2.24 m/s for overtopping failure

and piping failure respectively which are well within the recommended limits.

❖ It is observed that the inundation on both sides of the river is significant in case of flood

due to large controlled release.

❖ At a distance of approximately 53 km from the dam site, it is observed that the flood water

will be confined to the river course.

❖ Flood maximum depth, maximum velocity, Flood arrival time, Water surface elevation and

vulnerability maps are prepared at a scale of 1:25000.

❖ The developed inundation maps are useful for preparation of EAP (Emergency Action

Plan).



REFERENCES:

1. ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Dataset,

Version 1 Earth Observation Research Center (EORC), Japan Aerospace Exploration

Agency (JAXA). March 2017.

2. Design Flood Studies report of Amarja Dam “Water Resources Development

Organization” May 2015.

3. KERS report on “Kabini Dam Break Studies” March 2018.

4. TD-39 Using HEC-RAS for Dam break studies, August 2014, US Army Corps of

Engineers, Hydrologic Engineering Center.

5. CPD-68A; HEC-RAS River Analysis System 2D Modeling User’s Manual, Version 5, Feb

2016.

6. Doc.No. CDSO-GUD-DS-05-VI.0 Guidelines for Mapping Flood Risks Associated with

Dams January 2018, CWC, MOWR, River Development and Ganga Rejuvenation, GOI.

7. An Empirical Model of Embankment Dam Breaching by David C Froehlich, third National

Dam Safety Conference 18-19 Feb 2017, Roorkee, India.

8. Embankment Dam Breach Parameters and their Uncertainties by David C Froehlich,

Journal of Hydraulic Engineering, Dec 2008.

9. Manual on Estimation of Design Flood by CWC, New Delhi Mar 2001.

10. Predicting Peak Discharge for gradually breached embankment dam, by David C

Froehlich, Journal of Hydrologic Engineering, July 2016.

11. IS 11223-1985 (RA-1995), Guidelines for fixing spillway capacity.

12. CPD-74A; Hydrologic Modeling System HEC-HMS, User’s Manual version 4.2, Aug

2016 by US Army Corps of Engineers, Hydrologic Engineering Center.

13. Projected Population of Karnataka 2012 – 2021 issued by Directorate of Economics and

Statistics, Bangalore – 2013.

14. Population 2011 census data, GoI, data.gov.in




Phone No: 080-22262042/43/44 Fax No: 080-22262045

ACIWRM

The Advanced Centre for Integrated Water Resources Management (ACIWRM) was

established to become a Global Centre of Excellence by Government of Karnataka in

February 2012. ACIWRM acts as a think tank to the government’s Water Resources

Department (WRD). It is engaged in policy analysis, research, planning, capacity building

and developing the knowledge base for gearing up the department up to its future vision

2030. The ACIWRM works with the various departments, civil society, the private sector,

farmers and water user associations and other organizations to produce integrated advice to

the WRD for managing the State’s water resources.

KEY AREAS ❖ Karnataka Water Resources Information System (K-WRIS)

❖ IWRM Training and Capacity Building

❖ River Basin Planning & Management

❖ River Basin Modelling

❖ Communication, Awareness Raising and Participation

❖ Water Use Efficiency, Water Accounting and Water Productivity

❖ State IWRM Policy and Strategy

❖ Sustainable Groundwater Management

❖ Participative Land and Water Management Plans (LWMP)

❖ Climate Change / Variability / Adaptability for Water Sector

SUGAR FACTORY

KARALLI

PLACE 2 NEAR KORAHALLI

AMARJA DAM

Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, andthe GIS User Community

76°34'0"E

76°34'0"E

76°35'0"E

76°35'0"E

76°33'0"E

76°33'0"E17

°29'0"

N17

°28'0"

N

9

8

5

76

32

4

111512 13 16

17

1014

Source: Esri, DigitalGlobe, GeoEye,Earthstar Geographics, CNES/AirbusDS, USDA, USGS, AeroGRID, IGN,and the GIS User Community

Depth (m)0 - 0.30.30 - 0.600.60 - 1.201.20 - 2.002.00 - 3.003.00 - 5.005.00 - 10.00> 10.00

ROADSRAILWAYSSETTLEMENT

Locator Map

AMARJA DAM, KARNATAKAOVERTOPPING FAILURE

MAXIMUM DEPTH ¯

0 0.4 0.8 1.2 1.60.2Km

WATER RESOURCES DEPARTMENTGOVT. OF KARNATAKADAM REHABILITATION AND IMPROVEMENT PROJECTADVANCED CENTRE FOR INTEGRATED WATER RESOURCES MANAGEMENT (ACIWRM)

Name of Dam : AMARJA DAM, KARNATAKAState : KARNATAKA

Doc No :MAP No: MARCH, 2019

Title : OVERTOPPING FAILUREMAXIMUM DEPTHKaWRD_MAP_AMARJA_01

1 / 17 May 2019

project rehabilitation report of amarja dam,

Documents