Teesta Barrage Project IMIP

Feasibility Study Report

SR-4 Irrigation and Drainage System

May 2016

Bangladesh Water Development Board

Mott MacDonald Ltd (UK) in association with: Euroconsult Mott MacDonald (Netherlands)

Northwest Hydraulic Consultants (Canada)

SODEV Consultant Ltd (Bangladesh)

337483 IDD IDC 01 A

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20 July 2015

IMIP: Project Management and Design Consultant

Inception Report

Irrigation Management Improvement Project Project Management and Design Consultant Asian Development Bank (Loan 3135-BAN)

Teesta Barrage Project, IMIP

SR-4 Irrigation and Drainage System

May 2016

Bangladesh Water Development Board People’s Republic of Bangladesh

Project Management Unit (PMU), Hasan Court (3rd floor), 23/1 Motijheel, Dhaka-1000 This report was prepared at the request and with the financial support of the ADB. The views expressed are those of the Consultants and do not necessarily reflect those of the Government of Bangladesh or the ADB.

Mott MacDonald, Demeter House, Station Road, Cambridge CB1 2RS, United Kingdom

T +44 (0)1223 463500 F +44 (0)1223 461007 W www.mottmac.com

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IMIP: Project Management and Design Consultant TBP Feasibility Report

Revision Date Originator Checker Approver Description

A 17th May 2016

Alan K Clark AKM Sayeed Uddin

Nick Lockett 1st draft report

Issue and revision record

Information class: Standard

This document is issued for the party which commissioned it and for specific purposes connected with the above-captioned project only. It should not be relied upon by any other party or used for any other purpose.

We accept no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties.

This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it.

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IMIP: Project Management and Design Consultant TBP Feasibility Report

Key Data

Name of Project: Irrigation Management Improvement Project (IMIP)

Implementing Parties: Government of Bangladesh (GoB)

Bangladesh Water Development Board (BWDB)

Contractor: Mott MacDonald Ltd UK in association with:

Euroconsult Mott MacDonald, Netherlands

Northwest Hydraulic Consultants, Canada

SODEV Consultant Int. Ltd, Bangladesh

Contracting Authority: Asian Development Bank (ADB)

Loan No. 3135-BAN

Start/ End Date: 1st March 2015 to 28th February 2020

Beneficiaries: Farmers

Locations/ Schemes: Muhuri Irrigation Project (MIP)

Ganges Kobadak Irrigation Project (GKIP)

Teesta Barrage Project (TBP)

Distribution List

Recipient Copies Format

ADB in Bangladesh 2

1

Hardcopy

Electronic

Bangladesh Water Development Board 7

1

Hardcopy

Electronic

TBP SR-4 I&D SYSTEM (2).DOCX - 1 - 16-May-16

SR 4: IRRIGATION AND DRAINAGE SYSTEM

Contents

I. INTRODUCTION 1

II. OVERVIEW OF IRRIGATION AND DRAINAGE SYSTEM 3

A. Development of Irrigation Scheme and Project Area 3

B. River Flows and Irrigable Area 5

C. Pumping of Groundwater 8

D. Engineering Infrastructure 9

1. TBP Phase-I works 9

2. Buri Teesta Scheme 11

3. On-going works under GoB funded project (2007-2018) 12

4. Drainage 14

E. Current Irrigation Management 14

F. Farmer WMO Status and ISCs 14

G. Stakeholder Consultations 16

H. Modernization Concept/ Scope 16

III. CROP WATER REQUIREMENTS, IRRIGATION EFFICIENCY AND DUTIES 19

A. Climate and Reference Evapotranspiration 19

1. Rainfall 19

2. Climate Data and Reference Evapotranspiration 20

B. Land Categories, Potential Cropping Intensity and Cropping Calendar 21

C. Parameters Adopted to Calculate Crop Water Requirements 22

1. Crop Coefficients 22

2. Land Preparation for Paddy Cropping 23

3. Seepage and Percolation Losses for Rice Cropped Areas 24

4. Irrigation Application Efficiencies 25

D. Crop Water Requirements 26

1. Current and Future Cropping Pattern 26

2. Field Level Crop Water Requirements 27

E. Conveyance Losses and Design Duties 30

1. Losses and Duties at Quaternary and Tertiary Level 30

2. Losses at Secondary/ Main Canal Level 31

F. Section Summary 33

IV. CANAL LINING ASSESSMENT AND RECOMMENDATIONS 35

TBP SR-4 I&D SYSTEM (2).DOCX - 2 - 16-May-16

A. Assessment of Lining Options 35

1. Introduction 35

2. Concrete alone 35

3. Concrete with Geomembrane 36

4. Geo-composite liners 37

5. Concrete reinforced with light steel mesh 37

6. Flume Sections 38

B. Cost Benefit Analysis of Lining Options 38

1. Costs and Service Lift 38

2. Benefits 38

3. Results for Loams 39

4. Results for Sandy Loams 40

5. Results for Sands 40

6. Sensitivity of IRR to Service Life 41

C. Lining Proposals for TBP 41

V. IRRIGATION SYSTEM 43

A. Irrigation System Command and Development Zones 43

B. Canal Systems 46

1. Teesta Canal System 47

2. Dijanpur Canal System 50

3. Ranpur Canal System 52

4. Bogra Canal System 53

5. Tertiary Canals and Field Channels 53

C. Canal System Structures 56

1. Turnouts 56

2. Check Structures 56

3. Gates 56

D. Losses and Design Discharges 59

1. Design Duties 59

2. Seepage Losses 59

3. Operational Losses 59

4. Combined Seepage and Operational Losses 60

E. Problems Identified with Canal System 61

1. Teesta Canal System 61

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2. Dinajpur Canal System 62

3. Rangpur Canal System 63

4. Bogra Irrigation Canal System 63

F. Section Summary 63

VI. RIVER AND DRAINAGE CHANNEL SYSTEM 65

A. River Systems 65

B. Drainage Problems and Suggestions 67

1. 2004 Study Report Recommendations 67

2. River / Drainage Channel Excavation 69

VII. IRRIGATION MODERNIZATION PROPOSAL 71

A. Development Zones and Irrigation System Modernization 71

B. Canals 73

1. Main Canals and Command of Turnouts 73

2. Secondary Canals 73

3. Tertiary Canals 73

C. Main and Secondary Canal Structures 74

D. Electrification 75

E. Conjunctive Use Development – Levels 3 and 4 76

F. Inspection Roads 76

G. Drainage System 81

H. Rubber Dams 81

I. SCADA System 81

VIII. MANAGEMENT, OPERATION AND MAINTENANCE 85

A. Operation Challenges and Enabling Engineering Infrastructure 85

B. Scheme Operation and BWDB Staffing 86

C. Proposed Management/ Institutional Arrangements 87

1. BWDB and IMO 87

2. Farmer Water Management Organisations 89

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LIST OF ANNEXES

ANNEX A: INVENTORY OF CANAL SYSTEM

ANNEX A1: MAIN CANAL SYSTEMS

ANNEX A2: SECONDARY CANALS - TEESTA SYSTEM

ANNEX A3: SECONDARY CANALS - DINAJPUR SYSTEM

ANNEX A4: SECONDARY CANALS - RANGPUR SYSTEM

ANNEX A5: SECONDARY CANALS - BOGRA SYSTEM

Following Annexes A6 to A9 available on request:

ANNEX A6: TERTIARY CANALS - TEESTA SYSTEM

ANNEX A7: TERTIARY CANALS - DINAJPUR SYSTEM

ANNEX A8: TERTIARY CANALS - RANGPUR SYSTEM

ANNEX A9: TERTIARY CANALS - BOGRA SYSTEM

ANNEX B: LANDUSE, CULTIVABLE AND IRRIGABLE AREAS

(BWDB DATA AND GIS DATA/ PMDC)

ANNEX C: DATA FOR EXISTING STRUCTURES (GEOMETRY AND SILL LEVELS)

ANNEX C1: TEESTA SYSTEM

ANNEX C2: DINAJPUR SYSTEM

ANNEX C3: RANGPUR SYSTEM

ANNEX C4: BOGRA SYSTEM

ANNEX D: DISCHARGE STATEMENTS FOR SECONDARY CANALS IN DZ-1

TBP SR-4 I&D SYSTEM (2).DOCX - 5 - 16-May-16

LIST OF FIGURES

Figure II-1: Photographs of TBP Scheme, Phase-I Area ........................................................................ 3

Figure II-2: Planned Phased Development Areas................................................................................... 5

Figure II-3: Teesta River Flows at Dalia 291.5R ..................................................................................... 6

Figure II-4: Irrigation Coverage, Kharif II 2003........................................................................................ 7

Figure II-5: DTWs in TBP Area and Irrigation Layout ............................................................................. 9

Figure II-6: Buri Teesta Scheme ........................................................................................................... 11

Figure II-7: TBP O&M Divisions ............................................................................................................ 15

Figure III-1: Project area rainfall ........................................................................................................... 20

Figure III-2: Reference Evapotranspiration ........................................................................................... 21

Figure III-3: Typical Cropping Pattern by Land Category ..................................................................... 21

Figure III-4: Land Preparation ............................................................................................................... 24

Figure III-5: Imagery of part of T1-S1T showing basin sizes ................................................................ 26

Figure III-6: Field Water Requirements for current and future cropping patterns ................................. 29

Figure V-1: Map of Development Zones ............................................................................................... 44

Figure V-2 : Photographs of Canals ...................................................................................................... 54

Figure V-3: Map of Irrigation System .................................................................................................... 55

Figure V-4 : Photos of Teesta System Structures................................................................................. 58

Figure VI-1: Map of River Systems ....................................................................................................... 67

Figure VI-2 : Map showing Drainage Problem Areas, CAD-I Report, June 2004 ................................. 70

Figure VII-1 : Photos of Existing Inspection Roads .............................................................................. 77

Figure VII-2 : Map showing proposed Inspection Road Works ............................................................. 80

TBP SR-4 I&D SYSTEM (2).DOCX - 6 - 16-May-16

LIST OF TABLES

Table II-1: Land use for the Teesta Barrage Project area ...................................................................... 4

Table II-2: Ongoing works for TBP funded by GoB, 3rd RDPP January 2016 ...................................... 13

Table III-1: Project area rainfall and effective rainfall for dry, average and wet years ......................... 19

Table III-2: Reference Evapotranspiration (ETo) for average Saidpur Climate Data ........................... 20

Table III-3: Land Categories and Potential Cropping Intensity ............................................................. 22

Table III-4: Crop Calendar ..................................................................................................................... 22

Table III-5: Adopted crop coefficients, Kc ............................................................................................. 23

Table III-6: Basin sizes and irrigation times ......................................................................................... 25

Table III-7: Current and potential future cropping patterns for TBP area ............................................. 26

Table III-8: Field level crop water requirements for current and potential future cropping patterns ..... 28

Table III-9: Design Duties at Quaternary-Tertiary Level ....................................................................... 31

Table III-10: Results of seepage tests .................................................................................................. 31

Table III-11: Seepage loss rate, BWDB ................................................................................................ 31

Table III-12: Seepage losses for several soils and estimation methods ............................................... 33

Table IV-1: Cost and Durability of Liner Types, USBR Study ............................................................... 35

Table IV-2: Thickness of concrete liners ............................................................................................... 36

Table IV-3: Unit rates ............................................................................................................................ 38

Table IV-4: Assessment of Lining Options, Loams, 1km length of canal ............................................. 39

Table IV-5: Assessment of Lining Options, Sandy Loams, 1km length of canal .................................. 40

Table IV-6: Assessment of Lining Options, Sands, 1km length of canal .............................................. 40

Table IV-7: Sensitivity of IRR to service life, Sandy Loams .................................................................. 41

Table V-1: Land use, Cultivable and Irrigable Areas by Development Zone ........................................ 43

Table V-2: Cultivable and Irrigable Areas by Canal System ................................................................. 45

Table V-3 : Main Canal System Inventory ............................................................................................ 47

Table V-4 : Secondary Canal Systems Inventory by Main Canal System ............................................ 47

Table V-5 : Teesta Secondary Canal Systems ..................................................................................... 49

Table V-6 : Dijanpur Secondary Canal Systems .................................................................................. 51

Table V-7 : Rangpur Secondary Canal Systems .................................................................................. 53

Table V-8 : Number and Types of Turnouts (H-Regs) from Main and Secondary Canals ................... 57

Table V-9 : Proposed Loss Coefficients for Seepage and Operational Losses .................................... 60

Table V-10 : Indicative Flows and Duties at Tertiary, Secondary and Main Canal Level ..................... 60

Table VII-1: Development Zones and System Modernisation ............................................................. 72

Table VII-2: Headlosses for Selected Turnouts along Tessta Main Canal in DZ-1 ............................. 74

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Table VII-3 : Categories of Works to Upgrade Existing Inspection Roads .......................................... 77

Table VII-4 : Proposed Inspection Roads Works and Costs ................................................................ 79

Table VII-5: Summary of proposed SCADA system ............................................................................. 83

Table VIII-1: Existing BWDB staffing .................................................................................................... 86

Table VIII-2: Indicative C-IMO staffing requirements ............................................................................ 88

TBP SR-4 I&D SYSTEM (2).DOCX - 1 - 16-May-16

I. INTRODUCTION

1. This Supplementary Report presents data and analyses concerning the irrigation and

drainage system and its modernization.

2. Following this Introductory Chapter, CHAPTER II presents an overview of the irrigation

systems, including its development, the implications of low river flows in the Teesta, use of

groundwater, ongoing engineering works, current management, stakeholder consultations and

modernisation scope.

3. In CHAPTER III rainfall, climate and reference evaporation values are given, along with land

categories, current and future cropping pattern and calculations of crop water requirements at field

level for application efficiencies of 60% for all crops. Field level crop water requirements are 0.90

l/s/ha in the lean season for Rabi cropping, and 0.46 l/s/ha for Kharif-I and -II cropping. Estimates for

conveyance seepage and operational losses are given allowing design duties to be computed for both

buried pipe systems (quaternary level), and for open channel distribution. For buried pipe systems,

the required duty is 0.95 l/s/ha. 8.2 mm/d.

4. CHAPTER IV assesses canal lining, options and costs along with benefits, in particular

seepage loss reduction in the light (sandy) soils. The analysis concludes that lining is justified on the

basis of seepage water lost for canals where lean season water is supplied. For canals which do not

receive water in the lean season, lining cannot be justified. The analysis reflects the higher value of

water in the lean season, when it equals the cost to pump groundwater, compared to the wet season

when river flows are plentiful and can be supply by gravity.

5. CHAPTER V describes the irrigation system, and proposes adoption of Development Zones

which delineate between the areas for (i) gravity canal, and (ii) conjunctive use supply of irrigation

water. This is to allow targeted and cost effective engineering investments. In Development Zone-1

the focus will be on modernized canal irrigation with lining of secondary and canals and upgrading of

lined tertiary and quaternary systems, while in Development Zone-2 the focus will be on conjunctive

use with buried pipe systems at quaternary level. The chapter also notes that some of the secondary

canals have reverse slopes towards the tail; i.e. the bed levels towards the tail of some of the canals

are too high to allow irrigation. Many of the tertiary canals also have this problem.

6. The required diversion flows from the barrage in the lean season for Development Zone 1, will

be about 29.9 m3/s, based on an irrigable area of 18,707 ha, and a duty of 1.60 l/s/ha. If higher river

flows were available, they would be supplied to canals in Development Zone 2, thereby reducing

groundwater pumping costs.

7. For Kharif-I and -II cropping, the peak required diversion flows would be about 96.4 m3/s,

based on an irrigable area of 101,427 ha (i.e. for both development zones) and a duty of about 0.95

l/s/ha.

8. Chapter VI describes the drainage system, which comprises six river systems, and notes that

some localised drainage congestion occurs due to insufficient cross drainage at a few locations. Most

of the land is high or medium high and prolonged flooding is not a problem.

9. In CHAPTER VII irrigation modernisation proposals are given. Development Zones are

proposed to make optimum use of scarce river water, and to focus investments for canal and

conjunctive use development with groundwater, thereby ensuring supply through the year. In DZ- 1

the focus is on canal irrigation, while in DZ-2 the focus is on conjunctive use irrigation.

10. Engineering works to enable modern irrigation and efficient water, energy and management

include: (i) a canal system with sufficient capacity to carry the design discharges, and also able to

command offtakes for a variety of low flows; (ii) gated flow control structures to control flows and

water levels throughout the canal system; (iii) lined secondary and tertiary (and field) canals over a

cultivable area of 25,982 ha (21.2%) in DZ-1, and conjunctive use supply with buried pipes and DTWs

over a cultivable area of 89,912 ha (77.6%) in DZ-2; (iv) a SCADA system for water level and flow

monitoring and remote gates control along the main and selected secondary canal systems, and to

TBP SR-4 I&D SYSTEM (2).DOCX - 2 - 16-May-16

monitor usage/ consumption of water by tertiary Water User Groups, as well as energy use by

installation of pre-paid meters installed to pumps for the buried pipe systems; (v) sufficient cross

drainage structures to ensure against localized drainage congestion; and (vi) paved inspection roads

along the Main Canals and selected/ larger Secondary Canals.

11. CHAPTER VIII presents scheme Management, Operation and Maintenance arrangements

including indicative staffing for the proposed Irrigation Management Operator which will work, largely

at Secondary and Tertiary level, with the BWDB to deliver the Project and improved irrigation

services.