I= EFFECT OF VARYING DISCHARGES ON THE EQUITY OF WATER DISTRIBUTION IN THE IRRIGATION SYSTEM
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Title of Thesis
EFFECT OF VARYING DISCHARGES ON THE EQUITY OF WATER DISTRIBUTION IN THE IRRIGATION SYSTEM

Author(s)
Muhammad Nawaz Bhutta
Institute/University/Department Details
University Of Engineering And Technology Lahore/Centre Of Excellence In Water Resources Engineering
Session
1990
Subject
Water Resources Management
Number of Pages
224
Keywords (Extracted from title, table of contents and abstract of thesis)
variability, water deliveries, canals management, head of distributary, discharge, water supplies, surface water, varying discharges, water distribution

Abstract
This study was conducted at three distributaries of Upper Gugera Branch of Lower Chenab Canal, Punjab Province, Pakistan. Mananwala and Lagar Distributaries are in the head reach of the channel and Pir Mahal Distributary is at the tail.

Discharge of these distributaries and of selected outlets of these distributaries were measured. Field observation indicate that water deliveries at the head of distributaries are rarely in accordance with the original design criteria. The discharge at the head of the distributaries (perennial) is lower than 75 percent of the design for a period varying from 111 days to 198 days in a year.

Field measurement indicate that the distribution of surface water between the outlets of a distributary is substantially inequitable when the original design parameters of distributaries no longer prevail. The average discharge delivered to the outlets varies from 250 (head reach) to 0 (tail reach) percent of design values. The data suggest that two design assumptions for outlets are no longer valid; constant water level in the distributary and modular flow conditions of outlets.

The data also suggest that the intake structure of a secondary channel should be a gated one to attain reliable water supplies. Moreover, active management, e.g. altering position of stop logs from horizontal to vertical at the head of a distributary can reduce variation of water deliveries to the distributaries.

A computer model “Mistral” was adopted for the evaluation of management options. Tests performed by the model suggest that under current physical conditions the combination of rotation between the distributaries and along the distributaries can improve the equity conditions of the irrigation system. For example in the case of Lagar Dsitributary the discharge of tail outlets can be increased by 3 times of their existing discharge by introducing rotation between the tail of the distributary and Jhinda Minor. There wll be a small decrease in the discharge of Jhinda Minor by adopting this option. A combination of rotation between the distributaries and along the distributaries can increase the discharge of tail outlets up to 7 times of their existing discharges. The results of the model suggest that if the original design parameter of a distributary are restored, re-adjustment of non-modular and tempered outlets is necessary before equity of water distribution can be achieved.

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1932.41 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 Contents
KB
2 1 Introduction 1
71.86 KB
  1.1 Background 2
  1.2 Scope Of Study 4
  1.3 Variability In Water Deliveries 7
  1.4 Equity In Water Distribution 8
3 2 Objectives 10
35.06 KB
4 3 The Irrigation System In Punjab 14
142.45 KB
  3.1 Network Operation 14
  3.2 Intake Structures 19
  3.3 Flow Dividing Structures 20
  3.4 Outlets 21
  3.5 Irrigation Department Record 22
  3.6 Equitable Distribution Of Water To Individual Outlets 25
5 4 Review Of Literature 29
168.39 KB
  4.1 Variability And Equity In The Irrigation Systems 29
  4.2 Application Of Computer Models For Irrigation Canals Management 37
6 5 Data Collection Methodology And Preliminary Data Analysis 45
568.53 KB
  5.1 Description Of Study Site 45
  5.2 Experimental Limitation 56
  5.3 Main Channel Flows Data 58
  5.4 Discharges At The Head Of Distributary 58
  5.5 Rotational Schedule Of Bhagat Sub-Division 67
  5.6 Water Distribution Along The Distributary 67
  5.7 Physical Conditions Of Channels 82
  5.8 Irrigation Department Records 88
7 6 Results And Discussion 93
619.07 KB
  6.1 Discharge Variations At The Head Of Gugera Branch 94
  6.2 Relationship Between Main Channel Flow And Distributary Discharge 100
  6.3 Effect Of Location On Distributary Head Flows 101
  6.4 Variability Of Discharges At Distributary Heads 101
  6.5 Equity Of Water Distribution Along The Distributary 126
  6.6 Reliability Of Water Supply Along The Distributary 161
8 7 Application Of Hydraulic Model For Distributary Management 167
236.66 KB
  7.1 Selection Of The Model 168
  7.2 The Mistral Flow Simulation Model 169
  7.3 Software Application 172
  7.4 Software Input 174
  7.5 Data Collected In View Of Model Calibration 185
  7.6 Model Calibration 185
  7.7 Testing Different Operational Scenarios Under Existing Physical Conditions 188
  7.8 Maintenance Options For Irrigation Management 196
9 8 Conclusions And Recommendations 201
77.72 KB
  8.1 Conclusions 201
  8.2 Recommendations 207
10 9 References 216
38.02 KB
11 10 Appendices 214
110.81 KB