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Research Reports
IWMI’s mission is to improve water and land resources management for food, livelihoods
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ii
Research Report 46
Using Remote Sensing Techniques
to Evaluate Lining Efficacy of
Watercourses
International Water Management Institute
P O Box 2075, Colombo, Sri Lanka
R. Sakthivadivel
Upali A. Amarasinghe
and
S. Thiruvengadachari
ii
IWMI’s research is funded by the Consultative Group on International Agricultural
Research (CGIAR) and other donors. Support is also given by the Governments of
India, Iran, Mexico, Nepal, Pakistan, South Africa, and Sri Lanka.
The authors: R. Sakthivadivel is Irrigation Specialist and Upali A. Amarasinghe is Research
Statistician both of IWMI, Colombo, Sri Lanka and S. Thiruvengadachari formerly Group
Director, National Remote Sensing Agency, Hyderabad, India is a private consultant in India.
R. Sakthivadivel, Upali A. Amarasinghe, and S. Thiruvengadachari. 2001. Using remote
sensing techniques to evaluate lining efficacy of watercourses. Research Report 46.
Colombo, Sri Lanka: International Water Management Institute.
/ water management / water distribution / remote sensing / watercourses / canal linings/
seepage loss / SRS data analysis / groundwater development / surface water / performance
evaluation / equity / India /
ISBN 92-9090-416-X
ISSN 1026-0862
Copyright © 2001, by IWMI. All rights reserved.
Please direct inquiries and comments to: iwmi-research-news@cgiar.org
iiiiii
Contents
Summary v
Introduction 1
Study Area 3
Basic Data 9
Analysis of Multiyear Satellite Data 10
Performance Descriptors 13
Method of Analysis 14
Conclusions 24
Appendix 26
Literature Cited 29
iv
v
Summary
The cost of developing new irrigation potential is
escalating. A low-cost alternative strategy of
selective lining of watercourses to reduce
seepage and increase irrigated area is being
increasingly adopted in the Indian subcontinent.
However, studies on assessing the efficacy of
such lining are few. These studies have
depended mainly on a few sample watercourses
supported by limited water measurement and
agricultural data, and their results are not
conclusive.
Satellite Remote Sensing (SRS) is seen as a
cost-effective evaluation tool in view of its large
area of coverage, which is synoptic and
repetitive. The analysis of multiyear satellite data
has enabled to evaluate the lining efficacy of
about 30 watercourses located in the fresh,
marginal and saline groundwater zones of the
Bhakra canal command in Haryana, India. The
lined watercourses together with concomitant
groundwater development and use have sustained
tail-to-head uniformity of water distribution even
after 20 years of lining. The SRS technique can
be used as a stand-alone tool in an environment
where only small amounts of groundwater
supplies are used to support surface water
supplies. In areas with substantial groundwater
supplies, isolation of lining efficacy will require
additional data on groundwater support. The SRS
technique is particularly useful as a screening tool
to identify problem watercourses where field
verification data can be collected for cost-effective
and quick evaluation of watercourse lining. The
cost of using this technique works out to only
US$0.17 per hectare of the area served by the
watercourses. This cost is based on the 1996
cost of satellite images, covering a geographic
area of about 225 square kilometers.
1
Using Remote Sensing Techniques to Evaluate Lining
Efficacy of Watercourses
R. Sakthivadivel, Upali A. Amarasinghe, and S. Thiruvengadachari
Introduction
Irrigation diversion of river water through run-of-
river systems and supply from storage dams
have a long history in the Indian subcontinent. In
the postindependence years, both Pakistan and
India invested heavily in developing new
irrigation potential, which currently supports
about 30 percent of the world’s irrigated area.
The rate of expansion of irrigated area has
slowed down in recent decades with the cost of
developing irrigation potential becoming very
high, along with the rising cost of environmental
management. Externally assisted as well as
government-funded irrigation development
programs have now focused attention on
conserving the potential created so far, ensuring
its optimum utilization through better
infrastructure development and water
management practices. The alternative strategy
of increasing irrigation water supplies through
reducing water “losses”1 from canals and
watercourses by selective lining has been
increasingly adopted on the subcontinent.2 Since
watercourse conveyance losses in a typical
distribution system in alluvial soils are nearly
three times that of a distributary and one and a
half times that of a main canal, the lining of
watercourses has been embraced by the
engineering community as a means of ensuring
water supplies to the “unreached” in the tail
areas (National Seminar 1983). Methods have
been evolved for optimizing the length of a
watercourse to be lined to minimize cost
(Malhotra 1975). Watercourse lining is
recommended in saline groundwater areas (to
arrest the rising water table). Lining programs
have also been implemented in fresh
groundwater areas where the impact is to
reduce dependence on groundwater supplies
(World Bank 1995).
In spite of huge investments being made in
lining watercourses, definitive studies on
evaluating efficacy of lined watercourses in
maintaining flow and equity in water distribution
are limited in number and scope. The evaluation
studies done so far have depended heavily on
farmer surveys, inspection of sample
watercourses, and water measurements in a few
watercourses, as well as on a limited collection
of data on productivity of water consumed. While
these evaluations have indicated varying
1"Loss” is the normally used term, but in nonsaline areas the “lost” water is either conventionally stored underground for later use or moves
downstream for possible further use. Many people believe that by increasing the “efficiency” of irrigation (i.e., by reducing losses), the water
saved can be used elsewhere or be transferred to other sectors. IWMI’s work suggests the potential for such savings is not as great as often
assumed. For example, techniques to save water at the farm level may not translate into water savings at the system or basin level due to
recycling (Seckler, Barker, and Amarasinghe 1999).
2The cost of water saved through watercourse improvement was about 25 percent of the cost of developing an equal volume of new water
supply in Pakistan (World Bank 1995).
2
degrees of reducing seepage through
watercourse improvement, reliable information
and data on the effect of extent of lining and its
age on performance have been relatively poor
and scattered. The sustainability gains by lining
have also not been adequately evaluated,
although one study in Pakistan indicated that
benefits have been sustained for 10 years and
can be expected to continue for some more
years (World Bank 1995).
Because of the large number of
watercourses covering hundreds of kilometers
ground surveys become costly, time-consuming
and subjective, and staff from many departments
are required for data collection. It is in this
context that SRS techniques are seen as
promising tools to monitor and evaluate the
efficacy of watercourse lining. The large area
with synoptic coverage (over hundreds of square
kilometers) coupled with frequent revisits (limited
to a few days) and archived historical data
(more than a decade), enable to generate time
series on agricultural productivity at watercourse
level for detailed analysis. The increasing spatial
resolution (better than 10 meters) of current and
future satellites will further enhance the
capability to study spatial variability of irrigation
intensity, cropping pattern and crop productivity
of major crops across the watercourse
command.
The International Water Management
Institute (IWMI) undertook an investigation in
collaboration with the National Remote Sensing
Agency (NRSA) of India and the Haryana State
Water Resources Department in the Bhakra
canal command of Haryana, India, with the main
objective of answering the following two research
questions:
1. Can SRS techniques be used as a cost-
effective tool to evaluate efficacy and equity
in water distribution of a lined watercourse?
2. For what period of time can a lined
watercourse maintain its ability to preserve
equitable water distribution between the
head reach and the tail reach of a
watercourse with the existing level of
maintenance?
Twenty-eight lined sample watercourses
were selected from three blocks3 on a stratified
random basis and analyzed. The methodology
adopted was: a) generation of spatial data from
satellite imagery for a study period of 5 years on
irrigated area, area under wheat and non-wheat
crops and averaged NDVI4 of wheat crop in the
head and tail reaches of each selected
watercourse; b) spatial and temporal analyses of
changes in irrigation extent and crop condition
as a function of lining extent and age; and c)
analyzing the effect of canal lining on irrigation
extent in the presence of groundwater
development. The utility of SRS techniques was
demonstrated as a cost-effective tool for
objective and large-scale evaluation of efficacy
of watercourse lining, in the context of large
investments already made and planned in this
intervention. In view of cloud cover limitations,
this study focuses on SRS application only in
the rabi season.
In this water-short system with rotational
water supply, sample watercourses in three
zones with different groundwater quality were
studied through an analysis of satellite data from
the rabi seasons of 1987–1997. Information on
3Three sets of terminologies are used to describe the command area: the first is based on administrative unit: districts, tesils (subdivision of a
district) and blocks; the second is based on water distribution units: circles, divisions and subdivisions; and the third is based on quality of
groundwater: saline, marginal and fresh groundwater zones.
4NDVI is derived from satellite spectral measurements and is a measure of green vegetation biomass and vigor (Tucker 1979).
3
irrigated area, area under wheat and non-wheat
crops and wheat condition was generated for
spatial and temporal analyses. Efficacy of lining
is a function of many factors, including discharge
at the outlet of a watercourse; length of
watercourse; maintenance standard and history;
farmer organization at watercourse level; and
extent and age of lining. Only the last two
factors—extent of lining5 and age of lining—will
be addressed in this study. The results derived
from SRS techniques were supplemented with
data collected from field visits to selected
watercourses to investigate the conclusions
arrived at in this study.
Study Area
Bhakra Irrigation Project
Haryana is a chronically water-deficit state in
India. Eighty percent of the cultivated area of the
state (2.8 million hectares), is irrigated. The
extent of area irrigated by canal water is roughly
the same as that irrigated by groundwater and,
in many instances, conjunctive use of canal
water and groundwater is practiced.
The two major canal systems of the state
are the Bhakra canal system, which is fed from
the Indus basin, and the Western Yamuna canal
system, which receives its supply from the
Yamuna river. They make a 12,100-km long
network, providing 88 percent of the surface
irrigation supplies. The study area is situated in
the “Bhakra System.” The Bhakra canal network
with a cultivable command area (CCA) of 1.2
million hectares (figure 1) has three operational
systems: Narwana–Sirsa system, Barwala–Sirsa
system, and Bhakra Main Line (BML) system.
The command area is divided into five water
services circles: Ambala, Kaithal, Hisar-1, Hisar-
2, and Sirsa that, in turn, are divided into 13
divisions and 41 subdivisions. Box 1 presents
the system details.
Groundwater accounts for more than half the
irrigated area in the Bhakra canal command. The
Groundwater Cell of the Agriculture Department
monitors the depth to groundwater table and
groundwater quality. Groundwater levels are
observed twice a year, in June (pre-monsoon)
and October (post-monsoon). In the Hisar, Sirsa
and parts of Jind districts, where groundwater
development is low due to poor water quality,
the water table has risen over time. In parts of
Kaithal, Kurukshetra and Ambala districts, the
water table has gone down due to extensive
extraction of good quality groundwater. The
Agriculture Department reports areas irrigated by
canal water and groundwater separately while
the Irrigation Department reports areas irrigated
only by canal water. However, the area irrigated
by the conjunctive use of canal water and
groundwater within the canal command is not
reported by either department.
Irrigation water is supplied according to the
warabandi principle, which follows a rigid
rotational cycle of fixed duration, frequency, and
priority level (Berkoff 1987; Malhotra 1982).
5In Northwest India, watercourse lining always began from the head of a watercourse and proceeded downstream; generally, the tail end of a
watercourse is left unlined. Because of the uniformity in soil strata, very few partially lined watercourses were found with breaks in lining in
between.
4
FIGURE 1.
Index map of Bhakra canal command area showing study area blocks.
Originally, the warabandi principle was designed
to equitably distribute the uncertain run-of-river
flow through a procedure known as “rostering”
(Sakthivadivel et al. 1999). The system of
allocating water through rostering remains
unchanged even after creating a sustainable
reservoir storage in the Bhakra system that
provides stable and reliable supplies, although
the supply is inadequate to fully meet the
irrigation needs.
Kharif (June–October) and rabi (November–
April) are the two principal agricultural seasons.
When the irrigation system was planned, the
assumed cropping pattern of the Bhakra canal
command in kharif was fodder, cotton, gram,
barley, orchards, and vegetables and in rabi it
was wheat, fodder, gram, barley, and
vegetables. Presently, the cropping pattern and
the cropping intensity have changed dramatically,
with most of the irrigated area occupied by high-
yielding varieties of rice, wheat, and cotton. The
total irrigated wheat areas during the rabi
seasons of 1992–93 and 1993–94 were 68.6 and
71.4 percent, respectively, of the total irrigated
area, each percentage being more than double
the percentage of the planned total irrigated area
in the project. During rabi, in addition to wheat,
toria is the principal oilseed crop in Ambala and
5
BOX 1.
Profile of the Bhakra irrigation system.
·Cultivable command area (CCA) : 1.265 million ha
·Cultivable area (rabi 1995/96) : 1.056 million ha
·Annual average rainfall : 686 mm
·Annual average evaporation (ETo) : 1,544 mm
·Source of water supply : Storage reservoirs; run-of-river system and groundwater
·Mode of water use : Conjunctive
·Delivery structures : Gravity type; lined and unlined canals; structured system below distributary
·Predominant on-farm irrigation practice : Surface flooding
·Major crops : Kharif (rainy) season : Rice, cotton
Rabi (dry) season : Wheat, oilseeds
Two-season : Sugarcane
·Average farm size : 4.8 ha (Standard Deviation: 3.83 ha)
·Type of management : Government (main stream); farmer-managed (tertiary)
Two-Season: Sugarcane
Rabi: Wheat, oilseed Kharif: Cotton, rice
Cropping pattern Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct.
Long-term average 3.5 10.9 30.5 25.6 20.6 17.0 13.1 52.4 182.9 183.2 120.7 31.9
rainfall (mm)
ETo (mm) 65.0 36.4 34.8 68.6 121.1 168.6 213.4 225.5 187.8 158.2 156.1 111.1
0
50
100
150
200
250
Nov.
Jan.
Mar.
May
July
Sept.
Long-term average rainfall
(mm)
ETo (mm)
6
Kaithal circles and mustard is the principal
oilseed crop in the other three circles. Bengal
gram is cultivated mostly in the Hisar-1 circle.
Sowing of oilseed crops commences and ends in
November while wheat sowing commences in
late November and extends up to December.
With a semiarid to arid climate, prolonged
hot periods persist in the command between
March and October with rainfall concentrated
from July to September. The average annual
rainfall in the northeastern part of the command
is 750 mm and decreases to 400 mm in the
southwestern part. Rabi rainfall varies from 100
mm in the east to 50 mm in the west with
annual evapotranspiration varying between 1,250
mm in the northeastern part and 1,650 mm in
the southwestern part (IIMI 1997). This means
that the crop water requirement is high and
much of it must come from surface water and
groundwater sources during the rabi season.
Canal Watercourses
According to the Haryana State Canal and
Drainage Act of 1974, a watercourse means any
channel taking its supply from a government
canal (distributary, minor) through an ungated
outlet designed as an Adjustable Proportional
Module (APM) or Open Flume (OF) to irrigate
fields called a chak. The upkeep and
maintenance of canal watercourses are the
responsibility of the shareholders in a chak
irrespective of whether the watercourses are
earthen or lined. However, the government is
spending between Rs 2 and 5 (US$0.05 and
US$0.15)6 per meter of watercourse per year in
maintaining and repairing the lining (Sabherwal
1998). Generally, a watercourse serves a chak
of 200 to 350 hectares and about 50–70
farmers. Watercourses with a flat slope of 0.01
percent to 0.02 percent are aligned along the
micro-topographical ridges with a turnout or a
cut called nakka made in the bank to divert the
full stream to the field for the duration of a wari
or turn. The wari duration of the shareholders of
a chak is equal to the division of a week (7 x 24
= 168 hours) in the ratio of irrigator’s holding to
the chak’s culturable command area (CCA).
Weekly wari timings are fixed, taking into
account the filling (bharai) time and the emptying
(jharai) time of the watercourse. During the
operational turn of a watercourse, the parent
canal (distributary, minor) must run to its full
supply for the period of rotation to enable APM
or OF outlets to draw their designed discharge.
This proportionality of entitlement period to
holding size, and watercourse flow to size of
chak, is intended to ensure uniform volumetric
allocation per hectare per week for all the
farmers in the command under distributaries that
receive a supply during that week.
The design duty at the chak level is
generally 0.17 l/s/ha of command area so that
the capacity of watercourses ranges from 30 to
60 l/s. Seepage and percolation losses ranging
from 6.75 to 13.5 liters per 1,000 square meters
(20–40 cusecs per million square feet) of wetted
perimeter were reported in unlined watercourses
of Bhakra and Western Yamuna canal
commands of Haryana (Sabherwal 1998).
Seepage is then 10 to 15 percent of
watercourse discharge. Much of the watercourse
seepage and percolation reaches the
groundwater and get mixed with it diluting the
saline groundwater in and around the
watercourses; this process has been going on
since Bhakra water was brought to the area
about 40 years ago. This explains why the
increase in shallow tube wells (STWs) is mainly
confined to the head reaches of the
watercourses where the mixing of seepage water
is high, though in a few cases, the number of
STWs in the middle reach has also increased.
Groundwater, which is used to make up, to a
certain extent, for the shortages or mismatch in
6Rs refers to Indian rupees; in 1998, US$1.00=Rs 40.00.
7
canal supplies also helps to bring more area
under irrigation.
Lining of Watercourses
Watercourse lining was identified as an effective
intervention strategy to reduce seepage since
major water losses occur at this level of the
conveyance system (National Seminar 1983).
About 8,700 (66%) of Haryana’s 13,000
watercourses have been lined since 1973, a
length of over 20,000 km. The target is to
additionally line 2,800 watercourses at a total
cost of about Rs 400 million. In addition to
reducing seepage, the watercourse lining
program has relevance in controlling the water
table in the saline areas, which cover 65 percent
of the canal command. Another advantage of
lining is the reference level it provides for annual
desiltation of watercourses. However, farmers
perceive additional benefits that are far more
important than mere water saving.
From farmers’ perspectives, watercourse
lining has a number of additional advantages,
especially in areas underlain with saline
groundwater. The foremost benefit of lining the
watercourses is in making water available at the
remotest end of the watercourse. Previous to
the lining, water in earthen canals could not
reach the tail end of a watercourse. Due to this,
mixing of canal water with saline groundwater
took place only in the head reach of a
watercourse. Consequent to lining, extensive
spreading of canal water over a larger area
enabled mixing of fresh canal water with saline
water and farmers have constructed cavity type
wells to skim this mixed and diluted groundwater
to supplement their canal water. This, in effect,
increased their available water share for
irrigation. Also, improved canal water distribution
in lined irrigation channels together with
conjunctive use of groundwater and canal water
has resulted in an increased irrigation intensity
during rabi. An improved water supply for
irrigation due to lining has also resulted in a
changed cropping pattern. There is a significant
increase in oilseed crops, especially in the tail
end of the watercourse in the Sirsa block. The
time taken and the number of laborers required
to irrigate one hectare of land, according to
farmers, have been reduced considerably after
lining of watercourses. Also, both filling and
emptying times have been reduced due to
improved conveyance efficiency. This
improvement or saving in operational time in an
average chak was about an hour and was added
proportionally to the wari of each shareholder
resulting in an increased wari time.
Selection of Watercourses for the
Study
The study covers 28 watercourses distributed
among three blocks: Narwana, Hisar, and Sirsa
(figure 1). The selection scheme of the
watercourses consisted of the selection of three
blocks located in a satellite image covering 15
km x 15 km and having a different groundwater
quality and hence varying groundwater
contributions to irrigation. From each block about
10 watercourses were selected, based on the
age of lining and length of watercourse lined.
The quality of groundwater in Narwana,
Hisar, and Sirsa blocks with 82, 96, and 132
watercourses, respectively, is good,7 marginal,
and poor, also respectively. Satellite Remote
Sensing (SRS) data are available from 1986
onwards only. Therefore, to represent conditions
before and after lining, the watercourses in each
block were grouped to fall into four cells of an
approximately equal number of watercourses,
two cells containing watercourses lined before
1985 and two cells after 1985. The two cells
also represent watercourses located in the head
7Groundwater quality: good, if salinity<2 ds/m; marginal, if salinity=2–6 ds/m; poor, if salinity> 6 ds/m.
8
TABLE 1.
Characteristics of the watercourses.
Name Water- Minor/ Distance from
of course distributary the minor Extent of lining Lining period and age of lining Groundwater
block no. distributary by 1986 development
RD Loca- Length Extent Year of Age of Lining CCA
% tion lined high/low lining lining period ha/tube well
% (years) (years) 1986 1996
Narwana 1 Barsola mr* 15 Head 59 High 1981 5 2 - -
2 Chusdu mr** 90 Tail 80 High 1983 3 2 - -
3 Ghasso mr. 28 Head 55 Low 1981 5 2 - -
4 Mohalgorh mr. 45 Head 55 Low 1992 -6 1 - -
5 Molgarh mr. 50 Head 74 High 1982 4 2 - -
6 Shudkan dy. 99 Tail 54 Low 1983 3 2 - -
7 Sinor 67 Tail 40 Low 1983 3 2 - -
8 Sirsa parallel 89 Tail 44 Low 1995 -9 1 - -
Hisar 1 Badhawar dy. 65 Tail 72 High 1975 11 3 - -
2 Pinghal mr. 100 Tail 34 Low 1975 11 3 - -
3 Rana dy. 26 Head 36 Low 1975 11 3 - -
4 Rajli mr. 81 Tail 79 High 1977 9 3 - -
5 Kharkheri dy. 29 Head 53 Low 1976 10 3 - -
6 Badhawar dy. 73 Tail 83 High 1977 9 3 - -
7 Balak mr. 1 Head 53 Low 1992 -6 1 - -
8 Balak mr. 46 Head 55 Low 1992 -6 1 - -
9 Kharkhari dy. 7 Head 77 High 1996 -10 1 - -
10 Kharkhari dy. 1 Head 74 High 1995 -9 1 - -
Sirsa 1 Chormar dy. 73 Tail 71 High 1976 10 3 66 17
2 Chormar dy. 85 Tail 71 High 1976 10 3 455 41
3 Kaluana dy. 53 Head 63 High 1977 9 3 167 20
4 Maujgarh dy. 23 Head 79 High 1984 2 2 47 17
5 Maujgarh dy. 99 Tail 68 High 1985 1 2 62 31
6 Panna dy. 91 Tail 68 High 1978 8 3 39 21
7 Mithri dy. 26 Head 80 High 1982 4 2 101 41
8 Mithri dy. 100 Tail 69 High 1986 0 2 75 37
9 Maujgarh dy. 100 Tail 67 High 1978 8 3 68 34
10 Panna dy. 26 Head 76 High 1981 5 2 47 23
* mr. = minor.
** dy. = distributary.
RD = Relative distance.
and tail ends of the minor/distributaries. From
each of the first and last two cells, three and
two watercourses, respectively, were randomly
selected, giving a total of 10 lined watercourses
representing different ages of lining and locations
within a minor.
The salient features of the selected
watercourses and their locations along the
distributary/minor are shown in table 1. The
length of watercourse lined (extent of lining)
ranges from 34 percent of total length in the
Hisar block to more than 80 percent in all three
blocks. The earliest lining was started in 1975
and lining continued till as recently as 1996 in
the Hisar block. All watercourses in the Sirsa
block were lined before 1986.
9
Basic Data
For a comparative analysis of the performance
of watercourse lining, covering five selected rabi
seasons between 1986 and1997, data from a
number of Indian Remote Sensing (IRS)
satellites (IA, IB and IC) and Landsat with
different spatial and spectral characteristics were
used. Three overpass dates in each rabi season
were selected for optimum crop classification
from available cloud-free satellite data (table 2).
Field-level data of the selected watercourses
were collected during three field visits in
February, July and November 1997, both to
identify sample areas for computer-aided crop
classification and to validate classification results
obtained from satellite images.
Additionally, data were collected through
questionnaires (current and temporal changes in
cropping pattern and productivity level, source
and extent of irrigation support, etc.) and
through crop mapping on chak maps, which
were completed by field officers in a few
selected watercourses. A subsequent evaluation,
however, indicated large subjectivity in the
completed questionnaires and chak maps, and
hence questionnaire data were used after
verification with field-collected data. Topographic
maps (1:50,000 scale) of the three blocks and
chak maps (1:6,000 scale) of all the
watercourses were obtained for digitization and
overlaying on the satellite imagery.
TABLE 2.
Satellite data analyzed in the study.
Period Overpass date/Satellite *
Hisar block Narwana block Sirsa block
1996–97 15 Dec 96 IRS-1C 15 Dec 96 IRS-1C 22 Dec 96 IRS-1B
12 Jan 97 IRA-1B 12 Jan 97 IRA-1B 13 Jan 97 IRS-1B
17 Feb 97 LANDSAT 17 Feb 97 LANDSAT 26 Feb 97 IRS-1B
02 Nov 96 IRS-1C** 21 Mar 97 IRS-IC **
1995–96 21 Nov 95 IRS 1B 21 Nov 95 IRS 1B 22 Nov 95 IRS 1B
4 Jan 96 IRS 1B 4 Jan 96 IRS 1B 27 Jan 96 IRS 1B
26 Jan 96 IRS 1B 26 Jan 96 IRS 1B 18 Feb 96 IRS 1B
17 Feb 96 IRS 1B 17 Feb 96 IRS 1B 11 Mar 96 IRS 1B
10 March 96 IRS 1B 10 March 96 IRS 1B 02 Apr 96 IRS 1B
01 Apr 96 IRS 1B 01 Apr 96 IRS 1B
1992–93 22 Feb 93 LANDSAT 22 Feb 93 LANDSAT 27 Dec 92 LANDSAT
10 Mar 93 LANDSAT 10 Mar 93 LANDSAT 01 Mar 93 LANDSAT
26 Mar 93 LANDSAT 26 Mar 93 LANDSAT 02 Apr 93 LANDSAT
1989–90 12 Dec 89 LANDSAT 12 Dec 89 LANDSAT 03 Dec 89 LANDSAT
02 Mar 90 LANDSAT 02 Mar 90 LANDSAT 20 Mar 93 LANDSAT
04 Apr 90 LANDSAT 04 Apr 90 IRS 1A 10 Apr 90 LANDSAT
1986–87 20 Dec 86 LANDSAT 20 Dec 86 LANDSAT 27 Dec 86 LANDSAT
10 Mar 87 LANDSAT 10 Mar 87 LANDSAT 01 Mar 87 LANDSAT
26 Mar 87 LANDSAT 26 Mar 87 LANDSAT 17 Mar 87 LANDSAT
* Sensors are TM in Landsat, LISS II in IRS-1A, and 1B, LISS III and PAN in IRS-1C.
** PAN data only.
10
Analysis of Multiyear Satellite Data
data through the rabi season were acquired and
analyzed through a hybrid classification
approach of iteratively supervised and
unsupervised techniques to achieve complete
and accurate classification (figure 2). In the
supervised approach, useful information
categories such as wheat area and non-wheat
area are defined and then their spectral
separability is examined; in the unsupervised
approach, separable classes are determined and
then their informational utility defined.
Thiruvengadachari et al. (1997) have provided
complete details of this approach. The kappa
coefficient of classification accuracy (Congalton
1991) was computed at overall block level as
well as for two randomly selected watercourses
in the Hisar block, three each in the Narwana
and Sirsa blocks. The field verification was
conducted in at least 20 randomly selected
locations for wheat and in 10 locations for non-
wheat crops in each block and in each selected
watercourse. The average classification accuracy
was 92 percent at the watercourse level.
The satellite analysis results in statistics of
cropped area, area under wheat and non-wheat
crops, and NDVI of wheat and non-wheat crops
at pixel level. A typical map of temporal changes
in the rabi cropping pattern in a watercourse of
the Hisar block is shown in figure 3. The unit
cost of SRS analysis works out to US$0.17 per
hectare of irrigated area (1996 prices), which
includes the cost of satellite data covering
22,500 hectares of geographic area, field visits,
processing and analysis of data.
The next section provides a brief description
of performance descriptors used and their
justification for analysis purposes.
The methodology used to analyze digital
images includes a geo-referencing procedure
for co-registering the watercourse map in a
large scale (1:6,000) to the satellite imagery
and a robust approach for crop classification at
watercourse level, commanding only a limited
areal extent (of a few hundred hectares). The
results are in the form of spatial maps of
cropping pattern and statistics of cropped
areas and NDVI for head, middle and tail
reaches of each watercourse.
The topographic maps (1:50,000 scale)
covering the watercourse commands were
digitized and mosaicked to form the reference
map base, to which the satellite imageries
were geometrically rectified (root mean square
< 15 m) and co-registered. Due to the large
difference in chak maps and image scales and
the difficulty in locating control points, an
improved approach was called for, since
accurate co-registration of both is essential to
generate reliable statistics at watercourse
level. The chak maps of 1:6,000 scale were
digitized at 6-m resolution, vectorized and
registered first to IRS-IC Pan image with 6-m
resolution. After registration, the watercourse
vectors were encoded in a channel along with
Pan image data and geometrically corrected
using the rectification model between the Pan
and LISS II data sets, to achieve an RMS
error of 15 m. This innovative approach
significantly improved the location accuracy to
enable micro-level inventories using satellite
data.
The next step was to delineate the wheat
and non-wheat growing areas in the selected
rabi seasons. Multi-date cloud-free satellite
11
FIGURE 2.
Registration of watercourse chak map with satellite database.
12
FIGURE 3.
Temporal changes in rabi cropping pattern in a watercourse of the Hirsa block (watercourse@45872-R, Balak minor).
13
Performance Descriptors
The direct effect of watercourse lining is to
reduce seepage and leakage losses and make
more water available for crop production. The
extent to which seepage is reduced over a
period is an indication of how well lining is
sustained. In the case of the Bhakra canal
command, one of the major objectives of lining
watercourses is to convey and distribute the
canal water to the remotest area of a
watercourse and allow farmers to tap the
percolated and diluted groundwater for further
improving the irrigated extent. This, in effect,
has a marked effect on agricultural performance
of a chak on two counts: one is that a larger
area, which has hitherto not been cultivated,
has been brought under cultivation and the
other is that farmers have pumped additional
groundwater diluted by percolated canal water
to increase the extent of area irrigated and/or
cropping intensity. Because of these, evaluating
the agricultural performance of a chak with a
lined watercourse is more meaningful than just
to evaluate the extent of water saved due to
lining. Moreover, evaluating the efficacy of lining
through the extent of seepage reduction
requires considerable discharge measurements
in the field, which is difficult and costly to
achieve.
Watercourse lining is one of many factors
that contribute to improved performance of
irrigated agriculture. Apart from lining
characteristics, the location of the watercourse
with respect to the offtake channel and the
groundwater contribution are the two additional
factors contributing to a chak’s agricultural
performance. Agronomic factors such as soil
type, groundwater quality, agronomic practices,
crop varieties, etc., also contribute to
performance. However, they are assumed to be
uniform among the watercourses within a block.
During the field visits, these factors were looked
into and information obtained from the farmers
leads us to conclude that this assumption is
valid and is not likely to negatively impact on the
conclusions arrived at in this study. However, it
must be stated that no physical tests were
performed to ascertain the authenticity of
farmers’ statements and general uniformity of
the tracts with regard to spatial variability. The
surface water supply does not figure in the list of
variables because each watercourse in a block
gets the same water allowance per hectare.
Also, rainfall contribution in the rabi season in
the Bhakra canal command is minimal and,
therefore, it is not accounted for. To evaluate the
agricultural performance of a chak, six indirect
descriptors (defined on p. 14, were selected for
the analysis.
14
Method of Analysis
Field visits and focused group discussion with
farmers have indicated that agricultural
performance of lined watercourses has been
superior to that of unlined watercourses and that
this superiority is closely linked to the greater
development of groundwater in lined
No. Descriptor Definition Remarks
1. Wheat Area Intensity Irrigated wheat area Extent of wheat crop and its increasing
(WAI) Cultivable area trend over time is related to the availability
of sufficient good quality water from a canal
and wells.
Total irrigated area 1 ha of non-wheat area = 0.6 ha of wheat
converted to equivalent area-based on crop water consumption. EWAI
2. Equivalent Wheat wheat area is a surrogate for total water consumption. An
Area Intensity (EWAI) Cultivable area increasing trend of EWAI over time represents
possible augmentation of additional water.
3. Irrigation Intensity (II) Irrigated area Increasing trend in II indicates
Cultivable area additional water supply available
for crop production and/or cropping
pattern change with less water-
consuming crops.
4. Normalized Difference ro(infrared) - ro(red) High NDVI represents good crop
Vegetation Index (NDVI) ro(infrared) + ro(red) condition and hence better productivity.
5. Coefficient of Variation Reflects the variability in crop
of NDVI (CVNDVI) condition.
6. Tail-Head Ratio of Average NDVI of tail-reach area Reflects the equity of irrigation
NDVI (THRNDVI) Average of NDVI of head-reach area service.
watercourses. Therefore, improvement in
agricultural performance is closely linked to the
extent to which groundwater development has
taken place since the lining and its contribution
to agricultural performance, in addition to the
contribution of watercourse lining.
()
mean
n
i
meani
n
N
DVI
NDVINDVI
1
2
∑
=
−
ro = Land surface spectral reflectances.
15
FIGURE 4.
Tube-well density of Sirsa watercourses.
Detailed groundwater information is not
available for all the sampled blocks except for
Sirsa. For the Sirsa block, the irrigation
intensities before and after 1986 and
groundwater development details after 1986 are
available. In view of the data limitation, the
analysis was carried out in two stages.
In the first stage, no distinction was made in
agricultural performance due to lining and
groundwater development. A trend analysis of
agricultural performance indicators of all blocks
was conducted. Trends, if identified at this stage,
may be due to both watercourse lining and
groundwater development. In the second stage,
data of the Sirsa block for which groundwater
data are available (figure 4) were used to
separate the effect of groundwater development
factors from the lining-related factors.
Head-Reach and Tail-Reach
Classification
The watercourses were classified into two
groups: head reach and tail reach (table 1). The
watercourses close to the offtake point of the
distributary/minor are in the head reach. The
head-reach watercourses are those where
percent relative distance (% RD)8 of distributary
or minor is less than 55; watercourses with more
than 55% RD are in the tail reach. Four
watercourses in the Narwana block, 6 in the
Hisar block and 3 in the Sirsa block are in the
head-reach area, while 4, 4 and 6 watercourses
in the Narwana, Hisar, and Sirsa blocks,
respectively, are in the tail-reach area.
8Percent Relative Distance (% RD) = Distance of the watercourse along the distributary/minor from offtake x 100
Total distance of the distributary/minor
16
High and Low Extent of Lining
The extent of lining of a watercourse is the lined
length of the watercourse as a percent of its
total length. The incremental benefits of the
extent of lining beyond 60 percent of its total
length are not significant (Malhotra 1975). A 60-
percent extent of lining of a watercourse would
have, for example, the same influence as that of
an 80-percent extent of lining. Therefore,
watercourses are classified into two groups:
“high” extent of lining and “low” extent of lining
(table 1). The watercourses with less than 59
percent extent of lining are in the “low” group.
Those with more than 59 percent extent are in
the “high” group.
Five watercourses (with 40–55% extent of
lining) and 3 watercourses (with 59–80% extent
of lining), respectively, are in the low and high
extent of lining groups in the Narwana block
(table 1). In the Hisar block, 5 watercourses
(with 34–55% extent of lining) and 5 (74–83%
extent of lining) are in the low and high group,
respectively. All watercourses (with 63–80%
extent of lining) in the Sirsa block are in the
group of high extent of lining.
Period of Lining
The lining of watercourses was carried out to
enhance the water delivery performances. As
the age of lining (defined as the number of years
that have elapsed after completion of lining)
increases, its performance gets reduced. The
age of lining can be computed with respect to
the current year or any base year. In this study,
the base year is selected as 1986 since satellite
data are available from that year and the age of
lining is computed with respect to 1986 as the
base year.
For analyzing the effect of age of lining on
the trends of performance, the sampled
watercourses are grouped into three distinct
periods of lining (table 3). The trends of
performance for different periods are estimated.
Results
The satellite data of sampled watercourses are
available for five years: 1986, 1989, 1992, 1995,
and 1996. Time series cross-sectional analysis
was employed to assess the trends of
performance of the sampled watercourses. The
trends of performance descriptors of
watercourses that were lined in different periods
were assessed separately for each block. In
addition to estimating trends, the differences
between blocks, between head-reach and tail-
reach watercourses, and between watercourses
with high and low extent of lining were captured.
The appendix describes the complete model
used for trend assessment and the results of the
TABLE 3.
Periods of lining.
Name of Block Period 1 of lining Period 2 of lining Period 3 of lining
(lined 8 years before 1986) (lined 1–5 years before 1986) (lined after 1986)
Narwana - 6 2
Hisar 6 - 4
Sirsa 5 5 *
* All the watercourses in this block were lined before 1986.
17
TABLE 4.
Characteristics of selected watercourses.
1. Factor WAI EWAI II ANDVI CVNDVI THRNDVI
2. Differences between blocks Narwana S+ S+ S+ S-
Sirsa S+ S+
3. Differences between head and tail reach Narwana S- S-
Hisar S+ S+
Sirsa S-
4. Differences between high and low extent of lining Narwana S+ S+ S+ S-
and low-extent of lining Hisar
5. Trends-Narwana Period 2 S+ S+ S-
Period 3 S-
6. Trends-Hisar Period 1 S+ S+ S+ S-
Period 3 S+ S+ S+ S-
7. Trends-Sirsa Period 1 S- S+ S-
Period 1 S- S+ S+ S-
regression analysis. This section discusses only
the major findings.
Table 4 summarizes the statistically
significant results of the analysis for the
performance descriptors: wheat area intensity
(WAI), equivalent wheat area intensity (EWAI),
irrigation intensity (II), average NDVI (ANDVI),
coefficient of variation of NDVI (CVNDVI), and the
ratio of tail and head NDVI (THRNDVI). The
notations “S+” and “S-” in table 4 indicate that
there is a statistically significant positive or
negative difference (in the rows 2, 3 and 4) or a
statistically significant increasing or decreasing
trend (in the last three rows). The blank cells
indicate no statistically significant differences or
trends.
Differences between Blocks
The watercourses in the Narwana block have, on
average, a significantly higher wheat area
intensity, equivalent wheat area intensity and
irrigation intensity and a significantly lower
coefficient of variation of NDVI (figures 5, 6, 7,
and 9, and table 4). That is, a higher quantity of
good-quality water supply, both canal water and
groundwater, is more equitably available in the
Narwana block than in the other two blocks.
This is not surprising since the Narwana block is
in a fresh groundwater area while both the other
blocks, Hisar and Sirsa, are in marginal and
saline groundwater areas. Also the wheat area
intensity and equivalent wheat area intensity in
the Sirsa block are significantly higher than
those of the Hisar block. This is primarily
because of the stable water supply from the
Bhakra dam and the higher water allowance per
hectare in the Sirsa block.
Differences between Head- and Tail-
Reach Watercourses
The influence of the location of the watercourses
from the offtake of the distributary canal or minor
18
on the performance descriptors is mixed for the
three blocks. In the Hisar block, the wheat area
intensity and the equivalent wheat area intensity
of the watercourses located in the head reach of
the canals are higher than those of the
watercourses located in the tail reach. This is
primarily due to percolation of additional canal
water from the canal network in the head
reaches. In the Narwana block, the equivalent
wheat area intensity and the irrigation intensity of
the head-reach watercourses are lower than
those in the tail-reach watercourses. In the Sirsa
block, there is no significant locational effect. The
locational differences in the Narwana may be due
to several factors: reliability of canal water supply,
the extent of groundwater use and quality of
pumped water supply, etc. Unfortunately, there
were no data to verify these.
Differences between High and Low
Extent of Lining
The effect of the extent of lining of watercourses
on the performance is also mixed. Only a few of
the performance descriptors in the Narwana
block had some significant effect. In the
watercourses of the Narwana block, the higher
the extent of lining, the higher the wheat area
intensity, the equivalent wheat area intensity and
the irrigation intensity. In the other two blocks,
the extent of lining is not a significant factor for
farmers to grow more wheat crops. This
indicates that only watercourses with a high
extent of lining and located in the fresh
groundwater areas have a higher wheat
intensity. A conclusion that can be drawn from
this is that farmers, who do not have provision
to supplement canal water with fresh
groundwater, do not prefer a higher wheat area
even after lining of watercourses. A plausible
reason for this is that groundwater supply in the
Hisar and Sirsa blocks is not suited for
excessive wheat growing.
Trends of Performance
The trend analysis shows that the trends of
most descriptors of performance of
watercourses in all blocks are affected to some
extent by the period of lining. An important
observation is that regardless of the period of
lining, none of the descriptors show a significant
decreasing trend of performance between 1986
and 1996. The wheat area has increased
significantly in all bocks, except in the Sirsa
block (figure 5) where it has decreased
significantly. Farmers in this block opted for salt-
tolerant low water-consuming crops with an
increasing water supply. Indeed, increasing
trends of equivalent wheat area intensity and
irrigation intensity (figure 6 and 7) of
watercourses in the Sirsa and Hisar blocks
indicate an increasing water supply.
The average NDVI (figure 8), which is a
measure of overall productivity over the years,
has improved. Moreover, the variation of the
crop condition (indicated by the coefficient of
variation of average NDVI) within watercourses
has decreased significantly in all three blocks
(figure 9).
What prompted the increase in performance
of watercourses in all blocks? Within a
watercourse, it cannot be presumed that there
are significant variations of agronomic conditions
and agronomic practices because of a uniform
NDVI within a block (figure 10). Given this,
water supply and distribution within watercourses
are the most plausible factors influencing the
increase in performance. This is especially true
in the Hisar and Sirsa blocks.
In the fresh groundwater zone of the
Narwana block, almost all the area is irrigated
with wheat and the wheat intensity is high. So
there is no scope for further significant increase
in wheat area or intensity. However, there is a
significant reduction in the variation of crop
condition indicating better water distribution
within watercourses.
19
20
21
22
In the marginal groundwater zone of the
Hisar block, an increasing water supply was
used for increasing the wheat area, increasing
the wheat intensity and reducing the variability of
distribution. Watercourse lining has helped
reduce the conveyance losses making it possible
to distribute water even to the remotest area.
This has contributed to increasing the wheat
area of the watercourses, which were lined
recently. With the increase in the age of lining of
watercourses, the surface water seeping into the
aquifer increases, diluting more of marginal
groundwater. Pumping this groundwater
contributes to increasing the wheat area of the
watercourses, which were lined several years
before 1986. Indeed, it was observed that
groundwater development has increased rapidly
in these areas.
In the saline groundwater zone of the Sirsa
block, wheat area was decreasing, but the water
supply was increasing (slightly) and the irrigation
intensity was increasing; but the variation of the
crop condition within watercourses was
decreasing. With the increase in the age of
lining, the surface water seeping into the
aquifers makes the shallow groundwater less
saline. In the watercourses of the Sirsa block,
farmers use this less-saline groundwater in
conjunction with surface water for growing more
salt-tolerant crops such as oilseed. This has
resulted in significantly decreasing the wheat
area and significantly increasing the irrigation
intensity. This, in turn, implies that the irrigation
performance in the watercourse command areas
stayed the same or improved because of the
additional water available to the farmers from
pumped groundwater.
The preceding discussion leads us to
conclude that lining of watercourses and the
consequent groundwater development affect the
trends of performance of all blocks. Indeed, the
almost similar trend of performance for different
periods of lining within a block indicates the
combined effect of watercourse lining and
groundwater development. The challenge,
therefore, is to separate the effect of lining on
the performance from that of groundwater
development. This is the objective of the second
part of the analysis.
Effect of Lining in the Presence of
Groundwater Development
In the method employed in assessing the
influence of lining the “before” and “after” type of
analysis was used. Here, the effect of
groundwater development on the performance
descriptors was controlled while the differences
of performance before and after lining of
watercourses were assessed. This type of
analysis requires performance and other data
both before and after lining of watercourses.
Groundwater development data, in terms of
number of tube wells in the command area,
were available only for the Sirsa block.
Therefore, this part of the analysis was carried
out only for this block. Irrigation intensity data,
both before and after lining of the watercourses
in the Sirsa block, were obtained from the
Irrigation Department. These data were used for
assessing the effect of lining in the presence of
groundwater development. However, some
additional data are required for this analysis.
Even though the irrigation intensities were
available for years both before and after lining,
the groundwater development information for the
watercourses was available only after 1986
(table 1). Therefore, estimates of groundwater
development within watercourses before 1986
were first obtained. Then these were used to
assess the impact of lining.
Groundwater Development
The groundwater development in the
watercourses indicates different growth patterns
(table 1). For example, the command area
served in one watercourse decreased from 455
23
hectares per tube well in 1986 to 41 hectares
per tube well in 1992. In another watercourse,
the corresponding values decreased from 66 in
1986 to 17 in 1992. Therefore, the possible
different growth patterns of groundwater
development for watercourses after 1986 were
estimated. Next, estimated annual growth rates
were used to extrapolate the extent of
groundwater development before 1986.
The tube-well intensity, i.e., number of tube
wells per unit command area, which is the
reciprocal of command area served per tube
well, was used as an indicator for groundwater
development. A regression analysis, with
stepwise model selection was used to estimate
the overall trends of tube-well density and any
significant deviation from it for different
watercourses (table 5).
Analysis shows that, in 1986, the tube-well
density of watercourse numbers 2, 3, 7 and 8
was higher than in others. Also the growth rates
of groundwater development in watercourse
TABLE 5.
Estimates of trends of ln (well density) in the Sirsa block.
Variable Coefficient
Intercept -3.98*
Intercept difference - WC2a-2.26*
Intercept difference - WC3 -0.94*
Intercept difference - WC7 -0.72*
Intercept difference - WC8 -0.58*
Trend 0.098*
Trend difference - WC2 0.152*
Trend difference - WC3 0.102*
Trend difference - WC5 -0.048*
Trend difference - WC6 -0.057*
R20.90
a WC2 means watercourse 2 in table 2.
* Statistically significant at .05 level of significance
numbers 2 and 3 were higher while the growth
rates of the watercourse numbers 5 and 6 were
lower than those of the others. The estimated
growth rates were then used in extrapolating the
tube-well density of watercourses before 1986.
Impact of Lining
In impact of lining, the differences of irrigation
intensities before and after watercourse lining in
the presence of groundwater development were
estimated. The tube-well density was used to
filter the effect of groundwater development. To
capture the differences before and after lining
three dummy variables (equal 0 for years before
lining completed and equal 1 for years after
lining completed) were introduced for
watercourses where linings were completed by
1977, 1982 and 1986. Additionally, a dummy
variable was used to capture the differences
between watercourses (offtaking from a
distributary canal or a minor) located in the head
reach and those located in the tail reach.
Regression estimates show (table 6) that
tube-well density is indeed significant in
explaining the variations of irrigation intensity.
However, even after filtering the effect of
groundwater development, the irrigation intensity
before the lining of watercourses is significantly
lower than after lining in all three lining periods.
For example, of the watercourses that were lined
before 1977, the average irrigation intensity
before lining is about 12 percent lower than after
lining. Of the watercourses that were lined
before 1982, the irrigation intensity before lining
is about 10 percent lower than that after lining.
Similarly, in those watercourses that were lined
recently (between 1982 and 1986), the irrigation
intensity before lining is 12 percent lower than
that in the years after lining.
24
The SRS data were used for assessing the
recent trends of performance of watercourses. It
was seen that performance of the watercourses
from 1986 to 1992 shows no deteriorating trend.
In fact, some of the indicators show a significant
increasing trend. Both water supply and irrigation
intensity are increasing. Equity of water
distribution was maintained and the variation of
water supply is seen to be still decreasing.
Indeed, the performance of most descriptors has
increased over time. Some of the watercourses
in the analysis were lined 20 years before the
data collection period. The lining is not the only
factor that contributed to the significant increase
in trends of performance. The groundwater
development, as a result of lining of
watercourses, is also seen to be contributing to
performance increase. However, as shown in the
second part of the analysis, even after
accounting for the contribution of groundwater,
performance—for example the irrigation
intensity—after watercourse lining is significantly
higher than before the watercourse lining,
regardless of the lining period. This supports the
hypothesis that lining has improved the
performance. Further research needs to be
continued in this area to answer specific
research questions such as:
•What is the contribution of groundwater
development in a lined watercourse chak as
compared to an unlined one?
•To what extent do factors such as
groundwater quality, management efforts,
reliability of canal supplies, in addition to
lining, contribute to agricultural performance?
The SRS data can be used very effectively
to look at the trend of several performance
parameters after watercourse lining. The fact
that NDVI values within a block are not very
much different corroborates the assumption
made with regard to uniform agronomic factors
such as soil type, groundwater quality and
agronomic practices within a block. In fact, the
Conclusions
TABLE 6.
Effect of lining on irrigation intensity in the Sirsa block.
Variable Coefficient estimate T-value
Constant 41.4 15.4*
Tube-well density 344.0 3.4*
Location dummy for head and tail watercourses -5.3 -1.8
Time dummy for before and after lining – 12.4 2.2*
watercourse lining completed by 1977
Time dummy for before and after lining – 10.4 3.1*
watercourse lining completed by 1982
Time dummy for before and after lining – 11.7 2.4*
watercourse lining completed by 1986
R20.30
* Statistically significant at .05 level.
25
SRS can be used very effectively in assessing
the efficacy of watercourse lining in an
environment where very little groundwater is
used to support surface water supplies. In
areas with groundwater support, it provides
information on the combined effect of
groundwater development and watercourse
lining. Isolation of the latter will require data on
surface water and groundwater supplies. The
SRS technique can particularly be useful as a
screening tool for identifying watercourses
where more ground data need to be collected
to make the evaluation of watercourse lining
holistic.
26
The SRS data of watercourses are available for
five time periods: 1986, 1989, 1992, 1995 and
1996. Therefore, time series cross-sectional
analysis was used to assess the trends of
performance.
To capture the average difference between
blocks dummy variables were introduced to the
Narwana and Sirsa blocks. For example, for the
Narwana block, the dummy variable equals one
if an observation is from a watercourse in the
Narwana block, and zero otherwise. Dummy
variables were also introduced to each block, to
capture the possible effect of the watercourse
location from the offtake of the distributary or
minor.
The incremental effect of the extent of lining
beyond 60 percent of the total length is not
significant. Therefore, the extent of lining is
divided into two groups, one more than 60
percent and the other less than 60 percent. The
extent of lining of each sampled watercourse
from the Sirsa block is beyond 60 percent of its
length. Therefore, only two dummy variables
were introduced to the Hisar and Narwana
blocks to indicate whether the watercourses
selected from those blocks have extents of lining
more than 60 percent.
The lining of the watercourses within a block
was completed in one of three time periods.
Some of the watercourses were lined 8–11 years
before 1986, some 1–5 years before 1986 and
others after 1986. The trends of performance
between 1986 and 1996 may be different for
watercourses having different lining periods.
Therefore, for each block separate slope
coefficients were estimated for trends of
performance of watercourses with different lining
periods.
The trends of performance descriptors,
Wheat Area Intensity, Equivalent Wheat Area
Intensity, Irrigation Intensity, Average NDVI,
Coefficient of Variation of NDVI, and the Ratio of
Tail to Head Reach NDVI were assessed.
Appendix table 1 presents the results of the
regression analysis.
Wheat Area Intensity (WAI): The average
WAI of watercourses in the Narwana and Sirsa
blocks is significantly higher (about 49% and
32%) than that in the Hisar block. The location
of the watercourses from the head of the canal
has no significant effect on WAI in any block
except in the Hisar. The extent of lining has a
significant effect only on the Narwana block,
where the higher the extent of lining the higher
the WAI. The WAI of the watercourses in the
Narwana block that were lined between 1981
and 1985 shows a significant increasing trend.
By 1986, almost all the area in this fresh
groundwater zone was irrigated with wheat. The
WAI of the Hisar block shows a significant
increasing trend regardless of the period of
lining. In the Sirsa block, WAI is decreasing for
all watercourses regardless of the period of
lining.
Equivalent Wheat Area Intensity (EWAI):
The differences of Equivalent Wheat Area
Intensity (EWAI) between blocks are similar to
those of WAI of the three blocks (column 4,
appendix table 1). The differences of EWAI
between head and tail reach watercourses follow
a similar pattern to those of WAI in the Hisar
and Sirsa blocks. Surprisingly, the EWAI of the
head reach watercourses in the Narwana block
is significantly lower than that in the tail reach.
As in WAI, the higher extent of lining has a
significant positive effect on EWAI only in the
Trend Analysis of Performance Descriptors
Appendix
27
Narwana block. The EWAI in the Narwana block
has no significant increasing trend (figure 6)
indicating no change in crop water consumption.
The EWAI in the other two blocks indicates an
increasing crop water consumption within
watercourses but a decreasing rate of growth
with the age of lining. The trends of EWAI in the
Hisar block are significant for both lining periods,
but the rate of growth is higher in the recently
lined watercourses. The trends in the Sirsa block
are significant only for the recently lined
watercourses.
Irrigation Intensity (II): The irrigation
intensity in the Narwana block is significantly
higher than that in the other blocks (figure 7).
There is no difference of II in the other two
blocks. The II of head-reach watercourses in the
Narwana block is lower than that of the tail-
reach watercourses. There are no differences in
II due to location in the other two blocks. The
higher extent of lining has a significant effect
only in the Narwana block. Irrigation intensity is
high in the Narwana block and shows no
significant trend after 1986.
Irrigation intensity of watercourses in the
Hisar and Sirsa blocks shows significant
increasing trends regardless of the period of
lining. However, the watercourses that were lined
recently (in the Hisar block after 1986) have a
higher rate of increase.
It appears that in the watercourses where
the saline or marginal groundwater is mixed with
canal water, the pumping of diluted water has
increased resulting in an increase in the
irrigation intensity. Cropping pattern changes
also add—especially in the Sirsa block—to
positive trends in II. With the pumping of diluted
water, farmers in the Sirsa have switched from
wheat to oilseeds that require less water and
hence have a higher cropping intensity.
Average NDVI (ANDVI): There is no significant
difference of average NDVI between blocks.
There is a significantly increasing trend in crop
condition after 1986 in the Narwana block.
Coefficient of Variation of NDVI (CVNDVI):
The coefficient of variation of NDVI indicates the
overall variability of crop condition within a
watercourse. This is lowest in the Narwana block
and is significantly different from that in other
blocks. The location of the watercourses or the
extent of lining has no effect on CVNDVI.
The CVNDVI of watercourses in all blocks
shows a decreasing trend regardless of the time
of lining. This trend indicates improvements in
water distribution within watercourses. The
increasing use of tube wells in this area
indicates the increasing contribution of
groundwater in improving the variation of water
supply.
Ratio of Tail-End Area NDVI to Head-End
Area NDVI (THRNDVI): The ratio of tail-end area
NDVI to head-end area NDVI within a
watercourse indirectly indicates uniformity of
water distribution between the head and tail
ends. These NDVI ratios for the three blocks are
not significantly different and are close to 1.
There are no significant trends in the ratios
within any of the blocks.
28
Explanatory Wheat EWAI II ANDVI CVNDVI THRNDVI
variable area-%
of total
Constant 29.3 46.3 68.9 146.7 0.184 1.000
Dummy – Narwana block 49.1* 40.0* 35.8* 4.2 -0.059* 0.005
Dummy – Sirsa block 32.1* 18.1* 4.8 -11.7 0.008 -0.119
Dummy – Head reach of Narwana -2.9 -14.2* -14.9* -1.6 0.008 0.021
Dummy – Head reach of Hisar 10.4* 7.1* 3.1 6.8 -0.017 -0.024
Dummy – Head reach of Sirsa 5.2 -1.9* -5.8 4.0 -0.006 -0.108*
Extent of lining – Narwana 10.1* 15.4* 12.2* 5.6 -0.007 -0.046*
Extent of lining – Hisar 3.2 -2.9 -5.3 0.8 -0.005 -0.004
Trend – Lining period 2, Narwana 0.9* 0.0 -0.2 3.0* -0.004* 0.002
Trend – Lining period 3, Narwana 0.9 0.4 0.1 2.7 -0.004* -0.004
Intercept difference – Period 2&3 -13.0 -7.7 -3.6 -12.4 0.014 -0.046
Trend – Lining period 1, Hisar 1.1* 1.6* 1.5* -0.4 -0.002* 0.000
Trend – Lining period 3, Hisar 2.0* 2.8* 2.5* 0.3 -0.005* -0.003
Intercept difference – Period 1&3 10.0* 15.6* 13.8* 8.9 0.035 -0.036
Trend – Lining period 1, Sirsa -2.4* 0.3 1.3* 0.5 -0.008* -0.005
Trend – Lining period 2, Sirsa -1.4* 0.3* 1.2* 0.6 -0.008* 0.005
Intercept difference – Period 1&2 5.3 -5.1 -5.1 -0.7 0.005 -0.061
R20.63 0.59 0.49 0.19 0.6 0.38
APPENDIX TABLE 1.
Trends of performance from 1986 to 1996.
* Significant at 95% confidence level.
29
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