Canal Water Distribution and Its Impact on Farmers' Inncome Along a Distributary

8/8/2019 Canal Water Distribution and Its Impact on Farmers' Inncome Along a Distributary

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CANAL WATER DISTRIBUTION AND ITS IMPACT ON INCOME OF

FARMERS ALONG A DISTRIBUTARY.

MUHAMMAD TOUSIF BHATTI

[email protected]

ABSTRACT

Quantification of inequity in water distribution along selected watercourses of Thaman

distributary, near Kasur, Pakistan, was carried out. Two watercourses were selected each

at head middle and tail reaches of the distributary. Discharges were measured at head,

middle and tail ends of the watercourses during Rabi season 2004, to find out the inter-

relation of water distribution and crop production. The farmers in the command areas of

selected watercourses were also interviewed. The results revealed that inequity of water

distribution was present at all watercourses as average Delivery Performance Ratio

(DPR) accounted for 0.87, 0.68 and 0.43 at head, middle and tail ends, respectively. Gini

coefficient for the distributary was calculated to be 0.591. Furthermore the economic data

confirmed the decrease in income of the farmers with increase in distance along the

watercourses as well as along the distributary.

Key Words: Water, distribution, inequity, DPR, Gini coefficient, crop yield, farmers‟

income.

INTRODUCTION AND BACKGROUND

Water needs to be equally distributed at various levels of the irrigation system for

sustainable irrigated agriculture. Increased crop yield and income of the farmers is

influenced by many factors like land holding, farm operations, fertilizers, pesticides,

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natural hazards and government interventions but water is the most influencing factor,

particularly in arid and semi-arid climates. In evaluating the performance of gravity

irrigation systems numerous studies have been conducted by many researchers at

primary, secondary and tertiary levels of the irrigation system [ Bhutta 1990, Chambers

1998, Sarfaraz 1998, Hussain 2003, Latif 2003]. The results of these studies have

confirmed that inequity in water distribution is a global problem and threat for irrigated

agriculture, especially in country like Pakistan, where the overall economy is based on

irrigated agriculture. Farmers being the biggest stake holders of the agriculture industry

suffered the most by this problem, especially the tail-enders.

The literature lacks the direct socio-economic impact of inequity in water

distribution. The present paper focuses on the socio-economic condition of the farmers

who are deprived of their promised water share that has direct impact on their income at

different locations of the irrigation system.

Economy of Pakistan depends on agriculture which contributes 24 percent of

Gross domestic Product (GDP). Apart from producing food, it provides raw material for

agro- based industry. Out of about 22.16 million hectares (Mha) of country‟s total

culturable land, 17 Mha are irrigated with a culturable waste of about 9.30 Mha

(MINFAL 200). Approximately 10 million hectare-meters (Mhm) of irrigation water is

diverted annually to the canal system. The overall irrigation efficiency is estimated below

40 percent with maximum losses occurring in tertiary irrigation channels i.e.

watercourses (Kemper and Clyma 1980).

THORATICAL CONSIDERATIONS



Among the different irrigation performance indicators available in the literature

Bos et al. (1994) introduced delivery performance ratio (DPR) as the simplest, and yet

probably the most important hydraulic performance indicator, defined as:

D P R = Actual Discharge / Target Discharge ……………... (1)

This measure enables a manager to determine the extent to which water is delivered as

planned at any moment in time and at any location in the system. In fact, the delivery

performance ratio can generally be considered to be the ratio of actual discharge

delivered to the required discharge (designed) as: DPR= Qa /Qr. It may also be used as

deliverable or scheduled water in order to assess, not only the performance of overall

system, but also the contribution of the structural and management components of the

system to the performance, as presented by Molden and Gates (1990).

Gini (1912) developed “the Gini coefficient” to measure the degree of

concentration (inequality) of a variable in a distribution of its elements. The Gini

coefficient is based on Lorenz curve (Lorenz 1905). It compares the Lorenz curve

(Figure 1) of a ranked empirical distribution with line of perfect equality. This line

assumes that each element has the same contribution to the total summation of the values

of a variable. The Gini coefficient ranges between zero when there is no concentration

(perfect equality), and one when there is total concentration (perfect inequality).



Figure 1: Lorenz Curve.

The area of concentration between Lorenz curve and the line of perfect equality,

expresses a proportion of the area enclosed by the triangle defined by the line of perfect

equality and the line of perfect inequality. The closer to one the coefficient is, the more

unequal the distribution will be. The Gini Coefficient can be calculated as.

Gini Coefficient =

n

i 1

[{(δXi + 1) - δXi} × {(δYi + 1) +δ Yi}] -1 …………………

Where

δ X, δY = Cumulative percentages of X and Y variables in fractions.

(In the present study X is the distance in meters along the distributary and Y

is discharge in cusecs)

n = Total number of elements (observations).

i = Index ranging from 1, 2, 3, …………..n

2



THE STUDY AREA

This study was undertaken in the command area of Thaman distributary that

off-takes at RD 1549/L from Lower Main Branch Canal near district Kasur in Punjab

province of Pakistan as shown in Figure 2.

Figure 2: Map of the Study Area.



M B Lower Canal

T a i l

H e a d

M i d d l e

The total discharge of the distributary is 7.70 cumecs with total command area

of 31846.5 hectares. A total of 50 outlets originate from the distributary along its length

of 30.85 km. Time and finance constraints did not permit to incorporate all the 50 outlets

for field measurements under the present study, therefore an optimum sample number of

outlets were selected for detailed analysis. For this purpose the distributary was divided

into three reaches (hereafter called as head, middle and tail reaches respectively) and two

watercourses were selected in all the three reaches, hence a total of 6 watercourses were

incorporated under the present study as shown in Figure 3.

Figure 3: Schematic diagram of Thaman distributary indicating selected watercourses.

DATA COLLECTION

The physical measurements of discharge actually flowing through the sampled outlets

were performed for one complete warabandi1

cycle for all the selected watercourses.

Calibrated current-meter was used for discharge measurement at head, middle and tail of

the watercourses. For locating the measurement points, lengths of selected watercourses

were approximated from Chakbandi2 maps as well as by „Pacing‟ method1 in the field,

1Warabandi is a local term defined as allocation of water share on the basis of time and area.

2 Local term used for scaled irrigation plan.

RD 25309/L

RD 39500/L

RD 61794/L

RD 91790/L

RD 54147/L

RD 85200/L



where number of „paces‟ were counted and multiplied with the average length of one

pace to get the distance. Finally three sites one each at head, middle and tail of the

selected watercourses with regular cross-sections and having minimum turbulence, were

chosen to measure the discharge. The first measuring point at the head was chosen just

downstream the outlets. Here again due to financial constraints the measurements of

discharges could not be performed for all the warabandi cycles during the Rabi season

2004. It was assumed that the DPR will follow similar pattern for all the Warabandi

cycles in sampled outlets. Data regarding the authorized and measured discharges along

with the command areas of the watercourses is presented in Table 1.

Table 1: Command areas and measured discharges of selected watercourses.

Sr No

Location on

distributary Command

area

(hectares)

Authorized

discharge

(cumec)

Location

on W/C

Distance

from

the

outlet

(m)

Measured

discharge

(cumec)

1

Head

H 1 0.0345

184.5 0.0368 M 1750 0.0297

T 3100 0.0212H 1 0.0218

2 127.9 0.0255 M 1000 0.0187

T 1890 0.0110

Middle

H 1 0.0323

3 112.1 0.0224 M 750 0.0238

T 1500 0.0119

H 1 0.0224

4 162.3 0.0323 M 1400 0.0178

T 2800 0.0116

Tail

H 1 0.01875 110.9 0.0212 M 700 0.0122

T 1400 0.0093

H 1 0.0108

6 113.3 0.0195 M 750 0.0088

T 1500 0.0048

1Pacing is a crude method of distance measurement but other methods were difficult to use in the field

conditions of the study area.



For economic investigation farmers were interviewed and questionnaires were filled for

collecting detailed information about the input costs and income calculations after the

crop harvest. Irrigation scheduling data such as warabandi schedules and sanctioned

outlet discharges were collected from secondary sources such as the Irrigation

Department and the Farmers Organizations.

RESULTS AND DISCUSSION

Equity of Canal Water Supply

Gini Coefficient and Delivery Performance Ratio (DPR) at head, middle and tail ends

were calculated for the selected watercourses and the results are summarized in Table 1.

The DPR values at head reaches of the watercourses were closer to 1 for head and middle

reaches of the distributary but it decreased to 0.71 at the tail end of the distributary even

at head of the watercourses. The DPR decreased to 0.51 to 0.77 at middle of the

watercourses. The situation of water supply further deteriorates at the tail ends of

watercourses where the DPR reduced to 0.35 to 0.51. These results clearly show that

farm locations have significant impact on canal water supply. The tail end farmers suffer

the most as they receive only 35 to 51 percent of their authorized (sanctioned) water

supply.

The results obtained from Gini coefficient values are in agreement with those obtained

from DPR. The highest value of Gini coefficient is 0.65 for watercourse No. 4. In spite

of good equity conditions at the head end, the watercourse assumed the high Gini

coefficient value due to the largest difference of DPR values between head and tail ends

of the watercourse as shown in the last column of Table 2 which is 0.63.



Table 2: Delivery Performance Ratios and Gini coefficient values for selected watercourses atThaman distributary.

Watercourse No.Location on

distributary

Distancealong

distributary

GiniCoefficient

Delivery Performance

Ratio

Watercourse location

Head Middle Tail

Maximum

difference

with respect

to head

1Head

25309/L 0.55 0.94 0.81 0.58 0.36

2 39500/L 0.58 0.86 0.72 0.43 0.43

Average 0.57 0.9 0.77 0.51

3Middle

54147/L 0.58 0.98 0.8 0.52 0.46

4 61794/L 0.65 1 0.74 0.37 0.63

Average 0.62 0.99 0.77 0.45

5Tail

85200/L 0.59 0.88 0.57 0.44 0.44

6 91790/L 0.60 0.54 0.45 0.26 0.28

Average 0.60 0.71 0.51 0.35

Overall Average 0.59 .87 0.68 0.43

Use of Canal-water and Groundwater

Canal water supply is decreasing along the distributary as well as watercourses as

discussed in the previous section. To meet the crop water requirements, the farmers use

groundwater except the head-end farmers located at head and middle reaches of the

distributary. The use of groundwater progressively increases downstream the

watercourses as well as along the distributary (Table 3). It is clear from the table that the

tail end farmers use 40 to 70 percent of their crop water needs from groundwater.



Table 3: Groundwater use and additional expenses for pumping groundwater at selectedwatercourses.

Watercourse

No

Location on

Distributary

Percent of water used from

GroundwaterAbiana

(Rs)

Additional Expenses for

Tubewells (Rs/ha)

Head Middle Tail Head Middle Tail

1 25309/L 0 20 40 70 0 309 618

2 39500/L 20 30 40 70 309 462 618

3 54147/L 0 20 50 70 0 309 771

4 61794/L 0 30 40 70 0 462 618

5 85200/L 20 40 60 70 309 618 926

6 91790/L 50 50 70 70 771 771 1082

Average 15 32 50 70 231 488 772

Increase in percentage of groundwater irrigations at head, middle and tail ends of the

watercourses are compared with DPR in Figure 4. It was observed that percentage use of

groundwater for irrigation showed an increasing trend as the DPR line showed the

negative slope along the watercourse length. The maximum groundwater pumpage was

observed at watercourses No. 5 and 6 located at the tail reach of the distributary. The

results of increasing groundwater usage to cop with the canal water deficit and additional

expenses for pumpage are presented in Table 3.



0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Head M id dle Tail

Lo cation at waterco urse

0

10

20

30

40

50

60

70

80

90

100

watercourse No.1 watercourse No.2 watercourse No.3

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Head M id dle Tail

Loc ation at watercourse

0

10

20

30

40

50

60

70

80

90

100

watercourse No.4 watercourse No.5 watercourse No.6

Figure 4: Delivery Performance Ratios and use of ground water along selected

watercourses.

Income of Farmers

Net income per hectare decreased from head to tail of the watercourses. The difference in

net incomes with respect to the tail end farms was calculated. The results are summarized

in Table 4. The largest difference was found in head and middle reach watercourses due

to the greater differences in head and tail end DPR values at these watercourses.

Groundwater usa e % .



Table 4: Comparison of net incomes at head, middle and tail ends of watercourses.

Watercourse NoNet Income in rupees per hectare at

Head Middle Tail

110517 8250

7459(41)* (11)

210147 8522

8114(25) (5)

38875 8657

7553(17) (15)

49354 7857

7810(20) (1)

58452 7872

7563(12) (4)

67101 7101

6175(15) (15)

Difference in net income with respect to the tail end farms in percent.

CONCLUSIONS

Water scheduling aiming at equal water supply among all the shareholders plays a vital

role in crop production on profitable and sustainable basis. Spatial variations in water

availability transforming into the curse of water diminishing at tails of the irrigation

system is the factor that create a gap of yield and income between farmers located at

different locations of the irrigation system. The farmers at tail ends of the watercourses

are receiving 35 to 45 percent less water resulting in 15 to 41 percent decrease in income

per hectare in comparison with the head-end farmers. Where this situation glamorize the

lust of land holdings near the outlets, it also give birth the rivalry among the farmers at

the command area of the same outlet.

The evidences of inequity of water distribution and resulting yield and income gaps

gleaned from this study pose different aspects for the attention of irrigation planners. The

policies should be aimed at reduction of water losses by rehabilitation of watercourses

and more importantly designing improved water schedules on the basis of precise

estimation of available water resources.



REFERENCES

Bos, M. G., D. H. Murray-Rust, D. J. Merrey, H. G. Johnson, and W. B. Snellen. 1994.

Methodologies for assessing performance of irrigation and drainage management. Irrigation and

Drainage Systems 7 :231-261.

Bhutta, M. N. 1990. Effect of varying discharges on the equity of water distribution in the irrigationsystem. PhD dissertation, Center of Excellence in Water Resources Engineering, Lahore.

Corey, G.L. and Clima, W. 1973 Improving farm water management in Pakistan, Publication No.

CSU Field Report No 1 L-12.

Chambers, Robert; Saxena, N. C.; and Shah, Tushaar. 1987. To the hands of the poor: Water an

dtrees, Delhi, India: Oxford IBH Publishing Co.

Gini, C. "Variabilitá e mutabilita." 1912. Reprinted in Memorie di metodologia statistica (Ed. E.

Pizetti and T. Salvemini.) Rome: Libreria Eredi Virgilio Veschi, 1955.

Hussain, I., Sakthivadivel, R., Amarasingh, U., Mudassar, M., and Molden, D. 2003. Land and

water productivity of wheat in western Indo-Gangetic plains of India and Pakistan. Research ReportNo. 65 .International water Management Institute, Colombo, Sri Lanka.

Kemper, W.D., Clyma, W., Skogerboe, G.V. and Trout, T.J. 1980 Watercourses improvement

research in Pakistan, Water Management Technical Report No. 56, Colorado State University, Fort

Collins, USA.

Latif, M., and Pomee, M. S. 2003. Impacts of Institutional Reforms on Irrigated Agriculture in

Pakistan, Irrigation and Drainage Systems 17; 195-212. Kluwer Academic Publishers, the

Neterlands.

Lorenz, M. O. 1905. "Methods for Measuring the Concentration of Wealth." Amer. Stat. Assoc. 9,

209-219.

MINFAL 2002. Agriculture Statistics of Pakistan, 2000-2001. Ministry of Food, Agriculture and

Livestock, Government of Pakistan.

Molden, J., and T. Gates. 1990. Performance measurements for evaluation of irrigation delivery

systems. J. Irrig. Drain. Eng. Am. Soc. Civil Eng. 116: 804 – 823.

Sarfaraz, M., Kawij, I., and Brouwar M. 1998. Assesmsnt of water distribution at watercourse and

minor level of Bahdurwah Minor. Report No. 55. International Water Management Institute,

Pakistan.

Canal Water Distribution and Its Impact on Farmers' Inncome Along a Distributary

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