Computation of Seepage Losses and Economic Analysis of Canal Lining- A Case Study of Hajira Branch Canal

doi:10.21203/rs.3.rs-3090309/v1

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Computation of Seepage Losses and Economic Analysis of Canal Lining- A Case Study of Hajira Branch Canal

https://doi.org/10.21203/rs.3.rs-3090309/v1

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Canals are the major conveyance system of any irrigation project, delivering irrigation water to fields. Irrigation schemes include an extensive distribution system which is an expensive proposition. So, it is necessary to ensure that large water losses do not occur due to seepage. Most of these canals are earthen so considerable water losses occur due to seepage. These losses can be overcome by lining the bed and sides of the canal cross-section with impervious material. Canal lining improves the efficiency of the canal by reducing the canal seepage. Improved efficiency leads to saving huge amounts of irrigation water, and thereafter, can cover more land area under irrigation. The main aim of this study is to find out which kind of lining is best suited to canal cross-section in accordance with the cost criteria. The study area is the Hajira branch canal which takes off from the Kakarapar right bank main canal. The present work is divided into 3 parts. In the first part, seepage losses from the canal are computed. In the second part, different types of lining are studied and the lining which is best suited to the canal is selected and its design is done. In the third part cost estimation is done of the canal lining.

Canal

Cost

Irrigation

Lining

Seepage

As time goes, water becomes difficult to acquire and the need of secure water is contaminated. This problem is more increased due to urban water demands and increased agriculture production in remote areas around the world. To overcome this problems canals have been constructed to transport the water from its source to where it is needed.

A system of irrigation canals which is also known as canal network transports water from its source to fields. The canal network comprising of main canal, branch canal, major & minor distributaries, field channels & water courses. In canals mainly two kind of losses are taken place, one is evaporation loss and another is seepage loss. As the canal water is exposed to atmosphere, evaporation losses are taken place. It may range from 0.25–1% of canal discharge. In most of cases evaporation losses are not significant. The rate of loss of water mainly depends upon the temperature of a region, prevailing wind velocity of the region, humidity and area exposed to the atmosphere.

Seepage loss is the most significant irrigation water loss from a canal. In canals 50% or more amount of water is lost due to seepage. Seepage loss mainly depends upon ground water conditions, porosity of soil, and physical properties of canal water.

Many of these canals are earthen canal which is inexpensive to construct but loses 50 percent or more water due to seepage. They are more liable to get eroded, weed growth and other problems that gently reduces its effectiveness over the time Old earthen irrigation channels in permeable soil, considerable water loss takes place due to seepage from its sides & bed. This losses leads to low conveyance efficiency. Also, earthen canals get clogged due to weed growth which reduces its water carrying capacity. This losses overcomes by providing lining to earthen canals which a resistant layer is made of concrete. Lining of irrigation canals gives the best opportunities to extend limited water supplies. It is not only reducing the seepage but also gives a measure against breaks & reducing maintenance cost.

Lining of irrigation canals is a very important part of any irrigation project. As it improves the flow characteristics, reducing seepage rates, weed growth much water is saved which can be utilized for the extension & improvement of irrigation. In lined canals high velocities are achieved which leads to saving in cross-sectional area of canal & land width required, with corresponding saving in the excavation cost & masonry work. Many materials have been used for canal lining such as earth, concrete, asphalt are most commonly used. Many new materials have been investigated now a days like butyl rubber, plastic film, soil stabilizers. The choice of lining material will be depend on available site conditions, availability of materials, materials and equipment, cost structure and labours.

Canal liners are one of the new and cost effective way to line canals compared to the traditional concrete. In traditional concrete lining cost as much as 30 times or more compared to the cost of liners.

The impact of project on economic welfare in terms of associated benefits and costs. If benefits are more than the costs, it indicates that nation would be beneficial by adopting the project. On the other hand, an excess of costs over benefits implies that there is a wastage of money. So, in general project should be only taken up if benefits exceeds costs.

Hajira Branch Canal was constructed as unlined canals in 1954 and 1975 respectively. Hazira branch canal is taking off from kakarapar right bank main canal having total discharge of 1207 cusecs and having total length of 34 km. Study area is shown in Fig. 1.

A. Seepage Analysis

The principal factors affecting seepage from an earthen canal are nature of soil material, deposition of silt, groundwater table with respect to canal water surface, depth of water in canal, hydraulic conductivity of the soil, inflow seepage water and chemistry of the soil and water (Arshad, Zaman, & Madani, 2008; Mahesh M. Karad, 2013). Quantitative knowledge of seepage losses can be obtained by direct measurements, or by indirect methods. From an unlined Hajira branch canal sample was collected .Indirect measurements of seepage by determining coefficient of permeability of field samples in laboratory by using particle size analysis was performed and observing the water table profile in the field from which seepage loss rates were computed by knowing the requisite aquifer characteristic which has shown that lining of canals in the study area will save about 34.16 % of water which otherwise is going waste for various easons described above. The saving of water by lining will enable the project to facilitate the irrigation in additional area. This will also solve the problem of water logging in the initial stretch of canal where excessive use of water by farmers and seepage.

B. Economic analysis

To calculate the cost of lining the total length of 34.45 km of canal is divided in 17 parts as shown in the table as the cross section is varying. The total requirement of lining calculated as shown in the table is 56728.52sq.m (Memon, et al., 2013).From the SOR of Surat Irrigation Circle, total cost of lining alone comes to Rs. 285185363.54. To this other cost is added the total cost of lining comes out to be Rs. 293740924.45.The objectives were to study how Benefit derived and Cost incurred in the project can be worked out. Thus benefit-cost ratio is to be studied in addition to technical feasibility and economic viability (S.M.S.Shah, 2011).

Table 1

Details of Calculation Showing the Total Area of Lining
Chainage	Length	Area	Perimeter	Discharge	Area of lining
0 to 4754.88	4754.88	36.09	21.57	35.90	102562.8
4754.88 to 6530.34	1775.46	34.40	21.06	33.712	37391.19
6530.34 to 10506.46	3976.12	29.90	20.03	27.51	79641.68
10506.46 to 11417.81	911.35	28.90	19.82	30.634	18062.96
11417.81 to 12752.83	1335.02	28.90	19.82	28.322	26460.1
12752.83 to 14173.20	1420.37	24.32	17.27	23.35	24529.79
14173.20 to 17487.90	3314.70	23.69	16.92	22.74	56084.72
17487.90 to 21892.26	4404.36	22.25	16.12	21.14	70998.28
21892.96 to24646.13	2753.87	16.08	13.19	17.21	36323.55
24646.13 to 25054.56	408.44	11.72	11.73	12.96	4791.001
25054.56 to 27444.19	2389.63	10.76	11.22	11.62	26811.65
27444.19 to 27736.8	292.61	10.76	11.22	12.27	3283.084
27736.8 to29332.73	1595.93	8.47	9.73	7.25	15528.4
29332.73 to 30623.26	1290.53	12.5	12.33	10.375	15912.23
30623.26 to 31927.8	1304.54	14.07	13.24	12.04	17272.11
31927.8 to 33832.8	1905	12.13	12.61	9.69	24022.05
33832.8 to 34452.76	619.96	11.65	12.21	7.96	7569.712
				Total	567245.3

C. Project economic evaluation

Abstract
Sr. No.	Dscription of Item	Unit	Amount
Job	Dismentalling the R.C.C. work, Masonary work Pipes lining work & disposing off the stuff including stacking of the useful materials etc. complete as directed.	M²	143455.40
	Dewatering the foundation trenches during excavation of canals, drains, foundation tranches, concrete, masonary etc. till completion and diversion of surface and sub surface water by using pumps of suitable capacity either diesel or electrical driven including cost of labour, pipelines etc. for delivery distance beyond 50 meters.	Hp Hr.	141666.00
	Clearing the canal land width including removing the shrub, bushes, cactus, weeds other vegetation including cutting down trees upot 0.50cm girth and depositing the removed materials outside the canal land width up to lead of 50 meter as directed etc. complete.(Without water pool)	M²	2256334.86
	Excavation of canal/drains in all sorts of soils (including wet and slushy condition of soil) including depositing the excavated stuff in uniform layers in canal banks or in spoil banks or as and where directed including dressing the canal section upto lead of 50 meter and all lift including clearing the site etc. complete (By machinery )	M³	5929266.75
	Earth work in embankment using soil, soft and hard murrum excavated from borrow area / village tank etc.including breaking clods,dressing to the design section with lead upto 5 Km lead and all lifts (By JCB-4CX Machinery)	M³	13788752.61
	Compaction of soil/hard murrum / soft murrum in even thickness of 15 to 20 cms including watering rolling of suitable capacity etc. complete as directed.	M³	1050596.09
	Mechanised trimming of the canal section for preparing sub grade for laying cement concrete lining in all sort of soils and murrum including watering and compacting bed and side slopes using slope compactors as and where required.	M²	5979013.52
	Providing and laying 10 cm thick in bed & in slope 10cm thick plain /reinforced cement concrete Paver lining of M-15 grade in bed, side slopes and curvature including batching, mixing,transporting placing, smooth finishing, curing including dewatering where required.(With machinary based).
	(b) 10 cm thick Bed lining	M²	134217746.96
	(e) 10 cm thick slope lining ( with membrane curing ).	M²	66702255.90
	Providing and filling the polysulphide joint selent of the approved make in the expansion and contraction joints in the c.c. lining including clearing the joints with air water jet.	M	48936977.21
	Excavation for foundation in all sorts of soil including sandy and gravelly soil, soft murrum including depositing the excavated stuff as and where directed including back filling the tranches with suitable excavated stuff etc. complete for lead up to 50 and lift as under.(Manuly without dewatering)	M³	68250.12
	(b) Lift 1.5 meter to 3.00 meter
	Providing and placing in position reinforcement bars including cutting, bending welding, joints where necessary, hooking etc. complete as per drawing for all lead and lifts. (TMT Bar)	Qtl	3801922.80
	Providing and laying plain/ reinforced ordinery portland cement concrete of various grade with cement, sand and coarse aggregates including centering, shuttering, batching, mixing, transporting, placing, vibrating, smooth finishing, curing etc. complete for all lead and lift.(Machinary Based, Excluding dewatering), M-15 Grade	M³	2169125.32
	Total Rs.	285185363.54
	Add 2% for contigency	5703707.27
	Add 1% foruality control	2851853.64
	Net total Rs.	293740924.45
	Say Rs.	29.37 crores.

Reduction in seepage loss after providing lining

Total water loss obtained as per Particle size method = 0.76 m³/s

Total seepage considering canal is running 91 days in all seasons continuously,

= 0.76 X 60 X 60 X 24 X 91 m³/year

= 5975424 m³/year

After providing plain cement concrete lining 90% water can be reduce from seepage.

Thus, 5975424 X 0.90

= 5377881.6 m³/year

Therefore 0.68 m³/s water can be saved after providing lining from seepage loss.

Table 2

Reduction in seepage loss after lining
Description	Value Before Lining	Value after lining
Canal	Unlined Lined by PCC	Unlined Lined by PCC
Section	Trapezoidal canal	Trapezoidal with rounded bottom canal
Seepage Rate	0.76 m³/s	0.08 m³/s

D. Benefits derived from project

Table 3

Benefits derived from the project
Sr. No	Name of crops	Present yield and production			Max yield and production after completion of project			Additional Production	Production income difference
Sr. No	Name of crops	Area in HA	Yield in Qtl./Ha	Production in Qtl	Area in HA	Yield in Qtl./Ha	Production in Qtl	Additional Production	Rate / Qtl	Amount Rs. in Lacs
1	2	3	4	5	6	7	8	9	10	11
1	Sugarcane	6000	750	14500000	6400	825	5280000	780000	225.00	1755.00
2	Paddy	8000	25	200000	8200	30	246000	46000	900.00	414.00
3	Vegetables and others	1200	85	102000	1300	85	110500	8500	1500.00	127.50
										2296.50

E. Benefit-Cost Ratio of Plain Cement Concrete

(A) Benefit

As per statement 2296.50Lac

(B) Annual Cost

(i)	Capital Cost (a) Construction Cost	2937.40 Lac
(ii)	Interest @10% on capital cost	293.740 Lac
(iii)	Depreciation charges @ 2% on capital cost	58.75 Lac
(iv)	Operation and maintenance charges @ 15% on Capital cost	440.61 Lac
(v)	Total annual cost (ii) + (iii) + (iv)	793.1 Lac

Therefore B/C ratio = Total annual Benefit /Total annual cost

= 2296.50 / 793.1

= 2.89

As in the above project the Benefit/Cost ratio comes out to be 2.89 the project can be taken up as it is economically viable in addition to its technical feasibility.

Estimation cost of the project works out to Rs 29.36 Crores as per SOR 2015-16.Benefit -Cost Ratio of the project works out to 2.89. Due to increase in capacity of canal certain canals which became inoperative in tail end area will start functioning Concrete lining would reduce the seepage loss drastically hand has lower operation and maintenance costs. After providing plain cement concrete lining 1.65 crores of rupees water can be save.

Total water loss obtained as per Particle size method = 0.76 m³/s

Total seepage considering canal is running 91 days in all seasons continuously,

= 0.76 X 60 X 60 X 24 X 91 m³/year

= 5975424 m³/year

After providing plain cement concrete lining 90% water can be reduce from seepage.

Thus, 5975424 X 0.90

= 5377881.6 m³/year

Therefore 0.68 m³/s water can be saved after providing lining from seepage loss

Considering Rs. 2.37 per cum of water charges total cost of water save by lining in all season

= 12745579.39 Rs.

Thus, 1.27 Crores rupees of water can be save by lining which can be used in nonagriculture like Industries, GIDC, water supply scheme, nagarpalika.

As the lining provides a smooth surface rugosity coefficient will be decreased so that there is low resistance to flow and velocity of flow will be increased. The lining of canals will save about 25–30% of water which is going waste for various Reasons described above. The saving of water by lining will enable the project to fascinate the irrigation in additional area of about 2000 Ha. Lining of canal not only seepage can be reduced, but it will also Minimize the problem of water logging. Whatever quantity of water saved can be used for improvement of crop pattern.

Acknowledgements: We are grateful to the surat irrigation circle for providing necessary data and support to design lined canal.

Author contribution:KM had done all the work of estimating the seepage loss and designing the canal lining. RB and JP provided the necessary support and guidance for conducting research work.

Funding: All the expenses beared by main author KM,as they were minimal.

Data avaibility: The priliminary data for canal lining design are available at Surat Irrigation circle, Gujarat, India. And Schedule of Rates was procured from Surat Municipal Office.

Conflict of Interest: The authors declare no competing interests.

Bureau of Indian Standards. (1982). ‘‘Criteria for design of lined canals and guidelines for selection of type of lining.’’ IS: 10430, New Delhi.
Manual of canal lining.’’ Tech. Rep. No. 14, Central Board of Irrigation and Power, New Delhi.
Ashfaque A. Memon1, Khalifa Q. Leghari1, Agha F. H. Pathan1, Kanya L. Khatri2, Sadiq A. Shah2, Kanwal K. Pinjani3, Rabia Soomro2, Kameran Ansari, June 20, 2013, “ Design and Evaluation of Dadu Canal Lining for Sustainable Water Saving”, 5, 689-698
Mahesh M. Karad1, R.A. Panke2, P.A. Hangargekar, Vol. 2 Issue 11, November – 2013, “Seepage Losses through Canals & Minors”.
Mr. Amrut Sangale, Dr. S. S. Valunjkar, May 2015, “Cost Effectiveness of Different Canal Lining Materials”, Volume-3.
M. Arshad, Q. Zaman and A. Madani, “Lining Impact on Water Losses in Watercourses: A Case Study in Indus Basin, Pakistan,” Annual Conference of the Canadian Society for Bioengineering, North Vancouver, 13-16 July 2008, pp. 1-12.
S. M. S. Shah, Z. M. Maan and M. K. Sarwar, “Impact of the Alternative Lining of Water Course on Cost and Effi- ciency,” Science, Technology and Development, Vol. 30, No. 4, 2011, pp. 31-38.
Pradeep Shau, “The Use of Canal Lining Avilable Material and Its Comparative Study” e-ISSN: 2278, ISSN: 2320-334X, Volume 11, Issue 3 Ver. IV (May-June 2014).

No competing interests reported.

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Computation of Seepage Losses and Economic Analysis of Canal Lining- A Case Study of Hajira Branch Canal

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Abstract

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1. Introduction

2. STUDY AREA

3 Methodology

4. Conclusion

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References

Additional Declarations

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