TRAINING PROGRAMME ON ENGINEERING DESIGNS-CANAL STRUCTURES GENERAL DESIGN PRINCIPLES

TRAINING PROGRAMME ONTRAINING PROGRAMME ON

ENGINEERING DESIGNS-CANAL STRUCTURESENGINEERING DESIGNS-CANAL STRUCTURES

GENERAL DESIGN PRINCIPLES GENERAL DESIGN PRINCIPLES

CANALS & CANAL LINGINGCANALS & CANAL LINGING

BY BY

ROUTHU SATYANARAYANAROUTHU SATYANARAYANA

FORMERFORMER CHIEF ENGINEER CHIEF ENGINEER

FORMER ADVISOR, GOVERNMENT OF A.PFORMER ADVISOR, GOVERNMENT OF A.P

Canal & Design PrinciplesCanal & Design Principles Definition: A canal is an artificial Definition: A canal is an artificial

channel, trapezoidal in shape to carry channel, trapezoidal in shape to carry water to the field from a source, such as water to the field from a source, such as a reservoir, river or a tank.a reservoir, river or a tank.

• The motive force in the flow of an open The motive force in the flow of an open channel is the slope of the water surfacechannel is the slope of the water surface

• The water flows from higher level to lower The water flows from higher level to lower level by virtue of gravity.level by virtue of gravity.

• The resistance in the canal are surface The resistance in the canal are surface tension, atmospheric pressure, surface tension, atmospheric pressure, surface friction at the bottom and sides.friction at the bottom and sides.

Canal & Design PrinciplesCanal & Design Principles Canal Alignment:Canal Alignment:

• The canal has to be aligned in such a way The canal has to be aligned in such a way that it covers the entire area proposed to that it covers the entire area proposed to be irrigated with the shortest possible be irrigated with the shortest possible length and at the same time its cost length and at the same time its cost includes the cost of Cross Drainage and includes the cost of Cross Drainage and Cross Masonry works and they are the Cross Masonry works and they are the minimum.minimum.

• A shorter length ensures less loss of head A shorter length ensures less loss of head due to friction and smaller loss of due to friction and smaller loss of discharge due to seepage and discharge due to seepage and evaporation. evaporation.

Canals & Design PrinciplesCanals & Design Principles Classification of Canals based on Classification of Canals based on

• Canal excavation in Soils:Canal excavation in Soils:• Alluvial Canals and Non- alluvial CanalsAlluvial Canals and Non- alluvial Canals

• Functions of the Canal: Functions of the Canal: • Irrigation Canal -Carrier Canal Feeder canal – Irrigation Canal -Carrier Canal Feeder canal –

Navigation Canal – Power CanalNavigation Canal – Power Canal• Shape of channel: Shape of channel:

• Circular, Rectangular, Trapezoidal, Triangular, Circular, Rectangular, Trapezoidal, Triangular, Parabolic Parabolic

• Canal alignment: Canal alignment: • Contour Canals - Ridge Canals or water shed canals – Contour Canals - Ridge Canals or water shed canals –

Side Slope Canals.Side Slope Canals.• Discharge and Importance: Discharge and Importance:

• Main Canal-Branch Canal-Major and Minor Main Canal-Branch Canal-Major and Minor Distributaries-Water course.Distributaries-Water course.

• Nature of the Canal: Nature of the Canal: • Un-lined canal-Lined canal. Un-lined canal-Lined canal.

Canals & Design PrinciplesCanals & Design Principles Design parameters: Design parameters:

DischargeDischarge: : The discharge capacity of the canal is the maximum discharge The discharge capacity of the canal is the maximum discharge

required for the ayacut for the given duty and the losses in the required for the ayacut for the given duty and the losses in the system. system.

It shall be fixed based on, It shall be fixed based on, The cultivable command area, The cultivable command area, Water allowance, i.e. the outlet capacity in cumecs/s per thousand Water allowance, i.e. the outlet capacity in cumecs/s per thousand

hectares considering the duty, intensity, proposed crop ratio, water hectares considering the duty, intensity, proposed crop ratio, water availability, etc; and availability, etc; and

Transmission losses due to seepage and evaporation from canals Transmission losses due to seepage and evaporation from canals water courses and irrigated area. water courses and irrigated area.

The carrying capacities of the canals and distributaries have to be The carrying capacities of the canals and distributaries have to be worked out from head to tail.worked out from head to tail.

Canals & Design PrinciplesCanals & Design Principles Design parameters: Design parameters:

• Best Discharging Channel is that which for Best Discharging Channel is that which for the same Cross Section and slope, passes the same Cross Section and slope, passes water with the maximum velocity and the water with the maximum velocity and the maximum hydraulic mean radius (R=A/P), maximum hydraulic mean radius (R=A/P), and with the smallest absorption losses and with the smallest absorption losses commensurate with economy.commensurate with economy.

• The canal has to be aligned in such a way The canal has to be aligned in such a way that it covers the entire area proposed to be that it covers the entire area proposed to be irrigated with the shortest possible length irrigated with the shortest possible length and at the same time its cost includes the and at the same time its cost includes the cost of Cross Drainage and Cross Masonry cost of Cross Drainage and Cross Masonry works and they are the minimum.works and they are the minimum.

Canals & Design PrinciplesCanals & Design Principles Design parameters: Design parameters:

• The common procedure is to determine the Width The common procedure is to determine the Width (W) and Depth (D) of a canal for a given discharge (W) and Depth (D) of a canal for a given discharge (Q), coefficient of rugosity, side slopes, surface fall (Q), coefficient of rugosity, side slopes, surface fall or bed gradient, and minimum and maximum or bed gradient, and minimum and maximum velocity. The formula for determine the discharge velocity. The formula for determine the discharge capacity of the canal.capacity of the canal.

Discharge (Q) = A (area ) x V ( Velocity)Discharge (Q) = A (area ) x V ( Velocity)• The Cross section of the canal will be in The Cross section of the canal will be in

• Full cuttingFull cutting• Full banking orFull banking or• Partial cutting and Partial bankingPartial cutting and Partial banking

Canals & Design PrinciplesCanals & Design Principles Discharge Formula for open head channel : Discharge Formula for open head channel :

Discharge (Q) in cumecs = AxV Discharge (Q) in cumecs = AxV where , A= Cross sectional area in Sq.mwhere , A= Cross sectional area in Sq.m

V= Mean velocity of flow in m/sV= Mean velocity of flow in m/sVelocity is computed using Manning’s formulaVelocity is computed using Manning’s formula

V= (RV= (R2/32/3SS1/21/2)/n)/nwhere,where, R= Hydraulic mean radius (A/P) in m R= Hydraulic mean radius (A/P) in m

S=Surface Slope of water/bed slopeS=Surface Slope of water/bed slope P= Wetted perimeter in mP= Wetted perimeter in m n= Coefficient of rugosity.n= Coefficient of rugosity.

Canals & Design PrinciplesCanals & Design Principles Design parameters: Design parameters:

• Coefficient of rugosity ’n’: To over come surface tension Coefficient of rugosity ’n’: To over come surface tension friction on sides and bottom of the canal. friction on sides and bottom of the canal.

____________________________________________________________________________________________________________________________ CanalCanal Un-linedUn-lined canal canal Lined canalLined canal____________________________________________________________________________________________________________________________AlluviumAlluvium 0.0225 to 0.025 0.0225 to 0.025GravelGravel 0.025 0.025Natural drainsNatural drains 0.03 to 0.035 0.03 to 0.035Concrete liningConcrete lining 0.018 to 0.0200.018 to 0.020Shot Crete finishShot Crete finish 0.018 to 0.0220.018 to 0.022

• Free Board: Measured from FSL/HFL to top of bund or top of liningFree Board: Measured from FSL/HFL to top of bund or top of lining__________________________________________________________________________________________________________________________________________

Canals & Design PrinciplesCanals & Design Principles Design parameters :Design parameters :• Free Board: Measured from FSL/HFL to top of bund or top of Free Board: Measured from FSL/HFL to top of bund or top of

lininglining

____________________________________________________________________________________________________________________________________Canal discharge Canal discharge lined canal lined canal in Cumecsin Cumecs in mmin mm______________________________________________________________________________________________________________________

< 0.10< 0.10 150150< 1.00< 1.00 3003001.00-3.001.00-3.00 5005003.00- 10.003.00- 10.00 600600>10.00>10.00 750750

__________________________________________________________________________________________________________________________

For unlined canals , minimum free board=500mm up to For unlined canals , minimum free board=500mm up to Q,<10cumecs and 750mm for Q.10 cumecs.Q,<10cumecs and 750mm for Q.10 cumecs.

Canals & Design PrinciplesCanals & Design Principles Design parameters: Design parameters:

• Bank Top widths: For distributaries <3 cumecs discharge formation of service road Bank Top widths: For distributaries <3 cumecs discharge formation of service road may not be necessary, but only land widths ay be provided on the natural groundmay not be necessary, but only land widths ay be provided on the natural ground

__________________________________________________________________________________________________________________________________________ Canal discharge Canal discharge UN-lined canal in mUN-lined canal in m Lined canal in mLined canal in m

in Cumecsin Cumecs Inspection Non inspt.Inspection Non inspt. Insp.Insp. Non-Insp.Non-Insp.____________________________________________________________________________________________________________________________________________

0.15-1.500.15-1.50 5.005.00 1.50 1.50 4.004.00 1.501.501.50-3.001.50-3.00 5.005.00 1.50 1.50 4.004.00 2.002.003.00-7.503.00-7.50 5.005.00 1.50 1.50 4+dowel4+dowel 2.502.507.50-10.007.50-10.00 5.005.00 2.50 2.50 4+dowel4+dowel 2.502.5010.00-10.5010.00-10.50 6.006.00 2.50 2.50 4+dowel4+dowel 2.502.5010.50-15.0010.50-15.00 6.006.00 2.50 2.50 5+dowel5+dowel 4.004.0015.00-30.0015.00-30.00 7.007.00 3.50 3.50 5+dowel5+dowel 4.004.00> 30.00> 30.00 -------- ----- ----- 6.+dowel6.+dowel 5.005.00

______________________________________________________________________________________________________________________________________________________Dowel Banks: To protect the inner slops from rain waterDowel Banks: To protect the inner slops from rain water• Main canal and Branches: 500mm top width, 500mm high with 1.5:1 slops on either Main canal and Branches: 500mm top width, 500mm high with 1.5:1 slops on either

sideside• Distributaries: 300mm top width and 300 mm high.Distributaries: 300mm top width and 300 mm high.

Canals & Design PrinciplesCanals & Design Principles Design parameters: Design parameters: Inner slopes of the canal: To safe guard against sudden draw down condition.Inner slopes of the canal: To safe guard against sudden draw down condition.

----------------------------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------------------------- Type of soilType of soil Side slopes, Horizontal to verticalSide slopes, Horizontal to verticalin embankmentin embankment in cuttingin cutting

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------All soilsAll soils 2:12:1 1.50:11.50:1Rock - DisintegratedRock - Disintegrated RockRock …… 1.00:11.00:1HDRHDR …… 0.50:10.50:1Hard RockHard Rock …… 0.25:10.25:1

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------• B/D Ratio:B/D Ratio:

____________________________________________________________________________________________________________________________________________________Discharge in CumecsDischarge in Cumecs B/D RatioB/D Ratio____________________________________________________________________________________________________________________________________________________0.05 to 0.500.05 to 0.50 1.0 to 1.501.0 to 1.500.50 to 5.000.50 to 5.00 1.5 to 2.001.5 to 2.005.00 to 50.005.00 to 50.00 3.5 to 6.003.5 to 6.0050 to 20050 to 200 6.00 to 8.006.00 to 8.00Above 200Above 200 8.00 to 10.008.00 to 10.00____________________________________________________________________________________________________________________________________________________

Canals & Design PrinciplesCanals & Design Principles Design parameters:Design parameters:

• Mean Velocity:Mean Velocity:__________________________________________________________________________________________________________________________________________________

SoilSoil Mean Velocity in m/sMean Velocity in m/s____________________________________________________________________________________________________________________________________________________

All soilsAll soils0.6 to 1.10.6 to 1.1GravelGravel 1.5 to 1.81.5 to 1.8RockRock 1.4 to 2.71.4 to 2.7Hard rockHard rock 4.5 to 7.64.5 to 7.6Stone MasonryStone Masonry 3.003.00Concrete < M30Concrete < M30 4.004.00 > M30> M30 6.006.00Steel and Cast IronSteel and Cast Iron 10.0010.00

________________________________________________________________________________________________________________________________________________* Mean Velocity of 1.5 to 2 m/s even up to 2.7 m/sis desirable for lined canals* Mean Velocity of 1.5 to 2 m/s even up to 2.7 m/sis desirable for lined canals

Canals & Design PrinciplesCanals & Design Principles Radius of curvature : as per IS: 5968-1987 and IS: 10430-2000Radius of curvature : as per IS: 5968-1987 and IS: 10430-2000

RADII OF CURVES FOR CANALSRADII OF CURVES FOR CANALSAs per table 1.of IS; 5968 – 1968 Reaffirmed 2003)As per table 1.of IS; 5968 – 1968 Reaffirmed 2003)

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Un lined canalsUn lined canals Lined canals Lined canals------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------DischargeDischarge RadiusRadius DischargeDischarge RadiusRadius In cumecs In cumecs in m in m in cumecsin cumecs in min m

__________________________________________________________________________________________________________________________________________________________________________________________________________80 and above80 and above 15001500 280 and above280 and above 90090080 to 3080 to 30 10001000 280 to 200280 to 200 750 75030 to 1530 to 15 600600 200 to 140200 to 140 60060015 to 315 to 3 300300 140 to 70140 to 70 4504503.0 to 0.33.0 to 0.3 150150 70 to 4070 to 40 300300Less than 0.3Less than 0.3 9090 40 to 1040 to 10 0000• 10 to 310 to 3 150150

3.0 to 0.33.0 to 0.3 100100Less than 0.3Less than 0.3 5050Note 1. The above radii are not applicable to un-lined canals located in hilly reaches and highly permeable soils.Note 1. The above radii are not applicable to un-lined canals located in hilly reaches and highly permeable soils.2. On lined canals where the above radii may not be provided proper super elevation shall be provided.2. On lined canals where the above radii may not be provided proper super elevation shall be provided.

__________________________________________________________________________________________________________________________________________________________________________________________________________

Canals & Design PrinciplesCanals & Design Principles TRANSMISSION LOSSES:TRANSMISSION LOSSES:

The losses take place in account of evaporation and seepage.The losses take place in account of evaporation and seepage. These losses are quite considerable and accounts roughly 25 to 50 These losses are quite considerable and accounts roughly 25 to 50

percent of canal discharge in unlined canals. percent of canal discharge in unlined canals. The seepage losses are influenced by the nature and porosity of The seepage losses are influenced by the nature and porosity of

the soils, the depth turbidity and the temperature of the water.the soils, the depth turbidity and the temperature of the water. The age and the shape of the canal and the ground water table etc;The age and the shape of the canal and the ground water table etc; Seepage losses dependent on nature and permeability of soil, Seepage losses dependent on nature and permeability of soil,

depth of water in the canal and the sub soil water table.depth of water in the canal and the sub soil water table. Generally canal reaches having permeability 10Generally canal reaches having permeability 10-5-5cm/s or less need cm/s or less need

not be lined.not be lined.

In case of lined canals, seepage losses may be assumed In case of lined canals, seepage losses may be assumed as 0.60 cumecs/million square meters of wetted perimeter.as 0.60 cumecs/million square meters of wetted perimeter.

Canals & Design PrinciplesCanals & Design Principles SEEPAGE LOSSES IN UNLINED CANALSSEEPAGE LOSSES IN UNLINED CANALS

(As per table 2 of Manual on Irrigation and Power Publication no.171 by CWC)(As per table 2 of Manual on Irrigation and Power Publication no.171 by CWC)----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Character of material Character of material Seepage Seepage loss in Cumecs per loss in Cumecs per Million sq. m of wetted perimeterMillion sq. m of wetted perimeter

__________________________________________________________________________________________________________________________________________

Impervious clay LoamImpervious clay Loam 0.90 to 1.200.90 to 1.20Medium clay loam under laid with hard pan at depth 1.20 to 1.80Medium clay loam under laid with hard pan at depth 1.20 to 1.80of not over 0.60 to 0.90m below level of not over 0.60 to 0.90m below level Ordinary clay loam silt soil or lavash loam Ordinary clay loam silt soil or lavash loam 1.80 to 2.70 1.80 to 2.70Gravelly or sandy clay loam, cemented gravel,Gravelly or sandy clay loam, cemented gravel, 2.70 to 3.702.70 to 3.70Sand and claySand and claySandy loamSandy loam 3.60 to 5.20 3.60 to 5.20Loose sandy soilsLoose sandy soils 5.20 to 6.10 5.20 to 6.10Gravelly to sandy soilsGravelly to sandy soils 7.00 to 8.80 7.00 to 8.80Porous gravelly soil Porous gravelly soil 8.80 to 10.70 8.80 to 10.70Very gravelly soilsVery gravelly soils 10.70 to 21.3010.70 to 21.30

Note: In the case of lined canals, seepage losses may be assumed as 0.6. Cumecs per Note: In the case of lined canals, seepage losses may be assumed as 0.6. Cumecs per million square meters of wetted perimeter.million square meters of wetted perimeter.

______________________________________________________________________________________________________________________________________

Canals & Canal LiningCanals & Canal Lining Lining of canal :Lining of canal :

• It is an important feature, as it improves the flow characteristics It is an important feature, as it improves the flow characteristics and minimizes the loss of water due to seepage. and minimizes the loss of water due to seepage.

• The water thus saved can be utilized for the extension and The water thus saved can be utilized for the extension and improvement of the irrigation. improvement of the irrigation.

• Lining assumes special significance in pumped water supply as the Lining assumes special significance in pumped water supply as the water is relatively costly.water is relatively costly.

Studies indicate that seepage losses in irrigation channels Studies indicate that seepage losses in irrigation channels constitute 25 to 50 percent. Generally canal reaches having constitute 25 to 50 percent. Generally canal reaches having permeability of 1x10permeability of 1x10-3-3 cm/s and more may be lined. cm/s and more may be lined.

Experiments in south India it is found that cement concrete lining Experiments in south India it is found that cement concrete lining has a rate of seepage of only about 0.50 cusec per million square has a rate of seepage of only about 0.50 cusec per million square feet against 8.0 cusecs in an unlined canal.feet against 8.0 cusecs in an unlined canal.

For the purpose of economic analysis, the life expectancy of For the purpose of economic analysis, the life expectancy of concrete, brick/ tile and stone pitched lining may be assumed to be concrete, brick/ tile and stone pitched lining may be assumed to be of the order of 60 years.(IS:10430-2000)of the order of 60 years.(IS:10430-2000)

Canals & Canal LiningCanals & Canal Lining Advantages of lining: Advantages of lining:

• Seepage control.Seepage control.• Prevention of water logging.Prevention of water logging.• Increased hydraulic efficiency.Increased hydraulic efficiency.• Increased resistance to erosion/abrasion.Increased resistance to erosion/abrasion.• Reduction in cross sectional area. Reduction in cross sectional area. • Low operation and maintenance cost. Low operation and maintenance cost. • Prevention of weed growth. Prevention of weed growth. • Elimination of siltation due to permissible higher velocity.Elimination of siltation due to permissible higher velocity.• Resistance against burrowing animals.Resistance against burrowing animals.

Cement concrete in-situ lining is the most conventional type of Cement concrete in-situ lining is the most conventional type of lining. lining.

• Higher velocity up to 2.7 m/s can be permitted.Higher velocity up to 2.7 m/s can be permitted.• It eliminates weed growth, resistance against burrowing animals, It eliminates weed growth, resistance against burrowing animals,

and improves flow characteristics and low maintenance costs. and improves flow characteristics and low maintenance costs. • A distinct disadvantage is its lack of extensibility, which result in A distinct disadvantage is its lack of extensibility, which result in

frequent cracks due to contraction, shrinkage and settlement of frequent cracks due to contraction, shrinkage and settlement of sub grade.sub grade.

Canals & Canal LiningCanals & Canal Lining

Specifications:Specifications:• The provisions in the relevant Indian Standards are to be The provisions in the relevant Indian Standards are to be

followed in Toto in the case of CC lining for main canals, branch followed in Toto in the case of CC lining for main canals, branch canals and larger distributaries having bed width of more than canals and larger distributaries having bed width of more than 10m (for canals with sub-strata of non-expansive soils) and or 10m (for canals with sub-strata of non-expansive soils) and or discharge of more than 10 cumecs. In the case of smaller size discharge of more than 10 cumecs. In the case of smaller size distributaries, the recommendations of the Expert Committee distributaries, the recommendations of the Expert Committee on Nagarjuna sagar Project Main canals and Branch canals are on Nagarjuna sagar Project Main canals and Branch canals are being followed.being followed.

Canals & Canal LiningCanals & Canal Lining Thickness of In-Situ liningThickness of In-Situ lining

______________________________________________________________________________________________________________________Capacity of canal Capacity of canal depth of waterdepth of water Thickness of liningThickness of liningin cumecs. in cumecs. in m in m in mm (minimum)in mm (minimum)______________________________________________________________________________________________________________________

0 - 5 0 - 5 0 – 1 50 – 600 – 1 50 – 605 - 50 5 - 50 1 – 2.5 60 – 751 – 2.5 60 – 7550 – 200 50 – 200 2.5 – 4.5 75 – 1002.5 – 4.5 75 – 100200 – 300 200 – 300 4.5 – 6.5 90 – 1004.5 – 6.5 90 – 100300 – 700 300 – 700 6.5 – 9.0 120 – 1506.5 – 9.0 120 – 150______________________________________________________________________________________________________________________

Expert Committee recommended thickness for Expert Committee recommended thickness for DistributariesDistributaries______________________________________________________________________________________________________________________0 - 50 - 5 60 605 - 505 - 50 75 75

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Canals & Canal LiningCanals & Canal Lining Coping for Coping for lined canalslined canals::

• To check the ingress of rainwater behind the lining of the side slopes of the To check the ingress of rainwater behind the lining of the side slopes of the canals, horizontal cement concrete coping 100m to 150mm, depending upon the canals, horizontal cement concrete coping 100m to 150mm, depending upon the size of the canal should be provided at the top of the lining. size of the canal should be provided at the top of the lining.

• The width of the coping at the top shall be:The width of the coping at the top shall be:____________________________________________________________________________________________________________________________DischargeDischarge WidthWidth----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------i).i). up to 3.00 cumecsup to 3.00 cumecs 225mm225mmii)ii) 3 to 10 cumecs3 to 10 cumecs 350mm350mmiii).iii). Above 10 cumecsAbove 10 cumecs 550mm.550mm.----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

A parapet wall may replace a dowel. However, the height of the A parapet wall may replace a dowel. However, the height of the parapet should not be considered additional free board.parapet should not be considered additional free board.

BERMS:BERMS:• Berms are to be provided in all cuttings when the depths of cutting Berms are to be provided in all cuttings when the depths of cutting are are

more than 5m. It is desirable to provide berms of three to 5meters at every more than 5m. It is desirable to provide berms of three to 5meters at every 5m depth intervals on each slide for stability and 5m depth intervals on each slide for stability and maintenance.maintenance.

Canals & Canal LiningCanals & Canal Lining

Cross Section of the Lined Canal:Cross Section of the Lined Canal:• As per Cl. 8.8.1 of IS 10430: 2000, The cross section of the lined canal As per Cl. 8.8.1 of IS 10430: 2000, The cross section of the lined canal

may be trapezoidal may be trapezoidal with or without rounded cornerswith or without rounded corners, and the figure referred , and the figure referred there in , shows:there in , shows:

• Bed lining and side lining to be joined with circular curve of radius equal to Bed lining and side lining to be joined with circular curve of radius equal to full supply depth of the canal. full supply depth of the canal.

o The Radius of Curvature ( R ) adopted in the case of Indira Sagar The Radius of Curvature ( R ) adopted in the case of Indira Sagar Polavaram Project, and Sardhar sarovar Project Canals is1500mm.Polavaram Project, and Sardhar sarovar Project Canals is1500mm.

The Expert Committee on NSP , in a Specific case recommended the The Expert Committee on NSP , in a Specific case recommended the radius of curvature (R) equal to 1500mm.radius of curvature (R) equal to 1500mm.

UNDER-DRAINAGE - LINED CANALSUNDER-DRAINAGE - LINED CANALS

• Suitable under drainage should be provided to protect the lining, where the Suitable under drainage should be provided to protect the lining, where the canal crosses an area subjected to seasonal high ground water.canal crosses an area subjected to seasonal high ground water.

• Excessive hydrostatic pressure sufficient to damage the lining when the Excessive hydrostatic pressure sufficient to damage the lining when the canal is empty or canal is low water level.canal is empty or canal is low water level.

• Drainage arrangements provided mainly depend s up on the position of the Drainage arrangements provided mainly depend s up on the position of the water table and the type of sub grade.water table and the type of sub grade.

• Water table may be:Water table may be:• Below canal bed levelBelow canal bed level• Between canal bed level and full supply levelBetween canal bed level and full supply level Above canal full supply level Above canal full supply level

• The sub grade may beThe sub grade may be Free DrainageFree Drainage Poor DrainagePoor Drainage Practically ImperviousPractically Impervious

UNDER-DRAINAGE - LINED CANALSUNDER-DRAINAGE - LINED CANALS

Necessity of Drainage and Filters below lining:Necessity of Drainage and Filters below lining:

1.1. Water table below CBL:Water table below CBL:

A ). Sub grade free drainage A ). Sub grade free drainage • No drainage arrangements required, and no pressure relief arrangements No drainage arrangements required, and no pressure relief arrangements

requiredrequired

B ). B ). sub grade poor drainage sub grade poor drainage • Provide 150 to 200mm filters and pressure relief arrangements with Provide 150 to 200mm filters and pressure relief arrangements with

longitudinal and transverse drains with PRVs in the bed, PRVs in the longitudinal and transverse drains with PRVs in the bed, PRVs in the pockets filled with filters in the sides.pockets filled with filters in the sides.

C ). Sub grade impervious C ). Sub grade impervious • Sub grade to a depth of 600mm to be removed and refilled with sand, Sub grade to a depth of 600mm to be removed and refilled with sand,

murram or suitable pervious material and pressure relief arrangements as murram or suitable pervious material and pressure relief arrangements as above required.above required.

UNDER-DRAINAGE - LINED CANALSUNDER-DRAINAGE - LINED CANALS Necessity of Drainage and Filters below liningNecessity of Drainage and Filters below lining

22. Water table between CBL and FSL:. Water table between CBL and FSL: a). Sub grade free drainage a). Sub grade free drainage • provide 150 to 200mm filters and pressure relief arrangements with provide 150 to 200mm filters and pressure relief arrangements with

Longitudinal and Transverse drains I with PRVs in the bed and PRVs in Longitudinal and Transverse drains I with PRVs in the bed and PRVs in pockets filled with filters in the sides.pockets filled with filters in the sides.

b). Sub grade poor drainage b). Sub grade poor drainage • Provide 200 to 300mm filters and pressure relief arrangements as aboveProvide 200 to 300mm filters and pressure relief arrangements as above

c). Sub grade impervious c). Sub grade impervious • sub grade to a depth of 600mm to be remove and refilled with sand, sub grade to a depth of 600mm to be remove and refilled with sand,

murram, or suitable pervious material. Pressure relief arrangements in bed murram, or suitable pervious material. Pressure relief arrangements in bed and sides as above are required.and sides as above are required.

UNDER-DRAINAGE OF LINED CANALSUNDER-DRAINAGE OF LINED CANALS

Necessity of Drainage and Filters below liningNecessity of Drainage and Filters below lining

3. Water table above FSL3. Water table above FSLa). Sub grade free drainage a). Sub grade free drainage • provide150 to 200mm filtersprovide150 to 200mm filtersb). Sub grade poor drainage b). Sub grade poor drainage • Provide 200 to 300mm filtersProvide 200 to 300mm filtersc). Sub Grade impervious c). Sub Grade impervious • Remove the sub grade to a depth of 600mm and back filled with sand, Remove the sub grade to a depth of 600mm and back filled with sand,

murram, or suitable pervious materialmurram, or suitable pervious material• Pressure relief arrangementsPressure relief arrangements

a.a. Bed – Longitudinal and Transverse drains with PRVSBed – Longitudinal and Transverse drains with PRVSb.b. Sides- Transverse drains with PRVsSides- Transverse drains with PRVs

Longitudinal drains:Longitudinal drains: Trapezoidal with bottom width 500mm,and depth 525mm. Number depending on the bed Trapezoidal with bottom width 500mm,and depth 525mm. Number depending on the bed

width of the canal usually at least one drain for every 10m width.width of the canal usually at least one drain for every 10m width.

UNDER-DRAINAGE OF LINED CANALSUNDER-DRAINAGE OF LINED CANALS

• Transverse drains: Transverse drains: • Provided in the bed and on the side slopes up to free board levelProvided in the bed and on the side slopes up to free board level• Provided at 10m intervalsProvided at 10m intervals

• Pressure Relief Valves (PRV)Pressure Relief Valves (PRV) Provided on the longitudinal/Transverse drainsProvided on the longitudinal/Transverse drains Spacing, one row at every 4m on the sides, the first row 50cm above Spacing, one row at every 4m on the sides, the first row 50cm above

curve line and top row 50 t0100mm below FSL. If the depth of water is curve line and top row 50 t0100mm below FSL. If the depth of water is less than 1.5m, one row will be adequate.less than 1.5m, one row will be adequate.

Spacing one PRV for every 100 sq.m in the canal bed and one for Spacing one PRV for every 100 sq.m in the canal bed and one for every 40 sq.m for sidesevery 40 sq.m for sides

Porous concrete Plugs :Porous concrete Plugs : Size 100mm dia. And 400mm long may be provided in place Size 100mm dia. And 400mm long may be provided in place

of PRVsof PRVs

Longitudinal and transversesLongitudinal and transversesdrains – Canal liningdrains – Canal lining

PRVs Layout – Canal liningPRVs Layout – Canal lining

prvsprvs

PRVs Pocket on Slopes – Canal liningPRVs Pocket on Slopes – Canal lining

PRV Housing Pipe – Canal liningPRV Housing Pipe – Canal lining

Canal & Canal LiningCanal & Canal LiningPressure Relief ArrangementsPressure Relief Arrangements

Canals & Canal LiningCanals & Canal Lining Over excavationOver excavation: :

For slopes more than 1:1 in hard strata:For slopes more than 1:1 in hard strata:• Backfilled with gravel and aggregate and a layer of pea gravel as binding material. Backfilled with gravel and aggregate and a layer of pea gravel as binding material. • The bed may be compacted with road roller and the sides with rammers.The bed may be compacted with road roller and the sides with rammers.

For slopes less than 1:1 in hard strata :For slopes less than 1:1 in hard strata :• Back fill shall be chip masonry, Alternatively, lean concrete.Back fill shall be chip masonry, Alternatively, lean concrete.

Sleepers/profile wallsSleepers/profile walls: : • At intervals of 20m/17.5m in straight reaches and 10m /8.75 in curves. The size At intervals of 20m/17.5m in straight reaches and 10m /8.75 in curves. The size

shall be 250mm wide and 150mm deep built in the same grade of lining, for the shall be 250mm wide and 150mm deep built in the same grade of lining, for the main & branch canals and larger distributaries and 200mm X 150mm for other main & branch canals and larger distributaries and 200mm X 150mm for other distributaries.distributaries.

• Sleeper shall be placed centrally under the joints. (Cl.5.5.1.1.5 of IS 3873-1993)Sleeper shall be placed centrally under the joints. (Cl.5.5.1.1.5 of IS 3873-1993)

Expansion Joints: Expansion Joints: • These should not be provided except where a structure intersects is the canal. These should not be provided except where a structure intersects is the canal.

The Thickness of Expansion shall be 12mm.The Thickness of Expansion shall be 12mm. Construction Joint: Construction Joint:

• Joints are potential points of seepage. A construction joint is weak link in the Joints are potential points of seepage. A construction joint is weak link in the lining and deterioration starts from such joints. lining and deterioration starts from such joints.

• As such, number of joints shall be kept minimum. As such, number of joints shall be kept minimum. Dowel Banks:Dowel Banks:

• Main canal & branch canal: 500mm top width, 500mm high with side slopes 1.5:1Main canal & branch canal: 500mm top width, 500mm high with side slopes 1.5:1• Distributaries' : 300m top width, 300mm high with side slopes 1’5:1Distributaries' : 300m top width, 300mm high with side slopes 1’5:1

Canal liningCanal lining

Contraction jointsContraction joints Contraction joints should be provided in canal lining at interval of not more than 36 Contraction joints should be provided in canal lining at interval of not more than 36

times the thickness of lining, in both longitudinal and transverse directions. The times the thickness of lining, in both longitudinal and transverse directions. The following spacing is adopted for different thicknesses of lining. following spacing is adopted for different thicknesses of lining.

Thickness of lining(mm)Thickness of lining(mm) Spacing of contraction joints(mm)Spacing of contraction joints(mm)6060 200020007575 25002500100100 35003500120120 40004000

   Where in-situ CC lining is laid with mechanical pavers, PVC strips should be provided Where in-situ CC lining is laid with mechanical pavers, PVC strips should be provided

in the contraction joints. The size of the PVC strips for the longitudinal and in the contraction joints. The size of the PVC strips for the longitudinal and transverse contractions joints are shown .transverse contractions joints are shown .

Where alternate method of contraction joints is adopted by cutting the groove in the Where alternate method of contraction joints is adopted by cutting the groove in the lining concrete and filling with sealing compound, the dimensions of the groove lining concrete and filling with sealing compound, the dimensions of the groove should be as per the figure shown.should be as per the figure shown.

Canals & Canal LiningCanals & Canal LiningLongitudinal and Transverse stripsLongitudinal and Transverse strips

Canals & Canal LiningCanals & Canal LiningConventional Groove – Contraction JointConventional Groove – Contraction Joint

Canal liningCanal lining Construction jointsConstruction joints• The construction joints are provided in the canal lining, wherever there is The construction joints are provided in the canal lining, wherever there is

discontinuity of concrete work for a period of time leading to creation of cold joint. discontinuity of concrete work for a period of time leading to creation of cold joint. Generally bed lining is executed in advance of the laying side lining. As such Generally bed lining is executed in advance of the laying side lining. As such construction joints are required on either side of canal bed at the junction of bed construction joints are required on either side of canal bed at the junction of bed and side lining. Normally longitudinal construction joints are provided at about 500 and side lining. Normally longitudinal construction joints are provided at about 500 to 1000 mm from the tangent point of the curve at the junction of canal bed and the to 1000 mm from the tangent point of the curve at the junction of canal bed and the side slope on either side of the bed. In the case of small channels, where bed and side slope on either side of the bed. In the case of small channels, where bed and side lining are laid simultaneously, longitudinal construction joints are not provided. side lining are laid simultaneously, longitudinal construction joints are not provided. Transverse construction joints should be provided, where discontinuity of work for Transverse construction joints should be provided, where discontinuity of work for considerable time is expected. 200 mm x 150 mm size CC M15 grade sleepers are considerable time is expected. 200 mm x 150 mm size CC M15 grade sleepers are provided under the construction joints. The joint should be filled with hot pour provided under the construction joints. The joint should be filled with hot pour sealing compound as per specifications in IS: 5256 – 1992.sealing compound as per specifications in IS: 5256 – 1992.

StepsSteps• 1500mm wide (minimum) steps in CC M15 grade should be provided at 300 m C/C 1500mm wide (minimum) steps in CC M15 grade should be provided at 300 m C/C

staggered on either side of the canal as stipulated in IS: 3873 – 1993. 3000 mm staggered on either side of the canal as stipulated in IS: 3873 – 1993. 3000 mm wide steps are to be provided at the villages and structure locations. In the case of wide steps are to be provided at the villages and structure locations. In the case of smaller distributaries, steps are to be provided arbitrarily as per the certificate of smaller distributaries, steps are to be provided arbitrarily as per the certificate of the Executive Engineer.the Executive Engineer.

Canals and Canal LiningCanals and Canal LiningDetails of construction and contraction Joints Details of construction and contraction Joints

Sealing Compound for Grooves – Canal LiningSealing Compound for Grooves – Canal Lining

SPECIFICATIONS OF SEALING COMPOUND FOR FILLING SPECIFICATIONS OF SEALING COMPOUND FOR FILLING LONGITUDINAL AND TRANSVERSE CONTRACTION JOINT GROOVES:LONGITUDINAL AND TRANSVERSE CONTRACTION JOINT GROOVES:

  The sealant is prepared from the materials as under:The sealant is prepared from the materials as under:(i) Bitumen 85/25 . . . . . . . . . . . . . . . .. . . (i) Bitumen 85/25 . . . . . . . . . . . . . . . .. . . . . . . . . .. . . . . . . 55% 55%(ii) Sand (fineness modulus 1.0 to 1.5)…………….. 43%(ii) Sand (fineness modulus 1.0 to 1.5)…………….. 43%(iii) Asbestos powder(iii) Asbestos powder . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 2% 2%

  Bitumen: The Bitumen 85/25 shall be tested as per IS code 702-1961 prior Bitumen: The Bitumen 85/25 shall be tested as per IS code 702-1961 prior to its use.to its use.

Canals & Canal LiningCanals & Canal Lining Lining of Canals in Expansive Soils:Lining of Canals in Expansive Soils:

• Canals excavated in expansive soils, such as black cotton soils, Canals excavated in expansive soils, such as black cotton soils, pose several problems,pose several problems,

• Involving stability of slopes and shape of section. Involving stability of slopes and shape of section. • Cast in situ lining for bed and pre cost cement concrete slabs Cast in situ lining for bed and pre cost cement concrete slabs

for sides are common. for sides are common. • The lining material directly placed against expansive soils under The lining material directly placed against expansive soils under

go deformation by heaving, disturbing the lining .go deformation by heaving, disturbing the lining .• This deformation is due to unduly high pressure developed by This deformation is due to unduly high pressure developed by

the expansive soils when they absorb water. the expansive soils when they absorb water. • By protecting the soil, the heaving of the soil mass is contained By protecting the soil, the heaving of the soil mass is contained

mass with a thin layer of muram gravel. mass with a thin layer of muram gravel. • To counter the swelling pressure and prevent deformation of To counter the swelling pressure and prevent deformation of

the rigid lining material a cohesive Non-swelling (CNS) layer of the rigid lining material a cohesive Non-swelling (CNS) layer of suitable thickness depending on the swell pressure of the suitable thickness depending on the swell pressure of the expansive soil is sand- witched between the soils and the rigid expansive soil is sand- witched between the soils and the rigid lining material.lining material.

CNS Soils – Canal liningCNS Soils – Canal lining

Treatment of sub-gradeTreatment of sub-grade

The soils with swelling pressures of more than 50 kN/mThe soils with swelling pressures of more than 50 kN/m22 are classified as expansive are classified as expansive soils. Expansive soils sub-grade should be covered by a layer of CNS (cohesive non-soils. Expansive soils sub-grade should be covered by a layer of CNS (cohesive non-swelling soil) material of sufficient thickness before laying the canal lining.swelling soil) material of sufficient thickness before laying the canal lining.

Properties of CNS Material :Properties of CNS Material :The CNS soils are to be non-swelling soils with a maximum allowable swelling pressure The CNS soils are to be non-swelling soils with a maximum allowable swelling pressure of 10 KN/mof 10 KN/m22 when tested in accordance with IS 2720 (Part 41): 1977. when tested in accordance with IS 2720 (Part 41): 1977.

CNS soils should broadly confirm to the following range:CNS soils should broadly confirm to the following range:Clay (Less than 2 microns) . . . . . . . . . . . . Clay (Less than 2 microns) . . . . . . . . . . . . 15-20%15-20%Silt (0.06 mm - 0.002 mm) . . . . . . . . . . . . .Silt (0.06 mm - 0.002 mm) . . . . . . . . . . . . . 30-40%30-40%Sand (2mm - 0.06 mm) . . . . . . . . .. . . . . . .Sand (2mm - 0.06 mm) . . . . . . . . .. . . . . . . 30-40%30-40%Gravel (of size greater than 2mm) . . . . . . Gravel (of size greater than 2mm) . . . . . . 0-10%0-10%Liquid limit . . . . . . . . . .. . . . . . . . . . . . . . .Liquid limit . . . . . . . . . .. . . . . . . . . . . . . . . More than 30 but less than 50%More than 30 but less than 50%Plasticity Index . . . . . . . . . . . . . . . . . . . . . .Plasticity Index . . . . . . . . . . . . . . . . . . . . . . More than 15 but less than 30%More than 15 but less than 30%

The extent of provision of CNS for the treatment of sub grade, has been determined The extent of provision of CNS for the treatment of sub grade, has been determined through testing of soil samples for the swelling pressures.through testing of soil samples for the swelling pressures.

CNS Soils – Canal liningCNS Soils – Canal lining

Treatment of sub-gradeTreatment of sub-grade

Thickness of CNS layerThickness of CNS layerThe thickness of CNS layer is related to the swelling pressure of the expansive soil and the resultant deformation, The thickness of CNS layer is related to the swelling pressure of the expansive soil and the resultant deformation, the permissible deformation being 2 cm. The thickness of CNS layer required for balancing different swelling the permissible deformation being 2 cm. The thickness of CNS layer required for balancing different swelling pressures of the expansive soils shall be as per the following table:pressures of the expansive soils shall be as per the following table:

Canal carrying capacity less than 2 cumecs Canal carrying capacity less than 2 cumecs Min. thickness of CNS layer (cm)Min. thickness of CNS layer (cm)

Discharge(Cumecs)Discharge(Cumecs) Swelling pressure 50 – 150 kN/mSwelling pressure 50 – 150 kN/m22 Swelling pressure Swelling pressure more than 150 kN/mmore than 150 kN/m22

1.40 – 2.01.40 – 2.0 60 60 75750.70 – 1.400.70 – 1.40 5050 60600.30 – 0.700.30 – 0.70 4040 50500.03 – 0.300.03 – 0.30 3030 4040

  Canal capacity of 2 cumecs and more Canal capacity of 2 cumecs and more   

welling pressure of soil kN/mwelling pressure of soil kN/m22 Thickness of CNS layer cm (min)Thickness of CNS layer cm (min)50 – 15050 – 150 7575150 – 300150 – 300 8585300 – 500 300 – 500 100100

  Note: Optimum thickness of CNS materials needs to be determined for different swelling pressures by actual Note: Optimum thickness of CNS materials needs to be determined for different swelling pressures by actual experiments both in field and in laboratory, if necessary.experiments both in field and in laboratory, if necessary.

Canals & canal liningCanals & canal liningBottom Rail and Drainage for Expansive SoilsBottom Rail and Drainage for Expansive Soils

Canals & Canal LiningCanals & Canal Lining Canal lining in rock strataCanal lining in rock strata

The requirements for the canal lining in the rock strata shall The requirements for the canal lining in the rock strata shall be same as for lining in soil strata except for the under-be same as for lining in soil strata except for the under-drainage arrangements. 300 mm ф porous concrete blocks drainage arrangements. 300 mm ф porous concrete blocks with thickness equal to the lining thickness are provided in with thickness equal to the lining thickness are provided in the centre of each lining panel in the bed. The number of the centre of each lining panel in the bed. The number of porous concrete blocks is increased according to necessity. porous concrete blocks is increased according to necessity. For the canal side lining normal method is followed, where For the canal side lining normal method is followed, where the soil strata exist. In the case of deep cuts with steep side the soil strata exist. In the case of deep cuts with steep side slopes, shot Creting is adopted for the side lining and for slopes, shot Creting is adopted for the side lining and for drainage arrangement, perforated PVC pipes are provided in drainage arrangement, perforated PVC pipes are provided in two rows, with the pipes in the rows staggered and the two rows, with the pipes in the rows staggered and the distance between the pipes in each row shall be 70 m. distance between the pipes in each row shall be 70 m. Additional number of pipes shall be provided where Additional number of pipes shall be provided where necessary. necessary.

Canals & Canal LiningCanals & Canal Lining Shot Crete lining: (IS: 9012- 1978).Shot Crete lining: (IS: 9012- 1978).• Shot Crete is a type of lining, wherein cement motor/ Shot Crete is a type of lining, wherein cement motor/

cement concrete is applied to the surface by pneumatic cement concrete is applied to the surface by pneumatic pressure with or without reinforcement. pressure with or without reinforcement.

• Shot Crete lining can be easily placed over rough sub Shot Crete lining can be easily placed over rough sub grade and therefore, better suited for use on deep cut grade and therefore, better suited for use on deep cut reaches. reaches.

• The thickness of the lining limited to 5.0 cms mostly.The thickness of the lining limited to 5.0 cms mostly.

Stone pitched lining (IS 4515: 2002)Stone pitched lining (IS 4515: 2002)• Stone pitched lining will be useful in the following cases.Stone pitched lining will be useful in the following cases.• Prevention of erosionPrevention of erosion• Where the ground water level is above the bed of the canal, this Where the ground water level is above the bed of the canal, this

type of lining will allows water pressure to be released through type of lining will allows water pressure to be released through the interstices.the interstices.

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