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LARGE SCALE INSTALLATION OF SUBSURFACE DRAINAGE SYSTEM
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LARGE SCALE INSTALLATION OF SUBSURFACE DRAINAGE SYSTEM in Chambal Command, Rajasthan - Er. C.M. Tejawat, F.I.E., P. Eng., B.E. (Ag.), M.Sc. (Land Drainage Engineering) Deputy Director (Monitoring), ...

LARGE SCALE INSTALLATION OF SUBSURFACE DRAINAGE SYSTEM in Chambal Command, Rajasthan - Er. C.M. Tejawat, F.I.E., P. Eng., B.E. (Ag.), M.Sc. (Land Drainage Engineering) Deputy Director (Monitoring), CAD Chambal, Kota (Raj.)

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LARGE SCALE INSTALLATION OF SUBSURFACE DRAINAGE SYSTEM LARGE SCALE INSTALLATION OF SUBSURFACE DRAINAGE SYSTEM Presentation Transcript

  • LARGE SCALE INSTALLATION OF SUBSURFACE DRAINAGE SYSTEM in Chambal Command, Rajasthan Er. C.M. Tejawat, F.I.E., P. Eng., B.E. (Ag.), M.Sc. (Land Drainage Engineering)Deputy Director (Monitoring), CAD Chambal, Kota (Raj.)
  • Gandhi Sagar Dam (M.P.) Rana Pratap Sagar Dam (Raj.)Jawahar Sagar Dam (Raj.) Kota Barrage (Raj.)
  • LIFE LINE OF HADOTI View slide
  • Left Main Canal (Rajasthan) Right Main Canal(Rajasthan & M.P.) View slide
  • G.C.A. 4,85,000 ha Command Area - ChambalC.C.A. 2,29,000 haDistricts wise CCAKota – 1,04,000 haBaran - 28,000 haBundi – 97,000 ha
  • Chambal Command Area, RajasthanIrrigable Area 2,29,000 ha.Irrigation 1960StartedSoils Uniform Clay – Loam Vertisols Below 1.5 – 2.0 m • Yellowish brown heavy clay layer Yellow silty clay (murrum layer) 20-30 m with higher permeability
  • PROBLEMS Waterlogging in the fields of head reaches. Increase in Salinity and Alkalinity of Soil. Decrease in Crop Production. Wastage of Irrigation Water .
  • Extent of Problem Water logging : 1,61,000 ha. Soil Salinity : 25,000 ha.
  • UNDP Project To find means to protect the Land from Salinity and Waterlogging. To study problem of weed control in existing Irrigation Canals and Drains. To Design and Execute Irrigation Improvement, Land Shaping and Drainage on Pilot Areas. To develop proper Water Management Principals and to make recommendations. To develop proper Land Use Pattern and Farm Practices for Intensification of Agriculture.
  • World Bank Project Started in 1974 Planned to provide Surface Drainage in 1,67,000 ha area. 74 Drainages Sub-basins identified having Waterlogging problem. Sub-basin 1000-10,000 ha A Main Drain Several Secondary Drains at about 500 m spacing. Seepage drains alongside the canals.
  • Command Area Development ProjectMain Objectives Improvement and increase in the Capacity of Canal. Increase in Crop production with the help of improved Agriculture Techniques. On-Farm Development Works. The Major thrust was given to On Farm Development Works.
  • On Farm Development WorksObjectives Efficient water utilization to increase Irrigated Cropping Intensity. Maximum yields by scheduling Irrigation water application, providing adequate drainage & better cultivation techniques. Easy access to individual field through improved road network. Shaping the Land to enable efficient Irrigation of field Crops.
  • O.F.D. Works Construction of Irrigation & Drainage ditches for each field. Providing road network to each field. Land shaping for efficient Irrigation. Re-alignment of the farm boundaries.
  • RAJADRajasthan Agriculture Drainage Research Project (1992-1999) INSTALLATION OF R SUBSURFACE DRAINAGE SYSTEM A in Chambal Command, Rajasthan J A D
  • Selection of Reclamation Technology Subsurface Drainage + Surface Drainage + On Farm Development WorksProvides an integrated soil and water managementprogram to optimize sustainable crop production in saline &waterlogged lands. Chambal Command Area-Rajasthan
  • Area Selection•RAJAD Project - 25,000 haSalinityEc > 4 dS/m in top 1.5 m soil profile in at least50% of the selected area.WaterloggingWater table depth < 40 cm in 70% of the areafor duration of at least 3 days.Water table depth < 1.2 m in 70% of the areafor a continuous duration of at least 30 daysduring an average rabi/kharif season.
  • Area Selection
  • Drainage InvestigationECe (dS/m) Area Area (ha) (%)0-2 24569 48.902-4 7743 15.41Sub Total for 32312 64.31non saline area4-8 12869 25.618-16 4510 8.98>16 555 1.10Sub Total for 17934 35.69saline areaGrand total 50246 100.0
  • Area Selection•280 Observation wells installed•256 ha (1600 m grid)•2.5 m deep & 1.5 m deep•Measurements were taken on weekly basis•Farmers Participation was involved•Data of 275 wells were analysed•Monitoring period Dec. 94 to Jan. 97
  • Area Selection
  • Area Selection
  • Drainage InvestigationUse of Total Station Survey Equipment
  • Drainage Investigation Auger Hole Method
  • Data Storage and RetrievalComputerized Central Data Base System
  • Development of Design Criteria• 12 Research Sites International• 4 years of data monitoring Panel of Experts & analysis
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command AreaSaturated Hydraulic Conductivity• Measured at 1.0, 1.5, 2.0 & 2.5 m depth• Grid 8.58 ha• Test plot results indicated: •Top 1 m 0.25 – 0.55 m/day •1 – 1.5 m 0.02 – 0.20 m/day •Below 1.5 m 0.75 m/day
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMSGeometry of a Transient State Drainage System
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Modified Glower Dumn Equation 0.5 −0.5 ⎡K *d *t ⎤ ⎡ ⎛ H 0 ⎞⎤L=π⎢ ⎥ * ⎢ln⎜1.16 * ⎟⎥ ⎣ μ ⎦ ⎣ ⎝ Ht ⎠⎦ H0 d = de + 2 L de = 8*f h 2 [L- D* 2.0 ] 1 D fh = + * ln 8 * D* L π r 0 * 2.0
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Drainable Porosityμ = {0.0376 * (Ksat) 0.25} Chambal Varient (68%)μ = {0.0386 * (Ksat) 0.25} Kota Varient (28%)
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Water Table Draw Down20 cm in 3 days to control irrigation inducedsalinityUsed for spacing calculation in transientequation
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Average Drain DepthDepending on soil properties, crop,extent of soils salinity, gravity outlet1-1.5 m below ground surface withaverage of 1.2 m
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Simple Equations for Drain SpacingFor Chambal Soil Series• Drain Spacing = 8.71 + 73.36 * Ksat0.5For Kota Soil Series• Drain Spacing = 13.61 + 67.92 * Ksat0.5
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Computer Program for Drain Spacing For calculating drain spacing grid wise• Auger hole Ksat dat• Drainable porosity v/s Ksat• Design Criteria
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Drain SpacingCalculated for each grid (8.58 ha)Geometric mean of calculated spacing (100-150 ha area block)Rounded to next multiple of 5 mRange of spacing 35-85 m
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Drainage Coefficient• Laterals 1.5 mm/day• Collectors 3.0 mm/day For pipe capacity calculation only
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Pipe Size ⎡ q *S *L*n ⎤d =⎢ 8 d 3 ⎥ ⎣ 0.31168 * i ⎦ 1 2Minimum pipe diameter --- 72/80 mm
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Manning’s Roughness Coefficient & GradeI.D. (mm) O.D. (mm) n Minimum Grade (%)72 80 0.015 0.1088 100 0.015 0.10144 160 0.016 0.09178 200 0.017 0.08258 294 0.018 0.07315 355 0.019 0.06401 455 0.019 0.05
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Length of Lateral 8/3 1/2 0.31168 * d * i Lmax = qd * S * nDepends on physical limitation, farm size,layout pattern etc.
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMS Design Criteria for SSD in Chambal Command Area Minimum Soil CoverDepends on soil conditions & depth of outletdrainMinimum soil cover of 0.90 mExceptional cases:Up to 100 mm dia 0.60 m160-455 mm dia 0.80 m
  • DESIGN OF SUBSURFACE DRAINAGE SYSTEMSDesign Criteria for SSD in Chambal Command Area Envelope Requirement Clay % Envelope Requirement >40 Not required 30-40 & SAR >8 Required <30 RequiredPipe grade >0.4% --- not required
  • Design of SUBSURFACE DRAINAGE SYSTEMS
  • Design of SUBSURFACE DRAINAGE SYSTEMS
  • Outlet Conditions
  • Computer Aided Design Procedure
  • Computer Aided DesignProcedure
  • SSD Layout SystemParallelPerpendicular
  • Position of OutletField DrainCarrier DrainMain Drain
  • Minimum Permissible Clearance for SSD OutletDepth of Base Flow Allowance for Free Depth to SSD Outlet (db) Sedimentation Board Invert (ds) (df) Less than 65 cm 20 cm 15 cm SDBE+db+df Min 45 cm & Max. 85 cm More than 65 cm 20 cm Nil SDBE+db
  • Drainage MaterialUp to 100 mm corrugated PVC pipes were available Smooth Wall Rigid Pipes were used
  • Drainage Material Plant set up at Kota for Corrugated PVC pipes of 80, 100, 160, 200, 294, 355 and 455 mm dia. At Sangli 80-160 mm PVC & HDPE as well as double wall corrugated pipes up to 315 mm are produced Envelope Material
  • SSD InstallationExcavation of trenchLaying of Pipe on the gradeBackfilling of the trenchRestoration of ROW Manual
  • SSD InstallationManual Excavator Grade Control ???????
  • SSD InstallationLaser
  • SSD InstallationLaser Excavator
  • SSD InstallationBulldozer-Plow
  • SSD InstallationDrain Laying Plow
  • SSD InstallationDrain Laying Plow
  • SSD InstallationDrain Laying Plow
  • SSD InstallationDrain Laying Plow
  • SSD InstallationChain Trencher
  • SSD InstallationChain Trencher
  • SSD Installation
  • SSD InstallationChain Trencher
  • SSD Installation V Plow
  • SSD Installation V Plow
  • SSD Installation
  • SSD Installation
  • SSD Installation
  • SSD Installation Import of Drain Laying Equipments Right of WayCrop Compensation Irrigation Shut Off
  • SSD Installation Physical progress achievedS.No. SSD installation method at RAJAD 1 Manual installation 50 m/day with 20 labours 100 - 150 m/day per 2 Installation using excavator excavator Installed using a trenchless 4000 - 6000 m/day per 3 drain laying plow plow 1000 - 2000 m/day per 4 Installation using a trencher trencher About 2500 km of pipe installed in CCA
  • Supervision, Inspection and Quality ControlPreparation of Contract DocumentSpecification of Drainage Material &InstallationDevelopment of Contractors – national,international
  • Human Resources Development•Post Graduation in Drainage Engineering•National & international Drainage Courses•Use of Computers, Total Station, EM 38, GIS etc.•Several workshops, seminars, awareness camps etc.Assistance of International/NationalExperts and Local/GOR StaffPeople ParticipationSubsidyCoordination with State GovernmentMaintenance
  • Subsurface Drainage Installation in Chambal Command, RajasthanProject Area installed Year (ha)Small Test Sites 410 1991-1993Large Test Sites 1,010 1993-1994Pre-CON/1 700 1995-1996(Training Phase)CON/1 10,671 1996-1999Areas with Patchy 2,134 1997-1999SalinityTotal 14,925 1991-1999
  • Pre Monsoon - 93
  • Post Monsoon - 93
  • Yield 0 q/ha ECe 19.2 dS/m
  • Yield 9.45 q/ha ECe 11.3 dS/m
  • Yield 12.8 q/ha ECe 10.4 dS/m
  • Yield 25.2 q/ha ECe 5.1 dS/m
  • Yield 34.1 q/ha ECe 2.7 dS/m
  • Yield 43.0 q/ha ECe 2.36 dS/m
  • Yield 0 q/ha ECe 19.2 dS/m Yield 9.45 q/ha ECe 11.3 dS/m Yield 12.8 q/ha ECe 10.4 dS/mYield 25.2 q/ha ECe 5.1 dS/m Yield 34.1 q/ha ECe 2.7 dS/m Yield 43.0 q/ha ECe 2.36 dS/m
  • IMPACT OF SUBSURFACE DRAINAGESoil Salinity Reclamation• Continuous reduction in the salinity in the upper 15 cm depth.• For the lower depths salinity levels increased during first 3 years then salinity levels declined.• Over a period of 5 years, the salinity level reduced to below 4 dS/m• After SSD salinity reclamation could be achieved in 2 to 3 years for about 60% areas & within 3 to 4 years for 90-95% of the affected areas.• About 5-10% of the affected area could take more than 4 years for satisfactory reclamation
  • Crop Yield in Saline & Waterlogged areas and non-saline & non-waterlogged areas in the Chambal Command Area of Rajasthan. Crop Crop Yield (Quintals/ha) Saline Non-saline / /waterlogged Non waterloggedWheat 17.0 34.0Mustard 6.1 14.7Paddy 17.0 29.0Soybean 10.2 21.8Berseem 360.0 520.0Sugarcane na 567.5
  • Relationship betweenSoybean Yield and Water table Depth Average Water Soybean Relative YieldTable Depth (cm) Yield (t/ha) (%) 80.0 2.18 100 70.0 1.93 88 59.6 1.69 77 50.0 1.44 66 40.0 1.20 55
  • Water Table ControlA drainage rate of 1.5 mm/day (an equivalentwater table draw down of 20 cm from soilsurface in three days) was consideredadequate to maintain a favorable salt balance.Field observations since SSD installation invarious test sites have indicated that a watertable draw down of 20-40 cm in three days isachievable.
  • Water Table ControlThe water table control has an added positiveimpact in advancing soil trafficabilityconditions (tilth) by 6-10 days after a rainfallor irrigation event, thereby allowing farmersmore time for farming operationsGood tilth conditions also provide a furtherbenefit, namely an opportunity to save fuel inmachinery operations.
  • Crop PerformanceIncrease in Crop YieldThe average increase in the crop yield in SSD test sites compared with non-SSD sites was about• 56 percent for soybean and• 55 percent for wheat.Farmers have also reportedimprovements in the quality and quantityof produce, particularly vegetables.
  • Relationship with Soybean Yield, Water Table depth and Soil SalinityThe analysis showed that soybean yieldwas independent of the water table whenits depth was greater than 80 cm belowground surface. The yield decreased asthe water table depth approached soilsurface.The average optimum desirable watertable depth during growth season ofsoybean is 80 cm for the CCA conditions.
  • Relationship with Soybean Yield, Water Table depth and Soil SalinityMonitoring at RAJAD indicated that anaverage water table draw down of 20 – 40cm within three days was achieved.The majority of the drain flow rates fromthese sites ranged from 1-4 mm per day.The relationship between soybean yieldand soil salinity showed that crop yield isindependent of soil salinity, upto athreshold ECe value of 4.1 dS/m. Beyondthat, the yield decreases.
  • Increase in Cropping IntensityWater table control and salinity reclamationin the test sites significantly alleviatedthese constraints, which resulted in a 20-25percent reduction in the amount of fallowland in the Kharif season, and 5-6 percentreduction in fallow during the Rabi season.The pre-SSD cropping intensity was 150-160 percent and the post – SSD croppingintensity was 170-185 percent. Thecropping intensity is projected to furtherincrease.
  • POSITIVE IMPACTS OF SUBSURFACE DRAINAGES.No. Impact Improvement 1. Salinity reclamation I. Soils with EC 4-8 dS/m 2-3 years to achieve II. Soils with EC 8-16dS/m 3-4 years to achieve III. Soils with EC>16 dS/m > 4 years to achieve 2. Water table control 20-40 cm draw down in 3-4 days 3. Soil trafficability Advanced by 6-10 days
  • POSITIVE IMPACTS OF SUBSURFACE DRAINAGES.No. Impact Improvement 4. Crop Yield 56 % increase in soybean; 55 % increase in wheat yields 5. Cropping intensity Increased from 150- 160 percent to 170- 185 percent
  • Economics of Subsurface DrainageAs per economic and financial analysis of SSDAssuming• capital cost of SSD of RS. 34,250 per ha,• using a discount rate of 12 percent and• assuming that benefits would accrue from the entire SSD installed area,• the economic benefits of SSD for a 30 year life expectancy were calculated as follows.Benefit/cost ratio : 2.6Net present value (NPV) per ha : Rs.54,900
  • The internal rate of return (IRR) = 28 %.This relates to a 2.4 times return over themarket rate of interest that a farmer wouldhave to pay, if it was to be fully financed bythe farmer.The above analysis indicated that SSD is acost effective method to reclaimwaterlogged and saline lands in the CCA.This system can be replicated in other areasof Rajasthan and India.
  • THANK YOU
  • Selection of Reclamation Technology
  • Selection of Reclamation Technology
  • Selection of Reclamation Technology
  • Relationship between Soybean yield and Soil SalinityAverage ECe (dS/m) Soybean Relative Yield for the 0-30 cm Yield (t/ha) (%) Soil Depth 4.1 1.81 100 6.0 1.60 88 8.0 1.39 77 10.0 1.17 65