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PPT Conjunctive Use.pptx
- 1. INDIAN INSTITUTE OFTECHNOLOGY ROORKEE Conjunctive Use Planning in the Canal Command 2021 Seminar Presentation
- 2. 2 Contents • Canal Irrigationin India • Canal Command Issues • Understanding Conjunctive use • Potential benefits of Conjunctive Water Use in canal command • Constraints in implementing the Conjunctive Use • Methods used for Conjunctive Use • Policy Framework around Conjunctive Use • Case Study • Conclusion • Way Forward
- 3. 3 Canal Command • GrossCommand Area (GCA) in an irrigation scheme refers to the total area bounded within the boundary of the project which can be irrigated through it. It includes the area covered by roads, culverts, settlements, unculturable area etc. • While the area on which crops can be grown satisfactory is called Culturable Command Area (CCA). Image Source: NPTEL
- 4. 4 Irrigation Status inIndia • India has over 140 m Ha area under cultivation. • Statistical Year Book India, 2017 by MoSPI: Net Irrigated Area in 2013-14 = 68.1 million Ha. – 16.28 m Ha by canals (24%) – 1.84 m Ha by tanks (3%) – 42.44 m Ha by tubewells and other wells (62%) i.e. irrigation from GW – 7.54 m Ha by other sources (11%)
- 5. 5 Issues Faced inCanal Commands Water Logging • Mainly due to over-irrigation. • Prevalent near head reached Tail users suffer • Most of water consumed at head and middle reaches Report of Working Group setup by MoWR in 1991 Salinity increase • 3.30 m Ha affected by salinity/alkalinity in the irrigated commands Losses • Conveyance and Evaporation losses Despite of canal network GW Exploitation • Due to free electricity and 0 water tariffs
- 6. 6 Understanding Conjunctive Use •Conjunctive use is the combined & integrated management of surface and groundwater for optimal productive and allocation efficiency. • It recognizes the unified nature of water resources as a single natural resource and takes advantage of interaction between the surface and ground water in planning the use of the two resources. • It combines positives of both the surface and ground water based irrigation Thus, Conjunctive Use of Water could help in tacking the problems mentioned.
- 7. 7 Conjunctive Use: CombinesAdvantages of both Surface Water Gravity Flow More Regulated Flow Reservoirs serve multiple purposes Low Mineralization Ground Water More Dependable Yield Better Quality; Less Pollution No Storage Needed No Siltation & Evaporation losses Low Gestation Period
- 8. 8 Conjunctive Use: AchievedBenefits Benefits Better Dependability & Accessibility Less Water Logging & salinity Peak Demand Reduced Water to Tail Ends Higher Productivity Less Salinity
- 9. 9 Elements of ConjunctiveUse Planning Guidelines • 'Guidelines for Planning Conjunctive Use of Surface and Ground Waters in Irrigation Projects' by Ministry of Water Resources in 1995. • Estimating GW; Allocating GW for Conjunctive Use; Max/Min Extraction • Various strategies for CU; etc. Basin Assessment • Collect data about area & water resources: hydrological, precipitation, crop requirement, evapotranspiration etc. Mathematic -al Models • To simulate Hydrological conditions in the area e.g. MODFLOW • Should incorporate surface water and ground water interaction • Alternatives examined using different ratio of SW to GW
- 10. 10 Elements of ConjunctiveUse Planning Pilot Project • Taken up on a small area • 3 physical facilities needed: Water distribution; Artificial recharge; Pumping of groundwater Feasibility Study • Benefits and costs involved in the Pilot Project are analysed Implementa tion • If found feasible, it is implemented & Monitored. • Finally, the plan incorporated into Command area development scheme of the area.
- 11. 11 CU: Methods &Techniques Techniques Available Aquifer recharge Storm runoff Recharge pits Using GW in Rabi River augmen tation
- 12. 12 CU: Limitations andConstraints Land subsidence if excessive withdrawal Salt leaching may happen in ground water Power needed to extract groundwater Not suitable everywhere: salinity, deep WT etc. Administrative setup not conductive – Silos. Operation, supervision and control more Complex
- 13. 13 Case Study: CUin Canal Command Area, Odisha • Area Selected: – Pattamundai canal command area in Mahanga block of Cuttack district of Odisha. – It covered 2 distributaries (5a, 5b) and 1 minor (5b). – Total CCA was of 753 Ha and covered 12 villages. • Cropping Pattern: – 2 crops in a year – Kharif: Paddy in 71% to 87% area; Jute, vegetable & spices on rest. – Rabi: Vegetables, pulses, and groundnut and oil seeds • Average Yield of Paddy: Canal Command Reach Avg Yield (t/ha) Head Reach 2.7 – 3.0 Middle Reach 2.5 – 2.7 Tail Reach 2.2 – 2.5
- 14. 14 Case Study: Methodologyadopted Data Collection in command area: Cropping Pattern, canal release pattern and water availability, yield etc. Soil samples collected at various depths; Soil moisture & ET demand calculated. Bore well, Dug wells and water harvesting structures were constructed in 2007 to use Ground Water in a sub-part of command Impact Assessment in 3 crop seasons by comparing bore & dug well areas of command with rest of areas of command.
- 15. 15 Case Study: CanalWater Availability • Flow Pattern in the Study Area: Canal releases and flow was monitored for the 3 years from 2007-08 to 2009-10. Conclusion 1: In Kharif, Canal water is sufficient but in Rabi, even Canal + Rain water is less than ET needs of crops. 2009 Data No. of days of water release Canal Supply (ha- m) Rainfall (ha-m) Crop Demand (ha-m) Excess/Deficit Supply Kharif Season 121-129 days 1479.1 1326.0 553.4 + 2251.7 (Excess) Rabi Season 43-46 days 405.1 114.1 535.6 -16.4 (Deficit)
- 16. 16 Case Study: WaterAvailability • Kharif Season: • Rabi Season: Conclusion 2: Significant reduction of water along the canal. Kharif Season Dist – 5a Dist – 5b Minor – 5b Flow at head (cumec) 0.775 0.699 0.225 % Reduction in Middle 8.5% at 0.2 km 32% at 1.5 km - % Reduction at Tail 79% at 5 km 65% at 4.5 km 67% Rabi Season Dist – 5a Dist – 5b Minor – 5b Flow at head (cumec) 0.715 0.735 0.23 % Reduction in Middle 3.2% at 0.2 km 24% at 1.5 km - % Reduction at Tail 83% at 5 km 47% at 4.5 km 56%
- 17. 17 Case Study: GroundWater Level • Ground Water Table: – During pre-monsoon season, it ranges within 2.0 m to 3.18 m. – During monsoons, it remained about 2.0 m. – Post-monsoons, it ranged from 2.0 m to 3.2 m • The detailed analysis indicated that there is abundant amount of groundwater at shallow depth in all the canal command area Conclusion 3: Water Table remains at shallow depth all through the year.
- 18. 18 Case Study: Stepstaken under CU Planning • In a part of command area, water harvesting structures were developed in the year 2007 using Participatory approach. • 2 Dug wells were constructed upto 6.65 m depth with 3 meter diameter, irrigating an area of 2360 sqm and 1400 sqm respectively. • 1 bore well with 15 meter depth was constructed near to the water harvesting structures. Here tube-well was used. • Now, for next 3 crop seasons (2007-2010), various parameters like change in cropping pattern, water availability etc. were assessed.
- 19. 19 Case Study: Impactsof Conjunctive Use • In Dug Well-1 Command Area: – 3 crops grown viz. Jute-Paddy-Onion/Garlic each year from 2007- 10 instead of 2 earlier. – Increase in Avg Yield of Paddy: 2.8-3.0 t/ha in tail reach. – Increase in Net Return: highest in 2008-09 @ 1,10,839/ha. – Ground water still at shallow depth i.e. no excess depletion. • In Dug Well-2 command area: – Grew only 2 crops (Paddy & Vegetable) due to social constraints. – Highest Net Return was Rs. 48,974/ha. • In Bore Well command: – Increase in Avg Yield of Paddy: 4.8 t/ha in tail reach. – Highest Net Return was in 2009-10 @ Rs. 83170/ha.
- 20. 20 Case Study: Results •Increased from prevailing 151% to 300% (due to 3 crops) with high value & less water requirement crops. Increased Cropping Intensity in Tail End • Increased from 2.2-2.5 t/ha to 2.8-4.8 t/ha Paddy Average Yield in Tail End • For Potato increased to 8.413 kg /m3 of crop ET wrt the average of 12 villages @ 4.23 kg yield/ m3 of crop ET. 100% increase in Water Productivity • Water Productivity (kg fruit yield/ m3 of water used) highest in potato followed by brinjal. Potato as winner among Vegetables
- 21. 21 Case Study: ResultsContd. • Water was also available at tail ends due to dug and bore wells Equitability • A perceptible increase in Net Returns (Rs/ha) for farmers due to 3 crops a year. Prosperity • Water Table was found to be at shallow depth in Dug and Bore well commands, thus no excessive exploitation of GW. Conservation
- 22. 22 Conjunctive Use: Conclusions •Combined and Efficient use of Surface and Ground Water could increase Yields and Cropping Intensity. • Better availability of irrigation water at tail ends – Construction of Dug and Bore Wells could help in Tail Ends of Canals. • Ground water could be used efficiently – thus improving dependability of irrigation water. • All these lead to a higher Net Returns for the farmers.
- 23. 23 Conjunctive Use: WayForward • Sustained campaign to educate the stakeholders about benefits of conjunctive use and risks of water logging and salinization. • Better design and providing incentives for balanced groundwater use. • Involving Water User Associations (WUAs) for a balanced use of SW and GW - Participatory Irrigation Management (PIM) • Strengthening the institutional arrangements in water resource administration. • Recognizes the unified nature of water resources during planning phase of irrigation projects
- 24. 24 References • Ministry ofStatistics and Program Implementation, Government of India. “Statistical Year Book India, 2017”. • Central Water Commission, Ministry of Jal Shakti, Government of India. (1995) “Guidelines for Planning Conjunctive Use Of Surface And Ground Waters In Irrigation Projects”. • Prof T.I.Eldho, Dept of Civil Engineering, IIT Bombay. “Conjunctive use of Water Resources”. • Prof. Deepak Khare, IIT Roorkee. “Conjunctive Use of Surface and Ground Water”. • Ranu Rani Sethi, R.B.Singandhupe and Ashwani Kumar. (2014). “Conjunctive Planning of Surface and Groundwater Resources in Canal Command Area of Odisha-A Success Story”. IOSR Journal of Agriculture and Veterinary Science (IOSR-JAVS). Volume 7, Issue 9 Ver. III (Sep. 2014) PP 43-48. • National Water Mission. <www.nwm.gov.in>
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