Integrated watershed management


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Integrated watershed management

  1. 1. Integrated Watershed ManagementIntegrated Watershed ManagementAnd Rainwater HarvestingAnd Rainwater HarvestingProfessor Jayashree SadriAndDr Sorab Sadri
  2. 2. Lecture Contents(2 Lecture Hours)• India’s Water Resources• Watershed Development & Modelling• Integrated Watershed Management• Water Conservation & Harvesting• Successful Case Study
  3. 3. Integrated Water Resources Development andManagement: IWRDM.Integration of -- River basin resources- surface and ground.- Demands - consumptive and non-consumptive,and supplies.- Facilities - mega to micro.- Human and eco-systems.- S&T and engineering with social, economic,synergic needs.
  4. 4. INDIA’S LAND RESOURCE, IRRIGATIONAND FOOD PRODUCTION• India has 2% of world’s land, 4% of freshwater, 16% ofpopulation, and 10% of its cattle.• Geographical area = 329 Mha of which 47% (142 Mha) iscultivated, 23% forested, 7% under non-agri use, 23%waste.• Per capita availability of land 50 years ago was 0.9 ha,could be only 0. 14 ha in 2050.• Out of cultivated area, 37% is irrigated which produces55% food; 63% is rain-fed producing 45% of 200 M t offood.• In 50 years (ultimate), proportion could be 50:50
  5. 5. SOME INFERENCES FROM RIVER BASIN STATISTICS• Himalayan Rivers Water: 300 utilizable, 1200 BCMavailable.• Himalayan large dams presently store 80 BCM. Newdams under consideration could store 90 BCM.• Peninsular Rivers Water: 400 utilizable, 700 BCMavailable.• Peninsular large dams presently store 160 BCM. Newdams under consideration could store 45 BCM.• In all, large dams presently store 240 BCM. Newdams under consideration could store 135 BCM. Totalstorage thus could be 375 BCM only.
  6. 6. WITHDRAWAL OF WATER- 2050,AVAILABILITYIndia’s Yearly Requirement in 2050 (Km3= BCM)• For growing food and feed at 420 to 500 million tonnes = 628 to 807 BCM• Drinking water plus domestic and municipal use for rural population at150 lpcd and for urban population at 220 lpcd = 90 to 110 BCM•Hydropower and other energy generation = 63 to 70 BCM•Industrial use = 81 to 103 BCM•Navigational use = 15 BCM•Loss of water by evaporation from reservoirs = 76 BCM•Environment and ecology = 20 BCMTotal 970 to 1200 BCMAvailability 1100 to 1400 BCM
  7. 7. Where does the water come from?•New dams - inter-basin transfer•Groundwater - underdeveloped•Demand Management•Water savings - increase in efficiency,reduce evaporation.•Water productivity - increases in crop perdrop•Trade (virtual water), import food.
  8. 8. Part 2:Part 2: Watershed Development &ModellingLimited water resources,-more demand.Watershed is the basic scientific unit.Need for proper planning and management.Integrated watershed development approachDigital revolutionRecent advances in watershed modelling - use ofcomputer models, remote sensing and GIS.
  9. 9. WATERSHED Development• WatershedCharacteristics.• Hydrology ofwatershed.Watershed (ha) Classification50,000-2,00,00010,000-50,0001,000-10,000100-1,00010-100WatershedSub-watershedMilli- watershedMicro-watershedMini-watershed
  10. 10. WATERSHED Development …Parameters of Watershed• Size•Shape•Physiography•Climate•Drainage•Land use•Vegetation•Geology and Soils•Hydrology•Hydrogeology•Socioeconomics
  11. 11. WATERSHED MODELLING …Watershed modelling steps1. Formulation2. Calibration/verification3. ApplicationWatershed model constitutes1. Input function2. Output function3. Transform function
  12. 12. PrecipitationInterceptionStorageSurface RunoffGroundwaterStorageChannelProcessesInterflowDirect RunoffSurface StorageBaseflowPercolationInfiltrationETETFig Flowchart of simple watershed model (McCuen, 1989)WATERSHED MODELLING …
  13. 13. WATERSHED MODELLING …General Classification of ModelsBroadly classified into three typesBlack Box Models: These models describe mathematically therelation between rainfall and surface runoff withoutdescribing the physical process by which they are related.e.g. Unit Hydrograph approachLumped models:These models occupy an intermediate position between thedistributed models and Black Box Models. e.g. StanfordWatershed ModelDistributed Models:These models are based on complex physical theory, i.e. basedon the solution of unsteady flow equations.
  14. 14. Background• Large water resources development projects in Indiahave adverse socio-economic and environmental consequencesadverse socio-economic and environmental consequences.• The failure of such projects, contributed to indebtednessindebtedness,raising economic pressureeconomic pressure and jeopardising future development.• Indiscriminate expansion of marginal landsexpansion of marginal lands and over-utilisationof existing water resources for irrigation.• Traditional water harvesting systems have suffered sever neglect.• This type of development not only called into question• the adequacy of water resources schemesadequacy of water resources schemes but triggered the urgent• search for more effective and appropriate management strategies.• Major response to follow “Integrated Watershed Management Approach”.Part 3: Integrated Watershed Management
  15. 15. Concepts and Principles of IWMObjectives:Objectives: Water hasWater has multiples usesmultiples uses and must be managed in an integrated way.and must be managed in an integrated way. Water should be managed at theWater should be managed at the lowest appropriate levellowest appropriate level.. Water allocation should takeWater allocation should take account of the interests of allaccount of the interests of all who are affected.who are affected. Water should be recognised and treated as an economic good.Water should be recognised and treated as an economic good.
  16. 16. Concepts and Principles ofIWMStrategies:Strategies: A long term, viableA long term, viable sustainable futuresustainable future for basin stake holders.for basin stake holders. Equitable access to water resources for water users.Equitable access to water resources for water users. The application ofThe application of principles of demand managementprinciples of demand management for efficient utilisation.for efficient utilisation. Prevention of furtherPrevention of further environmental degradationenvironmental degradation (short term) and the restoration of(short term) and the restoration ofdegraded resources (long term). .degraded resources (long term). .
  17. 17. Concepts and Principles ofIWMImplementation Programs:Implementation Programs: Comprise an overall strategy that clearly defines the management objectives, a deliveryComprise an overall strategy that clearly defines the management objectives, a deliverymechanisms and amechanisms and a monitoring schedulemonitoring schedule that evaluatesthat evaluates program performanceprogram performance.. Recognise that the development of water resources may require research, to assess theRecognise that the development of water resources may require research, to assess theresource base throughresource base through modelling and development of DSSmodelling and development of DSS, and to determine the, and to determine thelinkage between water resources and thelinkage between water resources and the impacts on environment, socio-economyimpacts on environment, socio-economy.. Ensure that mechanisms and policies are established that enables long term support.Ensure that mechanisms and policies are established that enables long term support.
  18. 18. Integrated Watershed ApproachIWM is the process of planning and implementing water and naturalresources …… an emphasis on integrating the bio-physical, socio-economicand institutional aspects.Social issues are addressed through involvement of women and minority.Community led water users groups have led the implementation efforts.1970 1980 1990 2000PublicParticipationWatershed development programLowHighMainlywaterconservationSocio-economicwithwaterconservationSocio-economic,waterconservation,participationPublicparticipationplanning,design,implementationProject success
  19. 19. •The four engineering and management tools for effectiveand sustainable development of water resources in semi-aridrural India: -• Appropriate technologies• Decentralised development system• Catchment based water resources planning• Management information system•In past the efforts were more on the soil conservation andtaking measures on the land where as we used to neglect thewelfare of the land users.• For sustainable watershed management there is need tointegrate the social and economic development together withsoil and water conservation
  20. 20. IWA – Modeling throughAdvanced Technologies
  21. 21. Part 4: Water Conservation & HarvestingTotal water management forsustainable development?.
  22. 22. Water Conservation• Important step for solutions to issues of water andenvironmental conservation is to change peoplesattitudes and habits• Conserve water because it is right thing to do!.• What you can do to conserve water?• Use only as much water as you require. Close thetaps well after use. While brushing or other use, donot leave the tap running, open it only when yourequire it. See that there are no leaking taps.• Use a washing machine that does not consume toomuch water. Do not leave the taps running whilewashing dishes and clothes.
  23. 23. Water Conservation…• Install small shower heads to reduce the flow ofthe water. Water in which the vegetables & fruitshave been washed - use to water the flowers &plants.• At the end of the day if you have water left in yourwater bottle do not throw it away, pour it oversome plants.• Re-use water as much as possible• Change in attitude & habits for waterconservation• Every drop counts!!!
  24. 24. Rain Water Harvesting?.Rain Water Harvesting?.• Rain Water Harvesting RWH- process of collecting,conveying & storing water from rainfall in an area – forbeneficial use.• Storage – in tanks, reservoirs, underground storage-groundwater• Hydrological Cycle
  25. 25. Rain Water Harvesting?.Rain Water Harvesting?.• RWH - yield copious amounts of water. For anaverage rainfall of 1,000mm, approximately four millionlitres of rainwater can be collected in a year in an acreof land (4,047 m2), post-evaporation.•As RWH - neither energy-intensive nor labour-intensive•It can be a cost-effective alternative to other water-accruing methods.• With the water table falling rapidly, & concretesurfaces and landfill dumps taking the place of waterbodies, RWH is the most reliable solution foraugmenting groundwater level to attain self-sufficiency
  26. 26. • Roof Rain Water Harvesting• Land based Rain Water Harvesting• Watershed based Rain Water harvesting• For Urban & Industrial Environment –• Roof & Land based RWH• Public, Private, Office & Industrial buildings• Pavements, Lawns, Gardens & other openspacesRWH – MethodologiesRWH – Methodologies
  27. 27. Rain Water Harvesting– AdvantagesRain Water Harvesting– Advantages1.Provides self-sufficiency to water supply2.Reduces the cost for pumping of ground water3.Provides high quality water, soft and low in minerals4.Improves the quality of ground water throughdilution when recharged5.Reduces soil erosion & flooding in urban areas6.The rooftop rain water harvesting is less expensive& easy to construct, operate and maintain7. In desert, RWH only relief8. In saline or coastal areas & Islands, rain waterprovides good quality water
  28. 28. Part 5: Successful Case StudyCatchment Area =1800 km2
  29. 29. Jhabua Watershed: Case StudyMadhya Pradesh ( INDIA ), ~ altitude of 380 m to540 m. Area – 1800 sq.kmHighly undulating, sparsely distributed forest cover.~ 57% arable land including cultivable fellow and~ 18% notified as forest land.Average rainfall ~ 750 mm per annum.~ 20-30 events during June-September~ Classified as drought prone region.Moisture deficit during Januaryto May months each year.
  30. 30. Jhabua watershed: Case studyMajor crops:Maize, Cotton, Peanuts,Soyabeans;Gram, Black beans, Oilseeds.Predominantly tribal population, 92%engaged in agriculture.~ high seasonal migration~ economically one of themost backward district
  31. 31. Yearly rainfall departure from the mean for rainfall stationJhabuaSeasonalrainfalldepartureareextremelyvariable.
  32. 32. •Subsistence of rain-fed mono-cropping farming systemwith low agriculture productivity•Undulating topography and soil erosion due toovergrazing causing degradation of land.•High pressure of population on the agriculture landleading to substantial poverty causing immigration.•Absence of decentralized water resources and basicinfrastructure facilities.•Degradation of forestry land due to absence ofcommunity involvement in protection of the forest.Development Issues
  33. 33. Planning & ImplementationA Three step IWMA model approach1. Resources Mapping using GeographicalInformation System2. Appropriate Technology3. Management Information System
  34. 34. Resources mapping: Ground water dynamicsTotal alluvium area= 18.5 km2 Channel porosity = 20% Depth of wetting front = 4.0 mTotal storage capacity = 14.8 x106m3.
  35. 35. Resources mapping: Surface water storageReservoirinmainchannelTotal number of reservoirs = 144Storage capacity = 81.3 x 106m3
  36. 36. Appropriate TechnologyWater conservationand groundwaterrecharge techniquesWater harvesting cumsupplementaryirrigation techniques inJhabua
  37. 37. Water ConservationWater conservation interventions includescontour trenches, gully plugging, vegetativeand field bunding, percolation tanks.Overall land treatment against potential area is varying between 40-60%.45%30%25%Private land Fallow land Forest land28%65%2% 5%Contour bunding Gully pluggingStaggered trenching Level terracesType of land ownership forsoil and water conservationmeasuresTechniques of soil and waterconservation measures
  38. 38. Redevelopment of forest is essential for catering socio-economics needs of the people and ecological needsof the region.Forest committees are formed for forest protection andpart of area is made available for grazing on rotationbasis.Implementing agencies promoted the concept of “SocialFencing” people protecting the forest and grazing land.Joint Forest Management
  39. 39. Community participation and local capacitybuildingDevelopment of new village level institutions and local capacity building.Operation & maintenance of structures, regulation of financial matters, andconflict resolution.
  40. 40. DiscussionSuccess interventions reside in integration of appropriate technical andintegration of appropriate technical andmanagerial measuresmanagerial measures.People’s participation in the entire process are most important.The benefits of water harvesting and water conservation definitely reached.Efficient utilisation of funds, only 10-15% spent on non-project costs.Limitation: 100% drought proofing for every water use can not be achieved.Thus, IWM approach may be characterised by•Community management built on existing social structureexisting social structure,•Project management drawn from village level organisationsvillage level organisations,•Joint forest management with community participation,•Self-help water user groups and community based banking institutions.
  41. 41. Concluding RemarksThe integrated watershed management approachhave the following major components:• Promote sustainable economic developmentsustainable economic development through optimumutilisation of natural resources and local capacity building.• Restore ecological balanceecological balance through community participationand cost affordable technologies for easy acceptance.• Improving living conditionsliving conditions of the poorer through more equitableresources distribution and greater access to incomegenerating activities.
  42. 42. Concluding Remarks• Water security through IWM•Efficient utilisation of funds as only 10-15% of the total budgetspent on non-project costs.• The benefits of water harvesting and water conservation not only fordrinking water security but also for agriculture definitely reached.• About 2-4 meter water level increase is observed in selected wells.• Watershed management can easily cope with climate change impacts.