Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Waterproduc,vityinbasinmanagement:
ExperiencesfromFloodBasedFarming
Introducingfloodbasedlivelihoodsystems• Whatarefloodbasedlivelihoodsystems–theforgo@ensystem• Waterproduc,vityandbasinmanagement• IntroducingtheFBLN
Floodscouldsurpriseyou–wemaythinkofthemasahazardbuttheyareanassetjustaswel
FBLS makes use of temporarily predictable flood water to support farming, fishery, grazing grounds, recharge and groundwater storage
§ SpateIrrigation:diversion,distributionandmanagementofshortdurationfloodflowsfromseasonal
orephemeralrivers
§ Flood-spreadingweirs:usingaseriesofweirstomanageandspreadfloodsforrehabilitating
degradedland,enhancinggroundwaterrecharge
§ Roadsforwater:Waterharvestingfromroadsformultipleuse
§ Floodplainagriculture:cultivationoffloodplains,usingeitherrecedingorrisingfloodwaterorboth
§ Inundationcanalsystems:asabovewithhighwatercanalsguidingthefloodwater
MethodsofFlood-basedFarming
SpateIrrigation
Floodwaterspreadingweir
Harvestingfloodwaterfromroads
Flood-plainagriculture-recession
Flood-plainagriculture–floodrise
Deepwaterriceorsorghumvarietiesthatgrowinfloodedconditions:water>50cmdeepforatleastamonth
Morethan100millionpeopleinSouthandSoutheastAsiarelyondeep-waterricefortheirsustenance
Annualaveragefieldrise:3cm
Upto10%sedimentconcentrationinfloodwater
Flood-basedfarmingsystems:specialwaterrightsystems
Reversingthedestructivenatureoffloodsandhugesedimentchallengestheybringalongintoablessingfor:
§ Increasedcroppedareaandhigheryield:cereals,oilseeds,pulses,fruittrees
§ Preservingbiodiversity,rehabilitationofdegradedenvironments
§ Bettergroundwaterrecharge
§ Domesticandlivestockwatersupply
§ Mitigatingclimatechangeimpactandvariability
§ Stabilizingriverbasins
Floods–turningathreatintoanassets
§ Theyconstitutepovertypockets-centraltoourefforttolift700to800millionpeopleoutofpovertyandintoprosperity.
§ Theyaresignificant:15Millionhainaridandsemi-aridregionsinSSA-30millionha
worldwide.
§ Muchofthepotentialisstillunharnessed-theyareorphansleft-outbetweenrain-fed
andconventionalirrigatedAgriculture.
§ Muchscopeforinnovation
ReasonswhyweshouldinvestinFBFS
Chickpea-yield§ Rainfed:400to600Kg/ha-rainfed
§ Flood-Irrigated:2000-5200kg/ha-
FogeraFloodplain-Floodrecessionandrise:NorthWestEthiopia,EastofLakeTana
Weshouldinvest–FBFSareproductive
Flood-basedsystemsaredepositoriesoflocalbiodiversity-Naturalspeciesofvegetationareoftenofconsiderablevalueandmayprovideadditionalsourceofincometolocalcommunities
Whyinvest:preservingbiodiversity&providinglivelihood
Leadingtopromisingnichecrops:mushroomsandwildvegetables
Basin management and water produc@vity in flood based farming systems
• FBFS:• OEenonlysourceofwater• Unusedpoten,al• Direct(high)waterproduc,vity• Mi,gatefloods• Stabilizeproduc,velandscapes• Rechargegroundwater
Oftentheonlysourceofwter
Water productivity (consumption/supply) for all irrigated areas in Saudi Arabia averaged for the period 1975 to 2005. The wheat belt with (badly managed) centre pivot irrigation systems have an efficiency of 40%. The highest efficiencies (70%) are obtained at the spate irrigation systems along the Red Sea coast!
SaudiArabia:Waterproduc1vitycanbehighinfloodBasedfarmingsystems
Source:WaterWatch
Ploughing before irrigation Timely ploughing after irrigation
Soil mulching
Manage soil moisture
Sincefloodbasedirriga,onusuallyisbasedonpre-sowingirriga,onmoistureconserva,onisessen,al
Waterproducitivity:hugepotentialforbetterfieldwatermanagement
Nooverflowcontrolstructures
Openfieldintakewithstopblocks
Orificewithsettlingbasin
forslopingfields
Water productivity and basin management
In Pakistan, it is quite common to have large areas that are only irrigated in exceptional years: this creates social tension and discourages land preparation
Keepcommandareasmallandconcentrated
LOW RECHARGE WEIR TO SLOW DOWN AND SPREAD FLOODS
(Increasing) recharge
High value crops For instance: Papaya, Mango, Banana, Vegetables
Especially close to main river bed shallow water levels are high
How to op@mize recharge from spate flows? • Modifywaterdistribu,on• Rechargemainlyfrommainriverbed–farlessfrommainwadifloodchannelsorfields
• Rechargemosteffec,vefromgravellysec,onsoftheriverbed• Rechargemosteffec,ve,ifspateflowsslow• Rechargefromflatsec,onsoftheriverbed• Rechargefromwaterpondedatbundsandweirs• Rechargefrom(subsurface)baseflow• Spreadspateoverlargeareatoop,mizerecharge
• Network• Networkofprofessionals(800)>nowbecomingnetworkoffarmers• Countrychapters(4>10)• >Allfloodbasedlivelihoodsystems• Resources:
• Prac,calNotes,Guidelines,OverviewPapers• Library• Trainingpackage,tapedlectures,presenta,ons
FAOGUIDELINESONSPATEIRRIGATION
MoredetailedDesignguidelinesareunderpreparation
www.spate-irrigation.org
Looking for coopera@on and partnering