Water producvity in basin management: Experiences from ... · § Much of the potential is still...

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