Water for a food-secure world

Rainwater Management Systems in The NBDC: Emerging Menu of Alternatives

Birhanu Zemadim

Teklu ErkossaAmare HaileslassieMatthew McCartneyDeborah BossioBharat SharmaFergus Sinclair

Nile Basin Development ChallengeScience and Reflection WorkshopAddis Ababa, 4-6 May 2011

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Rainwater Management

Engineering practices are intended to improve water availability and access

Practices focus on: • Water Source (rainfall, rivers, springs and groundwater)• Water Storage to deal with variability in water availability • Water Distribution to improve application of water to fields and remove

excess when necessary

Different practices have different impacts under different biophysical conditions. Suitability must be assessed in terms of:

• technical feasibility • socioeconomic impacts • management requirements

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Conceptualization of the physical water storage continuum

Source: McCartney and Smakhtin, 2010

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Menu of Alternatives Practices Preconditions Desired Impacts

• Ponds/Tanks/Cisterns

• Water diversion schemes

• Hillside/ Stone/ Bench Terraces

• Cutoff drains

• Earthen bunds

● Micro-basins, Trench, Eyebrow terrace

● Vegetated stone-soil-stone bunds

•Gully plugging

•Percolation tanks/Infiltration zones

• Availability of construction materials

• Availability of knowledge/skills for construction

• Availability of land area and willingness by local farmers,

•Availability of training and extension support

•Availability of labor for construction and management

•Availability of capital

•Institutional structure for planning and management

•Increased water availability in dry periods

• Increased soil moisture

•Reduction of flood hazards

•Improved land and water productivity

•Reduced pressure on grazing land

•Better understanding of land and water management practices by the community

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Some RWM Options to enhance CWP

• RWM practices- are practices that enhance availability of water to plants and improve uptake and conversion by plants

• Two Approaches– Enhance Water Availability (Engineering)– Improve Water Uptake by plants (Agronomy)

2. Improve Water Uptake by plants• Crop management to enhance rainfall use

• Soil Fertility Improvement (organic, inorganic)

• Crop Varieties/species• Focus on high value crops

• Improved cropping strategies

Soil fertilityYield (t ha-1) WP (kg m-3)

Biomass Grain Biomass Grain

Poor 7.5 2.5 5.1 1.7

Near optimal 14.3 6.4 5.3 2.4

Non limiting 19.2 9.2 5.4 2.6

Menu of Alternative RWM practices that improve water uptake and use by plants

Alternative practices Likely impact Pre-conditions

•Introduce high yielding and high value: crops species/ varieties• Select suitable crop types and varieties for irrigated system

•Increased WP •Seed / seedlings supply•Input availability•Training of farmers•Market access

•Crop management practices :o Appropriate planting dateo Appropriate plant population o Appropriate fertilizationo Weed controlo Suitable irrigation methodso Supplemental irrigation in the rainfed systemo Conservation tillage and mulching

•Increased WP•Improved soil health•More land can be irrigated

•Availability of proven practices•Training of farmers•Extension manuals •Input availability•Market access

Advanced cropping systems: • Crop rotations, intercropping, alley/ relay cropping

•Increased WP•Diversified products

•Training of farmers•Extension support•Seed/seedlings supply•Market access

oUse lime and manure to ameliorate acidic soils

•Increased WP•Improved soil health

•Lime availability at affordable price

Four key strategies to improve Livestock Water Productivity

Principles Strategies ObjectivesImproving the WP feeds: on crops; grazing land

• Soil & water conservation & integrating productive species

Increasing H2O availability & plant H2O uptake

Enhancing efficient uses of feed resources produced under water productive environment & thus intensifies the goal of the previous principle at system scale

• Improving feed quality & supplementary feeding

• Virtual water transfer• Matching livestock activity &

production level to available feed

• Regulating animal movement• Strategic drinking water

supply

Improving livestock feed sourcing & feeding techniques

• Selective & cross breeding• Improving AI & Vet service • Strategic water supply

Improving livestock productivity

Principles for water productive RWMs

Practices Pre-conditions ImpactsIntegrated soil conservation measures on grazing lands; grass strip

Regulation of grazing practices

Increases biomass yield, productive use of water

Strategic water supply Improves income & water productivity

Cut off drains in valley bottoms grazing lands ; flood diversion

Planning how to use drained water

Enhances species diversity, feed quality & productive use of stagnating water

Grazing management, enclosures, improved management of CPR

Policy on grazing land

Reduces compaction; Increases infiltration; (Fogera biomass yield up 400% ( IPMS))

Intercropping legumes, control of invasive species,

Seed Increases biomass yield

Incorporating legume trees into grazing land and fallow land

Limit open grazing

Options for greed fodder in dry period

Rain water management practices: Water productive feed on grazing land

Rain water management practices: Efficient use of water productive feed

Practices Preconditions ImpactsSelection of quality feed, urea treatment, chopping of course crop residues ; improved feed storage & weed control.

•Awareness•Local institutions for CPR•Feed market• Genetic potential of livestock

•Higher quality feed saves water ( ~120m3/cow/year)which can be used for ecosystem services ( CO2 sequestration) & Enhances nutrient turnover

Institutional support and creation of incentive mechanisms for local initiatives of virtual water trading

•Improves regional & systems water productivity•Links upstream-downstream community

Cut and carry system

•Destocking•Enough labor

•Saves H2O ~400m3/cow/year

Rain water management practices: Efficient use of water productive feed

Practices Preconditions Impacts

Selective and cross breeding

•Sufficient feed•Access to market, credit& AI

Improves productivity livestock ( milk meat)

Incentives to involve more private AI services; Para-vet training

Policy measures Reduces morbidity & mortality

Destocking; matching traction needs and oxen owned; multiple use of livestock

Awareness creation Increases herd LWP

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The role of tree cover in rainwater management strategies

• Landscape niches (Polyscape, tomorrow)– different options to capture water in different places (flow

accumulation)– natural vegetation types may condition species choice– some parts of landscape more important than others– trade-offs and synergies with other ES

• Farming system niches (water productivity)– species choice

• high productivity (time), water use efficiency (associative ideotypes), markets, culture

– product and service mix• fodder, fertiliser, fruit, fuel, clean water

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Options – tree species and management

• Woodlots• Orchards (fruits)• Contour hedgerows (shrubs to re-inforce

terracing)• Boundary planting• Trees in fields