Aagw2010 June 10 Meshack Nyabenge Development of an Irrigation Master Plan for Rwanda

8/9/2019 Aagw2010 June 10 Meshack Nyabenge Development of an Irrigation Master Plan for Rwanda

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Development of an IrrigationMaster Plan for Rwanda


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Introduction

Although the agriculture sector in Rwanda employs90% of the labour force, the food and nutrition

needs of the population cannot presently be met, as

evidenced by the high prevalence of malnutrition

(MINECOFIN 2002).

Moreover, agriculture, despite its high potential,

does not contribute substantial revenue to the

economy. Rwandan agriculture is primarilyundertaken at the subsistence level, providing little

surplus for local markets.


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Introduction

The introduction of irrigation, together withassociated agricultural operations, can greatlychange this situation.

As a first step towards changing this situation, the

Government of Rwanda through its Ministry ofAgriculture initiated a study to develop an IrrigationMaster Plan (IMP).

The overal aim of an IMP for Rwanda was to develop

and manage water resources to promote intensiveand sustainable irrigated agriculture and to improvefood security.


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Objective of IMP

The planning tool will support decision making by:

identifying the most favourable areas to establishirrigation water infrastructure;

prioritizing distribution of irrigation water; identifying means of transporting water to

selected sites; and

Establishing irrigated agriculture in small-,

medium- and large-scale projects on hillsides,marshlands and other topographically suitableareas.


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Data requirements In this study, GIS was used as the central tool for data

handling and analysis.

Data collected for analysis in a GIS environment werecategorized into four groups:

Administrative and infrastructural: politicalsubdivisions, roads, electricity;

Land and soils: land use, land cover, geology,lithology, geomorphology, soil types, topographicdata;

Climate: temperature, precipitation, PET, ACZs;

Water resources: hydrology - hydrography,hydrogeology.


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IMP Planning tool

In order to produce the IMP, ICRAF developed aflow chart matrix that guides in identification ofarable areas and water sources.

The matrix uses MCA in GIS a environment tomap biophysical and socioeconomic parametersfor irrigation.

The matrix also assesses the financial andeconomic issues involved in the implementationof each irrigation scenario (currently on going)


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IRRIGATION MASTER PLAN FLOW CHARTThe Flow Chart depicts the process & activities culminating in the production of the IMP

along with its validation through piloting.

Slope and Relief

Analyze slope & relief data

Soil Type

Analyze pedological data

Produce a water balance

GroundwaterpotentialsSurface waterpotentialsRunoffpotentialRainfallpotentials

Rainwater partitioning at national level

Produce maps showing suitable

slope/relief by ranks & watersheds.

Produce maps showing suitable

soils & ranking for irrigation

Produce water

potential maps

Land use/Vegetation

Analyze land use data

Produce Map showing land

use/Land cover

Climatic data

Analyze climatological data 30 year

period

Produce maps depicting climatic

aspects.

Produce district plan maps

Use ranking to run

MCA Level 1 in GIS

environment

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Study methodology


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DEM

A l i i i


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Annual average precipitation

A l


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Annual average temperature


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Sub-basins


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Water resources


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The GIS methodology

Fields with potential for irrigated agriculturewould fulfill the following criteria expressed as aseries of conditions:

Well-drained sandy clay to clay, deep soil

Up to 40% slope (although 1640% slopes arediscouraged unless tree crops are planted orradical terraces are established to avoid

landslidesdetailed studies must therefore beconducted on sites with these slope categories)

Political location (province, district, sector)


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Location outside gazetted areas (national

parks, forests, protected marshlands, urbanareas)

Specific ACZ

Proximity to electricity (to power the pumps)

Accessibility (roads)

Proximity to water resources.

P/PET i


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P/PET ratio

Sl l


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Slope classes


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Soil suitability


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Results

In order to utilise the least-cost technologicaloptions for water abstraction and distribution,the IMP partitioned the country into six irrigationdomains.

Rwandas irrigation domains are thus categorized

as: Runoff for small reservoirs

Runoff for dams

Direct river and flood water Lake water resources

Groundwater resources

Marshlands

i i d i


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Irrigation water sources domains


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Rainwater partitioning

Potential Dam Sites


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Potential Dam Sites


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River water Domains


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Lake water Domains

S t ti i i


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Summary o potentia irriga eareas

The assessment of Rwandas irrigation potentialindicates that the country has a national irrigationpotential of 589 713 ha, taking into considerationthe following domains:

Runoff for small reservoirs (125 627 ha) Runoff for dams (27 907 ha)

Direct river and flood water (79 847 ha)

Lake water resources (100 107 ha) Groundwater resources (36 432 ha)

Marshlands (219 793 ha)


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Examples of District plan maps


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Documents

Aagw2010 June 10 Meshack Nyabenge Development of an Irrigation Master Plan for Rwanda