A GIS based framework for assessing and mapping potential irrigation areas in rwanda

A GIS based Framework for Assessing and Mapping Potential Irrigation Areas in Rwanda

The TeamMowo Jeremias, Maimbo Malesu,a Alex Oduor,a Reginauld Kipruto Cherogonya, Meshack Nyabengea, Douglas Nyoleia, Prime Ngabonzizab; Reverien Harindintwalib Charles Gachenec, Elijah Biamahc, Mick O’Neild, Iiyama Miyukia, Jephine Mogoia

, Yodfat Engineers, MS Consultancy, IMP Steering Committee, Dan Dvoskine

• a World Agroforestry Centre• bRwanda Agricultural Development Authority• cUniversity of Nairobi• dNew Mexico University• eEbony Enterprises

IMP Planning tool: Purpose• To develop and manage water resources to promote

intensive and sustainable irrigated agriculture and improve food security in Rwanda

• In this study, GIS was used as the central tool for data handling and analysis.

• Data collected were categorized into four groups:– ADMINISTRATIVE AND INFRASTRUCTURAL: political subdivisions, roads,

electricity;

– LAND AND SOILS: land use, land cover, geology, lithology, geomorphology, soil types, topographic data;

– CLIMATE: temperature, precipitation, PET, ACZs;

– WATER RESOURCES: hydrology - hydrography, hydrogeology.

CAADP Climate-Smart Agriculture Program Design Workshop Dakar 31-Oct-11 to 3-Nov-11

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• Identifying the most favorable areas to establish irrigation water infrastructure

• Estimating the water stock that can be used for irrigation – WATER BALANCE

• Prioritizing abstraction, distribution of irrigation water

• Identifying and establishing small, medium and large scale projects on topographically suitable areas;

• Identifying options for upgrading the agricultural value chain through training and extension

• Recommending options for water harvesting and storage

• Producing plans maps for potential irrigation areas- PIAs.

• Articulating the national policy options concerning the distribution of irrigation water.

Specific objectives

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 ReliefAnalyze slope & relief data

Soil TypeAnalyze pedological data

Produce a water balance

Groundwater potentials

Surface water potentials

Runoff potential

Rainfall potentials

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/VegetationAnalyze land use data

Produce Map showing land use/Land cover

Climatic dataAnalyze climatological data ≥ 30 year period

Produce maps depicting climatic aspects.

Produce PIA & district plan maps

Use ranking to run MCA Level 1 in GIS

environment

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Irrigation site(s)Identify irrigation site/size from DEM & Landform analysis

Runoff waterEstimate runoff potential at individual site level

Surface WaterEstimate potential of rivers/lakes etc.

Dam/intake siteIdentify and assess dam/intake site

GroundwaterEstimate potential

General feasibility and planning•Is it economically and financially viable?•Consider water quantity needed versus available•Consider water quality, health•Undertake preliminary EIA•Community management structure•Training needs assessment•Land tenurePreliminary costing

Carryout hydrogeological and geotechnical survey

Ignore

Is the project still feasible?

AdequateInadequate

YES

NOAdequateInadequate

Inadequate Adequate

Are crack identified low flow ratesNO

NO

Does site appear feasible?

YES

Gazetted/protected AreasAre the areas protected or gazetted by Government(e.g. forest reserves, national parks)?

Produce Mapshowing irrigable areas with gazetted/ protected areas annexed

NOYES

Is it prudent to degazette?NO

YES

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Sample soils in detail and interpret results

Identify the most suitable crop(s) and livestock for irrigation/watering

Determine ETc for this crop and water requirements for livestock and humans

Planning: Labour; Mechanization; Community cost sharing

Legal issues/permits

Final technical design•Topographic survey•Geotechnical studies•Soil and water conservation•Agroforestry •Mechanization•Livestock•Extension

Financial & Economic AnalysisPrepare financial report

Socio-economic/cultural surveyMarkets, infrastructure access and potential demography/poverty levels

Review costs, prepare detailed plan, including:•Construction plan•Bill of quantities•Design report and drawings•Irrigation layouts

PRODUCE TENDER DOCUMENTS & SUBMIT TO MINAGRI

Undertake detailed EIA

Is the project still feasible?

YESNO

Discard Site

Crop Water Use with FAO’s CROPWAT 8.0

DEM

Slope classes

Soil Map – FAO

Soil suitability

P/PET ratio

Rainwater partitioning

Runoff Potential

Potential Dam Sites

River water Domains

Lake water Domains

Estimated lake volumesLake ID Lake name Surface area (Mm2) Volume (Mm3)

1 Burera 52 31162 Ruhondo 28 8683 Muhazi 34 4544 Mugesera 21 2535 Bilira 7 856 Sake 58 5957 Gaharwa 5 408 Kirimbi 3 199 Mirahi 3 17

10 Rumira, Kidogo 4 2511 Gashanga 2 2012 South Cyohoha 19 18313 North Cyohoha 8 24214 Nasho, Kagese, Cyambwe, Rwampanga 78 96015 Rwanye, Kizinga 7 4816 Muhindi 124 185917 Hago 25 29418 Nkumba 37 29019 Ihema 19 70620 Lake Rwakibare 32 260421 Lake Kivu 1069 18156122 Lake Rweru 34 423

Total 1669 194662

Borehole locations and distribution

Districts with borehole yields above 10 m3 h-1

District Depth (m) Yield (m3 h-1)Gasabo 20 60.00Nyarugenge 20 36.00Kicukiro 5 18.00Kayonza 81 15.00Kayonza 48 12.96Kayonza 83 12.60Kayonza 49 12.00Nyarugenge 20 12.00Kayonza 57 10.80Kayonza 43 10.29Kayonza 61 10.29Kayonza 61 10.29Kirehe 78 10.20Kayonza 42 10.00

Size of Irrigation domains

Marshlands – 219,793 ha.

Small Reservoirs -125,627 ha.

Lakes – 100,107 ha.

Rivers – 79,847 ha.

Groundwater – 78,847 ha

Run-off 27,907 ha.

Examples of District plan maps

Examples of soil profiles for Nyanza site

Suitability class

Soil mapping Area (ha) Constraints/ limitations

S1.1 USvd/A; USvd/BC; USd/C; (AA/A)

1006.68 (+ 8.84)

Fertility, AA/A highly suitable if put under paddy rice (see also below under NS)

S1.2 USd/D 52.19 Fertility, requires intensive labour for levelling land due to slopes (> 16%)

S1.3 USs/C 243.06 Soil moisture storage capacity, fertility, can be utilised for crops with rooting depths of < 50 cm

NS AA/A* 8.84 Seasonally flooded, drainage limiting for most crops, except for paddy rice

Potential land suitability classification for commonly grown crops in Mugesera site

Comparative Mango CWR for 3 Districts

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Financial and Economic Analysis

Investment

BCR & NPV

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• Data collection– Limited data archives for precipitation and surface water

flow– Before 1994, there were 200 met stations with data sets

from year 1907– During the 1994 genocide most records were destroyed

leaving data from 100 stations with data sets from 1940.– Lack of Hydrological, hydrogeological and hydro

chemical data– Lack of hydrometric, hydro chemical and environmental

monitoring

Constraints

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• Capacity Building– Generally limited professional capacity– ICRAF performed all GIS mapping and analysis– Results were discussed with steering committee and

validate through field visits– MINAGRI attached their GIS expert to understudy the GIS

work– ICRAF with support from UNEP conducted a GIS training

course for 30 Rwandan professionals– MINAGRI has established a GIS unit and all data has been

transferred

Opportunities

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• MINAGRI is using IMP as principle decision support tool for irrigation development in Rwanda

• All GIS work is archived and updated at the established GIS unit at MINAGRI.

• An irrigation task force has been established to lead all irrigation work in Rwanda.

• MINAGRI has embarked on developing an irrigation strategy and establishing an irrigation board to strengthen institutional arrangements and coordination.

Impact

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• Improved water resources management for climate-smart agriculture requires increased capacity to make decisions at the national level down to the farm level.

• Information and knowledge about water resources should be a major driver of decision making at all levels.

• Institutions from national ministries down to local water user associations can engage in more effective data collection, analysis, and forecasting.

Take Away Messages

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Questions