This document describes a GIS-based framework developed to assess and map potential irrigation areas in Rwanda. A team of experts from various organizations collected climate, soil, land use and water resources data to analyze suitability for irrigation. The framework identifies favorable locations for irrigation infrastructure, estimates available water supply, prioritizes water distribution, and produces maps of potential irrigation areas. The overall goal is to promote sustainable irrigated agriculture and improve food security in Rwanda by developing and managing the country's water resources.

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

2. The Team
Mowo 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

3. 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.

4. Specific objectives
• 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.
CAADP Climate-Smart Agriculture Program
Design Workshop Dakar 31-Oct-11 to 3- 4
Nov-11

5. IRRIGATION MASTER PLAN FLOW CHART
The Flow Chart depicts the process & activities culminating in the production of the IMP
along with its validation through piloting.
Slope and Relief
Produce maps showing suitable
Analyze slope & relief data
slope/relief by ranks & watersheds.
Soil Type Produce maps showing suitable
Analyze pedological data soils & ranking for irrigation
Land use/Vegetation Produce Map showing land
Analyze land use data use/Land cover
Climatic data
Produce maps depicting climatic
Analyze climatological data ≥ 30 year
aspects.
period
Rainwater partitioning at national level
Rainfall Runoff Surface water Groundwater
potentials potential potentials potentials
Use ranking to run
Produce water
Produce a water balance MCA Level 1 in GIS
potential maps
environment
Produce PIA & district plan
maps
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6. Irrigation site(s)
Identify irrigation site/size from
DEM & Landform analysis
Runoff water
Estimate runoff potential at individual site level
Inadequate Adequate
Surface Water Dam/intake site
Estimate potential of rivers/lakes etc. Identify and assess dam/intake site
NO
Does site
Inadequate Adequate appear feasible?
YES
Groundwater General feasibility and planning
Estimate potential •Is it economically and financially viable?
•Consider water quantity needed versus available
•Consider water quality, health
Inadequate Adequate •Undertake preliminary EIA
•Community management structure
•Training needs assessment
Ignore •Land tenure
Preliminary costing
Gazetted/protected Areas
Are the areas protected or gazetted by Government Is the project still feasible?
NO
(e.g. forest reserves, national parks)?
YES
YES NO
YES Carryout hydrogeological and geotechnical
survey
Is it prudent to degazette?
NO
Produce Mapshowing irrigable areas with Are crack identified low
NO flow rates
gazetted/ protected areas annexed

7. 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
Crop Water Use with FAO’s CROPWAT 8.0
livestock and humans
Planning: Labour; Mechanization; Community cost
sharing
Socio-economic/cultural survey
Markets, infrastructure access and potential
Final technical design demography/poverty levels
•Topographic survey
•Geotechnical studies
•Soil and water conservation
•Agroforestry
•Mechanization
•Livestock
•Extension Legal issues/permits
Undertake detailed EIA Review costs, prepare detailed plan, including:
•Construction plan
•Bill of quantities
•Design report and drawings
Is the project still feasible?
•Irrigation layouts
YES
NO Financial & Economic Analysis
Prepare financial report
Discard Site
PRODUCE TENDER DOCUMENTS & SUBMIT
TO MINAGRI
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8. DEM

9. Slope classes

10. Soil Map – FAO

11. Soil suitability

12. P/PET ratio

13. Rainwater partitioning

14. Runoff Potential

15. Potential Dam Sites

16. River water Domains

17. Lake water Domains

18. Estimated lake volumes
2 3
Lake ID Lake name Surface area (Mm ) Volume (Mm )
1 Burera 52 3116
2 Ruhondo 28 868
3 Muhazi 34 454
4 Mugesera 21 253
5 Bilira 7 85
6 Sake 58 595
7 Gaharwa 5 40
8 Kirimbi 3 19
9 Mirahi 3 17
10 Rumira, Kidogo 4 25
11 Gashanga 2 20
12 South Cyohoha 19 183
13 North Cyohoha 8 242
14 Nasho, Kagese, Cyambwe, Rwampanga 78 960
15 Rwanye, Kizinga 7 48
16 Muhindi 124 1859
17 Hago 25 294
18 Nkumba 37 290
19 Ihema 19 706
20 Lake Rwakibare 32 2604
21 Lake Kivu 1069 181561
22 Lake Rweru 34 423
Total 1669 194662

19. Borehole locations and distribution

20. Districts with borehole yields above 10 m3 h-1
District Depth (m) Yield (m3 h-1)
Gasabo 20 60.00
Nyarugenge 20 36.00
Kicukiro 5 18.00
Kayonza 81 15.00
Kayonza 48 12.96
Kayonza 83 12.60
Kayonza 49 12.00
Nyarugenge 20 12.00
Kayonza 57 10.80
Kayonza 43 10.29
Kayonza 61 10.29
Kayonza 61 10.29
Kirehe 78 10.20
Kayonza 42 10.00

22. Size of Irrigation domains

23. Marshlands – 219,793 ha.

24. Small Reservoirs -125,627 ha.

25. Lakes – 100,107 ha.

26. Rivers – 79,847 ha.

27. Groundwater – 78,847 ha

28. Run-off 27,907 ha.

29. Examples of District plan maps

31. Examples of soil profiles for Nyanza site

32. Potential land suitability classification for commonly
grown crops in Mugesera site
Suitability Soil mapping Area (ha) Constraints/ limitations
class
S1.1 USvd/A; USvd/BC; 1006.68 Fertility, AA/A highly suitable if put under
USd/C; (AA/A) (+ 8.84) 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

33. Comparative Mango CWR for 3 Districts

34. 34

35. 35

37. Financial and Economic Analysis
Investment
BCR & NPV

38. Constraints
• 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
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39. Opportunities
• 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
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40. Impact
• 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.
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41. Take Away Messages
• 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.
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42. Questions
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