Africa Water Balance high/lowland crops, 1987

The Africa Water Balance data set which is prepared by watershed and
by country, belongs to the group of "Irrigation and Water Resources
Potential" study. It covers 55 countries and 25 major basins which
contain 335 watersheds. The digitized data base for Africa and the
World was originally prepared for an FAO/UNEP project on
Desertification in 1982-1984. UNEP financed preparation and analysis
of the digitized map data and FAO prepared the data and methodology.
The main input maps (all in Miller Oblated Stereographic projection)
are the 1975 UNESCO Geological Map of Africa (originally at a scale of
1:10 million); the FAO/UNESCO Soil Map of Africa; Mean Annual Rainfall
Map from hand drawn FAO/AGS climate maps; Template; Watersheds; and
Administrative Units map - all at a scale 1:5 m.

The methodology was based on water balance approach. This determines
the suitability of the soil for irrigation and estimates the amount of
water the soil requires. Estimates of the surface and groundwater are
then compared to the potential irrigation use. If use exceeds
available water resources, the irrigable area is correspondingly
reduced; in the event of water surplus, some of the water is routed to
the downstream basin.

The classification was done for two major crop types: lowland crops
(flooded rice), and upland crops (for all other irrigated crops except
lowland crops).

For further details refer to FAO contact for the 1987 FAO Irrigation
and Water Resources Potential for Africa AGL/MISC/11/87.

FAO, Land and Water Development Division via Delle Terme di Caracalla,
00100, Rome, Italy

Vector Member
The file is in Arc/Info Export format.

Reference:
FAO. Irrigation and Water Resources Potential for Africa. (1987)
FAO. Final Report UNEP/FAO world and Africa GIS data base (1984),
unpublished publication of ESRI, FAO and UNEP.
UNESCO. Geological Map of Africa (1975). Scale 1:5 000 000.