Managing Trans-Regional Water Transfer in Dry African Countries to Mitigate Shortages

Abstract

The deficiency of water resources is limiting directly and severely the socioeconomic development and ecological environmental protection in the Internal Drainage
basin (IDB) in the central part of Tanzania which is considered to be semi-arid region. Due
to the regional differences in water availability a revised setting of in country water
distribution is required. The objective of the work described here within is to determine the
least-cost solution for a national water transportation system among the regions,
simultaneously meeting the water delivery requirements in the IDB and complying with all
other relevant regulatory criteria. The principal of optimal water transportation from eight
administrative source basins to the IDB by cost minimization has been implemented. The
results obtained by using 70% level of annual renewable water for Environment Water
Requirements (EWR) suggest that excess annual renewable water resources from source
basins is sufficient to supply the IDB. Transportation constraints imposed in the water
management model limits some of the basins to be considered as preferred water sources.
On the basis of the modeling results, Lake Tanganyika basin, Lake Rukwa basin and
Wami/Ruvu river basins (all are in Tanzania) have been identified as reasonably preferred
water sources. Pangani basin in the north-eastern part of Tanzania is under water shortage,
water withdrawal from the Pangani basin would further damage the Pangani river ecology
and water environment. The optimum total costs (operation costs, capital investments and
maintenance of the concrete pipeline) range between 0.69 and 1.37 US $/m3.