CONCLUSIONS AND RECOMMENDATIONS - Sustainable Irrigation Development in the White Volta Sub-Basin - page 219

basin, results in annual streamflow reduction of 3.310 x 10 6 m 3 (35%) from
the White Volta sub-basin. This equals 8.8% of mean annual water inflow
into the Volta Lake; the largest water user being for hydropower production
in the Akosombo dam.
It was estimated that a 8.8% decrease in inflows would result in a drop of
electricity production of about 520 GWh/a and an average drop of the water
level in Lake Volta of about 2.3m, assuming operating policies for electricity
production would remain the same.
From the financial analysis of the two competing water uses, it is clear that,
more financial profits would be made from upstream irrigation in tomatoes
(429-2,805 million US$/a) than the revenue loss (42.5 million US$/a) due to
reduced hydropower generation at Akosombo. The loss to hydropower
generation is marginal compared to the total income generation for farmers
and labourers in the poorest areas of the country. Moreover, an amount of
330 x10 6 m 3 /yr otherwise lost to evaporation from the Volta Lake would be
productively used in food production upstream. So in this case 10% of the
reduced inflows is fully compensated by reduced evaporation losses, leading
to an increase in water use efficiency at the basin scale. From the above
findings it can be concluded that upscaling irrigation development in the
White Volta sub-basin will maximize the overall benefits derived from water
resources in the Volta Basin.
9.1.4 Sustaining Irrigation Development in the
White Volta sub-basin
The current level of irrigation development in the study area does not pose
challenges to water resources management. It does not affect competing
water uses neither does it affect the sustainability of the water resources.
Thus irrigation development can still be encouraged in the White Volta sub-
basin.
Finally, effective water resources management of the Volta Basin is needed to
ensure efficient, productive, sustainable and maximum benefits of water
resources development. Effective collaboration between the White Volta
Basin Board and the Volta River Authority is needed to maximize benefits
from irrigation development and hydropower generation for socio-economic
development.