Agriculture Reference
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shallow groundwater. However 85% of the current irrigation in Anayari and
Atankwidi catchments depends on shallow groundwater.
The current trend of irrigation development demonstrates that inhabitants
are willing to exploit the potential benefits of irrigated farming and therefore
have resorted to affordable shallow groundwater irrigation technologies. This
trend is likely to continue in the next fifteen years since most potential
irrigable lands remain untapped. The results also show that the introduction
of new technologies which abstract groundwater for irrigation beyond shallow
groundwater levels is sustainable provided that abstractions do not exceed a
certain threshold. One challenge is the impact this will have on farmers using
traditional water abstraction methods which can only reach shallow
groundwater. The localised impact of new irrigation technologies in
abstracting groundwater for irrigation on various groundwater users was not
addressed in this study and needs to be investigated.
The non-perennial nature of rivers in the study area is a major contributor
to the intensifying shallow groundwater use for irrigation. Another reason is
that the development of reservoirs (small and large) for irrigation is
relatively expensive and cannot be borne by individual farmers. The
government and development partners have been the major developers of
reservoirs for irrigation. The development of more reservoirs in the next two
decades for irrigation may continue but not comparable to the rate of
development of the 1970s. There are however, a significant number of small
reservoirs which are currently not functioning and which may be
rehabilitated for irrigation purposes as has been done in recent times in the
sub-basin (LACOSREP, 2000).
8.5.2 Impact of Intensifying Irrigation on Water
Resources and Competing Water Uses
The model analysed three scenarios, 5% annual growth, 10% annual growth
and sustainable level of irrigation development. Amongst the three scenarios
the most realistic scenario is arguably the 5% annual growth in irrigation
development. This impact analysis uses the 5% annual growth in irrigation
development as the benchmark.
Impact of surface water irrigation
In the Atankwidi and Anayari catchments actual surface water irrigation is
about 2ha (0.02%) and 217ha (0.3%) respectively. In the Yarigatanga
catchment this figure is about 214ha (0.6% of the catchment). If current
irrigation would grow at 5%/a, by 2025, surface water irrigation in the
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