IMPACT OF INTENSIFYING IRRIGATION DEVELOPMENT AND IMPLICATIONS FOR SUSTAINABLE WATER RESOURCES MANAGEMENT IN THE WHITE VOLTA SUBBASIN - Sustainable Irrigation Development in the White Volta Sub-Basin - page 192

1) The situation in 2025 if irrigation continues to expand at the current
rate of 5%/a;
2) The situation in 2025 if irrigation expands at a rate of 10%/a;
3) Sustainable irrigation development by 2025:
a. 10% of the catchment area is put under groundwater
irrigation and 2% under surface water;
b. Improving groundwater and surface water irrigation efficiency
to 70%;
c. 8% of catchment under groundwater irrigation and 2% under
surface water with improved irrigation efficiency;
4) Impact of variations in groundwater recharge on model results.
In the scenario analysis the impact of each of these scenarios on water
demand coverage for various water uses, groundwater and surface water
sources is investigated. Finally, WEAP is used to investigate the sustainable
level at which groundwater can be used for irrigation development amongst
other uses in the study area.

8.4.1 The situation in 2025 if irrigation should

have expanded at a rate of 5%/a

The first scenario considered for the analysis is based on the current growth
rate of irrigation in the three catchments. The previous chapter found that
the irrigated area in the three catchments has been growing at about 5.6%/a
since 2005. In this scenario, 5% growth is applied to both surface and
groundwater irrigation. The growth is projected to 2025 and the extent of
irrigation that is anticipated at 2025 is determined. The extent of irrigation
at 2025 is then simulated in the model to determine the impact.
Table 8.5 : Input values for 5% annual growth in irrigation at 2025

Permanent
Shallow
Wells

Temporal
Shallow
Wells

Riverine
Alluvial
Dugouts

Small
Reservoirs

Large Reservoir Riverine
Water

tomatoes tomatoes tomatoes rice tomatoes tomatoes tomatoes

Crop

Water abstraction
( mm/season)

640 1550 980 1550 640 1310 900

I rrigation Efficiency 0.73 0.28 0.50 0.68 0.77 0.34 0.49

Water Consumption
( %)

88 66 76 85 90 69 77

I rrigated
Area (ha)

Anayari 585.9 594 0 0 0 1026 648

Atankwidi 5.4 56.7 0 0 0 270 189

Yarigatanga 78.3 8.1 216 175.5 108 4.1 1.4