An evaluation of irrigation water supply infrastructure to improve conveyance efficiency and water availability at Dzindi Irrigation Scheme, Limpopo Province
A water use and availability study was conducted at the Dzindi Irrigation
Scheme in Limpopo Province. The problems experienced at Dzindi Irrigation
Scheme regarding water allocation, concern water availability at a field level.
Although water is continuously being diverted into the main canal, farmers at
the bottom end of the system claim not to receive adequate water supplies,
forcing them to practice dry land irrigation (farming). Water losses occur
between the source and the point of application, and the causes of loss need
to be identified so that water availability can be improved.
The study focused on water released to Block 2, and an analysis was made of
all losses which occur from the weir where water is released to the point of
application in the fields. An estimation of water supplies that return to the river
as an unused delivery, and conveyance losses that occur along the
distribution channels, were determined through a water balance drawn up
from measured canal inflows, such as seepage and evaporation.
A total volume of 371096 m3 was supplied to Block 2 during a 45 day
monitoring period. For a planted area of 16.52 ha, this works out to 22463 m3
/ha supplied, or a relative irrigation supply of 14.2 times the irrigation
Losses originate from a number of sources. Results indicated that losses that
occurred in the main canal were very low, with a conveyance efficiency of
96% recorded. Knowledge of irrigation water management and practical
irrigation scheduling at a scheme level is weak. The biggest immediate need
is to improve the management of the infrastructure. The main system
capacity is adequate, and losses due to seepage, evaporation and return
flows are within acceptable limits. The return flows are mostly caused by the
farmers’ lack of understanding that led to them removing the entire sluice
gates at the head of the secondary canals of Block 2. This results in water
running to the first two secondary canals only, and not reaching the rest of the
Based on the requirements identified by all the stakeholders, training should
be provided to the water bailiffs and farmers to implement management
practices that are both effective and sustainable. Together with prioritised
infrastructure upgrading, more acceptable water delivery should be possible.
The challenge lies in making the technical and the social aspects converge in
such a way that the result is acceptable to both systems and can be sustained
over time. The opportunities for capacity building by equipping the
stakeholders with new skills are considerable, but the time and effort required
to achieve this should not be underestimated.