Water meters
For irrigation schemes, it is recommended that a portable transit
time meter be obtained (available for either canals or pipelines),
which can be used to easily measure flow at nearly any location
to calibrate other measuring devices or settle disputes.
Implementing a water measurement system is, however, not a
cheap exercise, with the typical cost per measuring point being
between R15 000 & R35 000, depending on the device selected.
It is therefore recommended that a managed implementation
approach be applied when selecting and installing measuring
devices. Guidelines for such an approach are also offered in the
training material.
Correct irrigation system design and management will result in uniform water
applications and growth
The water balance framework allows for a closer analysis and
refinement of existing systems and strategies, which would often
yield far greater benefits at a much lower cost than switching from
one system to another.
Water measurement
The use of the water balance implies that a large number
of measurements need to be made to quantify the different
components. Measuring also makes business sense for
management at any water use level.
Many suitable and proven technologies are available to collect the
required data such as flow rates, pressure, soil water content, flow
depth, climatic data as well as soil and water quality parameters,
and most of the measurements can be managed remotely
using modern communication technology such as modems and
the internet, enabling real-time water management and more
effective decision-making. Appropriate modern technologies
should be used as far as possible to improve water management.
Measurement is at best an approximation and will always have a
degree of error. In general, the more accurate the data, the more
expensive the measurement device or method will be. Care should
be taken to ensure that expensive, high accuracy measurement
devices or methods are strategically used or positioned.
The acceptable level of accuracy for a certain water balance
component depends on the situation. In the field, measuring
devices are more often than not subject to less-than-perfect
conditions, resulting in X