Any change during a project involves an interaction between the following three factors.
Cost
Quality
Time
Figure 3. Cost-quality-time triangle
For instance, if a certain task’s completion date needed
to be brought forward (time), it could only be done by
increasing resources (cost) or reducing quality. The time
cannot be reduced by keeping costs and quality as they
were.
The later the changes, the worse the effect on one or
more of cost, quality and time. The following looks at
the feasibility of changes to the irrigation design during
each of these phases.
Changes in irrigation design – Definition phase
The preliminary irrigation design takes place during this
definition phase. Changes are very feasible. This phase
is earmarked for changes and this is the phase to get a
reasonably clear idea of what one wants.
Changes in irrigation design – Planning phase
This is the phase where the irrigation design is formulated. Materials will be procured against this design.
Changes are still reasonably feasible during the planning phase.
Changes in irrigation design – Implementation
phase
Procurement of materials occurs during this phase.
Once procurement has begun, changes are more difficult. Irrigation equipment for instance is often only
manufactured-to-order. Construction and installation
occurs during this phase. Changes now begin to have a
more severe effect with increased costs, time delays or
a reduction in quality.
This is the phase in irrigation systems where most
changes through inadequate planning come to light.
Changes in irrigation design – Close-out
This is when commissioning takes place and where
changes are for all intents and purposes not feasible.
The Project Manager and the integration of the irrigation with the rest of the project
The irrigation part of the project cannot be viewed in
isolation at any time during the project life-cycle. The
irrigation involves the interaction of the following aspects and individual specialist personnel, which must be
catered for, planned and integrated from the outset.
The Project Manager is the key person who must be on
the ground from beginning to end to facilitate interaction of the irrigation designer and irrigation contractor
with:
Agronomy, including:
Cultural practices
Nutrition
Water source
Land-levelling
Greenhouse design and installation including:
Climate control
Heating
Electrical power supply
Infrastructure, including:
Roads
Buildings