3.1 Five FIWs (Foundational Ideas About WUS)
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Because of its centrality to water management, it is crucial to promote learning
approaches that make water balance more robust and transparent. Most of the time,
balancing water is complex and needs an explicitly designed learning methodology
that properly includes all types of stakeholders that are essential for advancing with
better data in time.
Water balance has four parts, viz., total inflow, total outflow, change in storage,
and time interval. The first two parts are rather obvious and the third one is explained
in the next paragraph. Here, it is sufficient to mention that water balance and its first
three parts must be associated with a specific time interval, such as, a day, month or
year. A good reference for a better understanding of scales and model time periods
is Loucks and van Beek (2005).
The third part, i.e., the change in storage of a WUS, is considered to be negligible
for some periods of analysis, such as a day or a year, hence making inflows equal to
outflows. If needed, reasonable changes to WPTs, such as OS or RP would establish
the needed water balance. A WUS, such as a farm, city, industrial plant or region,
is different from a water resource, such as a river or an aquifer. The former does
not have change in storage within an appropriate period of time, but the latter may
have. To ignore such a fundamental distinction between resource and WUS (see also
Sect. 2.1) is a major point of misunderstanding and mismanagement. A resource is
basically a storage, however a WUS interacts with water flowing through it with
relatively negligible storage meaning that even if there is a change in storage, it is
negligible relative to the total inflow into the WUS during its time interval. This
specific time depends on the nature of the WUS during which any change in storage
should be ignored. Let us see three examples:
• If a farmer pumps groundwater for irrigating his farm (WUS), the water balance
of the farm during a season or a year can be written as inflows = outflows even
though on a daily or monthly basis this may not be correct. However, during the
year, the pumping caused the storage of the resource (groundwater) to diminish.
• In many studies, water supply and wastewater systems (WUS) are routinely
considered as having no storage, at least for monthly, seasonal or annual studies.
There are, of course, storage reservoirs in almost all the urban areas, however,
their combined change in storage is negligible, say on a monthly or yearly basis,
and indeed it is almost zero relative to the total flow into the WUS.
• Normally, a dam has almost the same amount of water storage at the beginning
and at the end of a chosen time interval, such as a year. This means that its
inflows are the same as outflows during that period, even though there may be
considerable storage (more inflows than outflows) at one particular period, e.g.
January to March.
FIW1b) Data of the three Pillars should be transparent and reasonable which
technology can promote.
The data of the three Pillars (water quantity, quality and benefits) effectively used
to make final decisions must be transparent, having in mind that the start of good
management is data transparency. This means that the data should be open, clear and
25
Because of its centrality to water management, it is crucial to promote learning
approaches that make water balance more robust and transparent. Most of the time,
balancing water is complex and needs an explicitly designed learning methodology
that properly includes all types of stakeholders that are essential for advancing with
better data in time.
Water balance has four parts, viz., total inflow, total outflow, change in storage,
and time interval. The first two parts are rather obvious and the third one is explained
in the next paragraph. Here, it is sufficient to mention that water balance and its first
three parts must be associated with a specific time interval, such as, a day, month or
year. A good reference for a better understanding of scales and model time periods
is Loucks and van Beek (2005).
The third part, i.e., the change in storage of a WUS, is considered to be negligible
for some periods of analysis, such as a day or a year, hence making inflows equal to
outflows. If needed, reasonable changes to WPTs, such as OS or RP would establish
the needed water balance. A WUS, such as a farm, city, industrial plant or region,
is different from a water resource, such as a river or an aquifer. The former does
not have change in storage within an appropriate period of time, but the latter may
have. To ignore such a fundamental distinction between resource and WUS (see also
Sect. 2.1) is a major point of misunderstanding and mismanagement. A resource is
basically a storage, however a WUS interacts with water flowing through it with
relatively negligible storage meaning that even if there is a change in storage, it is
negligible relative to the total inflow into the WUS during its time interval. This
specific time depends on the nature of the WUS during which any change in storage
should be ignored. Let us see three examples:
• If a farmer pumps groundwater for irrigating his farm (WUS), the water balance
of the farm during a season or a year can be written as inflows = outflows even
though on a daily or monthly basis this may not be correct. However, during the
year, the pumping caused the storage of the resource (groundwater) to diminish.
• In many studies, water supply and wastewater systems (WUS) are routinely
considered as having no storage, at least for monthly, seasonal or annual studies.
There are, of course, storage reservoirs in almost all the urban areas, however,
their combined change in storage is negligible, say on a monthly or yearly basis,
and indeed it is almost zero relative to the total flow into the WUS.
• Normally, a dam has almost the same amount of water storage at the beginning
and at the end of a chosen time interval, such as a year. This means that its
inflows are the same as outflows during that period, even though there may be
considerable storage (more inflows than outflows) at one particular period, e.g.
January to March.
FIW1b) Data of the three Pillars should be transparent and reasonable which
technology can promote.
The data of the three Pillars (water quantity, quality and benefits) effectively used
to make final decisions must be transparent, having in mind that the start of good
management is data transparency. This means that the data should be open, clear and