5.1 Categories
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being more insightful and easy to summarize in three categories, and hence the
option in this book. To set up this choice for the indicator of interest, we need four
thresholds, which are the boundaries between two consecutive categories. Sometimes
the naming, their four values and corresponding colours are already defined within
laws and regulations, e.g., at the national level, however we employ the following
generic naming with Amax > Max > Min > Amin:
• Absolute minimum (Amin): the value of the indicator of interest for any member
must be greater than or equal to Amin
• Minimum (Min): the value of the indicator of interest for any member must be
greater than or equal to Min under non-transitory conditions
• Maximum (Max): the value of the indicator of interest for any member must be
less than or equal to Max under non-transitory conditions
• Absolute maximum (Amax): the value of the indicator of interest for any member
must be less than or equal to Amax
Transitory conditions should be rare, and the system design should be under
normal or non-transitory state. Let us be clear that these thresholds are set at the lowest
level of authority as possible. For example, if there is no national level regulation on
any of these thresholds, then local water managers should define them in consultation
with all the stakeholders. Anyhow, in setting the thresholds, international guidelines
such as the following can be very helpful:
“One of the most important recent milestones has been the recognition in July 2010 by the
United Nations General Assembly of the human right to water and sanitation. The Assembly
recognized the right of every human being to have access to sufficient water for personal
and domestic uses (between 50 and 100 litres of water per person per day), which must
be safe, acceptable and affordable; (water costs should not exceed 3 per cent of household
income), and physically accessible (the water source has to be within 1000 m of the home
and collection time should not exceed 30 min).” (UN-Water 2019)
The Amin and Min thresholds are rather common in programs and publications,
however, the Amax and Max thresholds are less discussed and analysed. Almost
everything in our universe work according to an equilibrium between minimum
and maximum for most of descriptors, because outside these extremes the system
becomes unsustainable. Let us see examples:
• Why cells of our body should stop dividing after their maximum? (if not, we call
it cancer)
• Why human body temperature has maximum?
• Why speed in the physical universe has a maximum? (of light)
• Why plants have maximum rate of transpiration?
• Why speed of the automobiles in a highway should have maximum?
• Why the discharge of a specific water pump has a maximum?
The answer to these and many other similar questions is that we live in a vast and
deep interconnected world, and the necessary human and nonhuman relationships
proceed from the reality of things, and not our superficial and superstitious perceptions (at least in long term). This has many meanings, including the fact that there
73
being more insightful and easy to summarize in three categories, and hence the
option in this book. To set up this choice for the indicator of interest, we need four
thresholds, which are the boundaries between two consecutive categories. Sometimes
the naming, their four values and corresponding colours are already defined within
laws and regulations, e.g., at the national level, however we employ the following
generic naming with Amax > Max > Min > Amin:
• Absolute minimum (Amin): the value of the indicator of interest for any member
must be greater than or equal to Amin
• Minimum (Min): the value of the indicator of interest for any member must be
greater than or equal to Min under non-transitory conditions
• Maximum (Max): the value of the indicator of interest for any member must be
less than or equal to Max under non-transitory conditions
• Absolute maximum (Amax): the value of the indicator of interest for any member
must be less than or equal to Amax
Transitory conditions should be rare, and the system design should be under
normal or non-transitory state. Let us be clear that these thresholds are set at the lowest
level of authority as possible. For example, if there is no national level regulation on
any of these thresholds, then local water managers should define them in consultation
with all the stakeholders. Anyhow, in setting the thresholds, international guidelines
such as the following can be very helpful:
“One of the most important recent milestones has been the recognition in July 2010 by the
United Nations General Assembly of the human right to water and sanitation. The Assembly
recognized the right of every human being to have access to sufficient water for personal
and domestic uses (between 50 and 100 litres of water per person per day), which must
be safe, acceptable and affordable; (water costs should not exceed 3 per cent of household
income), and physically accessible (the water source has to be within 1000 m of the home
and collection time should not exceed 30 min).” (UN-Water 2019)
The Amin and Min thresholds are rather common in programs and publications,
however, the Amax and Max thresholds are less discussed and analysed. Almost
everything in our universe work according to an equilibrium between minimum
and maximum for most of descriptors, because outside these extremes the system
becomes unsustainable. Let us see examples:
• Why cells of our body should stop dividing after their maximum? (if not, we call
it cancer)
• Why human body temperature has maximum?
• Why speed in the physical universe has a maximum? (of light)
• Why plants have maximum rate of transpiration?
• Why speed of the automobiles in a highway should have maximum?
• Why the discharge of a specific water pump has a maximum?
The answer to these and many other similar questions is that we live in a vast and
deep interconnected world, and the necessary human and nonhuman relationships
proceed from the reality of things, and not our superficial and superstitious perceptions (at least in long term). This has many meanings, including the fact that there