Physical Supply and Use tables (PSUT)

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Physical Supply and Use tables (PSUT)
SEEAW training New York, 13-17 November 2006
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Outline

• What do PSUT measure?
• Basic definitions
• Industry breakdown
• SEEAW standard tables
• Supplementary tables/information
• Breakdown of water flows
• Matrix of flows within the economy
• Water losses in distribution

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What do PSUT measure?

• PSUT describe in physical units
• The exchanges of water between the environment
  and the economy (abstraction and returns)
• The exchanges of water within the economy (supply
  and use within the economy)

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Why compiling PSUT

• PSUT are important because
• They allow for the identification of the
  activities/sectors which put more pressure on the
  environment
• They provides indication of the more consumptive
  use
• Together with monetary data, they provide
  information for water allocation policies

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Basic concepts and definitions
Evapotranspire

Economic activity/ Households
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PSUT

• By columns, industries, households and the Rest
  of the world
• By rows, types of flows
• SNA identity Supply is equal to the Use holds
• They consist of three part
• Flows from the environment to the economy
• Flows within the economy
• Flows from the economy to the environment

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Industry breakdown

• Standard PSUT distinguishes the following groups
• ISIC 1-3 which includes Agriculture, Forestry and
  Fishing
• ISIC 5-33, 41-43 which includes Mining and
  quarrying, Manufacturing and Construction
• ISIC 35 - Electricity, gas, steam and air
  conditioning supply
• ISIC 36 - Water collection, treatment and supply
  
• ISIC 37 - Sewerage
• ISIC 38, 39, 45-99, which corresponds to the
  Service industries.

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Industry breakdown

• ISIC 36 and 37 are key activities for the
  distribution of water and wastewater services
• ISIC 35 is a major user of water for
  hydroelectric power generation and cooling
  purposes it abstracts and returns into the
  environment enormous quantities of water.
  Aggregating information on water use and supply
  by ISIC 35 with that of other industries would
  provide misleading information.

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Industry breakdown

• ISIC does not classify according to the
  institutional sector (government, households,
  NPISH and corporations) to which a statistical
  unit belongs.
• Activities carried out by government units that
  are specifically attributable to other divisions
  of ISIC should be classified in the appropriate
  division of ISIC and not in division 84, ISIC
  Rev. 4.

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Flows from the environment to the economy
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Basic concepts and definitions

• Abstraction is defined as the amount of water
  that is removed from any source, either
  permanently or temporarily, in a given period of
  time for consumption and production activities.
  Water used for hydroelectric power generation, is
  also considered as abstraction.

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Abstraction

• Abstraction from soil water includes rainfed
  agriculture
• Collection of precipitation is the direct
  collection of precipitation for production and
  consumption activities (rain roof harvest)
• Abstraction from the sea includes the cases of
  water used for cooling purposes (the
  corresponding wastewater flow is generally
  returned to the sea or ocean) and for
  desalination processes

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Flows within the economy
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Water supply

• Water supply is recorded net of losses in
  distribution
• Water losses in distribution volume of water
  lost during transport through leakages and
  evaporation between a point of abstraction and a
  point of use, and between points of use and
  reuse.
• Losses in distribution may occur because of
  leakages and evaporation

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Wastewater

• Wastewater water which is of no further
  immediate value to the purpose for which it was
  used or in the pursuit of which it was produced
  because of its quality, quantity or time of
  occurrence.
• Wastewater can be discharged directly into the
  environment (return flow), supplied to a
  treatment facility (ISIC 37) (wastewater to
  Sewerage) or supplied to another industry for
  further use (reused water).

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Reused water

• Reused water wastewater delivered to a user for
  further use with or without prior treatment.
  Recycling within industrial sites is excluded.
• It is important to record this reused water as it
  can alleviate the pressure on water resources by
  reducing direct abstraction of water.

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Flows from the economy to the environment
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Standard PSUT
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Water Use

• Water use water intake of industries and
  households for production and consumption
  activities. Water Use is the sum of water use
  within the economy and water use from the
  environment.
• Water use within the economy water intake for
  production and consumption activities, which is
  distributed by industries or households and by
  the Rest of the World (Imports).
• Water use from the environment water abstracted
  from water resources, seas and oceans, and
  precipitation collected by industries and
  households for production and consumption
  activities, including rainfed agriculture.

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Water Supply

• Water supply water leaving/flowing-out from an
  economic unit (Industries, Households and rest of
  the world). Water supply is the sum of water
  supply to other economic units and water supply
  to the environment.
• Water supply to the environment (also Water
  returns) water returned into the environment
  during a given period of time after use. Returns
  can be classified according to the receiving
  media (i.e. water resources and sea water) and to
  the type of water (e.g. treated water, cooling
  water, etc.).
• Water supply within the economy water
  distributed to households and industries
  (including agriculture) and to the rest of the
  world (exports). Water supply within the economy
  is net of losses in distribution.

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Water consumption

• Water consumption part of water use which is not
  distributed to other economic units and does not
  return to the environment (to water resources,
  sea and ocean) because during use it has been
  incorporated into products, consumed by
  households or livestock.
• It is calculated as a difference between total
  use and total supply, thus it may include losses
  due to evaporation occurring in distribution and
  apparent losses due to illegal tapping and
  malfunctioning metering

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Supplementary information (1)

• Abstraction for own use
• Hydroelectric power generation
• Irrigation water
• Mine water
• Urban runoff
• Cooling water
• Other

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Supplementary information (2)

• Use of water received from other economic units
• Reused water
• Supply of water to other economic units
• Desalinated water

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Supplementary information (3)

• Matrix of flows within the economy

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Supplementary information (4)

• Tables on losses in distribution