Physical Supply and Use Tables in SEEAW Data sources and methods

Regional Workshop on Water Accounting Santo Domingo, Dominican Republic 16-18 July 2007 Michael Vardon United Nations Statistics Division 1

Consumption = 45 units 5 by Water Supply industry + 35 by all other industry + 5 by households WATER SUPPLY INDUSTRY 100 units abstracted from environment Evaporation 5 units 15 units leakage Leakage 15 units ENVIRONMENT WATER USERS ALL INDUSTRY - 60 units HOUSEHOLDS -20 units 40 units returned to environment (25 by industry, 15 by households)

Physical Use Table

Simplified table with data from diagram on consumption and losses

1. Total Abstraction

1.a Abstraction for own use 1.b Abstraction for distribution

2. Use of water from other economic units 3. TOTAL USE (=1+2)

Physical Supply Table Water Supply ISIC 36 100 0 100 100 Water Supply ISIC 36 All Industry All ISIC (except 36) 60 60 All Industry All ISIC (except 36) Households 20 20 Households Row Total 0 100 80 180 Row Total

4. Supply of water together economic units 5. Total returns to environment 6. TOTAL SUPPLY (=4+5) 7. CONSUMPTION (=3-6)

80 15 95 5 25 25 35 15 15 5 80 45 135 45

A practical example

• • • • • • Cola City Soft drink production ISIC 11 Electricity production ISIC 35 Water supply ISIC 36 Sewerage ISIC 37 Transport ISIC 49 Households Water source Surface water – the Soda River

Only households in city 16 6 Cola City 26 Losses 4 30 5 4 Transport use 5t ISIC 49 Losses 1 Losses 14 Soft Drink Production ISIC 11 100 Water Supply Industry ISIC 36 62 48 2 Hydro-Electricity production ISIC 35 1 150 149 Soda River 4 5 6 24 Sewerage Treatment ISIC 37

SEEA Water in practice

• SEEA Water provides a clear picture of what water accounts should look like.

• However detailed guidance on how to populate the tables is lacking • UNSD is developing a practical manual to help countries implement SEEA Water • Some material to help you get started follows The material is not meant to provide comprehensive. It is a brief introduction.

Getting started on PSUT

Data Sources • Consult widely on data availability Some likely problems • While there may be data, it is unlikely to be exactly what you need for water accounts If you wait for perfect data, you will never get started!

Data sources

• • • • • • Surveys, particularly of water supply industry Annual reports of water supply industry Industry Association Reports (they sometimes conduct their own surveys) Government reports Administrative data (e.g. of licensed abstractions) Based on correlated data and some industry specific coefficients of water use (e.g. irrigate area, number of employees, value added)

Some likely problems with data

• • • • For many cell in the tables, there are no or poor quality data Data is available for different spatial boundaries Data is available for different time periods Data from some sources that are not consistent with SEEA Water (e.g. ISIC not used)

No data or poor quality data

• • • In the short term these problems may be overcome through use of coefficients Good data are needed for Agriculture, Energy Supply (especially hydropower), Water Supply and Sewerage industries (ISIC 1, 35, 36 and 37). In the long term, you will need to collect data or identify alternative data sources (may be a a potential source has been overlooked?)

Spatial boundaries

• • • • Administrative areas: e.g. countries, provinces, statistical classifications, water supply areas (e.g. cities) Physical areas: e.g. River Basins, drainage divisions, water catchments • Apparently no international classification system Some issues • Country borders override river basins • Physical boundaries overlap groundwater aquifers vs river basins Water Accounting catchments: hybrid areas using the best possible compromise between the different boundaries. • The may align with one set of boundaries completely.

Different spatial boundaries

Administrative regions Overlapped areas River basins Administrative regions River basins

China 10 hydrological regions at 1st class 31 provincial regions 750 statistics units overlapping prefectures and hydrological regions at 2rd class

Reallocating data from one spatial boundary to another

A simple solution is to assume data are equally spread across the areas and may be allocated based on amount of area. This is relatively easy if you have access to a Geographic Information System (GIS)

Reallocation method

E.g. If 25% of the area of Administrative Region A is in River Basin 1 , then 25% of the water use may be allocated to Region A. River Basin 2 Region A River Basin 1 Legend River basin boundary Administrative boundary River Region A

Accuracy of reallocation

Reallocation produces errors!

• Example from Australia

Data are available for different time periods

• Calendar years 1 January – 31 December • Financial years Business accounting periods which vary from country to country • Water years “continuous 12-month period selected in such a way that overall changes in storage are minimal so that carryover is reduced to a minimum”

Data is not consistent with ISIC

While data sources from national statistical departments are likely to use ISIC, others may not, particularly for the classifications of water users. In these cases, the other classifications need to be harmonized with ISIC.

It is typical that water supply industry will use very simple classification. For example: • Households/all other uses or • Rural/urban. Rural often means agricultural • Rural/Urban household/Urban industry In these cases additional information is needed to split the data and allocate to ISIC industries.

Final thoughts

• • • Water accounts are complex They will take time to develop There will be lots of problems but most can be solved There many ways to populate the tables with data – which you use will depend on the data and other resources available to you • • • You will need to: Be patient, systematic, thoughtful Work with a wide range of people – you will need to convince people to cooperate with you Work hard and imaginatively to overcome problems

Contact details

Ilaria Di Matteo United Nations Statistics Division New York 10017 USA Room DC2 1524 Phone: +1 917 963 8491 Fax: +1 212 963 1374 Email: [email protected]

Michael Vardon United Nations Statistics Division New York 10017 USA Room DC2 1532 Phone: +1 917 367 5391 Fax: +1 212 963 1374 Email: [email protected]