ANNUAL
WITHDRAWALS OF GROUND AND SURFACE WATER |
Environmental |
Chapter 18 |
Driving Force |
1. Indicator
(a)Name: Annual withdrawals of ground and
surface water as of a percent of available water.
(b)Brief Definition: The total annual gross volume of ground and
surface water extracted for water uses, including conveyance losses,
consumptive uses and return flows, as a percentage of the total average
annually available volume of freshwater.
(c)Unit of Measurement: %.
2. Placement in the Framework
(a) Agenda 21: Chapter 18: Protection of the
Quality and Supply of Freshwater Resources: Application of Integrated
Approaches to the Development, Management, and Use of Water Resources.
(b) Type of Indicator: Driving Force.
3. Significance (Policy Relevance)
(a) Purpose: The purpose of this indicator
is to show the degree to which available water resources are being
exploited to meet the country's water demands. It is an important measure
of a country's vulnerability to water shortages.
(b) Relevance to Sustainable/Unsustainable
Development: The indicator can show to what extent freshwater
resources are already used, and the need for adjusted supply and demand
management policy. It can reflect the extent of water resource scarcity
with increasing competition and conflict between different water uses and
users. Limited availability of water could have negative effects on
sustainability constraining economic and regional development, and leading
to loss of biodiversity with degradation of freshwater ecological systems.
Sustainability assessment of changes in the indicator is linked to water
availability. The indicator's variation between countries as well as in
time is a function of climate, population, and economic development, as
well as the economic and institutional capacity to manage water resources
and demand.
(c) Linkages to Other Indicators: The
indicator's interpretation would benefit from linkage with established
water vulnerability indicators, such as available freshwater resources per
capita, measures of the country's economy, such as Gross Domestic Product
(GDP), and poverty incidence as an indicator of equity of access. The
indicator also needs to be matched with population, social and economic
indicators, irrigation as % of arable land, and drought frequency.
Interpretation will benefit from linking this indicator with groundwater
reserves and unused buffer water resources.
(d) Targets: No international target exists
other than those set by international treaties between countries.
(e) International Conventions and Agreements:
For international water law, see reference in section 7 below. International
water sharing agreements also exist between many countries.
4. Methodological Description and Underlying
Definitions
(a) Underlying Definitions and Concepts: A
major problem is to define available water and to differentiate between
groundwater and surface water. The only approach which respects the
physical integrity of the water resources is to consider where it is
produced internally, that is from precipitation inside the boundaries of
the country/area. Internal renewable water resources does not account for
water generated in neighbouring countries nor does it make the distinction
between groundwater and surface water. This approach brings a number of
limitations which are described below.
(b) Measurement Methods: The indicator
measures total water abstractions divided by available water.
(c) The Indicator in the DSR Framework: The
indicator is a reflection of socioeconomic factors, such as population
growth and economic development. The expansion of irrigated lands can have
a large impact on water demand. Thus, the indicator represents a Driving
Force within the DSR Framework.
(d) Limitations of the Indicator: This
indicator has several important limitations, most of them related to the
computation of available water. Accurate and complete data are scarce.
Countries may be able to use important non-renewable fossil groundwater at
a sustainable rate. Available waters are internal from endogenous
precipitation or shared and external from outside the country. Except in a
few cases, no consideration is given to recycling or the possible double
counting of shared water resources. Available waters can be enhanced
through water resources development (flow-regulating reservoirs,
inter-basin transfers, groundwater development etc.) and policy measures
(allocation and pricing), and need to be judged by economic and
environmental considerations and institutional capacity. Return flows and
percolation losses which could enhance available waters are not
considered. Local sub-national variation of water availability and water
use abstractions could be considerable, and this indicator does not
reflect the local or individual watershed situation. Seasonal variation in
water availability is not reflected. There is no consideration of
distribution among uses and policy options for mitigating scarcity, for
example, re-allocation from agricultural to other uses. Available water
does not consider water quality and its suitability for use.
(e) Alternative Definitions: The indicator
could consider withdrawals and available waters at different levels of use
efficiency and economic and environmental water costs and values. The data
for such calculations, however, are not readily available. For some
countries, calculation of the indicator at sub-national levels would be
more appropriate. The indicator could be disaggregated to show available
water, withdrawals, and irrigation use.
5. Assessment of the Availability of Data from
International and National Sources
(a) Data Needed to Compile the Indicator:
Annual water withdrawals divided with average annual available water.
Current water uses need to be known.
(b) Data Availability: Data is available for
most countries, at the national level. Data quality is a problem in
AQUASTAT (see 5c below) as the data are estimated by countries at various
periods, are often repeatedly developed from the same original sources,
are often interpolated and national data on withdrawals and available
water are sometimes biased and intentionally over- or underestimated.
(c) Data Sources: Recent data are available
at the country level and recorded at the international level by the UN
Food and Agriculture Organization (FAO) in AQUASTAT (1994/1995).
6. Agencies Involved in the Development of the
Indicator
The lead agency is the United Nations Food and
Agriculture Organization (FAO). The contact point is the Assistant
Director General, Sustainable Development Department, FAO; fax no. (39 6)
5225 3152.
7. Further Information
Mar del Plata 1977, Dublin ICDE 1992. International
Water Law. Helsinki Rules on Use of Waters of International Rivers 1966
and Seoul Rules, International Groundwaters 1986.
Shiklomanov. Global Water Resources. 1990.
DOMESTIC
CONSUMPTION OF WATER PER CAPITA |
Environmental |
Chapter 18 |
Driving Force |
1. Indicator
(a) Name: Domestic consumption of water per
capita.
(b) Brief Definition: Domestic consumption of water per capita is
the amount of water consumed per person for the purposes of ingestion,
hygiene, cooking, washing of utensils and other household purposes
including garden uses. Where it is customary for domestic animals to be
kept at or in the living environ their needs are also included in the
assessment.
(c) Unit of Measurement: Litres per capita per day.
2. Placement in the Framework
(a) Agenda 21: Chapter 18: Protection of the
Quality and Supply of Freshwater Resources: Application of Integrated
Approaches to the Development, Management, and Use of Water Resources.
(b) Type of Indicator: Driving Force.
3. Significance (Policy Relevance)
(a) Purpose: The indicator assesses the
quantity of water needed and/or available to individuals in particular
communities for their basic needs. It helps to identify communities where
these basic requirements are not being met enabling actions to be planned
and priorities for water supply development to be set.
(b) Relevance to Sustainable/Unsustainable
Development: Adequate quantities of water for meeting basic human
needs are a prerequisite for existence, health, and development. If
development is to be sustained, adequate quantity of water must be
available. In fact, as development increases, in most instances, the
demand for water will also increase on a per capita basis for personal,
commercial, and agricultural purposes. Thus, the indicator can be used as
a useful indirect indicator of the level of social and economic
development.
If sustained development is achieved without, or
with a limited increase in per capita water consumption it can be a direct
indicator of effective water resource management. There is also a direct
relationship between per capita water consumption and water
availability/scarcity and pricing. Domestic water consumption is also
closely linked to climatic conditions and water availability. Clearly in
arid and semi-arid areas where water supplies are limited, consumption is
constrained.
(c) Linkages to Other Indicators: This
indicator is closely linked with several other socioeconomic and
environmental indicators, such as population growth rate, population
density, rate of growth of urban population, land use change, annual
withdrawals of ground and surface water, and irrigation percent of arable
land.
(d) Targets: Agenda 21 established a target
of access to at least 40 litres per capita per day of safe water in urban
areas by the year 2000.
(e) International Conventions and Agreements:
The United Nations Water Conference recommended that Governments reaffirm
their commitment made at Habitat to "adopt programmes with realistic
standards for quality and quantity to provide water for urban and rural
areas". The goal of universal coverage was reiterated at the World
Summit for Children in 1990. See also Agenda 21, section 3d above.
4. Methodological Description and Underlying
Definitions
(a) Underlying Definitions and Concepts:
Domestic water consumption although normally present in terms of litres
per capita per day is a computed figure since the parameter is household
water consumption. Household water consumption can be measured by meters
connected to a water distribution network or through a survey of the
number of journeys per day made to a standpost or water point.
(b) Measurement Methods: Per capita water
consumption can be measured (or estimated) through metered supply, local
surveys, sample surveys or total amount supplied to a community divided by
number of inhabitants.
(c) The Indicator in the DSR Framework: This
indicator measures water consumption per capita. As such, it is a Driving
Force in the DSR Framework.
(d) Limitations of the Indicator: Per capita
water consumption provides only one part of the picture with regard to
water supply. To assess the overall status of water supply provided to an
individual, it is necessary to combine consumption data with complementary
information on the quality of the water provided, the type of system used
to deliver the supply, the distance to be travelled to collect water,
number of people per households per water point, etc.
(e) Alternative Definitions: For domestic
use, this indicator can be replaced with household consumption per day.
However, this is a more limited measure of water consumption.
5. Assessment of the Availability of Data from
International and National Sources
(a) Data Needed to Compile the Indicator:
Record of water authorities' meter readings and the results of household,
sample and other surveys and research projects, as well as information
from project designs.
(b) Data Availability: Data is not normally
available on a routine basis but the World Health Organization (WHO) has
been obtaining estimates of national average figures from governments as
part of its water supply and sanitation monitoring activities.
(c) Data Sources: The data is available from
national water authorities and water supply utilities, field project
evaluation reports, and records of water supply development organizations.
6. Agencies Involved in the Development of the
Indicator
(a) Lead Agency: The lead agency is the
World Health Organization (WHO). The contact point is the Director,
Division of Operational Support in Environmental Health, WHO; fax no. (41
22) 791 4159.
(b) Other Organizations: Other relevant
organizations include: the United Nations Children's Fund (UNICEF) and the
United Nations Centre for Human Settlements (HABITAT).
7. Further Information
The International Drinking Water Supply and
Sanitation Decade, End of Decade Review (as at December 1990). WHO,
Geneva, WHO/CWS/92.12.
Water Supply and Sanitation Sector Monitoring
Report 1993. Sector Status as of 31 December 1991. WHO/UNICEF.
GROUNDWATER
RESERVES |
Environmental |
Chapter 18 |
State |
1. Indicator
(a) Name: Groundwater reserves.
(b) Brief Definition:
(c) Unit of Measurement:
2. Placement in the Framework
(a) Agenda 21: Chapter 18: Protection of the
Quality and Supply of Freshwater Resources: Application of Integrated
Approaches to the Development, Management, and Use of Water Resources.
(b) Type of Indicator: State.
(Indicator under development)
CONCENTRATION OF FAECAL
COLIFORMS IN FRESHWATER
|
Environmental
|
Chapter 18
|
State
|
1. Indicator
(a) Name: Concentration of faecal coliforms
in freshwater bodies.
(b) Brief Definition: The proportion of freshwater resources
containing concentrations of faecal coliforms which exceed the levels
recommended in the World Health Organization (WHO) Drinking Water
Guidelines.
(c) Unit of Measurement: %.
2. Placement in the Framework
(a) Agenda 21: Chapter 18: Protection of the
Quality and Supply of Freshwater Resources: Application of Integrated
Approaches to the Development, Management, and Use of Water Resources.
(b) Type of Indicator: State.
3. Significance (Policy Relevance)
(a) Purpose: The indicator assesses the
quality of water available to communities for basic needs. It identifies
communities where faecal contamination of water at source or in the supply
is posing a threat to health.
(b) Relevance to Sustainable/Unsustainable
Development: The concentration of faecal coliforms in freshwater
bodies is an indirect indicator of contamination with human and animal
excreta. Water contaminated with faecal coliforms poses a serious health
risk and is therefore unsuitable for potable supply without being
disinfected (chlorination). Faecal indicator organisms remain the most
sensitive and specific way of assessing the hygienic quality of water.
Escherichia coli (E. coli), the thermotolerant and other coliform
bacteria, the faecal streptococci and spores of sulphite-reducing
clostridia, are common indicators of this type used, with E. coli being
the most specific of all indicators. This measure indicates situations
where treatment is required or has to be improved to guarantee safety of
supply. As population density increases and/or more people are provided
from a supply system, the more critical safe, potable water becomes.
Diarrhoeal diseases, largely the consequence of
faecal contamination of drinking water supply, are variously estimated to
be responsible for around 80% of morbidity/mortality in developing
countries. A prerequisite for development is a healthy community. Ill
health not only reduces the work capability of community members but
frequent diarrhoeal episodes disrupt children's education which, in the
longer term, can have serious consequences for sustainable development.(c)
Linkages to Other Indicators: The indicator is closely linked with
several others in the environmental and socioeconomic (health) categories,
including annual water withdrawals, domestic consumption of water per
capita, biochemical oxygen demand in water bodies, waste water treatment
coverage, and percent of population with adequate excreta disposal
facilities.
(d) Targets: The standards are available in
the WHO Drinking Water Guidelines. These have been adopted by most
countries.
(e) International Conventions and Agreements:
The United Nations Water Conference recommended governments reaffirm the
commitment made at Habitat to adopt programmes with realistic standards
for water quantity to provide sanitation for urban and rural areas. The
goal of universal coverage was reiterated at the World Summit for Children
in 1990.
4. Methodological Description and Underlying
Definitions
(a) Underlying Definitions and Concepts:
Ideal faecal indicator characteristics are difficult to find in any one
organism. However, many useful characteristics are found in E.coli and, to
a lesser extent, in the thermotolerant coliform bacteria. For this reason
E. coli tends to be the preferred/recommended faecal contamination
indicator. Faecal streptococci satisfy some of the criteria and tend to be
used as supplementary indicators of faecal pollution indicating human and
animal faeces.
(b) Measurement Methods: Microbiological
examination provides the most sensitive, although not the most rapid,
indication of pollution by faecal matter. Because the growth medium and
the conditions of incubation, as well as the nature and age of the water
sample, can influence microbiological analysis, accuracy of results may be
variable. This means that the standardization of methods and laboratory
procedures are extremely important. Established standard methods are
available through the International Organization of Standardization (ISO),
American Public Health Association (APHA), the UK Department of Health and
Social Security, and the Guidelines for Drinking-Water Quality (WHO).
Determination of sample size is the first important
step in the examination. The source of the sample will determine in the
first instance the concentration of organisms. Under normal conditions,
the volume of sample for a lake or reservoir sample would be 100 ml.,
while in the case of raw municipal sewage only 0.001 ml. would be
required. Larger samples would result in too large a number of organism to
make counting possible. Time-of-travel may often be of relevance and
changes in the bacterial characteristics of samples can be reduced to a
minimum by ensuring the samples are not exposed to light and are kept
preferably between 4 and 100C. Such precautions are particularly important
in tropical climates where ambient temperatures are high and sunlight
(ultra-violet radiation) is brightest.
(c) The Indicator in the DSR Framework: The
indicator shows the level of health risk for the community utilizing the
source of water for potable and hygienic purposes. It represents a State
indicator in the DSR Framework.
(d) Limitations of the Indicator:
Concentration of E. coli in a water sample provides only one part of the
picture with regard to water quality. To assess the overall status of
water at source and supplied for potable and other uses, it is necessary
to combine the information of this indicator with complementary data on
physical and chemical quality. E. coli is an indicator but not a pathogen
by itself.
(e) Alternative Definitions: The indicator
could be shown as the proportion of the population using water source for
domestic water supply that do not meet the standards. The microbiological
quality of water in relation to faecal contamination can be defined in
terms of Escherichia coli, thermotolerant coliform bacteria, total
coliform organisms, faecal streptococci, sulphite-reducing clostridia/
coliphages and bifidobacteria.
5. Assessment of the Availability of Data from
International and National Sources
(a) Data Needed to Compile the Indicator:
Records of water authorities' laboratories, hydrogeological institutes,
universities, municipal public health laboratories, research institutes,
and special studies which show the level of E. coli.
(b) Data Availability: Data are normally
available from municipal water supply authorities on a routine basis.
Ministries of health in many countries often check on the bacterial
quality of new sources when they are being considered for supply purposes.
(c) Data Sources: The data are available
from national water authorities and water supply utilities, ministries of
health, and research institutes.
6. Agencies Involved in the Development of the
Indicator
(a) Lead Agency: The lead agency is the
World Health Organization (WHO). The contact point is the Director,
Division of Operational Support in Environmental Health, WHO; fax no. (41
22) 730 6449.
(b) Other Organizations: Other organizations
contributing to the development of this indicator include: the Water and
Environmental Sanitation Section, United Nations Children's Fund (UNICEF);
United Nations Centre for Human Settlements (HABITAT); and the Land and
Water Division, Food and Agriculture Organization (FAO).
7. Further Information
(a) Further Readings:
WHO. Guidelines for Drinking-Water Quality. Second
Edition, Volumes 1 and 3 Recommendations, WHO, Geneva, 1993.
American Public Health Association, American Water
Works Association, and Water Pollution Control Federation. Standard
Methods for the Examination of Water and Wastewater. 17th Edition. 1989.
International Organization for Standardization.
Water Quality: Detection and Enumeration of the Spores of Sulphite-reducing
Anaerobes (clostridia). Part 1: Method by Enrichment in a Liquid Medium.
ISO 646171.
International Organization for Standardization.
Water Quality: Enumeration of Viable Micro-organisms--Colony Count by
Inoculation in or on a Nutrient Agar Culture Medium. ISO 6222.
International Organization for Standardization.
Water Quality: General Guide to the Enumeration of Micro-organisms by
Culture. ISO 8199.
International Organization for Standardization.
Water Quality: Detection and Enumeration of Coliform Organisms,
Thermotolerant Coliform Organisms and Presumptive Escherichia coli, ISO
9308-2; Part 1 Membrane Filtration Method, Part 2 Multiple Tube. ISO
9308-1.
International Organization for Standardization.
Water Quality: Detection and Enumeration of Pseudomonas Aeruginosa; Part 1
Method by Enrichment in Liquid Medium, Part 2 Membrane Filtration Method.
ISO 8360-2.
International Organization for Standardization.
Water Quality: Detection and Enumeration of Faecal Streptococci; Part 1
Method by Enrichment in a Liquid Medium, Part 2 Method by Membrane
Filtration. ISO 7899/2.
BIOCHEMICAL
OXYGEN DEMAND IN WATER BODIES |
Environmental |
Chapter 18 |
State |
1. Indicator
(a) Name: Biochemical oxygen demand (BOD) in
water bodies.
(b) Brief Definition: BOD measures the amount of oxygen required or
consumed for the microbiological decomposition (oxidation) of organic
material in water.
(c) Unit of Measurement: mg/l of oxygen consumed in 5 days at a
constant temperature of 20oC.
2. Placement in the Framework
(a) Agenda 21: Chapter 18: Protection of the
Quality and Supply of Freshwater Resources: Application of Integrated
Approaches to the Development, Management, and Use of Water Resources.
(b) Type of Indicator: State.
3. Significance (Policy Relevance)
(a) Purpose: The purpose of this indicator
is to assess the quality of water available to consumers in localities or
communities for basic and commercial needs.
(b) Relevance to Sustainable/Unsustainable
Development: Sustainable development is heavily dependant on suitable
water availability for a variety of uses ranging from domestic to
industrial supplies. Strict water quality standards have been established
to protect users from health and other adverse consequences of poor water
quality. The presence of BOD as an indicator of faecal contamination can
restrict water use and development or necessitate expensive treatment. Ill
health due to water quality problems can reduce work capability and affect
children's growth and education. It is, therefore, important to monitor
organic pollution to identify areas posing a threat to health, to identify
sources of contamination, to ensure adequate treatment, and provide
information for decision making to enhance water sustainability.
(c) Linkages to Other Indicators: Several
indicators are directly linked to the concentration of organic material in
freshwater. These measures include annual withdrawals of ground and
surface water, domestic consumption of water per capita, concentration of
faecal coliforms in freshwater, percent of population with adequate
excreta disposal facilities, access to safe water, infant mortality rate,
nutritional status of children, environmental protection expenditures as a
percent of Gross Domestic Product, and expenditure on waste collection and
treatment.
(d) Targets: Not available.
(e) International Conventions and Agreements:
The Resolution II and Plan of the United Nations Water Conference
recommended governments reaffirm the commitment made at Habitat to
"adopt programmes with realistic standards for quality and quantity
to provide water for rural and urban areas". The goal of universal
safe water coverage was reiterated at the World Summit for Children in
1990.
4. Methodological Description and Underlying
Definitions
(a) Underlying Definitions and Concepts: BOD
is an empirical test to provide a measure of the level of organic material
in a body of water. The test involves the incubation of a diluted sample
for a period of five days at a constant temperature of 20oC. The sample is
diluted to bring it within the operational parameters of the test
procedure. The test represents a standard laboratory procedure usually
referred to as the BOD5 test.
The procedure is used to estimate the relative
oxygen requirements of waste waters, effluents, and other polluted waters.
Micro-organisms use the oxygen in the water for biochemical oxidation of
polluting matter, which is their source of carbon.
(b) Measurement Methods: The method used
consists of filling to overflowing an airtight bottle of specified size
with the water sample to be tested. It is then incubated at a constant
temperature for five days. Dissolved oxygen is measured initially and
after incubation. The BOD5 is then computed from the difference between
the initial and final readings of dissolved oxygen.
(c) The Indicator in the DSR Framework: This
indicator is a measure of the State of water quality.
(d) Limitations of the Indicator: The main
limitation of the indicator is that it provides empirical and not absolute
results. It gives a good comparison among samples, but does not give an
exact measure of the concentration of any particular contaminant. It is
important to follow laboratory procedures precisely to obtain consistent
results. The five-day time-frame to obtain results represents the main
operational drawback of the indicator.
(e) Alternative Definitions: Chemical Oxygen
Demand (COD) is an alternative measure of the oxygen equivalent of the
organic matter content of a sample that is susceptible to oxidation by a
strong chemical exigent. COD can be empirically related to BOD5. After
this correlation is determined for a specific source, it is a useful
measure obtained from an instantaneous chemical test.
5. Assessment of the Availability of Data from
International and National Sources
(a) Data Needed to Compile the Indicator:
BOD5 results from laboratories.
(b) Data Availability: Data is normally
available from municipal waste water treatment and discharge facilities on
a routine basis.
(c) Data Sources: The data is available from
the laboratories of water or public health authorities, water research
institutes, and universities. At the national level, the data sources
include national water authorities, water supply utilities, ministries of
health or environment, and research institutions.
6. Agencies Involved in the Development of the
Indicator
(a) Lead Agency: The lead agency responsible
for the development of this indicator is the World Health Organization
(WHO). The contact point at WHO is the Director, Division of Operational
Support in Environmental Health; fax no. (41 22) 791 4159.
(b) Other Organizations: Other agencies
assisting in the development of this indicator include the United Nations
Children's Fund (UNICEF); United Nations Centre for Human Settlements
(Habitat); and the United Nations Food and Agriculture Organization (FAO).
7. Further Information
American Public Health Association, American Water
Works Association, and Water Pollution Control Federation. Standard
Methods for the Examination of Water and Wastewater. 17th Edition. 1989.
International Standards Organization. Water
Quality--Determination of Biochemical Oxygen Demand after Five Days
(BOD5). ISO 5815. 1989.
International Standards Organization. Water
Quality--Determination of the Chemical Oxygen Demand. ISO 6060. 1989.
WASTEWATER
TREATMENT |
Environmental |
Chapter 18 |
Response |
1. Indicator
(a) Name: Wastewater treatment coverage.
(b) Brief Definition: The treatment of wastewater can be defined as
the collection of waste- water from household, commercial, industrial or
public premises and its conveyance to a location where it receives
treatment sufficient to permit its discharge to the environment without
adverse impact on public health and the ecosystem.
(c) Unit of Measurement: %. Proportion of the wastewater generated
by the community receiving acceptable levels of treatment prior to
discharge.
2. Placement in the Framework
(a) Agenda 21: Chapter 18: Protection of the
Quality and Supply of Freshwater Resources: Application of Integrated
Approaches to the Development, Management, and Use of Water Resources.
(b) Type of Indicator: Response.
3. Significance (Policy Relevance)
(a) Purpose: This indicator assesses the
potential level of pollution from domestic and industrial/commercial point
sources entering the aquatic environment, and monitors progress towards
reducing this potential within a framework of integrated water resources
management. It helps to identify communities where wastewater treatment
action is required to protect the ecosystem.
(b) Relevance to Sustainable/Unsustainable
Development: In many countries the large proportion of wastewater is
discharged to the environment with little or no treatment. This is
economically, socially, and environmentally unsustainable, especially
recognizing the increasing demands on finite water resources, rapidly
expanding populations particularly in urban areas, industrial expansion,
and the need to expand irrigated agriculture. Low water quality reduces
the availability of water resources for specific uses, in particular
domestic needs; and has adverse implications for public health. Wastewater
treatment, therefore, is central to the requirements for sustainability.
The situation is particularly serious in developing countries where
financial resources for pollution control are scarce.
(c) Linkages to Other Indicators: This
indicator has important linkages to other socioeconomic and environmental
indicators, such as annual withdrawals of ground and surface water, the
levels of biochemical oxygen demand (BOD) in water resources,
concentration of faecal coliforms, population growth, informal
settlements, infrastructure expenditure, and generation of waste.
(d) Targets: Agenda 21 recommends that
quantitative and qualitative discharge standards for municipal and
industrial effluents are established and applied by the year 2000.
(e) International Conventions and Agreements:
The United Nations Water Conference recommended governments reaffirm the
commitment made at Habitat to adopt programmes with realistic standards
for water quantity to provide sanitation for urban and rural areas. The
goal of universal coverage was reiterated at the World Summit for Children
in 1990.
4. Methodological Description and Underlying
Definitions
(a) Underlying Definitions and Concepts: The
proportion of wastewater treated is the percentage of water consumed and
returned to the environment according to criteria and standards that
ensure that it does not impact on the aquatic environment to the detriment
of sustainable development. Within this context, treatment can comprise a
wide range of processes including simple screening, sedimentation,
biological-chemical processes, or appropriately designed marine discharge.
(b) Measurement Methods: The proportion of
domestic waste (sewage) treated in urban areas can be determined on the
basis of the quantity of water consumed by households as compared to the
capacity of wastewater treatment facilities. It can also be estimated on
the basis of areas of a community connected to the sewerage system and the
population inhabiting these localities.
In the case of industrial waste a similar approach
can be taken for those installations which are connected to a central
sewerage system, using water consumption and allowing for the
differentiation between process and cooling waters. In many cases,
industrial establishments, either discharging their effluents direct or
through the public sewerage system, have their own treatment facilities.
As far as the efficacy of treatment is concerned,
this can only be determined from the performance information for each
waste treatment plant judged against established discharge criteria.
(c) The Indicator in the DSR Framework: This
indicator reflects a societal Response towards the treatment of waste and
the protection of human health and ecosystems.
(d) Limitations of the Indicator: The main
limitation of this indicator is the effort required to collect and collate
the information. This can be avoided at least to some extent, through the
use of estimates. This indicator provides information on the degree of
treatment. It does not, however, deal with the level of treatment required
to meet the requirements of specific ecosystems.
(e) Alternative Definitions: The proportion
of wastewater treated can be converted into a quantity of wastewater.
These loadings can be defined in terms of a weekly, monthly, or annual
burden by catchment, water source, or other boundary. For some countries,
it may be practical and useful to keep household, and commercial and
industrial wastes separate.
5. Assessment of the Availability of Data from
International and National Sources
(a) Data Needed to Compile the Indicator:
The data required include records of water authorities' meter readings;
data on the capacity service area; and performance of waste treatment
facilities; information on industrial processes and trade-waste treatment
plants; information from wastewater laboratories; and number of house
connections to the sewerage system.
(b) Data Availability: Data is often not
available, or is incomplete. Without surveys of individual industrial
establishments or environmental impact assessments associated with new
industrial developments, data will remain partial or, at best professional
estimates.
(c) Data Sources: The data are available
from national water authorities and water supply utilities, river basin/catchment
authorities, municipal authorities, industry and field project evaluation
reports.
6. Agencies Involved in the Development of the
Indicator
(a) Lead Agency: The lead agency is the
World Health Organization (WHO). The contact point is the Director,
Division of Operational Support in Environmental Health, WHO; fax no. (41
22) 791 4159.
(b) Other Organizations: Other contributing
organizations include the United Nations Centre for Human Settlements
(HABITAT) and the United Nations Environment Programme (UNEP).
7. Further Information
The World Bank. Development and the Environment:
World Development Indicators. World Development Report 1992.
DENSITY OF
HYDROLOGICAL NETWORKS |
Environmental |
Chapter 18 |
Response |
1. Indicator
(a) Name: Density of hydrological networks.
(b) Brief Definition: Density of hydrological networks is defined
as the average area served by one hydrological station. It is derived by
dividing the area of the territory by the number of hydrological stations
operated within this territory.
(c) Unit of Measurement: Area in km2 per station.
2. Placement in the Framework
(a) Agenda 21: Chapter 18: Protection of the
Quality and Supply of Freshwater Resources: Application of Integrated
Approaches to the Development, Management, and Use of Water Resources.
(b) Type of Indicator: Response.
3. Significance (Policy Relevance)
(a) Purpose: To assess the adequacy of
existing hydrological networks to provide the necessary information on
freshwater in the context of freshwater assessment. The density should be
sufficient to avoid deficiencies in assessing, developing, and managing
water resources.
(b) Relevance to Sustainable/Unsustainable
Development: Adequate hydrological networks to provide data on
freshwater are important to support sustainable development. Hydrological
observations from appropriate spatial and temporal coverage, provide
information to decision makers to facilitate informed, preventative
action. These early warnings are essential where sustainable development
is threatened.
Before considering forecast and response
strategies, it is important to know how much water and of what quality is
available. The basic hydrological network should therefore provide a level
of hydrological information that would preclude gross mistakes in decision
making related to freshwater.
(c) Linkages to Other Indicators: This
indicator is closely linked to most of the other freshwater resource
indicators, including groundwater reserves; BOD and COD in freshwater
bodies; concentration of coliforms in freshwater bodies; annual
withdrawals of groundwater; and surface water as a percent of available
water.
(d) Targets: The World Meteorological
Organization (WMO) offers guidance on the minimum density of international
hydrological networks for various hydrological variables and conventions
or for different physiographic, climatic and geographic zones.
(e) International Conventions and Agreements:
See section 3d above.
4. Methodological Description and Underlying
Definitions
(a) Underlying Definitions and Concepts: The
density of hydrological networks is measured as the average area for one
hydrological station. The territory in question may be divided according
to its physiographic and/or climatic features. The density is understood
as a set of values representing densities of stations monitoring different
hydrological variables; such as, precipitation, streamflow, groundwater,
sediment load, water quality (for surface water, groundwater and
sediment), and evaporation.
The network is understood here to comprise a series
of sub-networks each composed of gauges and stations within the territory
which are collecting data on a different hydrological variable. The
territory itself might be an administrative unit such as a country, state,
or province, or a physical entity such as a river basin.
(b) Measurement Methods: Calculated on the
basis of lists and maps of observation stations.
(c) The Indicator in the DSR Framework: The
density of hydrological networks indicates a government policy Response to
the need to monitor hydrological variables for assessing, developing and
managing freshwater resources.
(d) Limitations of the Indicator: The
minimum recommended density is not uniform either
worldwide or for all hydrological variables. Its
value may indeed depend on such factors as the economic development of the
country, population density, climate, or geographic zone.
(e) Alternative Definitions: The scope of
this indicator could be broadened to take into account other monitoring
networks, such as air quality, land use change, etc. It would then become
an indicator of environmental monitoring and observation. In such a case,
it would probably best fit as an institutional response indicator.
5. Assessment of the Availability of Data from
International and National Sources
(a) Data Needed to Compile the Indicator: Number
of stations where the variables of concern have been observed, and their
location.
(b) Data Availability: Data of this type
have been analyzed within the framework of the INFOHYDRO and Basic Network
Assessment Projects (BNAP) of WMO.
(c) Data Sources: The principle data sources
are national hydrological or hydrometeorological agencies, and other data
collecting organizations. The WMO Secretariat has compiled a set of such
data.
6. Agencies Involved in the Development of the
Indicator
The lead agency is the World Meteorological
organization (WMO). The contact point is the Director, Hydrology
and Water Resources Department, WMO; fax no. (41 22) 734 2326.
7. Further Information
WMO. Guide to Hydrological Practices. Fifth
Edition, WMO-No. 168, Chapter 20, 1994.
WMO. INFOHYDRO Manual. WMO-No. 683, 1987 (Second
edition in press).
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