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   Chapter 18: Protection of the Quality and Supply of Freshwater
   Resources

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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15 December 2004