Water Scarcity
Managing Water Scarcity for Water Security
Prepared for FAO by J.T. Winpenny - Edited to suit this e-mail conference
The nature and scale of the problem
Water scarcity and water stress
[W-1] In popular usage, "scarcity" is a situation where there is insufficient water to satisfy normal requirements. However, this commonsense definition is of little use to policy makers and planners. There are degrees of scarcity - absolute, life-threatening, seasonal, temporary, cyclical, etc. Populations with normally high levels of consumption may experience temporary "scarcity" more keenly than other societies, who are accustomed to using much less water. Scarcity often arises because of socio-economic trends having little to do with basic needs. Defining scarcity for policy-making purposes is very difficult.
[W-2] Terms such as water scarcity, shortage and stress are commonly used interchangeably, though have the following specific meanings:
1. water shortage: a dearth, or absolute shortage; low levels of water supply relative to minimum levels necessary for basic needs. Can be measured by annual renewable flows (in cubic metres) per head of population, or its reciprocal, viz. the number of people dependent on each unit of water (e.g. millions of people per cubic kilometre).
2. water scarcity: an imbalance of supply and demand under prevailing institutional arrangements and/or prices; an excess of demand over available supply; a high rate of utilisation compared to available supply, especially if the remaining supply potentials difficult or costly to tap. Because this is a relative concept, it is difficult to capture in single indices. However, current utilisation as a percentage of total available resources can illustrate the scale of the problem and the latitude for policymakers.
3. water stress: the symptoms of water scarcity or shortage, e.g. growing conflict between users and competition for water, declining standards of reliability and service, harvest failures
Prepared for FAO by J.T. Winpenny - Edited to suit this e-mail conference
The nature and scale of the problem
Water scarcity and water stress
[W-1] In popular usage, "scarcity" is a situation where there is insufficient water to satisfy normal requirements. However, this commonsense definition is of little use to policy makers and planners. There are degrees of scarcity - absolute, life-threatening, seasonal, temporary, cyclical, etc. Populations with normally high levels of consumption may experience temporary "scarcity" more keenly than other societies, who are accustomed to using much less water. Scarcity often arises because of socio-economic trends having little to do with basic needs. Defining scarcity for policy-making purposes is very difficult.
[W-2] Terms such as water scarcity, shortage and stress are commonly used interchangeably, though have the following specific meanings:
1. water shortage: a dearth, or absolute shortage; low levels of water supply relative to minimum levels necessary for basic needs. Can be measured by annual renewable flows (in cubic metres) per head of population, or its reciprocal, viz. the number of people dependent on each unit of water (e.g. millions of people per cubic kilometre).
2. water scarcity: an imbalance of supply and demand under prevailing institutional arrangements and/or prices; an excess of demand over available supply; a high rate of utilisation compared to available supply, especially if the remaining supply potentials difficult or costly to tap. Because this is a relative concept, it is difficult to capture in single indices. However, current utilisation as a percentage of total available resources can illustrate the scale of the problem and the latitude for policymakers.
3. water stress: the symptoms of water scarcity or shortage, e.g. growing conflict between users and competition for water, declining standards of reliability and service, harvest failures
References: Dyson, Tim, 1996: Population and food: global trends and future prospects. Routledge, London. Engelman, Robert & LeRoy, Pamela, 1995: Sustaining Water: an update. Population Action International, Washington DC. Falkenmark, Malin and Lindh, Gunnar, 1993: "Water and economic development", in Peter H. Gleick (ed.) Water in crisis: a guide to the world 's fresh water resources. Oxford University Press, 1993 FAO, 1993: The State of Food and Agriculture 1993 Fisher, Franklin, 1995: "The economics of water dispute resolution, project evaluation and management: an application to the Middle East" Water Resources Development, Vol. 11, No 4. Frederiksen, Harald D., 1996: "Water crisis in developing world: misconceptions about solutions". Journal of Water Resources Planning and Management, March/April. Overseas Development Institute, 1996: The impact of drought on sub-Saharan Africa. London Parry, Martin, 1990: Climate change and world agriculture Serageldin, Ismail, 1994: Water supply, sanitation and environmental sustainability. World Bank, Washington, D.C. Winpenny, J.T., 1991: Values for the environment: a guide to economic appraisal. HMSO, London. Winpenny, James, 1994: Managing water as an economic resource. ODI/Routledge. World Resources Institute (WRI), 1996: World resources: a guide to the global environment, 1996/7. WRI, Washington, DC.