|
1. Definition
| Name |
WATER
AVAILABILITY |
| Brief
definition |
Describes the availability
of water for irrigation or consumption per person, per year
in a region.
 |
Dam
converting the water of a river in a channel to be used
for irrigation (photo by C. Kosmas) |
|
| Unit
of measure |
- Annual withdrawal of
ground and surface water (m³/yr/inh)
- Domestic consumption
per capita (m³/yr/inh)
|
| Spatial scale |
Regional |
| Temporal scale |
Annual |
2. Position
within the logical framework DPSIR
3. Target and
political pertinence
| Objective |
Contribution
to the measures to combat desertification. |
| Importance
with respect to desertification |
In a water
management balance, water demand and supply in a region are
compared to assess the challenges and options in water practices,
which are aimed at compensating differences between demand and
supply at present and in the future. In this case, water shortages
may be addressed through anticipatory planning measures. If
water is available in an area for irrigation during the dry
period, then desertification risk is reduced. |
| International
Conventions and agreements |
A variety of
transboundary legislation exists, as well as EU directives. |
| Secondary objectives
of the indicator |
Evaluation
of the best available water management practices in combating
desertification. |
4. Methodological
description and basic definitions
| Definitions
and basic concepts |
Effective management of
water resources at catchment level warrants some anticipation
of how water resources are going to change in the future under
the influence of both natural and man made changes. Methods
for the quantitative analysis include: (1) methods for the
analysis of water supply including water availability and
water management options; (2) methods for analyzing the water
demand in different sectors; (3) models and tools for forecasting
both water demand and availability; (4) methods for both optimizing
and simulating water resources systems at river basin level.
Knowledge of the hydrological
regime of a region or a watershed is a crucial prerequisite
for any hydrological work. The available water has to be assessed
with regard to quantity and quality of groundwater resources,
surface water and marine or coastal waters.
Groundwater resources
are of high importance, especially in arid and semi-arid regions
where surface water is limited. They include deep and shallow
aquifers that are connected to rivers, streams or seas and
non-rechargeable (fossil) resources that have been created
by precipitation during the last Ice Age. Increasing needs
for groundwater systems have basically two implications: the
"mining" of groundwater (in which the abstraction
exceeds the rate of replenishment) and the degradation of
water quality due to point and non-point pollutants. In coastal
areas, overexploitation of aquifers can reverse the natural
flow into the sea, so that seawater intrusion occurs.
|
| Benchmarks
Indication of the values/ranges of value |
For a quantitative analysis
it is important to have sound estimates of the recharge of
the aquifer over a given time period as well as its interactions
with surface waters (recharge and discharge). For an assessment
of groundwater resources it is essential to have repeated
observations of groundwater levels at a relatively large number
of observation wells, since groundwater systems respond to
short-term and long-term changes in climate, groundwater withdrawal
and (artificial) recharge and land uses. Estimates of groundwater
storage require the knowledge of aquifer storage properties
and accurate interpolation of groundwater level measurements.
Surface waters encompass
both rivers and lakes and can quantitatively be assessed by
long term averages of the available water resulting from endogenous
precipitation. Temporal variations also have to taken into
account.
|
| Methods of
measurement |
Hydrological
balance estimates. Simulation models. |
| Limits of the
indicator |
The concept
of a sustainable yield is commonly used to limit the extraction
from aquifers. Sustainable yield is defined as the long-term
average annual recharge that can be extracted each year without
causing unacceptable impacts on the environment or other groundwater
users. The sustainable yield of a given aquifer is usually given
as a fraction of the long-term annual recharge but it is clear
that it can only be applied individually to each aquifer. |
| Linkages with
other indicators |
Rainfall,
Soil depth, Slope
gradient, Water quality,
Vegetation cover, Population
growth rate, agricultural water use. |
5. Evaluation
of data needs and availability
| Data required
to calculate the indicator |
Hydrological
balance parameters (rainfall, runoff, infiltration etc)
|
| Data sources |
Necessary data
are usually available and accessible. |
| Availability
of data from national and international sources |
Data can be
obtained from national agencies, various regional institutions
involved in collecting and elaborating water related data. |
6. Institutions
that have participated in developing the indicator
| Main institutions
responsible |
Agricultural
University of Athens, Greece.
|
| Other contributing
organizations |
Universities
of Lisbon, Murcia and Basilicata. |
7. Additional
information
| Bibliography
|
Mediterranean Commission
on Sustainable Development (MCSD), 2000:Indicators for the
sustainable development in the Mediterranean region, Plan
Blue,URL: www.planbleu.org
OECD (Organization for
Economic Co-operation and Development):Environmental indicators,
towards sustainable development, OECD, 2001.
|
| Other references |
American Society of Civil
Engineers (ASCE) and UNESCO/IHP-IV Project M-4.3, 1998: Sustainability
Criteria for Water Resource Systems, ASCE
International Union for
Conservation of Nature and Natural Resources (IUCN), URL:
www.iucn.org
Simonovic, S.P., Burn
D.H and Lence, B., 1997: Practical Sustainability Criteria
for Decion-Making, Int. J. of Sustainable Development and
World Ecology, 4(1997), pp. 231-244
Walmsley, J.J., 2002:
Framework for Measuring Sustainable Development in Catchment
Systems, Environmental Management, Vol. 29, No.2, pp 195-206
World Bank, 1999: Environmental
Performance Indicators, A Second Edition Note, Environmental
Economic Series, World Bank Environment Department
World Resources Institute
(WRI), 2000: Pilot Analysis of Global Ecosystems (PAGE), URL:
www.wri.org/wr2000
Young, M.D., 1992: Sustainable
Investment and Resource Use. Man and the Biosphere Series,
Volume 9, Parthenon Publishing, Carnforth and UNESCO, Paris.
|
| Contacts Name
and address |
Dr. Ch. Karavitis
Agricultural University
of Athens, Greece
email: lsos2kok@aua.gr
|
|
