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Desertification Indicator System for Mediterranean Europe


1. Definition

Name

AQUIFER OVER-EXPLOITATION

Brief definition

Aquifer over-exploitation is a significant cause water resources deficiency due to bad management.

Unit of measure

hm³ of water/year

Spatial scale

Sub-region

Temporal scale

Annual

2. Position within the logical framework DPSIR

Type of Indicator

Pressure

3. Target and political pertinence

Objective

Identification and mapping of ESAs, predicting the areas in which the degradation process will be more important. Prioritisation of mitigation actions to combat desertification.

Importance with respect to desertification

Environmental effects of aquifer over-exploitation:

  • increase in depth of water table,
  • decrease in flow of rivers and springs,
  • soil salinization,
  • ground water pollution,
  • subsidence and landslide processes.

International Conventions and agreements

 

Secondary objectives of the indicator

To generate a map of aquifer over-exploitation at sub-watershed scale.

4. Methodological description and basic definitions

Definitions and basic concepts

In the Spanish dry areas the ground water is pumped up for urban water supply and irrigated crops. In some of those areas, the ratio between the aquifer exploitation rate and the aquifer recharge rate is greater than one.

Benchmarks Indication of the values/ranges of value

Classes of aquifer exploitation:

  • exploitation > recharge,
  • recharge > exploitation > 0.8·recharge,
  • local problems of over-exploitation,
  • without problems of over-exploitation.

Methods of measurement

Assessment of water consumption, estimation of the decrease in river and spring flow, ground water monitoring and appraisal of the recharge rate.

Limits of the indicator Difficulties in the measurement of the quantity of water pumped up from aquifers. Illegally irrigated crops. In drought situations controlled aquifer over-exploitation might be allowed by certain water administrations. At the end of the drought, conditions should be changed to enable the aquifer to recover.

Linkages with other indicators

Groundwater depth (change in), Water quality.

5. Evaluation of data needs and availability

Data required to calculate the indicator

Water table depth evolution, or input/output water balance of the aquifers over a period of time.

Data sources

Field and remote sensing data.

Availability of data from national and international sources

In Spain the National Water Administration keeps an inventory and track of aquifer usage.

6. Institutions that have participated in developing the indicator

Main institutions responsible

Dirección General de Conservación de la Naturaleza (DGCN), Secretaría de Medio Ambiente, Ministerio de Medio Ambiente, Spain.

Other contributing organizations

 

7. Additional information

Bibliography

Programa de Acción Nacional contra la Desertificación (DGCN, Ministerio de Medio Ambiente, Spain).

Desertification Indicators for the European Mediterranean Region (Enne, G. and Zucca,C. 2000).

Libro Blanco de las Aguas Subterráneas (Ministerio de Industria y Energía, Spain, 1994).

Libro Blanco del Agua en España (Ministerio de Medio Ambiente, Spain, 1998).

Other references

 

Contacts Name and address

Leopoldo Rojo Serrano <LRojo@mma.es>
Dirección General de Conservación de la Naturaleza
Ministerio de Medio Ambiente
Gran Vía de San Francisco 4
28005 Madrid (Spain)