Degradation of groundwater quality

Groundwater quality is perhaps the most significant but not the most urgent challenge to the long-term sustainability of groundwater resources. Yet, accord-

Table 13.4. The effects of the WFD on the irrigation sector. (From Garrido and Calatrava, 2006.)

RBA

Present rate

Tariff increase

Results

Type

Levelsa(€/cm)

Medium

FCRb

Farm income

Water demand

Other results

Duero

Per hectare

0.01

0.04

0.06

-40% to -50%

-27% to -52%

Great influence of

agricultural policies

Guadalquivir

Per hectare

0.01-0.05

0.05

0.1

-10% to -19%

0% to -10%

Same

and volume

Duero

Per hectare

0.01

0.04

0.1

-10% to -49%

-5% to -50%

Technical response

and volume

Guadalquivir

Per hectare

0.01-0.05

0.06

0.12

-10% to -40%

-1% to -35%

Technical and crop

and volume

response

Guadalquivir

Per hectare

0.01-0.05

0.03

0.09

-16% to -35%

-26% to -32%

Technical and crop

and volume

response

Guadiana

Per hectare

0.005

0.03

0.06

-15% to -20%

-30% to -50%

Technical and crop

response

Júcar

Per hectare,

0.03-0.15

0.06

0.15

-10% to -40%

0% to -40%

Technical response

volume and

hourly rates

Segura

Per hectare,

0.05-0.30

0.10

0.25

-10% to -30%

0% to -10%

Very inelastic demand

volume and

hourly rates

bFCR = Full cost recovery rates.

aEquivalent measure.

bFCR = Full cost recovery rates.

ing to the Kuznet's curve, countries implicitly accept a degradation of their environmental quality in return of higher living standards, up to a point where the preferences are reversed. This point has been empirically estimated to be in the range of $6000-10,000 of per capita income.

Restoration of contaminated aquifers can be a very costly and difficult task. Most often, degradation of groundwater quality is primarily related to as point or non-point source pollution from various sources such as return flows from irrigation, leakage from septic tanks and landfills or industrial liquid wastes. These problems are not exclusive to industrialized countries but also may be serious in developing countries. The WFD emphasizes the recovery of groundwater quality in the EU but pays little attention to groundwater quantity problems. This situation may be caused by the insufficient participation of European Mediterranean experts in the preparation of the WFD. Therefore, other arid and semiarid countries should be very prudent in taking the WFD as a good paradigm for their water policy. Groundwater abstraction can also cause changes in groundwater quality. Some indicators of the susceptibility of an aquifer to water quality degradation are given in Custodio (2000). Although groundwater pollution is possibly the most serious problem from a long-term perspective, the quantitative issues may be the more urgent and politically pressing ones. In these cases, the problem is often related to inadequate well field location and not necessarily to the total volumes abstracted. Technical solutions to deal with problems of saline or lower-quality water intrusion have been developed and applied successfully in some places such as California and Israel. Unfortunately, the public awareness in Spain about groundwater pollution problems is still weak, mainly due to the scarcity of government reports and action to assess and to abate groundwater pollution.

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