J3 300000 200000 100000

Figure 6: Irrigated area according to irrigation systems in different regions (INE, 2003).

Finally, the last use of water which the water resources of CLM must satisfy, although no less important, are environmental requirements. In order to cover these necessities, ecological volumes have been established by the Hydrographic Confederations.

The established ecological flows for the main rivers of the region are indicated:

• Tajo River: 10 m3 s-1 when flowing by the town of Toledo. This volume is not sufficient to counteract the high pollution level of the river, as it receives a great part of the sewage from Madrid.

• Júcar River: 2 m3 s-1 downstream of the reservoir of Alarcón. This volume diminishes as a result of its infiltration into the aquifer 08.29 Mancha Oriental, as the river crosses the province of Albacete.

• Segura River: 4 m3 s-1, it has not generally reached this value, except for particular moments of water transport towards irrigable areas.

• Guadiana River basin: at least 1% of the total of water gathered in its reservoirs will be drained annually for ecological uses.

It is necessary to indicate that in CLM numerous wetlands exist with special importance to migratory birds. These wetlands are typically supplied with underground water that has risen to the surface; the wetlands are very sensitive to the reduction of piezometric levels. Of them, the National Park of the Tablas de Daimiel (PNTD), belonging to the basin of the Guadiana, and situated on the HU 04.04 Mancha Occidental, is the one of greatest importance

The Geologic and Mining Institute of Spain (Instituto Geológico y Minero de España, IGME) developed a study using the historical progression of a piezometer network, since 1974, distributed in the surroundings of the PNTD. According to this study, reductions are registered of the piezometers with, in some cases, differences of more than 15 m since the

Was this article helpful?

0 0

Post a comment