**3. Results**

#### **3.1 Regional differences in water availability**

**Figure 2** shows the mean values (1970–2000) of water surplus per person for each one of the Chilean regions. The lowest values have been recorded in the Metropolitan Region (due to its high population density) and the desert regions of Antofagasta y Tarapacá. Contrariwise, the highest values were observed in Aysén, Magallanes, and Los Lagos. The regions of the north of Chile show relatively low values of annual water comparing inputs by rainfall and losses by evapotranspiration. Of particular interest are the central regions of the country where, on the one hand, the dominant climate is Mediterranean (naturally erratic) and, on the other hand, the pressure for water resources is particularly higher (the Metropolitan region of Santiago is inhabited by more than 7 million people, for instance).

In fact, the highest spatial variability was observed in the central regions of the country where, regardless people and their activities, they show a significant contrast in natural water surplus. These differences start to be visible in the Region of Valparaíso (V) where climatic conditions change to Mediterranean and evapotranspiration is significantly reduced. The five northern regions of Chile (Arica and Parinacota, Tarapacá, Antofagasta, Atacama, and Coquimbo) are scarce in precipitation (<250 mm y<sup>−</sup><sup>1</sup> ), and their evapotranspiration is also high (>600 mm y<sup>−</sup><sup>1</sup> ), but their needs in water keep in consonance with other regions because their population density is less than 20 people km<sup>−</sup><sup>2</sup> in the best of the cases. These values contrast to the Metropolitan Region (462 people km<sup>−</sup><sup>2</sup> ) and Valparaíso Region (111 people km<sup>−</sup><sup>2</sup> ).

**13**

expected.

**3.2 Future scenarios**

**Figure 2.**

losses of about 1000 mm y<sup>−</sup><sup>1</sup>

foresees a reduction of 936 mm y<sup>−</sup><sup>1</sup>

(optimistic, 968 mm y<sup>−</sup><sup>1</sup>

now living.

1052 mm y<sup>−</sup><sup>1</sup>

1000 mm y<sup>−</sup><sup>1</sup>

*The Availability of Water in Chile: A Regional View from a Geographical Perspective*

The (optimistic and pessimistic) predictions considered in this research returned similar values for 2050. It means the effects of climate change will be particularly remarkable in the central regions of Chile, characterized by their Mediterranean climate type and their high population densities. Both scenarios foresee the highest decrease in annual precipitation (**Figure 3A**) and increase in evapotranspiration (**Figure 3B**). Regarding water surplus they forecast annual

*Regional distribution of the mean annual values of water surplus in Chile (period: 1970–2000).*

losses are particularly worrying in the centre where most of Chilean people are

The existing differences between both scenarios (optimistic vs. pessimistic) are not significantly different between them. For instance, the most optimistic

of the number of people and the water consumption of their agricultural activities. In the south of the country, the model returns predictions of an increase in precipitation much higher than the foreseen increase in evapotranspiration. It means much more available water will be in the south, and perhaps it can suppose migrations from the north and central of the country to these regions. Regarding the desert regions of the north of Chile, the future situation will be presumably similar than the current one. So, no significant effects on local population are

. Regarding water surplus, both scenarios forecast losses around

in many regions of the country (**Figure 3C**). These

in precipitation and the pessimistic one of

) regardless

, vs. pessimistic, 1094 mm y<sup>−</sup><sup>1</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.92169*

*The Availability of Water in Chile: A Regional View from a Geographical Perspective DOI: http://dx.doi.org/10.5772/intechopen.92169*

**Figure 2.** *Regional distribution of the mean annual values of water surplus in Chile (period: 1970–2000).*
