ABSTRACT
In attempting to assess water needs in the drylands of the south-east of Spain, because of the lack of data, López Rodriguez (1991) had to use a computer-based water-balance model to estimate how soil water was distributed. This model takes account of the soils and vegetation in different areas, to produce a water budget. The results for Almería and Cordoba are shown in Figure 18.4 and, according to López Rodriguez, mainly represent the contrast in soil types between the two areas, because the model used for estimation is very sensitive to infiltration characteristics of the soils. Cordoba has deeper soils in lowland river valleys, while Almería has thin, skeletal soils, mainly on mountain slopes. Almería is generally much drier than Cordoba and the summers are exceptionally so with, on average, five to seven months per year without rain, compared to three to five months in Cordoba. Moreover, while Almería has one ‘rainy’ period in the year (March to April), Cordoba has two (autumn and spring). These general statistics on rainfall, evapotranspiration and so on reflect not only seasonal variability in rainfall and the vegetation cover, but also strong contrasts in rainfall from year to year. One of the strong contrasts in Figure 18.4 is the very low proportion of recharge to groundwater (VR) in Almería soils compared with Cordoba and the higher modelled proportions of the volume runoff (VE) for Almería compared with Cordoba. These differences show not only the differences in soils and seasonality, but also reflect the more intense storms that occur in Almería.
