A technique for the definition of environmental geologic units and for evaluating their environmental value

Abstract This paper describes the criteria used to define environmental geologic units in the coastal zone of Santander, Northern Spain, and the technique applied to estimate their environmental value. The work reported is part of an integrated environmental study of the area. Environmental geologic units have been defined using two main criteria, morphology and lithology. Two separate maps were produced and then combined to obtain an environmental geologic map, in which each unit has uniform morphological and lithological features. A series of parameters were chosen as indicators of the resource value and the limitations for use by man of the different units. Each parameter was graded independently, for all units, in a relative scale and then added up for each unit to obtain a measure of its environmental value from the geological point of view. This value was corrected by multiplying the parameters by appropriate weighting and singularity coefficients. The figures obtained were standardised by means of cumulative frequency curves for the different distributions of values and five classes of “environmental geologic value” were obtained. The distributions of classes obtained are presented in maps which reflect the potential for use by man of different zones in the area of study. The different alternatives considered are compared and discussed.