Validation and quantification
Quantification and validation of the classification was an iterative process designed to reduce the number of individual soil classes while maintaining a homogeneity of response characteristics. Eventually the soils were preclassified into 11 conceptual hydrological response models which describe the dominant pathways of water movement through the soil and substrate.
The proportions of soils in each of these groups within the catchments were calculated and multiple regression analyses were used to determine the influence of the soils on the Base Flow Index. Some of these models were subdivided on the basis of the rate of the response to give a 29 class system.