Modeling infiltration for an urban runoff model in Saudi Arabia

Infiltration is an important parameter in any rainfall-runoff model. Modeling this accurately on a kingdomwide basis requires a vast amount of data on the physical properties of the soil. For the Kingdom of Saudi Arabia a comprehensive set of data on all soil types is provided in the "General Soil Map of the Kingdom of Saudi Arabia". In the study reported herein, this soil map has been used as a data base for computing the Holtan type infiltration models for forty eight groups of soils. These have been further subdivided into four hydrologic groups with the purpose of using them in an urban rainfall-runoff model. These models may be used under four different antecedent moisture conditions. The proposed model has been experimentally verified for hydrologic group No. 4 for "bone dry" antecedent conditions. The procedure for using these models also is provided.