A GIS-bascd distributed-parameter runoff simulation model for the Struma River Basin in southwestern Bulgaria calculates die monthly snow/rain proportion, direct or surface runoff, snow cover and snowmelt, soil moisture, evapotranspiration, and total runoff. Simulation during the Bulgarian hydrologic year from November to October was compared with observed runoff data. The model closely replicates mean monthly runoff from climate conditions during the years 1961-1990 as well as specific years. The simplified GIS model simulates hydrologic processes under limited data availability.
