The Hydrologic Evaluation of Landfill Performance (HELP) model is a quasi-two-dimensional, deterministic, computer-based water budget model. The model was developed and adapted from the U.S. Environmental Protection Agency HSSWDS model and the U.S. Department of Agriculture CREAMS Hydrologic model. The model uses climatologic and design input data in the form of daily rainfall, mean monthly temperatures, mean monthly solar radiation, leaf area indices, soil characteristics, and design specifications to perform a sequential daily analysis to determine runoff, evapotranspiration, percolation, and lateral drainage for the landfill. ...SOFTWARE DESCRIPTION: The program is written in the Fortran programming language for implementation on a IBM 370/168 MP computer under OS MVS/SPE Rel.1.3 and 8211. 50K bytes of core storage are required to operate the model.