The Valley Model is a steady-state, univariate Gaussian plume dispersion model designed for multiple point- and area-source applications. It calculates pollutant concentrations for each frequency designated in an array defined by six stabilities, 16 wind directions, and six wind speeds for 112 program-designated receptor sites on a radial grid of variable scale. The output concentrations are appropriate for either a 24-hour or annual period, as designated by the user. The model contains the concentration equations, the Pasquill-Gifford vertical dispersion coefficients and the Pasquill stability classes, as given by Turner. Plume rise is calculated according to Briggs. Plume height is adjusted according to terrain elevation for stable cases. Technical details of the program are presented, with descriptions of data requirements. Flow diagrams and input data forms are presented. Four appendices include a complete test-case analysis, a complete program listing and a paper in which estimated and observed data are compared at several sites for 24-hour periods during which the upper limits of concentrations were observed.

Issued Sept. 1977. Includes appendices. Includes bibliographical references (pages 5-1).