ISCST3 Tech Guide

Gaussian Plume Air Dispersion Model

6.5.4 Plume Rise Formulas

The complex terrain algorithm in ISC uses the Briggs plume rise equations described in Section 1.1.4. For distances less than the distance to final rise, the complex terrain algorithm uses the distance-dependent plume height (based on the radial distance) as described in Section 1.1.4.10. Since the complex terrain algorithm does not incorporate the effects of building downwash, the Schulman-Scire plume rise described in Section 1.1.4.11 is not used for complex terrain modeling. The plume height is used in the calculation of the Vertical Term described in Section 1.5.6.