E.4 Macintyre Analytical Method for CDF Discharge in Riverine Conditions

integral model that accounts for most near-field and some far-field steady state

dynamics. CORMIX is presently designed for use in shallow water systems

where the jet mixing processes are expected to encounter bottom boundary

interaction. CORMIX is capable of representing negatively buoyant plume

dynamics through application of mirroring principles; however, the present

version does not include sediment settling and deposition.

The current version of the CORMIX model requires some modifications to

extend its capabilities to simulate the characteristics of dredged material

discharges. Efforts are underway for adaptations of the CORMIX model for

simulating the mixing hydrodynamics of several types of dredged material

discharges. When these efforts are completed, the revised CORMIX model will

be included in subsequent revisions of this appendix.1

E.4 Macintyre Analytical Method for CDF

Discharge in Riverine Conditions

E.4.1 Introduction

This section presents a simplified approach that is applicable to relatively

shallow confined riverine water bodies. The method involves a simplistic two-

dimensional (2-D) calculation based on dispersion principles (MacIntyre 1987).

If the mixing-zone size as calculated using simple approximations is within

mixing-zone guidelines specified by regulatory agencies, more precise

calculations may not be necessary. The mixing-zone calculations depend on a

number of assumptions that are difficult to satisfy for estuaries and the tidally

influenced portions of rivers. The difficulties are discussed after the presenta-

tion of the procedure to be used for a riverine environment.

The analytical solution technique for calculating mixing-zone size described

in this section is based on theoretical and empirical relationships for dispersion

as summarized by Fischer et al. (1979). Only equations for calculating mixing-

zone size resulting from a single-point discharge are presented.

A schematic illustrating a typical single-source effluent discharging into a

receiving water body is shown in Figure E-1. For such a condition, the mixing-

zone length extends downstream and the body of the mixing zone remains close

to the shoreline of the receiving water body.

The latest release of CORMIX (Version 2.10) can be obtained without charge from

U.S. EPA Office of Research and Development, Center for Exposure Assessment

Modeling (CEAM), Athens Environmental Research Laboratory, 960 College Station

Road, Athens, Georgia 30605-2720. CORMIX can be either downloaded from CEAM's

on-line Bulletin Board System by calling 1-706-546-3402 (FTS 250 3402), or sent

through the mail by sending user-supplied diskettes or 9-track magnetic tapes to the

CEAM Model Distribution Coordinator at the above address. User documentation is also

available from the same source.

Appendix E Evaluation of Mixing in Surface Waters