Georgia Dosag (GaDosag) was developed for Georgia Environmental Protection Division (EPD) to compute the dissolved oxygen sag curve below waste discharge points in Georgia rivers and streams.

GaDosag is a modified steady-state, one-dimensional Streeter-Phelps model originally developed in 1976 by EPD in cooperation with the Georgia District of the U.S. Geological Survey for use on HP minicomputers. It was significantly enhanced by Dr. Roy Burke of EPD in the 1990's to run interactively under MSDOS. Version 3.0 was developed by Dr. Burke and Dr. Chris Wilson to run under Microsoft Windows operating systems. The primary purpose of the model is to predict dissolved oxygen concentrations in a branching river system, taking into account carbonaceous and nitrogenous biochemical oxygen demand (BOD) contributions from:

         headwater inflow

         multiple waste sources

         tributary inflows

         lateral inflows

         benthic demand

Natural reaeration is computed using either the Dobbins-O'Connor or Tsivoglou-Wallace equations.

GaDosag has the following features:

         Flexible spreadsheet-style entry of required model inputs

         Ability to load and save DOS Version 2.1 files

         Multi-model projects for convenient comparison of alternative modeling scenarios as well as partitioning

         Computation of ammonia toxicity limits based on EPA guidance documents

         Interactive graphical displays of results suitable for analysis and reporting