Report on nitrogen model verification for the Galveston Bay system

This report describes the formulation, computer implementation, and verification of a first-order steady-state sequential reaction nitrogen model for the Galveston Bay system. This model is capable of predicting concentration distributions of the various nitrogen forms in the estuarine system under various conditions of hydrology, meteorology, and waste discharges. The verification analysis employed two historical periods; one was a low-flow summer period, while the other was a moderate-flow winter period. The model was used to predict concentration distributions of organic nitrogen, ammonia nitrogen and nitrate nitrogen. Modeling results are presented and compared to the concentrations observed during the historical periods. The results were good for all species and for both periods. The model is now adequately verified and ready for use in evaluating the effects of proposed water quality management actions on nitrogen and oxygen distributions in the Galveston Bay system.