Final report on effluent requirements for the Houston Ship Channel.

An optimal allocation of waste loads for the entire Galveston Bay System has been made for both 1970 and 1990 estimated discharge conditions. The allocation was made with the aid of an implicit enumeration optimization model which was coupled to a water quality model for the upper Houston Ship Channel. This model coupling arrangement was used in conjunction with hydraulic and water quality models for the bay. These models produced an adequate initial assessment of the effects of waste loads on the entire estuary; however, more modeling verification work remains to be done before a final assessment can be completed. Results of the optimal allocations are presented in graphical and tabular form, defining the BOD and DO concentrations produced by existing, as well as optimal, waste discharges. Also presented are the waste load allocations (ppd BAD5) by location on the upper Houston Ship Channel and Galveston Bay perimeter. It was concluded that the estuary could receive a 61,400 ppd BOD5, distributed between the upper channel, the Texas City/Galveston area and the Trinity River. The upper channel region is optionally limited to 20,000 ppd, while the Texas City/Galveston area is limited to roughly 25,000 ppd. More modeling work is needed to evaluate the desirability of employing artificial reaeration and outfall relocation to increase the maximum waste discharges to the upper channel. Further, BOD5 toxicity should be carefully studied to determine whether the bay's assimilative capacity can be increased by eliminating the toxicity effects.