Predictive capabilities in oxygen transfer at hydraulic structures

Field measurements of oxygen transfer at four types of hydraulic structures are compared to predictions by 12 equations in the literature. The hydraulic structures were divided into weirs, spillways (gated and ungated), gated sills, and gated conduit outlets. For weirs, it was found that Avery and Novak's equation provides the best prediction of oxygen transfer. Rindels and Gulliver's equation and Wilhelms's equation provide the best prediction for spillways and gated sills, respectively. No equation provided an acceptable prediction of oxygen transfer at gated conduit outlets, probably because of the variety of hydraulic conditions that exist in these structures. The prediction of the transfer of other compounds from these equations also was discussed. It appears that it is currently possible to predict the transfer of another volatile compound from these oxygen transfer equations at these types of hydraulic structures, as long as the dimensionless Henry's law constant is greater than 10. The uncertainty of the prediction, however, would increase.