For wastewater discharged into one branch of a narrow estuary, the resulting
maximum concentration or temperature can vary markedly depending upon the proximity of
the discharge site to the branching and upon how the rate of discharge is adjusted. Explicit
formulae are derived for the optimal discharge rate to minimize the maximum concentration or
temperature experienced in the estuary, while disposing of a given total wasteload over a tidal
period. Graphs are used to show the approximately factors of two reductions in that minimized
maximum concentration or temperature when the second branch is large, the discharge close to
the branching, the decay rate large or the mean river flow large. By optimizing with respect to
one pollutant, there is a reasonably wide range of other pollutants for which the environmental
impact is nearly minimized.
This is a pre-print. The definitive version: SMITH, R., 2000. Optimal discharging in a branched estuary. Journal of Engineering Mathematics, 38(3), pp. 309-322.