Immediate and delayed oxygen depletion in rivers

It is important to distinguish between those processes that remove organic matter from the water phase of a river with an immediate oxygen consumption, as opposed to those processes that remove the organic matter by fixation at the bottom where it will be degraded with delayed consumption. An investigation of a steady-state discharge shows the importance of this distinction, but a theoretical analysis shows this to be of far greater importance during and after an abrupt discharge.

It is particularly true in case of storm overflows from combined sewers—as demonstrated experimentally in this and the following paper.