Estimating diluted bitumen entrained by suspended sediments in river rapids using O2 absorption rate

Abstract

Suspended sediments and river rapids can cause oil slicks to fragment and sink, greatly complicating the cleanup process of a spill. Responders need methods for estimating the severity of spilled oil entrainment in rivers in order to properly plan resource allocation. This work presents a novel technique for predicting the amount of oil entrained by suspended sediments in rivers, using the atmospheric oxygen absorption rate of rivers as a way to estimate the surface turbulence. The technique may be used by measuring the gas transfer velocity or by using parametric equations for gas transfer velocity based on river parameters such as slope, depth, and discharge rate. In very turbulent rapids, 13 % of a diluted bitumen slick could be brought down by clay-sized sediments in about 10 min if the sediment concentration is high enough, and 80 % would be brought down in 2 h.