Oxygen transfer in flow around and over stones placed in a laboratory flume

Oxygen transfer around stones located within a stream was studied in a laboratory-recirculating flume. The present study focused on two main points: first, it examined the change in dissolved oxygen (DO) levels between a section upstream and a section downstream of the stones and second, it documented the DO distribution around the stones. The presence of stones increased the DO transfer efficiency by 0-0.60 in the flume. Therefore stones could be used in river reclamation projects to provide aeration. The experiments with two stones resulted in higher DO transfer efficiencies such as 0.43 compared to those obtained in the case of a single stone with the highest values of 0.26. The relative depth of the flow compared to the height of the stone(s) is an important parameter characterizing the DO ratios. When the stone(s) was submerged, there were marginal to no changes in the level of DO in the flow. The changes in DO levels were substantial when the stones were piercing through the water surface. Some of the DO improvements obtained by including the stone(s) were comparable to those reported in the literature when man-made structures were placed in streams.