CP-2015-01
Evaluation of Stream Reaeration Capacity Based on Field Diurnal Dissolved Oxygen Data
Clark C.K. Liu, Pengzhi Lin, Hong Xiao, Xianghua Zhang, Baicang Liu, Yong Zhang and Lei San
Atmospheric reaeration is the interface transfer of oxygen from air to water when the dissolved oxygen (DO) content in the water is below its saturation level. In water quality modeling, river reaeration coefficient has been estimated either by using predictive formulas or by the field method. Predictive formulas were derived by considering the effects of stream turbulence on the interface transfer of oxygen. The field method requires the injection of conservative gas tracer into the stream and then measures the rate of decrease of tracer gas concentration downstream. These two approaches have their limitations: the reaeration coefficients of a stream segment estimated by using different predictive formulas often differ appreciably, while the field method is too expensive to implement. The diurnal DO variation of a stream segment is caused by primary production of plants photosynthesis and respiration, as well as reaeration. Therefore, stream reaeration of can be determined with observed diurnal DO variation and bioproductivity. In this study, a new alternative predictive formula was derived which calculates the reaeration coefficient of a stream based on observed diurnal DO variation. This new predictive formula was tested with data collected in a field water quality survey conducted in Canadaigua Outlet in Upstate New York.