Dynamics of gravity currents in the Chicago River, Illinois

GARCÍA, C.M.; OBERG, K.,; GARCÍA M.H.

Perth, Australia

Simposio; International Symposium on Stratified Flows (ISSF).; 2006

International Association of Hydraulic Engineering and Research (IAHR)

During the winter months, the Chicago River in Chicago, Illinois, USA, is subject to bi-directional flows, and gravity currents are thought to be responsible for such flow behavior. The occurrence, frequency, and evolution of gravity currents in the Chicago River have been described using a unique set of field observations made using an upward-looking acoustic Doppler current profiler (ADCP) during the period November 20, 2003 to February 1, 2004. Detailed field observations performed on December 2005, based on both ADCP and water-quality measurements, are employed to validate hypotheses about the characteristics of the currents and the source of the denser water. Observations indicate bi-directional flow is a common condition in the Chicago River system, and that density differences driving the gravity currents are mostly due to salinity differences between the North Branch and the main stem of the Chicago River, whereas temperature differences do not seem to affect the creation of gravity currents.