Circulation, mixing, and transport in nearshore Lake Erie in the vicinity of Villa Angela Beach and Euclid Creek, Cleveland, Ohio, June 10–12, 2019, and August 19–21, 2019

Villa Angela Beach, on the Lake Erie lakeshore near Cleveland, Ohio, is just west of the mouth of Euclid Creek, a small, flashy stream that drains approximately 23 square miles and is susceptible to periodic contamination from combined sewer overflows (CSOs; 190 and 189 events in 2018 and 2019, respectively). Concerns about high concentrations of Escherichia coli (E. coli) in water samples collected along this beach and subsequent frequent beach closures led to the collection of water-quality and water-velocity data in the nearshore area to gain insights into nearshore mixing processes, circulation, and the potential for transport of bacteria and other CSO-related contaminants from nearby sources to the beach. Synoptic surveys were completed by the U.S. Geological Survey on June 10–12, 2019, and August 19–21, 2019, to observe conditions during early and late periods of the summer season. This study follows several studies in this area. Data-collection methods for this study included deployment of an autonomous underwater vehicle and use of a manned boat equipped with an acoustic Doppler current profiler and a multiparameter sonde. Spatial distributions of water-quality constituents and nearshore currents indicated that the mixing zone near the mouth of Euclid Creek and Villa Angela Beach is dynamic and highly variable in spatial extent. Similar observations around the Easterly Wastewater Treatment Plant 1.5 miles to the southwest of Villa Angela Beach indicated a mixing zone that was likewise dynamic and highly variable in spatial extent. Observed circulation patterns during synoptic surveys in summer 2019 indicated that contaminants from CSOs in Euclid Creek and at CSO discharge points along the Lake Erie lakefront (as traced using specific conductance as a surrogate) tended to be transported differently depending on the magnitude and direction of winds and longshore currents. The southwesterly longshore current that was responsible for driving a recirculation pattern along the beach during a previous study in summer 2012 was not observed during the summer 2019 synoptic surveys. That was not surprising because continuous velocity data collected near Villa Angela Beach indicated that longshore currents with a northeasterly component occurred most (65 percent) of the time from June 12 to August 28, 2019.