The availability of suitable Lake Sturgeon (Acipenser fulvescens) spawning habitat and age-0 Lake Sturgeon habitat in the Cuyahoga River, OH. A one-dimensional model was developed with the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) 6.3.1 software to simulate flows at three discharges, representing the 25th, 50th, and 75th percentile of spring discharge (April-June) over an 11 to 34 year period, depending on availability of data at USGS gaging stations.

The upstream extent of the model domain was just downriver of the confluence of the Little Cuyahoga River at river kilometer (rkm) 70.919. The upper extent was chosen to avoid unaccounted flow inputs between the upstream extent of the model and the upstream most gaging station, U.S. Geological Survey (USGS) gage 04206000 in Old Portage, OH. The lower domain of the model was in the mouth of the Cuyahoga River at Lake Erie (rkm 0), approximately 7.5 kilometers from the National Oceanic and Atmospheric Administration (NOAA) tidal gage 9063063. The model domain included four USGS gaging stations: 04206000, 04206425 (Jaite, OH), 04208000 (Independence, OH), and 04208504 (Newburgh Heights, OH), which were used to determine the percentiles of spring discharge and to calibrate the model to the three discharges considered.

Known water surface elevations (KWSE) were utilized for the upstream and downstream reach boundary conditions for the steady-state flow analysis. For the downstream KWSE, daily mean water surface elevations were calculated from the NOAA gage (9063063) in Cleveland Harbor for each profile with profiles corresponding to dates when bathymetric surveys occurred, the three flow percentiles (i.e., 25th, 50th, 75th), and mean flow. Upstream KWSE was calculated by adding the gage height to the gage elevation (i.e., bed elevation) from the most upstream USGS stream gage (04206000).