K. Scott Jackson | USGS Science

USGS2003

Hydrologic and Hydraulic Analyses of Selected Streams in Lorain County, Ohio, 2003

Hydrologic and hydraulic analyses were done for selected reaches of nine streams in Lorain County Ohio. To assess the alternatives for flood-damage mitigation, the Lorain County Engineer and the U.S. Geological Survey (USGS) initiated a cooperative study to investigate aspects of the hydrology and hydraulics of the nine streams. Historical streamflow data and regional regression equations were used to estimate instantaneous peak discharges for floods having recurrence intervals of 2, 5, 10, 25, 50, and 100 years. Explanatory variables used in the regression equations were drainage area, main-channel slope, and storage area. Drainage areas of the nine stream reaches studied ranged from 1.80 to 19.3 square miles. The step-backwater model HEC-RAS was used to determine water-surface-elevation profiles for the 10-year-recurrence-interval (10-year) flood along a selected reach of each stream. The water-surface pro-file information was used then to generate digital mapping of flood-plain boundaries. The analyses indicate that at the 10-year flood elevation, road overflow results at numerous hydraulic structures along the nine streams.

Water-Resources Investigations Report↗

USGS1998

Hydrologic and hydraulic analyses of selected streams in Erie County, Ohio

Hydrologic and hydraulic analyses were done for parts of Abel Ditch, Edson Creek, Maurer Ditch, and Sherod Creek 1 in northeastern Vermilion Township, Erie County, Ohio. For each stream, instantaneous peak discharges for floods having recurrence intervals of 2, 5, 10, 25, 50, and 100 years were estimated using regional regression equations. Factors used in the regression equations were drainage area, a basin development factor, and average annual precipitation. Drainage areas at the selected stream locations ranged from 0.41 to 4.61 square miles. A step-backwater model was used to determine water-surface elevation profiles for the 10- year-recurrence-interval (10-year) flood along a selected reach of each stream. The water-surface profile information was then used to prepare a map of flood-plain boundaries. Hydraulic analyses indicated that the 10-year flood was generally confined within the stream channels. At three locations, however, some of the flood discharge escaped the main channel and flowed overland. In two cases, the overland flow returned to the channel from which it escaped. In the third case, flow drained into an adjacent basin. A separate analysis, in which concurrent flood peaks on the streams studied were assumed, indicated that water would spill over the Sherod Creek and the Maurer Ditch divides and that some of this water would eventually enter the Edson Creek Basin downstream from the study area. 1 Locally the upper reach of Sherod Creek, south of the Conrail Railroad, is known as Japson Ditch. However, for simplicity it will be referred to as Sherod Creek along its entirety.

Ohio↗