SIMULATION OF THE SUSPENDED SEDIMENT LOAD IN THE CUYAHOGA RIVER, NORTHEASTERN OHIO, USING LINEAR REGRESSION

The Cuyahoga River was heavily polluted with hydrocarbons in the 1950s and 1960s, to such a high degree that the river actually caught fire several times in that period. At the present time, water quality of the river has significantly improved as a result of concentrated cleanup efforts. However, many nonpoint-source pollution problems remain, including production of sediment from soil and riverbank erosion, which is the focus of this study.

The objective of this study is to simulate the suspended sediment load in the Cuyahoga River using linear regression analysis. The simulation was achieved by logarithmic regression equations in which the sediment load, a dependent variable, was calculated as a function of river-water discharge, an independent variable. The simulation was made on a monthly and annual basis using the daily sediment load and water discharge data of the Cuyahoga River published by the U.S. Geological Survey. The data covered a period of 37 years and was recorded at the gauging station near Independence, Ohio. The contributing drainage area of the Cuyahoga River above the gauging station at Independence is 707 square miles.

Results of the regression yielded a correlation coefficient of 0.89 for the monthly relationship and 0.80 for the annual relationship. Although the difference between the two correlations is not significant, it reflects the magnitude of the hydrologic variations that occur during the entire year compared to those that take place in each month.

Prediction of the suspended sediment load in the Cuyahoga River was made using the monthly relationship because of its higher correlation coefficient. The predicted sediment loads compare very well with the observed values.