Scientific Investigations Report 2006–5160

Simulation of Streamflow and Water Quality to Determine Fecal Coliform and Nitrate Concentrations and Loads in the Mad River Basin, Ohio

By David C. Reutter, Barry M. Puskas, and Martha L. Jagucki

A color map.


The Hydrological Simulation Program Fortran (HSPF) was used to simulate the concentrations and loads of fecal coliform and nitrate for streams in the Mad River Basin in west–central Ohio during the period 1999 through 2003. The Mad River Basin was divided into subbasins that were defined either by the 14–digit Hydrologic Unit (HU) boundaries or by streamflow–gaging–station locations used in the model. Model calibration and simulation processes required the formation of nine meteorologic zones to input meteorologic time–series data and water–quality data.

Sources of fecal coliform and nitrate from wastewater–treatment discharges and combined sewer overflow discharges (CSOs) within the City of Springfield were point sources simulated in the model. Failing septic systems and cattle with direct access to streams were nonpoint sources included in the study but treated in the model as point sources. Other nonpoint sources were addressed by adjusting interflow and ground–water concentrations in the subsurface and maximum storage capacities and accumulation rates of the simulated constituents on the land surface for each meteorologic zone. Simulation results from the calibrated model show that several HUs exceeded the water–quality standard of 1,000 colony–forming units per 100 mL for fecal coliform based on the maximum 30–day geometric mean. Most HUs with high fecal coliform counts were within or downstream from the City of Springfield. No water–quality standard has been set for instream nitrate concentrations; however, the Ohio Environmental Protection Agency (Ohio EPA) considered a concentration of 5 mg/L or greater to be of concern. Simulation results indicate that several HUs in the agricultural areas of the basin exceeded this level.

The calibrated model was modified to create scenarios that simulated loads of fecal coliform and nitrate that were either reduced or eliminated from selected sources. The revised models included the elimination of failing septic systems, elimination of direct access of cattle to streams, decrease in fecal coliform loads from the CSOs and selected wastewater–treatment facilities, and decrease in nitrate loads from land surfaces. The fecal coliform source–reduction model decreased the fecal coliform concentrations below a target concentration of 1,000 colonies per 100 milliliters for all HU outlets and decreased the load at the mouth of the Mad River by 73 percent. The nitrate source–reduction model decreased some HU mean concentrations to 5 milligrams per liter or less and decreased the load at the mouth of the Mad River by 52 percent. Other reduction scenarios may be run by Ohio EPA with the intent of identifying a management strategy that will attain a target concentration for the Mad River Basin.

This report is contained in the following file:


sir2006-5160.pdf (3.89MB)

The PDF file is readable with Adobe Acrobat Reader. The reader is available for free download from Adobe Systems Incorporated. Abobe Acrobat logo.




Purpose and Scope

Previous Studies

Basin Description

Physical and Hydrologic Setting




Land Cover

Water Quality

Designated Uses

Fecal Coliform


Simulation of Streamflow and Water Quality

Description of Model

Meteorologic Data

Streamflow Data

Model Segmentation

Model Limitations

Hydrologic Simulation

Hydrologic Calibration

Sensitivity Analysis


Water–Quality Simulation

Source Representations

Wastewater–Treatment Plants

City of Springfield Combined Sewer Overflows (CSOs)

Cattle in Streams

Failed Septic Systems

Commercial–Fertilizer and Manure Applications

Atmospheric Deposition

Observed Water–Quality Data

Water–Quality Calibration

Sensitivity Analysis

Simulation Results

Simulated Loads and Concentrations

Fecal Coliform


Result of Load–Reduction Simulations

Fecal Coliform


TMDL Requirements

Seasonal and Streamflow Variability

Margin of Safety

Target Concentrations

Summary and Conclusions


References Cited

Appendix 1. Percentage of each 14 digit unit with a given land–cover classification

Appendix 2. Values of selected parameters used in calibrated model to simulate streamflow

Appendix 3. Parameter values used in calibrated model to simulate fecal coliform concentrations

Appendix 4. Parameter values used in calibrated model to simulate nitrate concentrations

For more information about the USGS and its products:
Telephone: 1–888–ASK-USGS
World Wide Web:

Send questions or comments about this report to the author, David C. Reutter, at, 641-430-7732.

For more information about USGS activities in Ohio, visit the USGS Ohio Water Science Center home page.

Accessibility FOIA Privacy Policies and Notices

Take Pride in America home page. FirstGov button U.S. Department of the Interior | U.S. Geological Survey
Persistent URL:
Page Contact Information: USGS Publishing Network
Page Last Modified: Thursday, 01-Dec-2016 19:21:03 EST