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| Ohio Water Science Center |
U.S. Geological Survey Open-File Report 2007–1171
By Amie M.G. Brady
This report is available below as a 26-page PDF for viewing and printing.
Report covers 4 and 1 and report covers 2 and 3 (each is 11" by 17" tabloid) also are available for viewing and printing.
Mill Creek in Cleveland, Ohio, receives discharges from combined-sewer overflows (CSOs) and other sanitary-sewage inputs. These discharges affect the water quality of the creek and that of its receiving stream, the Cuyahoga River. In an effort to mitigate this problem, the Northeast Ohio Regional Sewer District implemented a project to eliminate or control (by reducing the number of overflows) all of the CSOs in the Mill Creek watershed. This study focused on monitoring the microbiological water quality of the creek before and during sewage-collection system modifications.
Routine samples were collected semimonthly from August 2001 through September 2004 at a site near a U.S. Geological Survey stream gage near the mouth of Mill Creek. In addition, event samples were collected September 19 and 22, 2003, when rainfall accumulations were 0.5 inches (in.) or greater. Concentrations of Escherichia coli (E. coli) were determined and instantaneous discharges were calculated. Streamflow and water-quality characteristics were measured at the time of sampling, and precipitation data measured at a nearby precipitation gage were obtained from the National Oceanic and Atmospheric Administration.
Concentrations of E. coli were greater than Ohio’s single-sample maximum for primary-contact recreation (298 colony-forming units per 100 milliliters (CFU/100 mL)) in 84 percent of the routine samples collected. In all but one routine sample E. coli concentrations in samples collected when instantaneous streamflows were greater than 20 cubic feet per second (ft3/s) were greater than Ohio’s single-sample maximum. When precipitation occurred in the 24-hour period before routine sample collection, concentrations were greater than the maximum in 89 percent of the samples as compared to 73 percent when rainfall was absent during the 24 hours prior to routine sample collection.
Before modifications to the sewage-collection system in the watershed began, E. coli concentrations in Mill Creek ranged from 220 to 29,000 CFU/100 mL. After major modifications, E. coli concentrations ranged from 110 to 80,000 CFU/100 mL. The percentage of sample E. coli concentrations in the former group greater than Ohio’s single-sample maximum was 88 percent, whereas 85 percent of sample concentrations was greater than the maximum after major modifications occurred. Instantaneous discharges of E. coli were calculated for each of the modification periods. No statistically significant difference was observed between the median instantaneous discharges of E. coli for the premodification and minor-modification periods (5.1 × 106 and 3.6 × 106 CFU per second, respectively).
During rainfall events in September 2003, samples were collected every 15 to 30 minutes. E. coli concentrations in all of these samples (n = 34) were greater than Ohio’s single-sample maximum for primary-contact recreation. On September 19, total accumulated rainfall was 1.7 in., and streamflow reached a peak of 1,040 ft3/s. Sample collection started after 0.8 in. of precipitation had fallen and continued throughout the remainder of the storm. For these samples, E. coli concentrations ranged from 32,000 to 140,000 CFU/100 mL. On September 22, total accumulated rainfall was 0.5 in., and streamflow reached a peak of 497 ft3/s. Sample collection began before the start of the rain and continued throughout the storm. E. coli concentrations ranged from 450 to 260,000 CFU/100 mL.
ContentsAbstract Introduction Purpose and Scope Description of Study Area Sewage-Collection-System Modifications Methods of Study Sampling Procedures and Microbiological Methods Water-Quality and Ancillary Environmental Information Quality Assurance and Quality Control Routine Sampling Streamflow and Rainfall Characteristics Relation of Concentrations of Escherichia coli to Streamflow and Precipitation Relation of Concentrations of Escherichia coli to Modifications of the Sewage-Collection System Rainfall-Event Sampling Summary Acknowledgments References Cited Appendix 1. Variability of Escherichia coli concentrations in Mill Creek, Garfield Heights, Ohio, August 2001–September 2004 |
| 1. Map showing location of the study area in northeast Ohio, showing all combined-sewer overflows present before sewage-collection system improvements. |
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| 2. Instantaneous streamflows near the mouth of Mill Creek, Garfield Heights,
Ohio, August 2001–September 2004, as related to period of sewage-collection-system modification. |
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| 3. Distribution of Escherichia coli concentrations for routine samples collected
near U.S. Geological Survey stream gage 04208460, Mill Creek, Garfield Heights, Ohio, August 2001–September 2004. |
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| 4. Distribution of Escherichia coli concentrations as a function of four ranges
of instantaneous streamflow during routine sampling near U.S. Geological Survey stream gage 04208460, Mill Creek, Garfield Heights, Ohio, August 2001–September 2004. |
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| 5. Distribution of Escherichia coli concentrations in routine samples collected
near U.S. Geological Survey stream gage 04208460, Mill Creek, Garfield Heights, Ohio, when there was no precipitation and when precipitation fell in the 24-hour period prior to 9 a.m. on the day of sampling, August 2001–September 2004. |
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| 6. Distribution of Escherichia coli concentrations in routine samples collected
near U.S. Geological Survey stream gage 04208460, Mill Creek, Garfield Heights, Ohio, during modification periods in the Mill Creek watershed, August 2001–September 2004. |
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| 7. Scatterplot of instantaneous discharges of Escherichia coli against
instantaneous streamflow before and during modifications to the sewage-collection system in the Mill Creek watershed, Cleveland, Ohio, August 2001–September 2004. |
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| 8. Distribution of Escherichia coli concentrations, instantaneous streamflow,
and precipitation for rainfall event samples collected near U.S. Geological Survey stream gage 04208460, Mill Creek, Garfield Heights, Ohio. |
| 1–1. Graph showing absolute value of the percent difference (log10-transformed data)
between quality-control replicate samples for concentrations of Escherichia coli in Mill Creek, Garfield Heights, Ohio, August 2001–September 2004. |
| 1. Streamflow, water-quality, and microbiological data for samples collected in Mill Creek, Garfield Heights, Ohio, August 2001–September 2004. |
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| 2. Streamflow and precipitation statistics for sewage-collection-system modification periods, Mill Creek watershed, Cleveland, Ohio, August 2001–September 2004. |
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| 1–1. Quality-control data for Escherichia coli concentrations in water samples collected in Mill Creek, Garfield Heights, Ohio, August 2001–September 2004, and analyzed by the Northeast Ohio Regional Sewer District and the U.S. Geological Survey. |
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| 1–2. Summary statistics for the percent differences (absolute value of the percent
difference of the log10-transformed data) for within-bottle and between-bottle comparisons of replicate quality-control samples for concentrations of Escherichia coli in Mill Creek, Garfield Heights, Ohio, August 2001–September 2004. |
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Whole report (1.68 MB) - 26 pages (8.5" by 11" paper)
Suggested Citation:
Brady, A.M.G., 2007, Escherichia coli concentrations in the Mill Creek watershed, Cleveland, Ohio, 2001–2004: U.S. Geological Survey Open-File Report 2007–1171, 26 p.
For more information about USGS activities in Ohio, visit the USGS Ohio Water Science Center home page.
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U.S. Department of the Interior, U.S. Geological Survey Persistent URL: https://pubs.water.usgs.gov/ofr20071171 Page Contact Information: USGS Publishing Network Last modified:: Wednesday, 07-Dec-2016 20:20:11 EST |
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