Scioto River

Scioto River watershedThe Scioto River watershed is located in central and southern Ohio.  It drains a total of 6,513 square miles and flows through all or part of 31 counties.  Major municipalities partially or fully in the watershed include Columbus and many of its suburbs, Delaware, Marysville, Chillicothe, Circleville, Jackson and Portsmouth.

The northern portion of the watershed is predominantly comprised of cultivated crops with some areas of substantial urban development.  The southern portion of the watershed is primarily comprised of forest with pockets of agricultural lands.

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Big Darby Creek Watershed

Big Darby Creek watershedThe Big Darby Creek watershed is located in central Ohio, draining agricultural areas and suburbs to the northwest and west of Columbus.  The basin is primarily in Logan, Union, Champaign, Clark, Madison, Franklin, and Pickaway counties.  Major streams included in the TMDL report are Big Darby Creek, Little Darby Creek, Hellbranch Run, and Flat Branch.

A comprehensive survey of the Big Darby Creek watershed was conducted by Ohio EPA in 2001-2002.  The primary causes of impairment include nutrient enrichment, siltation, organic enrichment, pathogens, low dissolved oxygen, and habitat alterations.  Pollution sources in the watershed include row crop agriculture and pastures, home sewage treatment systems, development, urban runoff, channelization, riparian removal, land application of manure, and sewage disposal.

According to the 2012 Integrated Report, this watershed will next be monitored in 2014.

The Big Darby Creek Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on March 31, 2006.  TMDL reports identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment with water quality standards.

TMDLs are established for phosphorus, sediment, fecal coliform bacteria, dissolved oxygen, ammonia, floodplain capacity, bedload, and habitat.  Some of the recommended solutions to address the impairments include storm water controls, point source controls, manure management, and habitat improvements.

Complete TMDL Report [PDF 5,107K] (includes all parts listed below)

The following implementation projects have been completed in the watershed.

Big Walnut Creek Watershed

Big Walnut Creek watershedThe Big Walnut Creek watershed is located in central Ohio, draining the east side of Columbus.  The basin is primarily in Delaware, Franklin and Morrow counties, and also includes small parts of Knox, Licking and Fairfield counties.  Major streams included in the watershed are Big Walnut Creek, Alum Creek, Blacklick Creek, and Rocky Fork.  Alum Creek Lake and Hoover Reservoir were not assessed.





A comprehensive survey of the Big Walnut Creek watershed was conducted by Ohio EPA in 2000.  The primary causes of impairment include nutrient enrichment, siltation, organic enrichment, pathogens, and habitat alterations.  Pollution sources in the watershed include row crop agriculture, home sewage treatment systems, development, urban runoff, and sewage disposal.

According to the 2012 Integrated Report, this watershed will next be monitored in 2020.

The Big Walnut Creek Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on September 26, 2005.  TMDL reports identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment with water quality standards.

TMDLs are established for phosphorus, pathogens, sediment and habitat.  Some of the recommended solutions to address the impairments include habitat improvements, point source controls, stream restoration, and improvements in home sewage treatment systems.  Much of the watershed is or will be included in watershed action plans being prepared by local watershed groups.

Bokes Creek Watershed

Bokes Creek watershedBokes Creek is located in Union, Delaware, and Logan counties in central Ohio and drains 108 square miles to the Scioto River.  Land use in the watershed is predominantly comprised of cultivated crops with pockets of pasture and hay lands.  Municipalities include West Mansfield, Magnetic Springs and a small portion of Delaware.






Biological and chemical stream surveys indicate that the primary causes of impairment of the Aquatic Life Use in the watershed include nutrients, low dissolved oxygen, and habitat alterations.  The main sources of impairment are agricultural runoff, failing septic systems, and habitat alteration.

According to the 2012 Integrated Report, this watershed will next be monitored in 2013.

The Bokes Creek Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on September 27, 2002.  TMDLs identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment.

The recommended actions include agricultural runoff controls and habitat protection and restoration.  Phosphorus loadings are targeted to address impairments associated with excessive nutrient loads.  In addition, a habitat analysis was included to help address widespread habitat degradation in the basin.

  • Final Report with Appendix A (September 2002, PDF 895K
  • Appendix B – Phosphorus Target Development for the Bokes Creek Basin [PDF 80K]
  • Appendix C – Model Development for Bokes Creek [PDF 103K]
  • Appendix D – Qualitative Habitat Evaluation Index (QHEI) Scores for the Bokes Creek Basin [PDF 1,113K]
  • Appendix E – Responsiveness Summary to Public Comments [PDF 13K]

There is no implementation information available at this time.

Deer Creek Watershed

Deer Creek watershedDeer Creek is located in south central Ohio.  Deer Creek flows into the Scioto River north of Chillicothe in Ross County.  Small portions of the watershed are located in Champaign, Clark, Franklin and Fayette counties.  The remainder of the watershed is located in Madison, Pickaway and Ross counties.  Land use in the watershed is predominantly comprised of row crop (79%), barren land (7%), developed land (6%) and forest (6%).  The watershed contains several recreational lakes, including Lake Choctaw, Madison Lake, Clark Run Lake and Deer Creek Lake.  There are also two Ohio State Parks located in the watershed: Madison Lake State Park and Deer Creek State Park.




The Deer Creek watershed was studied during 2011.  The watershed is divided into three subwatersheds, as follows:

  • 05060002 01        Deer Creek headwaters
  • 05060002 02        Sugar Run-Deer Creek
  • 05060002 03        Hay Run-Deer Creek

According to the 2012 Integrated Report, this watershed will next be monitored in 2024.

The TMDL report is in preparation.

There is no implementation information available at this time.

Mill Creek Watershed

Mill Creek watershedMill Creek is in the Scioto River basin, and flows through Logan, Union, and Delaware counties before its confluence with the Scioto River.  The Mill Creek watershed is located in Union, Logan and Delaware counties.  Municipalities include Marysville and Ostrander.  Land use in the watershed is 63% cultivated crops, 13% pasture and hay lands, 12% forested and 11% developed.  Marysville obtains its drinking water from surface waters in the watershed.





The entire Mill Creek (Scioto River basin) watershed is being studied during 2012.  The Mill Creek watershed consists of one 10-digit hydrologic unit: 05060001 06, Mill Creek.

The Mill Creek Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on September 2, 2003.  TMDLs identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment.

The impairment issues addressed by this TMDL are all in Union County; the portions of the stream in Logan and Delaware counties are in attainment.  The Mill Creek (Scioto) TMDL is primarily a point-source-oriented TMDL.  The TMDL addresses an in-stream dissolved oxygen problem attributed to the Marysville WWTP and ammonia and nutrient loading to Crosses Run, attributed to the Scotts Company.

  • Final Report with Appendices A and B (July 2003, PDF 2,084K
  • Appendix C – Model Development for the Mill Creek TMDL Project [PDF 381K]
  • Appendix D – Qualitative Habitat Evaluation Index Scores for the Mill Creek Basin [PDF 477K]
  • Appendix E – Responsiveness Summary to Public Comments [PDF 46K]
  • Appendix F – Scotts Consent Order [PDF 85K]
    • Consent Order Appendix A: Map of the Facility and the Site (not available electronically)
    • Consent Order Appendix B: Index of RCRA Corrective Action Guidance Documents [PDF 22K]
    • Consent Order Appendix C: Approved RFI Workplan (not available electronically)
    • Consent Order Appendix D: Site-Specific Corrective Measures Implementation Scope of Work [PDF 43K]
    • Consent Order Appendix E: Pond 3 Closure [PDF 15K]
  • Appendix G – Phosphorus Target Development for the Mill Creek Basin [PDF 134K]

There is no implementation information available at this time.

Olentangy River Watershed

Olentangy River watershedThe Olentangy River is located in Central Ohio in Crawford, Richland, Delaware, Franklin, Marion and Morrow Counties.  The Olentangy River is approximately 93 miles long and flows from the east side of Galion; west then south through agricultural land surrounding Caledonia; past the Villages of Claridon and Waldo before entering Delaware Lake.  Downstream from Delaware Lake the mainstem flows through the City of Delaware and areas of suburban development before reaching the City of Columbus.  The mainstem joins the Scioto River in downtown Columbus.









Ohio EPA conducted a comprehensive physical, chemical and biological survey of the Olentangy River watershed in 2003 and 2004, and several problems were identified.  The survey results were published in December 2005 (see below).  The primary causes of impairment are siltation, nutrient enrichment, habitat alteration, flow alteration, and contamination by pathogens.

According to the 2012 Integrated Report, this watershed will next be monitored in 2018.

The Olentangy River Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on September 19, 2007.  TMDL reports identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment with water quality standards.

TMDLs were calculated for total suspended solids, total phosphorus, fecal coliform, and habitat via the Qualitative Habitat Evaluation Index.  Recommendations include use of agricultural conservation practices for upland areas and progressive channel maintenance, addressing failing home sewerage treatment systems, better waste treatment for point sources, and a higher level of storm water management in urban and developing areas.

TMDL Report [PDF 765K]

Paint Creek Watershed

Paint Creek watershedThe Paint Creek watershed is part of the larger Scioto River watershed, covering about 1,100 square miles in six counties: Clinton, Fayette, Greene, Highland, Madison and Ross.  Paint Creek flows into the Scioto River at Chillicothe in Ross County.  Much of the watershed is used for agriculture row crop production in Clinton, Fayette, Highland and Madison counties.  Increased topography and forested land cover is more prevalent in the Ross County portion of the watershed.

The Paint Creek watershed is a surface water source of public drinking water for two communities, Washington Court House and Hillsboro.



The Paint Creek watershed is divided into ten subwatersheds plus the mainstem, as follows:

  • 05060003 01        Headwaters Paint Creek
  • 05060003 02        Sugar Creek
  • 05060003 03        Headwaters Rattlesnake Creek
  • 05060003 04        Lees Creek-Rattlesnake Creek
  • 05060003 05        Rocky Fork
  • 05060003 06        Indian Creek-Paint Creek
  • 05060003 07        Buckskin Creek-Paint Creek
  • 05060003 08        Headwaters North Fork Paint Creek
  • 05060003 09        Little Creek-North Fork Paint Creek
  • 05060003 10        Ralston Run-Paint Creek
  • Paint Creek main stem

According to the 2012 Integrated Report, this watershed will next be monitored in 2022.

The Paint Creek Watershed Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on September 18, 2012.  TMDL reports identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment with water quality standards.

TMDLs were prepared for bacteria, total phosphorus, and sediment and habitat.

Recommendations include improving waste water quality, reducing combined sewer overflows, compliance enforcement for home sewage treatment systems, protection and restoration of riparian areas, and best management practices for urban and cropland areas.

There is no implementation information available at this time.

Salt Creek Watershed

Salt Creek watershedThe Salt Creek watershed drains 555 square miles of southeast Ohio.  Salt Creek is a subwatershed of the Scioto River and covers portions of Fairfield, Pickaway, Hocking, Ross, Vinton, Pike and Jackson counties.  The largest municipality is Jackson; smaller municipalities include Coalton, Laurelville, Adelphi and Tarlton.






Ohio EPA conducted a comprehensive physical, chemical and biological survey of the Salt Creek watershed in 2004 and 2005, and several problems were identified.  The survey results were published in December 2008.  The primary causes of impairment are nutrients, sedimentation/siltation, organic enrichment, flow alteration and degraded habitats.

According to the 2012 Integrated Report, this watershed will next be monitored in 2021.

The Salt Creek Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on August 12, 2009.  TMDL reports identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment with water quality standards.

TMDLs were calculated for sedimentation and habitat via the Qualitative Habitat Evaluation Index.  Potential solutions include habitat improvement and stream restoration, reduction of nutrients through agricultural best management practices and improving treatment at municipal wastewater treatment plants.

Final TMDL Report without appendices [PDF 1,684K]

There is no implementation information available at this time.

Scioto Brush Creek

Scioto Brush CreekThe Scioto Brush Creek watershed is located in southern Ohio.  Scioto Brush Creek flows into the Scioto River near the town of McDermott in Scioto County.

The Scioto Brush Creek watershed is located in Scioto and Adams counties and drains nearly 273 square miles.  The dominant land use in the watershed is forest (73%).  Pasture/hay is next most common (10%), followed by various stages of developed land and scrub/shrub land at 5% each.  The main stems of South Fork Scioto Brush Creek and Scioto Brush Creek are frequently used for recreational activities such as swimming, boating or fishing.




The entire watershed was studied during 2006.  Scioto Brush Creek flows into the Scioto River at Rushtown in Scioto County.  The Scioto Brush Creek watershed is divided into two subwatersheds, as follows:

  • 05060002 14        South Fork Scioto Brush Creek
  • 05060002 15        Scioto Brush Creek

According to the 2012 Integrated Report, this watershed will next be monitored in 2022.

The Scioto Brush Creek Watershed Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on September 30, 2011.  TMDL reports identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment with water quality standards.

TMDL report without appendices [PDF 2,503K]

There is no implementation information available at this time.

Scioto River (lower) Watershed

Scioto River (lower) watershedThe Scioto River (lower) watershed is located in southern Ohio.  The Scioto River flows into the Ohio River at Portsmouth in Scioto County. 

The lower portion of the Scioto River begins in Pickaway and Fairfield counties and flows south through Ross, Pike and Scioto counties.  Small portions of the watershed are also located in Highland, Jackson and Adams counties.  Predominant land uses in the watershed include forest (47%), cultivated crops (26%) and pasture/hay (13%).  Approximately 7.5% of the watershed is developed land.




The Scioto River (lower) watershed was studied in 2011.  It is divided into seven subwatersheds and a large river, as follows:

  • 05060002 04        Scippo Creek-Scioto River
  • 05060002 05        Kinnikinnick Creek-Scioto River
  • 05060002 10        Walnut Creek-Scioto River
  • 05060002 11        Pee Pee Creek-Scioto River
  • 05060002 12        Sunfish Creek
  • 05060002 13        Big Beaver Creek-Scioto River
  • 05060002 16        Camp Creek-Scioto River
  • Scioto River mainstem

According to the 2012 Integrated Report, this watershed will next be monitored in 2026.

The TMDL report is in preparation.

There is no implementation information available at this time.

Scioto River (middle) Watershed

Scioto River (middle) watershedThe Scioto River (middle) watershed, including a portion of the Scioto River and some of its tributaries, are located in central Ohio.  The majority of the watershed is in Franklin, Pickaway, and Delaware counties, with a small proportion also included in Union, and Madison counties.  Forty-five percent of the area is developed to some degree (ranging from high to low density development) while cropland by itself accounts for forty percent of the area.  Forest and pastureland account for six and five percent respectively while the remaining four percent of the land area is distributed across other land classifications.

The City of Columbus has an intake for its Dublin Road water treatment plant on the Scioto River near the midpoint of the segment of the Scioto River included in the watershed (near downtown Columbus).  Several small parks and nature preserves owned by state and local entities are also located within the watershed.


The middle section of the Scioto River and its tributaries were studied during 2010.  The Scioto River flows into the Ohio River at Portsmouth in Scioto County.

Several of the major tributary watersheds to the Middle Scioto study area were monitored in recent years and currently have approved TMDLs.  These tributaries include the Olentangy River, Big Walnut Creek, and Walnut Creek.  The upper Scioto River watershed, which included the Scioto and its tributaries to the confluence with Bokes Creek, was studied in 2009.

The Scioto River tributaries and central mainstem project area is divided into two subwatersheds and two large river assessment units, as follows:

  • 05060001 12        Indian Run-Scioto River
  • 05060001 23        Scioto Big Run-Scioto River
  • 05060001             Scioto River (Little Scioto to Olentangy Rivers)
  • 05060002             Scioto River (Olentangy River to Darby Creek)

According to the 2012 Integrated Report, this watershed will next be monitored in 2024.

The TMDL report is in preparation.

There is no implementation information available at this time.

Scioto River (upper) Watershed

Scioto River (upper) watershedThe upper Scioto River watershed is located in the northwestern portion of central Ohio.  The Scioto River flows into the Ohio River at Portsmouth in Scioto County.  The majority of the upper Scioto River watershed is located in Hardin, Marion and Union counties.  Smaller portions are located in Allen, Auglaize, Logan, Wyandot, Crawford and Delaware counties.  The predominant land use in the watershed is cultivated crops at 80%.  Other relatively common land uses include developed land (8%), forest (6%) and pasture/hay (4%).





The upper portion of the Scioto River watershed was studied during 2009.  The upper Scioto River watershed is divided into five subwatersheds, as follows:

  • 05060001 01        Headwaters Scioto River
  • 05060001 02        Rush Creek
  • 05060001 03        Little Scioto River
  • 05060001 04        Panther Creek-Scioto River
  • 05060001 05        Fulton Creek-Scioto River

According to the 2012 Integrated Report, this watershed will next be monitored in 2024.

The TMDL report is in preparation.

The following implementation projects have been completed in the watershed.

Walnut Creek Watershed

Walnut Creek watershedThe Walnut Creek watershed, located in central Ohio, drains 286 square miles.  Land use in the watershed is predominantly cropland (58%) closely associated with pasture (13%) and forested (14%) areas.  About 15% of the watershed is developed or urban land, mostly in the northern portion along the periphery of southeast Columbus.  Current land development is most rapid in this part of the watershed, particularly in Violet Township in Fairfield County.





Ohio EPA conducted a comprehensive physical, chemical and biological survey of the Walnut Creek watershed in 2005, and several problems were identified.  The survey results were published in 2006 (see below).  Some areas of the watershed displayed exceptional quality, especially the lower several miles of Walnut Creek.

Primary causes of impairment are sediment and habitat degradation including altered stream hydrology, organic enrichment, and high concentrations of total dissolved solids.  Sources are run-off from agricultural landscapes and urban areas, wastewater treatment plants, channel modification, failing septic systems, and cattle with direct access to streams.

According to the 2012 Integrated Report, this watershed will next be monitored in 2020.

The Walnut Creek Watershed Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on May 4, 2010.  TMDL reports identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment with water quality standards.

TMDLs are calculated for fecal coliform bacteria, habitat and sedimentation.  TMDL recommendations include:

  • Reduce home sewage treatment system failures
  • Restrict livestock access to streams and improve manure management
  • Manage stormwater quantity and quality in suburban areas
  • Protect both floodplain and streamside areas and create effective buffer areas
  • Improve erosion and sediment control in all areas, particularly crop fields.

TMDL Report without appendices [PDF 3,794K]
Note: On 8/25/10, page numbers and a header were added to the report.

There is no implementation information available at this time.