Great Miami River Watershed

Great Miami River WatershedThe Great Miami River watershed is located in southwestern Ohio.  It drains a total of 3,802 square miles and flows through all or part of 15 counties.  Major municipalities partially or fully in the watershed include Dayton, Springfield, Sidney, and Cincinnati and some its suburbs.

The eastern portion of the watershed is a mixture of urban development and agricultural land uses such as cultivated crops.  The northern portion of the watershed is predominantly comprised of cultivated crops.  The southern portion of the watershed is predominantly comprised of pasture and hay lands, with some cultivated crops and pockets of urban development and forest.

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Great Miami River (upper) Watershed

Great Miami River (upper) watershed

The Great Miami River (upper) watershed is located in western Ohio in Logan, Shelby, Mercer, Auglaize, Darke, Champaign, Hardin and Miami counties and drains 748 square miles.  The river flows into the Ohio River west of Cincinnati.  The upper portion of the watershed covers approximately one-third of the drainage area of the Great Miami River basin and is home to two lakes used heavily for recreation (Indian Lake and Lake Loramie).  Bellefontaine, Sidney and Minster are the three largest communities in the watershed.  Land use in the Great Miami River (upper) watershed is comprised of 71% cultivated crops, 8% pasture and hay, 9% forest and 9% developed land.








The upper Great Miami River watershed is located in central western Ohio.  The entire upper watershed was studied during 2008.  The Great Miami River flows into the Ohio River west of Cincinnati; however, the upper Great Miami River basin that is the focus of this study ends at Sidney in Shelby County.  Loramie Creek, a major tributary, flows into the Great Miami southwest of Sidney in Miami County.

The upper Great Miami River watershed is divided into six subwatersheds, as follows:

  • 05080001 01 Headwaters Great Miami River
  • 05080001 02 Muchinippi Creek
  • 05080001 03 Bokengehalas Creek-Great Miami River
  • 05080001 04 Stoney Creek-Great Miami River
  • 05080001 05 Headwaters Loramie Creek
  • 05080001 06 Turtle Creek-Loramie Creek
Ohio EPA conducted water quality monitoring in 2008.  The Great Miami River and some of its tributaries displayed good quality, while tributaries in the western portions of the watershed were generally of a lower quality.  Aquatic life uses were supported at 64% of sites; 26% of sites partially attained and 10% did not attain.  The three most common causes of aquatic life use impairment include habitat alterations, nutrients and sedimentation.  Probable sources include channelization, agricultural land uses and point sources.  About 72% of the sites failed to meet bacteria water quality standards.  Probable sources of bacteria include failing septic systems and agricultural land uses.


According to the 2012 Integrated Report, the watershed will next be studied in 2023.

The Great Miami River (upper) Watershed Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on March 26, 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 calculated for total phosphorus, habitat, sediment, total dissolved solids and E. coli bacteria.  Recommendations include new effluent limits for total phosphorus and total dissolved solids, reducing overland flow and nutrient inputs, improving riparian vegetation and stabilizing stream banks, identifying and fixing failing home sewage treatment systems and using proper land application of manure and biosolids.

TMDL Report without Appendices

There is a long-standing watershed project in the Indian Lake area to educate the public about water quality.  The project has worked with local landowners in the watershed to substantially reduce sediment loading to the lake, primarily through filter strips and conservation tillage.  Loramie Valley Alliance, associated with Lake Loramie near Minster Ohio, deals with water quality concerns and works to educate and incorporate local landowners in the process of improving water quality.

Great Miami River (middle) Watershed

Great Miami River (middle) watershedThe majority of the watershed is located in Shelby, Miami and Montgomery counties.  Small portions are located in Champaign and Clark counties.  Land use in the watershed is dominated by cultivated crops (65%) and developed land (20%), with an additional 8% forest and 5% pasture/hay.  In general, the northern portion of the watershed is more agricultural while the southern portion is more urban and suburban developed land.










The Great Miami River (middle) watershed was studied in 2009.  The watershed includes the large river assessment unit and is divided into three subwatersheds, as follows:

  • 05080001 07        Tawawa Creek-Great Miami River
  • 05080001 08        Lost Creek-Great Miami River
  • 05080001 20        Honey Creek-Great Miami River
  • Great Miami River main stem

Piqua gets its drinking water from three locations: a gravel pit off Lockington Road (filled by ground water); the Great Miami River (from October to March); and Swift Run Lake (from March through September).  Sidney draws its drinking water from Tawawa Creek and the Great Miami River.  The Piqua drinking water supply was listed on the 303(d) list of impaired waters in 2008 with an impairment from atrazine. Communities downstream of Piqua rely almost exclusively on water from the Great Miami River Buried Valley Aquifer.  The river and its valley rest on a very thick and highly productive sand and gravel aquifer.  U.S. EPA designated it as a Sole Source Aquifer in the late 1980s, meaning that federal projects are subject to an extra review when they are located over the aquifer.

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

The TMDL report is in preparation.

The following implementation projects have been completed in the watershed.

Great Miami River (lower) Watershed

Great Miami River (lower) watershedThe majority of the Great Miami River (lower) watershed is located in Montgomery, Warren, Butler and Hamilton counties. There is also a small amount of the watershed in Preble County.  Land use in the watershed is dominated by developed urban and residential land (nearly 40%), agricultural land (28%) and forest (19%).  Several major cities are located along the river, including Dayton, Cincinnati, West Carrollton, Middletown, Fairfield, and Hamilton.









The Great Miami River (lower) watershed was studied during 2010; the upper and middle portions of the GMR were studied in 2008 and 2009, respectively. The Great Miami River flows into the Ohio River at the southwestern corner of the state in Hamilton County. The lower Great Miami River watershed is divided into four subwatersheds, as follows, and the large river assessment unit:

  • 05080002 01        Wolf Creek – Great Miami River
  • 05080002 04        Bear Creek – Great Miami River
  • 05080002 07        Dicks Creek – Great Miami River
  • 05080002 09        Taylor Creek – Great Miami River
  • Great Miami River main stem

According to the 2012 Integrated Report, the watershed will next be studied in 2025.

The TMDL report is in preparation.

There is no implementation information available at this time.

Stillwater River

Stillwater River watershedThe Stillwater River flows 67 miles from its headwaters in Indiana and northern Darke County to a confluence with the Great Miami River in Dayton.  Major tributaries include Greenville Creek, Ludlow Creek, Painter Creek, Swamp Creek and North Fork Stillwater River.  The watershed covers approximately 673 square miles (about 32 square miles in Indiana) and is drained by 280 miles of streams.  Many of those stream miles have been physically modified to maintain drainage for row crop agriculture.  Historically, almost one-third of the watershed may have been wetlands, but tile drainage and stream channelization have reduced this to one-half of one percent.  Agriculture composes over 80 percent of the land use, and Darke County has the second highest concentration of animal feeding operations in Ohio.






The Stillwater River is located in southwest Ohio.  The entire watershed is being studied during 2013.  The Stillwater River flows into the Great Miami River at Dayton in Montgomery County.  The Stillwater River watershed is divided into six subwatersheds, as follows:

  • 05080001 09        Headwaters Stillwater River
  • 05080001 10        Headwaters Greenville Creek
  • 05080001 11        Mud Creek-Greenville Creek
  • 05080001 12        Swamp Creek-Stillwater River
  • 05080001 13        Painter Creek-Stillwater River
  • 05080001 14        Ludlow Creek-Stillwater River
  • 05080001 90 02  Stillwater River mainstem

Ohio EPA has completed two TMDL reports based on monitoring completed in 1999.

  • 2004 report
  • 2009 report
    • U.S. EPA approved on September 8, 2009
    • Recalculates the phosphorus loads at a more refined scale
    • 2009 TMDL Report

The following implementation projects have been completed in the watershed.

Mad River

Mad River watershedThe Mad River is located in southwest Ohio in Logan, Champaign, Clark, Miami, Greene, and Montgomery counties.  The Mad River is a subwatershed of the Great Miami River, flowing southwest until it joins with the Great Miami River in Dayton.  The watershed drains 657 square miles.









Ohio EPA conducted a comprehensive physical, chemical and biological survey of the Mad River watershed in 2003, and several problems were identified.  The survey results were published in May 2005.  The primary causes of impairment are nutrients and degraded habitats, and contamination by pathogens.

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

The Mad River Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on January 26, 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 were calculated for nitrate, sedimentation, fecal coliform, and habitat via the Qualitative Habitat Evaluation Index.  Potential solutions include habitat improvement and stream restoration, reduction of nutrients through agricultural best management practices, fixing and replacing failing home sewage treatment systems, and implementation of the combined sewer overflow long term control plan in Springfield (once it is final).

Final TMDL Report with appendices

  • Attachment 1: United States Geological Survey: Simulation of Streamflow and Water Quality to Determine Fecal Coliform and Nitrate Concentrations and Loads in the Mad River Basin, Ohio

There is no implementation information available at this time.

Twin Creek Watershed

Twin Creek watershedThe Twin Creek watershed drains 316 square miles of southwest Ohio. Twin Creek is a subwatershed of the Great Miami River and covers portions of Darke, Preble, Montgomery, Butler and Warren counties. Larger municipalities include Lewisburg, West Alexandria, Germantown and Gratis.










Ohio EPA conducted a comprehensive physical, chemical and biological survey of the Twin Creek watershed in 2005 and several problems were identified. The survey results were published in October 2007 (see below). Major causes of impairment were bacteria, sediment and habitat. Major sources were agricultural and urban land uses, municipal wastewater treatment plants and failing home sewage treatment systems.

According to the 2012 Integrated Report, the watershed will next be studied in 2019.

The Twin Creek Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on March 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 were prepared for bacteria, sediment and habitat. A 4B alternative justification, aimed at correcting in-stream impairment via the NPDES permit, was prepared to address phosphorus and organic enrichment in Twin Creek downstream of the Lewisburg WWTP.

Potential solutions include habitat improvement and stream restoration, reduction of nutrients through agricultural best management practices, fixing and replacing failing home sewage treatment systems, and improved treatment and operation at the Lewisburg WWTP.

Final TMDL Report without appendices

There is no implementation information available at this time.

Fourmile Creek Watershed

Fourmile Creek watershedThe Fourmile Creek watershed originates in Preble County in southwestern Ohio.  Fourmile Creek flows south to Acton Lake in Butler County.  Acton Lake is a constructed 625-acre lake that is the centerpiece of the 3,600 acre Hueston Woods State Park.  The stream then flows southeast by the town of Oxford and continues to its confluence with the Great Miami River near Hamilton, Ohio.  This watershed drains 322 square miles of land, of which 22 are in Indiana. 

The dominant land uses in the Fourmile Creek watershed consist of approximately 53% cultivated crop, 18% pasture/hay, 15% deciduous forest, and 10% developed space.  This watershed supports a diverse group of aquatic organisms, including 63 species of fish and 334 taxa of macroinvertebrates.





Ohio EPA assessed Sevenmile Creek in 2002 and 2004. The Fourmile Creek watershed assessment unit was assessed in 2005. The Fourmile Creek watershed is comprised of two subwatersheds, as follows:

  • 05080002 05        Sevenmile Creek
  • 05080002 06        Fourmile Creek

Sevenmile Creek is the only major tributary to Fourmile Creek.  When studied by Ohio EPA in 2002, all of the biological sampling stations were fully meeting the state standards for aquatic life.

The TMDL report is in preparation.

A report discussing the results of the 2002 study in Sevenmile Creek was published (see below). Results from later sampling have not yet been published, but the study plan is available.

Conservation easements in the watershed are continually being created in concert with the local watershed group, the Three Valley Conservation Trust. Most recently, four local families donated development rights to areas of their farms. The Trust also runs the “Save an Acre” program, a local initiative to place land into conservation easements.

Indian Creek Watershed

Indian Creek watershedThe Indian Creek watershed consists of one 10-digit hydrologic unit (05080002 08) located in the Eastern Cornbelt Plains ecoregion of southwestern Ohio.  The Indian Creek watershed encompasses a drainage area of 106 square miles (34.4 of which are in Indiana).  The area includes the Indian Creek mainstem from the headwaters in Union County, Indiana to the confluence of the Great Miami River in Butler County, Ohio.  The largest communities in this watershed are the central and southern portions of West College Corner, the unsewered community of Reily, the Village of Millville and the Village of Shandon.

The dominant land uses in the Indian Creek watershed consist of approximately 35% pasture/hay, 32% cultivated crop, 22% forest, and 10% developed space.  Urbanization of the Interstate 75 corridor between Cincinnati and Dayton is changing the ratio of agricultural land to urban land in Butler and Warren counties.  There are 1,040 farms with an average size of 132 acres; total land in farms is 137,000 acres.



Ohio EPA assessed the Indian Creek watershed in 2005, measuring biology, chemistry and habitat at numerous sites.  According to the 2012 Integrated Report, the watershed will next be studied in 2019.

The Indian Creek watershed is not included on Ohio’s list of impaired waters.  Therefore, a TMDL report does not need to be prepared for this watershed.  However, several areas were noted that may not attain water quality standards in the future unless protective measures are taken.

Ohio EPA issued a Section 319(h) grant to the Three Valley Conservation Trust in 2007 to establish riparian corridor easements.

Conservation easements in the Twin, Fourmile and Indian Creek watersheds are continually being created in concert with the local watershed group, the Three Valley Conservation Trust. Most recently, four local families donated development rights to areas of their farms in the Twin and Fourmile Creek watersheds. The Trust also runs the “Save an Acre” program, a local initiative to place land into conservation easements.