Watershed Health


A watershed is the land area that water flows across or under on its way to a stream, river or lake.  Watersheds consist of surface water (streams, lakes, wetlands) and underlying groundwater.  Some watersheds  have mountains or hills, while some are completely flat.

U.S. Forest Service Image

Watersheds are interconnected, with smaller watersheds contained within larger watersheds (or, basins).  For example, the East Fork Little Miami River (EFLMR) is 500 square miles in total area.  The EFLMR is a tributary (tributary – a stream or river that flows into a larger stream) to the Little Miami River, which has a watershed of 1,758 square miles.  Both the East Fork and Little Miami are major rivers located within the larger Ohio River Basin, a region of 204,000 square miles covering parts of 14 states, including major cities such as Pittsburgh,  Cincinnati, Louisville, and Indianapolis.  

Headwater streams, which are the smaller streams in a watershed, make up the majority of river miles.  These smaller streams, which you typically find in your backyard, affect the larger watershed downstream.  Because we all live on the land, we all live in a watershed — thus watershed health is important to everyone.


A healthy watershed is a well-balanced system that provides clean water, food and habitat for native plants and animals.  Vegetation (trees, shrubs and plants) in the watershed help to absorb, filter, store and cycle water, keeping streams clean and healthy.


The factors listed below help to define healthy streams and watersheds:

  • Water quality high enough to support native and diverse aquatic species (fish, mussels and insects).

  • The streams and floodplains are connected and can withstand storms and high water without destructive flooding and erosion.

  • Streams have good habitat features, including deep pools, gravel bars, large pieces of wood to support fish and other aquatic wildlife.

  • The streambank (or riparian corridor) has a healthy, dense native plant community.

  • Upland forests and grasslands are intact to provide habitat for wildlife, and also to help manage rain water, reduce soil erosion and filter out pollutants before it enters nearby streams.

    Rayed Bean Mussel, endangered species (photo from USFWS). This mussel species indicates a healthy stream.


Protecting streams, especially the many miles of headwater streams, will help protect the larger watershed.  Below are simple ways communities and individuals can help with watershed protection.

  • Protect and restore stream bank (riparian) areas.  Keep these areas planted with trees, grasses and shrubs.

  • Plant native plants that fit your location.  A variety of native species of plants, shrubs, trees, wildflowers and grasses can help control erosion and also provide habitat for birds, bees and butterflies.

  • Reduce impervious surfaces and disconnect them from streams and storm drains.  Use porous alternatives such as gravel or pervious pavement for driveways and paths.  Collect roof runoff and slow its release through rain barrels, rain gardens and bioswales.

  • Keep water clean.  Prevent soil erosion, use non-toxic household and garden products, keep oil and animal waste out of streams and storm drains.

  • Learn more about your watershed and its specific issues and challenges.  Get involved with a local watershed group.



Sediment and nutrient pollution are one of America’s most widespread, costly and challenging environmental problems. 

Sediment & nutrient runoff

Areas that lack vegetation and are poorly maintained, often have problems with soil erosion. When it rains, vital topsoil is lost.  As sediment particles are washed off fields, fertilizers and chemicals are carried along and are flushed into nearby streams.  Fertilizers contain phosphorus and nitrogen (also referred to as nutrients) and excessive amounts in streams can be very damaging.  Failing septic systems are another source of these nutrients, along with animal manure, waste water discharges and power plant emissions.  

Water pollution caused by excessive amounts of nutrients is threatening Ohio’s water resources.  Approximately 48% of Ohio’s watersheds are degraded by nutrient loading from phosphorus and nitrogen. Conditions in Ohio’s surface waters have reached a critical situation.

In Ohio, nutrient pollution causes many problems such as:

  • Harmful algal blooms (HABs)

  • The issuance of public health warnings to avoid swimming

  • Widespread nuisance growths of aquatic vegetation

  • Increased water treatment costs for clean public water supplies

  • Changes in aquatic communities and declining fisheries

  • Fewer dollars being spent on water based recreation and tourism


Excessive amounts of nutrients (phosphorus and nitrogen) in streams can cause a Harmful Algal Bloom (HAB).  HABs have been increasing with frequency and intensity in watersheds across the U.S., including the Ohio River watershed.  HABs are caused by cyanobacteria (sigh-an-oh-bak-tee-ree-uh) – often referred to as blue-green algae (because it is a photosynthetic, aquatic bacteria that resembles green algae).

A summary on HABs from the Ohio Department of Health is provided below:

Cyanobacteria are commonly found in Ohio’s lakes, ponds, and slow-moving rivers. Although many species of blue-green algae do not produce toxins, some species of blue-green algae that do produce toxins can cause HABs.

HABs occur when there is a shallow body of fresh water, warm temperatures, sunlight, and excessive amounts of nutrients in the water. Under the right conditions, the numbers of blue-green algae can dramatically increase or “bloom” in a body of water. Some of these HABs are visible as thick mats or scum on the surface of the water. These mats can vary in color, including bluish-green, bright green, or even red or maroon.

How dangerous are HABs?

If you touch HABs, swallow water with HAB toxins or breathe in water droplets, you could get a rash, have an allergic reaction, get a stomach ache, or feel dizzy or light-headed. HABs also are toxic to pets.  Always look for HABs before going in the water.  Check for HAB advisories.  Ask the park manager if there has been a recent HAB because colorless toxins can still be in water.

How will I know if there is a HAB?

HABs have different colors and looks. Some colors are green, blue-green, brown, black, white, purple, red and black. They can look like film, crust or puff balls at the surface. They also may look like grass clippings or dots in the water. Some HABs look like spilled paint, pea soup, foam, wool, streaks or green cottage cheese curd.


Use the links below to find information on beach closures, advisories and surface water conditions related to HABs:

Ohio EPA HAB Surface Water & Public Water Systems








Ohio Dept. of Health Beach Closures & Advisories

The table below includes helpful links to websites with information on the health of Ohio’s streams, rivers and lakes.

Agencies and groups across Ohio work to monitor water quality in our streams, rivers and lakes.  Ohio EPA is tasked with water quality assessments and provides an integrated report every two years.  Click here to view an interactive map that provides water quality information across the state.

Ohio has an abundance of water resources with over 60,000 miles of rivers and streams, 942,000 acres of wetlands, 425 miles of Ohio river shoreline, more than 125,000 lakes, reservoirs and ponds covering nearly 265,000 acres.  There are also over 200 groups working to protect Ohio’s watersheds (click here to find a watershed group in your area).


The major watersheds in Southwest Ohio are outlined in the map below.  The 12-digit Hydrologic Unit Codes (HUC) are outlined in yellow.  HUCs are simply a sequence of numbers used to identify the boundaries of watersheds.  HUCs are reported in 8, 10 and 12 digits, with 8-digit HUCs representing the larger basins.  Ohio EPA reports water quality data at the 12-digit HUC for individual streams.

Watersheds located in the SOACM area



The East Fork Little Miami River (EFLMR) is a subwatershed of the Little Miami River Basin located in southwest Ohio.  The EFLMR watershed is approximately 540 square miles in total area and encompasses areas of Highland, Clinton, Brown, Warren, and Clermont counties. Clermont County occupies the largest area in the watershed, covering approximately 49% or 390 square miles.  The EFLMR flows 80 miles from its origin in Clinton and Highland counties southwest to its confluence with the Little Miami River near the Clermont/Hamilton Co. border.

The main stem of the EFLMR is designated as Exceptional Warmwater Habitat (EWH), which is the highest water quality designation given to Ohio’s streams.  The remaining streams in the watershed are designated as Warmwater Habitat (WWH).  The EFLMR is also designated as a Public Water Supply (PWS) at rive mile 22.6 due to the Clermont County Water intake in the William H. Harsha Reservoir.  As a whole, the EFLMR watershed supports diverse populations of fish, mussels and aquatic bugs – it is an outstanding natural resource!

Similar to other inland lakes across Ohio, William H. Harsha Lake has seen increasing problems with Harmful Algal Blooms (HABs).  Information and data collected locally indicate that nutrient runoff in the upper watershed and various land uses are contributing to the frequency and intensity of HABs.

For additional information on the East Fork watershed visit the Clermont SWCD website.

Harmful Algal Blooms (HABs)

Similar to other watersheds across the nation, the Ohio River watersheds, including the East Fork Little Miami River watershed, have shown increasing problems with nutrient pollution and Harmful Algal Blooms (HABs).  Excess sediment and nutrients in local waterways is caused by soil erosion (from bare/fallow fields), the over application of agricultural and residential fertilizers, and failing home septic systems.  Intense rain events, which are occurring more frequently, flood our streams and lakes with sediment and nutrients (i.e. nitrogen and phosphorus).  Excess nutrients, coupled with warmer water and air temperatures cause algae to bloom.  These algae blooms can produce toxins and also consume most of the oxygen in the streams, which is harmful to fish, mussels, and other species.  The health of Ohio’s streams is based on chemical water quality standards and the diversity of fish, mussels and bugs.  Based on these standards, many segments of local streams and rivers are not meeting state water quality standards. 

HAB at Chilo in Clermont Co.

Excess nutrients produce algal blooms.  Although most blooms are not harmful, there are some that are a type of cyanobacteria, commonly known as blue-green algae, that have the ability to produce toxins. These blooms are commonly known as harmful algal blooms (HABs).  HABs can cause illness or irritation – sometimes even death – in pets, livestock, and humans.  Cyanobacteria often float to form scums on or near the surface, forming colonies that often look like bright green paint.  Since 2011, there has been a steady increase in the occurrence of HABs in the William H. Harsha Reservoir (or, East Fork Lake), which has led to beach closures, public health advisories and the cancellation of public events.  In 2015, HABs stretched over 650 miles along the Ohio River and some of its major tributaries from August through October.  The HABs produced toxins that required additional treatment at drinking water plants and many communities were strained by the additional expense. It is critical to reduce the heavy load of nutrients flowing into local streams and rivers.  To reduce nutrient pollution in our watersheds, area SWCDs are focusing their efforts to streamline relevant information to help landowners implement effective conservation practices.

The East Fork Watershed Program began in 2001 as collaborative effort among the Soil & Water Conservation Districts (SWCDs) in Clermont, Brown, Highland, and Clinton counties.  These partners recognized a need to develop a comprehensive, grassroots approach to improve water quality in the East Fork Little Miami River (EFLMR).  Working together, they formed the East Fork Watershed Collaborative (EFWC) to develop watershed plans and oversee local projects.

The EFWC is an informal watershed group that includes representatives from area SWCDs and other local government agencies, along with representatives from community groups and individual citizens.   All EFWC meetings are open to the public and citizen participation in strongly encouraged.

If you would like to become a member of the Collaborative or learn more about our watershed management efforts, please contact the Clermont SWCD office.

The East Fork Watershed Cooperative (EWCoop), an extension of the work done by the Collaborative, is a group of agencies that works together to direct water monitoring and research in the watershed.  The EFWCoop key members include:

  • SWCDs (Clermont, Clinton, Highland & Brown) – each SWCD is involved in conservation education and promoting rural and urban best management practices (BMPs), implementing Farm Bill program and supporting local projects, including edge-of-field and stream monitoring;

  • USDA-NRCS – promotion and implementation of agricultural conservation practices, landowner assistance, Farm Bill activities;

  • Clermont OEQ – monitoring, sampling and research;

  • U.S. EPA Office of Research & Development – monitoring, modeling of stream conditions and BMP effectiveness;

  • U.S. Army Corp – monitoring and modeling of Harsha Lake;

  • Ohio EPA – stream monitoring, modeling assistance

  • Ohio State University Extension – education and outreach, landowner assistance and project implementation;

Clermont County OEQ

Our Mission

To protect and where possible, enhance environmental conditions in order to maintain a high quality of life for both present and future residents of Clermont County.  First formed in 1995, the Office of Environmental Quality (OEQ) continues to work with local, state and federal agencies and the general public to provide guidance and solutions to Clermont County’s environmental concerns.

What we do

OEQ is responsible for monitoring environmental conditions within Clermont County and characterizing the processes that impact the environment.  Through a better understanding of natural environmental processes, OEQ is working to predict future changes caused by human activities and to balance environmental conditions with continued growth and development.

Water Quality Program:

Since 1996, OEQ has been monitoring the water quality and the biological conditions throughout the East Fork Little Miami River Watershed, as well as other locations throughout Clermont County.  With the information collected, OEQ has developed a water quality model that helps to characterize current problems, predict future impacts and guide Clermont County’s watershed management strategy.

H2Ohio is the water quality initiative Governor DeWine introduced to invest in targeted, long-term solutions to ensure clean and safe water in Lake Erie and throughout Ohio.

Through collaboration among the Ohio Department of Natural Resources, Ohio Environmental Protection Agency, Ohio Department of Agriculture, and Ohio Lake Erie Commission, H2Ohio will address critical water quality needs and support innovative solutions to some of the state’s most pressing water challenges.

     Interactive Watershed Map (OEPA)

Map provides local water quality info