The Ohio River has a long and storied history with the many people that have been dependent upon it as a resource for hundreds of years.  It has long been a geographical staple for Native American tribes and English settlers, and has served as a valuable asset for transportation and shipping since at least the early 1600’s.  It has produced many great ecological benefits, and its  Beyond its great benefits to trade, serving as a major artery for commerce, the Ohio River has also provided rich ecological benefits to the many people that have encountered it.  Just as the river has shaped the people and the communities that have developed around it, so to have the people made an impact on the river.

While the river has been shaped drastically from its natural flow through the implementation of a series of locks and dams, its environmental quality has been significantly affected by the populations of the many cities that have emerged along its banks.  During the early and mid-1900’s, the booming production of steel in Pennsylvania and other heavily industrial areas along the river contributed as major sources of water pollution in the Ohio.  However, with the introduction of the Clean Water Act of 1972, the direct outflow of pollutants, or point sources, has largely been cleaned up and the water of the Ohio has improved dramatically.  Today, aside from rare oil and coal spills along the Ohio River watershed, and the impact of thermal pollution on fish populations due to the need to collect water to cool power plants along the Ohio, most of the pollution on the river is introduced indirectly as nonpoint source pollution.  These nonpoint sources can be due to industrial practices such as construction, mining, and agriculture, but are also due to increased urbanization along the river.

Urbanization brings with it greater amounts of impervious surfaces, such as buildings, rooftops, streets, and parking lots.  During periods of heavy rainfall, harmful chemicals that collect on these surfaces are transported directly into the streams or sewers and ultimately into the greater Ohio river.  Further, as more people move into densely populated urban areas it becomes an even greater issue dealing with their waste.  Indeed, sewage treatment and wastewater management are some of the most pressing issues affecting the environment of the Ohio River watershed today.

Sewage is not a recent issue for the Ohio River.  At older cities, such as Louisville, it was not uncommon for human waste to be dealt with by finding the most efficient method of getting it directly into the river.  As a result, during the 1820’s Louisville began to dig ditches that would ferry raw waste, completely untreated, into the Ohio River.  As time went on, this process was further refined as the city grew and its water needs and waste removal needs increased.  Larger sewers that could carry waste as well as storm water drainage were built underground, many of which are still in use today.  These sewers, or combined sewer overflows (CSOs), comprise one of the largest current environmental threats to the Ohio River Watershed.

The main benefit of using a combined sewer overflow is the ability to prevent the backing up of sewage into the public homes and business during times of heavy rain by using a large sewer to carry the excess water directly into nearby rivers.  During times when it is not raining, the low levels of water and waste in the sewers are intercepted by a small dam in order to redirect the water to a treatment center.  However, as more water is directed to these combined sewer overflows by the construction of more efficient drainage and a greater prevalence of impervious surfaces, smaller amounts of rainfall are required in order to flood the dams and waste water spills directly into the river more easily.  This issue becomes of even greater importance in cities such as Louisville where over a hundred CSOs are part of the sewage infrastructure.

Every year, millions of gallons of raw wastewater are discharged into the Ohio River during periods of intense rainfall.  This discharge can greatly affect the ecosystem of the watershed, leading to blooms of bacteria and depletion of nutrients necessary for larger invertebrate and vertebrate wildlife.  Naturally, this increase in bacteria can also affect the health of people that interact with the river.  According to the Ohio River Valley Water Sanitation Commission, many areas along the Ohio River have monthly levels of fecal coliform bacteria and E. coli that exceed safety criteria for human health.

Fortunately, there are solutions to this grave problem facing the Ohio River.  By developing green infrastructure in urban areas, such as creating rain gardens and developing green rooftops for buildings, there is potential in decreasing the amount of rain water that enters into the sewer system and thus decrease the amount of waste water that is discharged directly into the river.  It is also important to raise public awareness into the effects of the CSO system, and educate the public on ways to conserve water during periods of heavy rain to avoid stressing the system.  By taking action now, it is possible for the people that depend on the Ohio River to do their part in preserving the waterway for future generations.

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