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Environment | Water

A Clean Water Act Primer

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The Clean Water Act has reached its 40-year anniversary, but it is older than that if you count the law from which it grew. The original law, the Federal Water Pollution Control Act, was passed by Congress in 1948. In 1972, that law was amended, reorganized and expanded and became known as the Clean Water Act.

The overriding objective of the act: “To restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.”

And this is how the law spelled out the path to meet that objective:

  • Eliminate the discharge of pollutants into navigable waters by 1985.

  • By 1983, set water quality goals which, wherever attainable, provide protection and propagation for fish, shellfish and wildlife and provides for recreation in and on the water.

  • Prohibit the discharge of toxic pollutants in toxic amounts.

  • Provide federal financial assistance for building publicly owned waste treatment plants.

  • Develop and implement treatment management planning to assure adequate control of sources of pollutants in each state.

  • Develop technology necessary to eliminate the discharge of pollutants into navigable waters and waters of the contiguous zone and oceans.

  • Develop and implement expeditiously programs to control nonpoint sources of pollution so these goals can be met through control of point and nonpoint pollution.

In the Pacific Northwest, Oregon and Washington have the authority to implement the law and enforce it. In Idaho, the U.S. EPA handles that work. On Indian reservations, the tribes and the EPA do the work together. Of the 50 states, 46 are responsible for enforcing the Clean Water Act.

The Process

To begin, officials adopt water quality standards that take into consideration how the waters are used. Known as “beneficial uses.”


Next, officials determine the quality of the water. If they determine a body of water cannot support its beneficial uses, the water is deemed “impaired.”

The Clean Water Act then directs officials to calculate the amount of pollution an impaired water body can handle as it is cleaned up. This is called the Total Maximum Daily Limit, or TMDL. Based on the TMDL, the officials develop pollution discharge permits for the companies, municipal wastewater treatment plants and others who discharge wastes into the body of water.

The permits dictate how much of each pollutant may be discharged to the water. Pollutants often include temperature, total dissolved solids, turbidity, pH, zinc and copper. The permit holders then are required to monitor their discharges by collecting samples and sending them to licensed laboratories for analysis. The permit holders must then send the results to the state or federal officials, who in turn, check the reports for permit violations.

When officials find permit violations, they are responsible for enforcing the law. They may issue warning letters, notices of violation, orders to make changes and monetary fines. They also may work with permit violators to help them find technical assistance that can be used to fix their systems and come back into compliance.

Beneficial Uses

  • Drinking Water
  • Fish and Aquatic Life
  • Industrial use
  • Fishing
  • Recreation
  • Irrigation
  • Swimming
  • Wildlife and Hunting
  • Hydropower
  • Commercial Navigation
  • Travel
  • Aesthetics
  • Livestock watering

siletz River crabbing family (1 of 1)

Beneficial uses of rivers and bays include fishing and crabbing. A family prepares to go crabbing on Father’s Day on the Siletz River in Lincoln City, Oregon. Photo credit: Bonnie Stewart.


Water Temperature

What may surprise most people is that water temperature impairs more miles of rivers and streams in Washington, Oregon and Idaho than any other pollutant.

Sources: The use of water as a coolant by power plants and industrial manufacturers causes rising temperatures in lakes, rivers, and streams. Dam construction also contributes to increases in water temperature – known as thermal pollution. Water temperatures also rise due to loss of shade due to removal of shrubs and trees along rivers and streams.

Impact: Fish, insects, zooplankton and other water-dwelling organisms all have a preferred temperature range. Increases in water temperature gradually kills off species that aren’t able to adapt. Some species fail to reproduce at higher temperatures.

Dissolved Oxygen

A small amount of oxygen is dissolved in water molecules, and certain levels of dissolved oxygen are necessary for maintaining all life in surface waters. Because dissolved oxygen plays a crucial role in water ecosystems, it is a key measurement for assessing the health of lakes, rivers, and streams.

Source: As water temperature increases, its dissolved oxygen content decreases.

Impact: Fish, amphibians, and other oxygen dependent life either die or experience an increase in metabolism as their systems struggle to circulate enough oxygen to survive. This increased metabolism requires greater food consumption, which may disrupt the food chain. High levels also may lead to algal blooms.


Turbidity occurs when clay, silt, sediment and other materials cause water to become cloudy or opaque.

Sources: Construction, quarrying, mining and anything that disturbs land can send sediment into nearby waters. Urbanization can lead to increased bank erosion and runoff may carry pollution from paved surfaces to waterways.

Impact: Excessively cloudy water can be a breeding ground for pathogens and that could lead to waterborne diseases like gastroenteritis in people. Turbid water also can kill fish by clogging their gills.

Total Dissolved Solids

Total dissolved solids is a measure of the combined inorganic and organic particles suspended in a liquid. They include calcium, chlorides, nitrate, iron, sulfur, phosphorous, and other particles that will pass through a filter of two microns.

Sources: Fertilizers, sewage, soil erosion, storm runoff, and industrial discharges can all contribute total dissolved solids.

Impact: Can cause toxicity through increases in salinity for fish, including salmon. High concentrations of solids can also affect drinking water quality, and impact the efficiency of water treatment processes. The solids present in a stream affect water clarity, which impacts the amount of light that reaches aquatic plants, affecting photosynthesis.


pH is the measure of how acidic or basic water is. Water’s pH determines both its solubility and how biologically useful it is to aquatic life. In the case of nutrients, pH determines just how nutritious they’ll be. It also determines the toxicity level for metals.

Sources: Pollutants end up in lakes, streams and rivers through storm runoff, industrial processes, and precipitation (acid rain). These pollutants, which tend to be acidic, collect in streams and the surrounding soil and effectively lower the pH of the ecosystem.

Impact: High pH levels are harmful to fish and other aquatic life. The more acidic the water the faster it delivers heavy metals to fish. Water with a pH that is too high has a bitter taste and requires more treatment for drinking.

Fecal Coliform Bacteria

A type of bacteria found in human and animal feces. They may indicate the presence of pathogens, viruses, and protozoans that also live in the digestive tract. E. Coli is one species of fecal coliform.

Sources: Bacteria may enter lakes, rivers, and streams stormwater and agricultural runoff and from sewage treatment plant discharges or failed home septic systems.

Impact: The bacteria reduces dissolved oxygen in water, thus making it difficult for fish and other aquatic life to survive. Health hazards to humans include dysentery, viral and bacterial gastroenteritis and hepatitis A.

Total Dissolved Gas

Total dissolved gas is the measure of gas saturation in lakes, rivers and streams.

Sources: Hydroelectric and impoundment dams, warm water discharges from power plants and industrial facilities that practice water-cooling, and agricultural runoff are all causes of increased levels of total dissolved gas.

Impact: When the total pressure of gases in water exceeds the atmospheric pressure at the water’s surface, supersaturation occurs. When supersaturation exceeds safe levels, large populations of fish can die very suddenly.

United States Geological Survey
American Journal of Environmental Sciences 3 (1): 1-6, 2007
National Aeronautics and Space Administration

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