Total Maximum Daily Load - Getting to the Point of Pollution

Since the Clean Water Act (CWA) was passed in 1972, environmentalists have worked to clean and protect our rivers and lakes from industrial pollution. Now that almost 30 years have passed, much has been accomplished. But we are only now beginning to understand that there is much more to be done.

Much Work Remains
States and territories have identified over 20,000 individual river segments, lakes and estuaries across America as polluted. These polluted waters include approximately 300,000 miles of river and shoreline and approximately 5 million acres of lakes - polluted mostly by sedimentation, nutrients, and harmful microorganisms.

Much of this pollution was thought to have come from industrial discharge spewing from pipes into the river. Thirty years later we realize that there are a variety of sources and activities that contribute to water degradation. Point and Non-Point Sources of pollution each play a major role in impacting water quality.

Identifying the Source
Point sources can usually be traced to a pipe that discharges to a waterbody and typically requires a National Pollution Discharge Elimination System (NPDES) permit. Non-point sources may include run-off, atmospheric deposition, leaking underground storage tanks, unconfined aquifers, septic systems, stream channel alteration and damage to shoreline areas.

The U.S. EPA is proposing revisions to the NPDES program that will include non-point source data and facilitate Total Maximum Daily Loads (TMDL) for impaired waterbodies. The EPA maintains that listing impaired and threatened waters and establishing TMDLs are fundamental tools for identifying remaining sources of water pollution and achieving water quality goals.

Who is Responsible?
Today we know that non-point sources are equally responsible for poor water quality. It will be the responsibility of both point and non-point sources to comply with TMDLs and to reduce the pollution in impaired waterways. Ultimately, the responsibility lies on the shoulders of everyone who lives works or plays in a watershed that drains into an impaired waterbody.

What to Expect
In August 1999, the EPA proposed comprehensive revisions to its regulatory requirements for establishing TMDLs under the CWA. The purpose of the proposed revisions is to provide States with clear, consistent and balanced direction for listing impaired waters and developing TMDLs. This strategy includes:

  • Identify waterbodies that do not meet water quality standards and the particular pollutant causing the impairment;
  • Prioritize all waterbodies that do not meet standards for TMDL development;
  • Establish TMDLs (determine the amount of each pollutant a waterbody can handle) for all waterbodies that do not meet water quality standards. Assign responsibilities to all sources;
  • Develop a strategy to reduce pollution to the waterbodies and assess the progress made during the implementation of the strategy.

Although the EPA is only now receiving comments regarding these revisions, industry should expect major changes to their current discharge permits. Whether you discharge to a local POTW or directly to a waterway, the pollutant handling ability, or TMDL, of the waterbodies in your community will impact your discharge limitations.

An Ohio EPA comment to the proposed revisions states that more emphasis should be placed on "non-pollutant" waterbody impairments. Waters impacted by pollutants receive full attention, from identification to TMDL generation and corrective actions. However, waters with other types of problems, such as habitat impairment, will be identified but may suffer from a lack of follow-up actions to fix the problem.

For example, one form of habitat impairment in smaller watersheds is the lack of tree canopy cover. A non-attainment issue such as excessive nutrients may also impact the same water bodies. Small stream systems will not recover to a condition of chemical, physical and biological integrity without addressing both issues. Dealing with the nutrient inputs and tree canopy cover simultaneously will be far more effective than addressing either one alone.

Holistic Approach
A holistic approach to correcting impairment will help to achieve the economies and environmental benefits of TMDLs. However, with the lack of technical tools, models and information available to develop and implement TMDLs, this approach must be open to the idea of non-regulatory solutions.

With the overwhelming majority of the population living within 10 miles of polluted waters, the ability to identify and understand these issues will have a profound impact on the environment and health of communities across the country.