Water Quality Q & A

What is a water quality standard?

Water Quality Standards are the foundation of the water quality-based  pollution control program mandated by the Clean Water Act and the United States Environmental Protection Agency (EPA). Water Quality Standards Exit DEP Disclaimer define the goals for a waterbody by designating its uses, setting criteria to protect those uses and establishing provisions to protect waterbodies from pollutants.


What is the water quality standard for the Everglades?

The water quality standard is a science-based criterion for phosphorus of 10 parts per billion (ppb), with moderating provisions.


What is the criterion?

The Department of Environmental Protection proposed the 10 ppb as the first-ever numeric criterion for the amount of phosphorus in the Everglades. The criterion is based on science that indicates levels of phosphorus above 10 ppb alter the natural plant and animal life of the Everglades.


How is compliance achieved?

Compliance of the water quality standard is achieved by attaining the 10 ppb criterion or applying a moderating provision.


What is a moderating provision?

A moderating provision is a condition in the permit that is authorized under state and federal law and applied when natural conditions prevent attainment of the criterion or when existing technology is not available to achieve the criterion.


What are the moderating provisions in the proposed water quality standard?

The proposed water quality standard has two moderating provisions:

  1. If impacted areas do not meet the criterion, compliance is achieved by implementing best available technology to reduce phosphorus. This moderating provision does not apply to unimpacted areas.
  2. If reestablishing water flow in unimpacted areas provides greater benefits to the natural system than impacts from elevated levels of phosphorus, the discharge is allowed and compliance is achieved by implementing best available technology to reduce phosphorus.


Why are moderating provisions included in the water quality standard?

A natural phenomenon known as reflux will likely cause phosphorus levels to rise above 10 ppb criterion for years, perhaps even decades. Reflux happens when lower phosphorus loads entering the Everglades are likely to trigger a release of additional phosphorus from the soil. Moderating provisions allow the discharges to be in compliance with the water quality standard during the course of this natural cleansing process. Providing a mechanism for compliance in both the law (EFA) and water quality standard will allow the agencies to move forward with restoration through the implementation of Best Available Phosphorus Reduction Technologies (BAPRT).


What is the best available technology to reduce phosphorus?

Best available technology - improved farming practices to reduce phosphorus - and man-made treatment marshes - known as “green technology” - filter pollution from water entering the Everglades. To date, Florida's 45,000 acres of Stormwater Treatment Areas, combined with improved farming practices have prevented more than 3,200 metric tons of phosphorous from entering the Everglades


What is the plan for implementing best available technology?

Officially called the 2003 Everglades Protection Area Tributary Basins Conceptual Plan for Achieving Long-Term Water Quality Goals [pdf - 5.24 MB], the 13-year plan is designed to achieve 10 ppb in the Everglades and keep it there.


When will the entire Everglades attain 10 ppb?

Only nature knows. As less phosphorus enters the marsh, phosphorus embedded deep in the soil is released. This natural process, known as reflux, could cause phosphorus levels to rise above 10 ppb for years, perhaps even decades. Florida will continue to clean up water entering the system as well as explore scientific opportunities for cleaning up water within the natural system.


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Last reviewed: January 07, 2010