Development of Numeric Nutrient Criteria for Florida's Waters
News and Announcements
- In an effort to help Floridians understand the Federal
proposal, the Department is providing additional information and
analysis on this webpage to supplement
EPA’s Technical Support Document.
The State of Florida has initiated rulemaking to adopt quantitative
nutrient water quality standards to facilitate the assessment of
designated use attainment for its waters and to provide a better means
to protect state waters from the adverse effects of nutrient over
enrichment. The addition of excess nutrients, often associated with
human alterations to watersheds, can negatively impact waterbody health
and interfere with designated uses of waters - by causing noxious tastes
and odors in drinking water, producing algal blooms and excessive
aquatic weeds in swimming and boating waters, and altering the natural
community of flora and fauna.
The Florida Department of Environmental Protection (FDEP) plans to
develop numeric criteria for causal variables (phosphorus and nitrogen)
and/or response variables (potentially chlorophyll a and transparency),
recognizing the hydrologic variability (waterbody type) and spatial
variability (location within Florida) of the nutrient levels of the
state’s waters, and the variability in ecosystem response to nutrient
concentrations. FDEP’s preferred approach is to develop cause/effect
relationships between nutrients and valued ecological attributes, and to
establish nutrient criteria that ensure that the designated uses of
Florida’s waters are maintained.
Florida currently uses a narrative nutrient standard to guide the
management and protection of its waters. Chapter 62-302.530, Florida
Administrative Code (FAC), states that “in no case shall nutrient
concentrations of body of water be altered so as to cause an imbalance
in natural populations of flora or fauna.” The narrative criteria also
states that (for all waters of the state) "the discharge of nutrients
shall continue to be limited as needed to prevent violations of other
standards contained in this chapter [Chapter 62-302, FAC]. Man-induced
nutrient enrichment (total nitrogen or total phosphorus) shall be
considered degradation in relation to the provisions of Sections
62-302.300, 62-302.700, and 62-4.242, F.A.C.”
FDEP has relied on this narrative for many years because nutrients
are unlike any other “pollutant” regulated by the federal Clean Water
Act (CWA). Most water quality criteria are based on a toxicity
threshold, evidenced by a dose-response relationship, where higher
concentrations can be demonstrated to be harmful, and acceptable
concentrations can be established at a level below which adverse
responses are elicited (usually in laboratory toxicity tests). In
contrast, nutrients are not only present naturally in aquatic systems,
they are absolutely necessary for the proper functioning of biological
communities, and are sometimes moderated in their expression by many
natural factors.
The FDEP has been actively working with EPA on the development of
numeric nutrient criteria for several years. FDEP submitted its initial
DRAFT Numeric Nutrient
Criteria Development Plan to EPA Region IV in May 2002, and received
mutual agreement on the Numeric Nutrient Criteria Development Plan
from EPA on July 7, 2004. The FDEP revised its
plan in
September 2007 to more accurately reflect its evolved strategy and
technical approach, and FDEP received
mutual agreement on
the 2007 revisions from EPA on September 28, 2007. On January 14, 2009,
EPA formally determined that numeric nutrient criteria should be
established on an expedited schedule. On March 3, 2009 FDEP submitted
its Current
Numeric Nutrient Criteria Development Plan to EPA Region IV. This
revised plan reflects DEP’s current approaches and expedited schedule.
To limit nutrient
enrichment, Florida will develop nutrient criteria for all waters, guided by
recommendations from a Technical Advisory Committee (TAC) composed of
technical experts from throughout the state. The TAC will review all
available technical information to ensure that the resulting criteria
reflect the characteristics and aquatic life use of Florida’s diverse
waterbodies. Nutrient criteria development is very actively in progress, and this page
will contain links to updates of meetings and information.
DEP intends to use electronic mail, as well as this website, to
distribute information on the direction and status of numeric nutrient criteria
development for Florida's waterbodies. If you would like to be added to the
Department's Nutrient Criteria mailing list or for questions regarding the
development of the nutrient criteria, please contact DEP's Nutrient Criteria
Development Coordinator,
Ken Weaver.
Background Materials
Please contact
Ken Weaver if you are unable to download any of the documents from these
links or for directions to the meetings.
2010 State of Florida