The core function of the Watershed Assessment Section is to use the best available information to identify waterbodies and water segments (WBIDs) that are not meeting the applicable water quality standards and designated uses based on the Impaired Waters Rule, Chapter 62-303 and Florida's Surface Water Quality Standards, Chapter 62-302, Florida Administrative Code (F.A.C.).
What is the 303(d) list?
The term "303(d) list" is the list of impaired or threatened waters that do not meet applicable state water quality standards. The Clean Water Act Section 303(d) requires states to submit their list for EPA approval every two years (on even numbered years). To conform to the expectations of Section 303(d) of the Clean Water Act and federal regulations at 40 C.F.R. 130.7(b), waterbodies and associated parameters identified on the Verified or Study List are submitted to EPA as water quality limited segments.
What is the Biennial Assessment?
To fulfill the requirements of Section 303(d) of the Clean Water Act and Section 403.067, Florida Statues, the Florida Department of Environmental Protection (DEP or department) initially applied a rotating basin management approach. Florida’s 52 hydrologic unit code (HUC) basins are divided into 29 drainage basins that are distributed among the department’s 6 regulatory districts. There are five basins in the Northwest, Central, Southwest, South, and Southeast Districts, and four basins in the Northeast District (Basin Contacts Map). Using the rotating basin management approach ensured that one basin would be assessed in each district every five years (except the Northeast, which only has four basins).
Beginning in 2020, the department changed its approach for assessing waters under the IWR. With the new process, termed the Biennial Assessment, all basins in Florida are now assessed every two years rather than 20 percent of the state being assessed each year for five years in repeating cycles. All assessments now have the same assessment period and use consistent application of water quality criteria. The impairment analysis is done based on all available data, and an updated impaired waters list for the entire state is published every two years. Under the Biennial Assessment, the department continues to assess individual basins, identify impaired waters requiring the development of TMDLs, and work with local stakeholders to develop alternative restoration plans (ARPs, such as reasonable assurance plans and pollutant reduction plans) and basin management action plans (BMAPs) to restore water quality.
What is the Biennial Assessment Schedule?
| June 2024 | Initiate two-year assessment cycle |
|---|
| January 2024 - June 2024 | Data providers enter 2023 data into WIN |
| July 2024 | Extract data from WIN |
| July 2024 - August 2024 | IWR Master List output & Access database produced |
| August 2024 - April 2025 | Develop draft lists |
| May 2025 - September 2025 | Review draft lists/reviewer provide edits |
| September 2025 | Post draft lists |
| September 2025 - October 2025 | Hold public meeting, as a webinar |
| October 2025 - February 2026 | Respond to public comments/incorporate revisions and data changes; use "mini IWR" runs as necessary. |
| March 2026 - April 2026 | Hold briefing with Division management |
| May 2026 | Hold briefing with Secretary's Office |
| December 2026 - June 2027 | Compile and submit EPA submittal documentation |
What is the Biennial Assessment Year (Cycle)?
Assessment Year (Cycle) | Planning Period Assessment Start Date | Planning Period Assessment End Date | Number of Years in Assessment Period | Verified Period Assessment Start Date | Verified Period Assessment End Date | Number of Years in Assessment Period | Extraction Date | Evaluation Period |
|---|
2020 | 1/1/2008 | 12/31/2017 | 10 | 1/1/2013 | 6/30/2020 | 7.5 | 7/1/2020 | 2020-22 |
2022 | 1/1/2010 | 12/31/2019 | 10 | 1/1/2015 | 6/30/2022 | 7.5 | 7/1/2022 | 2022-24 |
2024 | 1/1/2012 | 12/31/2021 | 10 | 1/1/2017 | 6/30/2024 | 7.5 | 7/1/2024 | 2024-26 |
2026 | 1/1/2014 | 12/31/2023 | 10 | 1/1/2019 | 6/30/2026 | 7.5 | 7/1/2026 | 2026-28 |
2028 | 1/1/2016 | 12/31/2025 | 10 | 1/1/2021 | 6/30/2028 | 7.5 | 7/1/2028 | 2028-30 |
2030 | 1/1/2018 | 12/31/2027 | 10 | 1/1/2023 | 6/30/2030 | 7.5 | 7/1/2030 | 2030-32 |
2032 | 1/1/2020 | 12/31/2029 | 10 | 1/1/2025 | 6/30/2032 | 7.5 | 7/1/2032 | 2032-34 |
Why are waterbodies placed on the Verified List?
A waterbody is placed on the Verified List because one or more water quality parameters do not meet applicable water quality criteria, which indicates that the waterbody does not fully support its designated use. The listing determination is based on prescribed analytical protocols and minimum data sufficiency requirements as defined by Florida’s water quality standards and Impaired Waters Rule. For waterbodies placed on the Verified List, a total maximum daily load must be developed.
Why are waterbodies placed on the Delist List?
A previously Verified Listed waterbody segment may be proposed for removal from the Verified List, which is termed delisted. In general, waterbodies are delisted because they have either been shown to now attain the applicable standard(s) or a restoration plan has been adopted.
The specific reasons for delisting include:
- A demonstration that water quality criteria are currently being met;
- Completion and adoption of a TMDL;
- Correction to data used in original listing (e.g., failed laboratory audit, station reassignments);
- Development of an alternative restoration plan, such as a Reasonable Assurance Plan or Pollutant Reduction Plan;
- Changes in the applicable water quality criteria and a demonstration that the waterbody meets the revised criteria; or
- A demonstration that the “impairment” is due to a natural condition.
Why are waterbodies placed on the Study List?
A waterbody is placed on the Study List because one or more water quality parameters do not meet applicable water quality criteria, which indicates that the waterbody does not fully support its designated use; however, additional data or information is needed to determine attainment of the designated use. The listing determination is based on prescribed analytical protocols and minimum data sufficiency requirements as defined by Florida’s water quality standards and Impaired Waters Rule.
Why are waterbodies removed from Study List?
A waterbody segment may be proposed for removal from the Study List for several reasons:
- A demonstration that water quality criteria are currently being met;
- Correction to data used in original listing (failed laboratory audit, station reassignments, etc.);
- Development of an alternative restoration plan, such as a Reasonable Assurance Plan;
- Changes in the applicable water quality criteria and a demonstration that the waterbody meets the revised criteria; or
- A demonstration that the “impairment” is due to a natural condition.
What is a WBID?
A WaterBody IDentification (WBID) is the unique identifier for a waterbody or waterbody segment used to represent an assessment unit for a specific watershed, waterbody, or waterbody segment. WBIDs are identified by a specific and unique alphanumeric code. WBIDs are intended to represent portions of waterbodies with homogenous water quality. A WBID can be a stream, estuary, spring, lake, beach, or coastal area. WBIDs are revised based on stakeholder or staff input, as needed.
What are the designated uses addressed during the assessment?
The designated uses that are addressed during the assessment process can be classified in one of the categories below. The classification of a waterbody according to a particular designated use or uses does not preclude use of the water for other purposes. Water quality standards classifications are arranged in order of the degree of protection required, with Class I having generally the most stringent water quality criteria and Class V the least.
| Waterbody Class | Designated Use | Description |
|---|
| Class I | Potable Water Supplies | Includes 14 areas throughout the state that are used as a source of potable water. |
| Class II | Shellfish Propagation or Harvesting | Generally coastal waters where shellfish harvesting propagation occurs. |
| Class III | Fish Consumption; Recreation, Propagation and Maintenance of a Healthy, Well-Balanced Population of Fish and Wildlife | The surface waters of the state are Class III unless described in Rule 62-302.400, F.A.C. |
| Class III Limited | Fish Consumption; Recreation or Limited Recreation; and/or Propagation and Maintenance of a Limited Population of Fish and Wildlife | This classification is restricted to waters with human-induced physical conditions that, because of those conditions, have limited aquatic life support and habitat that prevent attainment of Class III status. |
| Class IV | Agricultural Water Supplies | Generally located in agricultural areas around Lake Okeechobee. |
| Class V | Navigation, Utility and Industrial Use | Currently, there are no waterbodies designated as Class V waters. The Fenholloway River was previously Class V but was reclassified as Class III in 1998. |
*For a more detailed description of classes and specific waterbody designations, see 62-302.400, F.A.C.
What are the assessment categories and what do they mean?
| Assessment Category | Assessment Category Definitions |
|---|
| 1 | Attains all designated uses. |
| 2 | Attains some designated uses and insufficient or no information or data are present to determine if remaining uses are attained. |
| 2b | Attains one or more designated uses and a Reasonable Assurance Plan has already been completed. |
| 2e | Attains one or more designated uses and an alternative restoration plan has already been completed. |
| 2t | Attains one or more designated uses and a state Total Maximum Daily Load (TMDL) has already been adopted. The waterbody meets applicable water quality standards for the parameter; however, this assessment category does not imply attainment of required TMDL load reductions or applicable BMAP restoration goals. |
| 3a | No data and information are present to determine if any designated use is attained. |
| 3b | Some data and information are present but not enough to determine if any designated use is attained. |
| 3c | Enough data and information are present to determine that one or more designated uses may not be attained according to the Planning List methodology. |
| 4a | Impaired for one or more designated uses but does not require TMDL development because a TMDL has already been completed. |
| 4b | Impaired for one or more designated uses but does not require TMDL development because the water will attain water quality standards due to existing or proposed measures. |
| 4c | Impaired for one or more criteria or designated uses but does not require TMDL development because impairment is not caused by a pollutant. |
| 4d | Waterbody indicates non-attainment of water quality standards, but the Department does not have enough information to determine a causative pollutant; or current data show a potentially adverse trend in nutrients or nutrient response variables; or there are exceedances of stream nutrient thresholds, but the Department does not have enough information to fully assess non-attainment of the stream nutrient standard. |
| 4e | Waterbody indicates non-attainment of water quality standards and pollution control mechanisms or restoration activities are in progress or planned to address non-attainment of water quality standards, but the Department does not have enough information to fully evaluate whether proposed pollution mechanisms will result in attainment of water quality standards. |
| 5 | Water quality standards are not attained and a TMDL is required. |
What are the steps of the Impaired Waters assessment/303(d) listing process?
- Evaluate Previous Cycle's Planning, Study, and Verified Lists.
- Development and Implementation of the Annual Strategic Monitoring Plans.
- Conduct IWR Evaluation.
- Produce Draft Master Lists (Includes Verified, Delist, Study List, and Study List Removals).
- Hold Public Meeting(s) and Request Public Comments.
- Develop Final Master Lists (Includes Final Verified, Delist, Study List, and Study List Removals).
- Secretarial Adoption of Verified and Delist Lists.
- Submit 303(d) List Updates to EPA 4.
Where can I learn more about the Impaired Waters assessment/303(d) listing process?
The Consolidated Assessment and Listing Methodology (CALM) for Florida is a report that provides an overview of the state’s assessment and listing methodology for surface waters. This document details Florida’s assessment objectives and strategy, how Florida determines whether applicable water quality standards are being attained or not, and how Florida communicates the assessment findings to stakeholders, including decision makers, the public, and EPA.
How can I download the Impaired Waters Database?
The Impaired Waters Rule (IWR) Database is a MS Access database and is produced typically two to three times during the calendar year.
Bioassessment Data from External Stakeholders
The department requests that external data providers who would like to submit applicable bioassessment data in support of the Impaired Waters assessment please download and complete the Biology Template available as a Microsoft Excel worksheet (.xlsx) on our website. Once the template has been completed, please submit the worksheet and supporting documentation (all field sheets, the program’s Quality Assurance Plan, photos, associated water quality results for the date of sampling, and the general sampling routine, etc.) by email to Kevin O'Donnell.
How can I provide feedback?
DEP is always interested in hearing feedback from its stakeholders. Comments and questions can be submitted to the Watershed Assessment Section by contacting Jessica Mostyn at 850-245-8441 or via email.
How can I receive updates on public meetings, listing actions, new IWR Runs databases, WBIDs and stations?
To receive notifications on upcoming public meetings and the department's activities related to the development and implementation of Clean Water Act section 303(d) list and watershed assessments, please enter your email address at our subscriber page.
