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Natural Background for the Group 1 Basins

Draft Assessments for Waters Potentially Impaired for Criteria Expressed Relative to Natural Background for the Group 1 Basins

The department announces the availability of the DRAFT lists of assessments for potentially impaired waters for criteria expressed relative to natural background for the Group 1 Basins: Everglades West Coast, Lake Okeechobee, Ocklawaha, Ochlockonee - St. Marks, Suwannee, and Tampa Bay.

The criteria for assessing several parameters are dependent on the comparison of values against background or natural background values. It is challenging to determine what represents “background” for some of the systems in Florida requiring very site-specific data collections. The parameters that fall into this category are pH, alkalinity, turbidity, and specific conductance. For the determination of impairment, the DEP performs a preliminary assessment for these parameters according to the following:

Assessment Criteria Implemented for Select Parameters through the IWR database

Parameter

Waterbody Class

Criteria

Assessment

Alkalinity

Class I & IIIF

Shall not be depressed below 20 mg/L.

In waterbodies with natural alkalinity levels below 20 mg/L, 
alkalinity shall not be reduced by more than 25%.

Potentially Impaired

pH

Class I & IIIF

pH measurements < 6.0 > 8.5 S.U.

Potentially Impaired

pH

Class II & IIIM

pH measurements < 6.5 > 8.5 S.U.

Potentially Impaired

Specific Conductance

Class I & IIIF

SpCond measurements >1275 umhos/cm

Potentially Impaired

Turbidity

Class I, II, IIIF, & IIIM

Turbidity measurements > 29 NTU

Potentially Impaired

Note: IIIF - Predominantly fresh waters; IIIM - Predominantly marine waters

The waterbodies or water segments in the following spreadsheets are considered to be impaired based on the preliminary assessment of these parameters. The department requests information from stakeholders that may assist in determining the appropriate assessment of these parameters for these waterbodies.  Specifically, information on the presence of pollutant sources and background conditions that could be used for comparison.  Since the above criteria do not fully implement the criteria as stated in Chapter 62-302, F.A.C., these waterbodies are placed into category 3c and included on the planning list if the impairment cannot be verified.  This action ensures that the waterbodies are included for strategic monitoring during the next cycle and background conditions can be established.

These assessments reflect the DEP’s current assessments for these waterbodies, but they are subject to change based on input received during the public comment period, which ends December 7th, 2018. During this period, we ask that interested parties submit their comments either electronically or by mail to Kevin O’Donnell at the address below. These lists will then be revised with the next iteration of the IWR Database (Run 56) and provided to the public for review. 

2018 DRAFT Natural Background Lists (MSExcel)

Date

Basin

11/7/2018

Everglades West Coast

11/7/2018

Lake Okeechobee

11/7/2018

Ocklawaha

11/7/2018

Ochlockonee - St. Marks

11/7/2018

Suwannee

11/7/2018

Tampa Bay

For best results, print on legal sized paper (8.5 x 14).

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Last Modified:
November 12, 2019 - 8:52am

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