The purpose of the rule is to adopt Total Maximum Daily Loads (TMDLs), and their allocations, for certain waters impaired for nutrients in the Hillsborough River Basin. Furthermore, in accordance with paragraph 62-302.531(2)(a), F.A.C., the nutrient ...

 

DEPARTMENT OF ENVIRONMENTAL PROTECTION

RULE NO.:RULE TITLE:

62-304.610Hillsborough River Basin TMDLs

PURPOSE AND EFFECT: The purpose of the rule is to adopt Total Maximum Daily Loads (TMDLs), and their allocations, for certain waters impaired for nutrients in the Hillsborough River Basin. Furthermore, in accordance with paragraph 62-302.531(2)(a), F.A.C., the nutrient TMDLs for Lake Thonotosassa and Flint Creek will constitute site specific numeric interpretations of the narrative nutrient criterion set forth in paragraph 62-302.530(48)(b), F.A.C., that will supersede the otherwise applicable numeric nutrient criteria in subsection 62-302.531(2), F.A.C., for these surface water segments.

SUMMARY: These TMDLs address certain nutrient impairments in the Hillsborough River Basin. Specifically, the nutrient TMDL rules being proposed for adoption are for Lake Thonotosassa (WBID 1522B) and Flint Creek (1522A). These waterbodies were verified for nutrient impairments due to elevated chlorophyll a concentrations, using the methodology established in Chapter 62-303, F.A.C. This rulemaking has been given an OGC case number 19-0212.

SUMMARY OF STATEMENT OF ESTIMATED REGULATORY COSTS AND LEGISLATIVE RATIFICATION:

The Agency has determined that this will have an adverse impact on small business or likely increase directly or indirectly regulatory costs in excess of $200,000 in the aggregate within one year after the implementation of the rule. A SERC has been prepared by the Agency.

The SERC estimates that there will be no additional costs within one year after the rule becoming effective, but total costs after implementation of the rule are estimated to be $11,384,857 per year for Lake Thonotosassa and Flint Creek; the majority of which is expected to be borne by governmental entities in the watersheds.

Pursuant to paragraph 403.067(6)(c), Florida Statutes, the proposed rules do not require legislative ratification.

Any person who wishes to provide information regarding a statement of estimated regulatory costs, or provide a proposal for a lower cost regulatory alternative must do so in writing within 21 days of this notice.

RULEMAKING AUTHORITY: 403.061, 403.067 FS.

LAW IMPLEMENTED: 403.061, 403.062, 403.067 FS.

A HEARING WILL BE HELD AT THE DATE, TIME AND PLACE SHOWN BELOW:

DATE AND TIME: June 14, 2019, 2:00 p.m.

PLACE: Bob Martinez Center, 2600 Blair Stone Road, Conference Room 176, Tallahassee, Florida

Pursuant to the provisions of the Americans with Disabilities Act, any person requiring special accommodations to participate in this workshop/meeting is asked to advise the agency at least 48 hours before the workshop/meeting by contacting: Erin Rasnake, [phone]. If you are hearing or speech impaired, please contact the agency using the Florida Relay Service, 1(800)955-8771 (TDD) or 1(800)955-8770 (Voice).

THE PERSON TO BE CONTACTED REGARDING THE PROPOSED RULE IS: Erin Rasnake, Division of Environmental Assessment and Restoration, Water Quality Evaluation and TMDL Program, Mail Station 3555, Florida Department of Environmental Protection, 2600 Blair Stone Road, Tallahassee, Florida 32399-2400, telephone [phone].

 

THE FULL TEXT OF THE PROPOSED RULE IS:

 

62-304.610 Hillsborough River Basin TMDLs

(1) through (12)  No change.

(13) Lake Thonotosassa. The nutrient TMDL for Lake Thonotosassa is a seven-year rolling average of annual loads of 46,962 pounds per year (lbs/year) TN and 3,137 lbs/year TP, which is intended to achieve an annual geometric mean chlorophyll a concentration of 32 µg/L not to be exceeded more than once in any consecutive 3-year period, and is allocated as follows:

(a) The WLA for wastewater point sources is not applicable,

(b) The WLA for discharges subject to the Department’s NPDES MS4 Permitting Program is a 29 % reduction of TN (calculated from 55,504 lbs/year) and a 89 % reduction of TP (calculated from 21,943 lbs/year), which are based on the average of annual loads from the 1999-2010 period,

(c) The LA for nonpoint sources is a 29 % reduction of TN (calculated from 55,504 lbs/year) and a 89 % reduction of TP (calculated from 21,943 lbs/year), which are based on the average of annual loads from the 1999-2010 period, and

(d) The Margin of Safety is implicit.

(e) While the LA for TN and TP has been expressed as the percent reduction needed to attain the applicable Class III nutrient criteria, it is the combined reductions from both anthropogenic point and nonpoint sources that will result in the restoration of nutrient conditions in the impaired waterbody. However, it is not the intent of this TMDL to abate natural background conditions.

(14) Flint Creek. The nutrient TMDL for Flint Creek is an annual geometric mean concentration not to be exceed more than once in any consecutive 3-year period of 1.80 mg/L TN which is intended to achieve an annual geometric mean chlorophyll a concentration of 18 µg/L not to be exceeded more than once in any consecutive 3-year period, and is allocated as follows:

(a) The WLA for wastewater point sources is not applicable,

(b) The WLA for discharges subject to the Department’s NPDES MS4 Permitting Program is a 28 % reduction of TN (calculated from 2.49 mg/L), which is based on the highest annual geometric mean concentration from the 1999-2010 period,

(c) The LA for nonpoint sources is a 28 % reduction of TN (calculated from 2.49 mg/L), which is based on the highest annual geometric mean concentration from the 1999-2010 period, and

(d) The Margin of Safety is implicit.

(e) While the LA for TN has been expressed as the percent reduction needed to attain the applicable Class III nutrient criteria, it is the combined reductions from both anthropogenic point and nonpoint sources that will result in the restoration of nutrient conditions in the impaired waterbody. However, it is not the intent of this TMDL to abate natural background conditions.

Rulemaking Authority 403.061, 403.067 FS. Law Implemented 403.061, 403.062, 403.067 FS. History–New 12-22-04, Amended 7-7-10, 6-7-13, _______.

 

NAME OF PERSON ORIGINATING PROPOSED RULE: Tom Frick, Director, Division of Environmental Assessment and Restoration

NAME OF AGENCY HEAD WHO APPROVED THE PROPOSED RULE: Noah Valenstein, Secretary

DATE PROPOSED RULE APPROVED BY AGENCY HEAD: April 19, 2019

DATE NOTICE OF PROPOSED RULE DEVELOPMENT PUBLISHED IN FAR: February 21, 2018