The purpose of this rulemaking is to revise minimum flows pursuant to Section 373.042, F.S., for the Chassahowitzka and Homosassa River Systems located in Citrus County. The effect of the rule is to support the District’s water supply planning, ...

 

WATER MANAGEMENT DISTRICTS

Southwest Florida Water Management District

RULE NO.: RULE TITLE:

40D-8.041: Minimum Flows

PURPOSE AND EFFECT: The purpose of this rulemaking is to revise minimum flows pursuant to Section 373.042, F.S., for the Chassahowitzka and Homosassa River Systems located in Citrus County. The effect of the rule is to support the District’s water supply planning, water use permitting, and environmental resource permitting programs.

SUMMARY: Section 373.042, F.S., requires the District to establish minimum flows and levels for water bodies located within the District’s boundaries. Section 373.0421(3), F.S., further requires the District to periodically reevaluate and revise adopted minimum flows and levels. This rule is necessary to revise the previously established minimum flows for the Chassahowitzka and Homosassa River Systems and associated springs in Citrus County. The establishment and periodic evaluation of minimum flows is required by statute to ensure that the minimum hydrologic requirements of the water resources and ecology of this spring group are maintained. The establishment of minimum flows for the Chassahowitzka and Homosassa River Systems are being developed using previously peer-reviewed, Governing Board adopted methods.

SUMMARY OF STATEMENT OF ESTIMATED REGULATORY COSTS AND LEGISLATIVE RATIFICATION:

The Agency has determined that this will not 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 not been prepared by the Agency.

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: 373.044, 373.113, 373.171, F.S.

LAW IMPLEMENTED: 373.036, 373.042, 373.0421, 373.086, 373.709, F.S.

IF REQUESTED WITHIN 21 DAYS OF THE DATE OF THIS NOTICE, A HEARING WILL BE SCHEDULED AND ANNOUNCED IN THE FAR.

THE PERSON TO BE CONTACTED REGARDING THE PROPOSED RULE IS: Doug Leeper, MFL Program Lead, 2379 Broad Street, Brooksville, FL 34604, [e-mail], [phone] or 1(800)423-1476 (FL Only) ext. 4272

 

THE FULL TEXT OF THE PROPOSED RULE IS:

40D-8.041 Minimum Flows. 

(1) through (15) No change.

(16) Minimum Flow for the Chassahowitzka River System.

(a) For purposes of this rule, the Chassahowitzka River System includes the watercourse from the Chassahowitzka Main Springs Complex to the Gulf of Mexico, including contributing tributaries, Blind Springs and all named and unnamed springs that discharge to the Chassahowitzka River river, and Blind Springs.

(b) The Minimum Flow for the Chassahowitzka River System is 92% 97% of the natural flow as measured at the United States Geological Survey (USGS) Gage Chassahowitzka River near Homosassa (Gage No. 02310650). Natural flow is defined for the purpose of this rule as the flow that would exist in the absence of water withdrawal impacts. The Minimum Flow is based on an 8% reduction from the natural flow of 61 cubic feet per second, which was adjusted for groundwater withdrawals using hydrologic modeling for the period of record from February 20, 1997, through October 15, 2018, at the USGS Chassahowitzka River near Homosassa, FL Gage No. 02310650. The Minimum Flow at any point downstream from this Gage is measured as the previous day’s natural flow at that point minus 3%.

(c) Status assessments of the Minimum Flow for the Chassahowitzka River System will be completed to determine whether the flow is below or projected to fall below the Minimum Flow. Each status assessment is independent from and not a determination of water use permit compliance or environmental resource permit compliance. Permit compliance is a regulatory function that is not within the scope of this subsection. As part of each status assessment, the District will use the following approach:

1. The District will evaluate the Minimum Flow annually to determine the extent to which the flow of the Chassahowitzka River System has been reduced due to withdrawals as of the date of each status assessment at the USGS Chassahowitzka River near Homosassa, FL Gage No. 02310650. The annual evaluation will be completed through a review of:

(a) flow data;

(b) water withdrawals;

(c) aquifer water levels;

(d) rainfall data; and

(e) hydrologic modeling.

2. The District will also evaluate the Minimum Flow every five years as part of the regional water supply planning process. This evaluation will include the use of hydrologic modeling.

3. If the Minimum Flow is being met based on the annual evaluation or the evaluation performed as a part of the regional water supply planning process, then no further actions are required beyond continued monitoring.

4. If the annual evaluation indicates the flow is below the Minimum Flow, or if the flow is projected to fall below the Minimum Flow within 20 years based on the evaluation performed as a part of the regional water supply planning process, the District will conduct a causation analysis to evaluate the potential causes of impacts on the Chassahowitzka River System. 

5. Based on the causation analysis, the District will re-evaluate the Minimum Flow for the Chassahowitzka River System, or adopt a recovery or prevention strategy consistent with the provisions of Section 373.0421(2), F.S.

(d) (c) The District will reevaluate the Minimum Flow by December 2029 within six years of adoption of this rule.

(17) Minimum Flow for the Homosassa River System.

(a) For purposes of this rule, the Homosassa River System includes the watercourse from the Homosassa Main Springs Complex to the Gulf of Mexico, including the southeast fork of the Homosassa River, Halls River, Hidden River and all named and unnamed springs that discharge to the Homosassa River these rivers.

(b) The Minimum Flow for the Homosassa River System is 95% 97% of the combined natural flow as measured at the United States Geological Survey (USGS) Homosassa Springs at Homosassa Springs, FL Gage (No. 02310678), and the USGS SE Fork Homosassa Spring at Homosassa Springs, FL Gage (No. 02310688). Natural flow is defined for the purpose of this rule as the flow that would exist in the absence of water withdrawal impacts. The Minimum Flow is based on a 5% reduction from the combined natural flow of 149 cubic feet per second, which was adjusted for groundwater withdrawals using hydrologic modeling for the period of record from October 1, 2000, through October 1, 2018, at the USGS Homosassa Springs at Homosassa Springs, FL Gage No. 02310678 and the USGS SE Fork Homosassa Spring at Homosassa Springs, FL Gage No. 02310688. The Minimum Flow at any point downstream from these Gages are measured as the previous day’s natural flow at that point minus 3%.

(c) Status assessments of the Minimum Flow for the Homosassa River System will be completed to determine whether the flow is below or projected to fall below the Minimum Flow. Each status assessment is independent from and not a determination of water use permit compliance or environmental resource permit compliance. Permit compliance is a regulatory function that is not within the scope of this subsection. As part of each status assessment, the District will use the following approach:

1. The District will evaluate the Minimum Flow annually to determine the extent to which the flow of the Homosassa River System has been reduced due to withdrawals as of the date of each status assessment at the USGS Homosassa Springs at Homosassa Springs, FL Gage No. 02310678 and the USGS SE Fork Homosassa Spring at Homosassa Springs, FL Gage No. 02310688. The annual evaluation will be completed through a review of:

(a) flow data;

(b) water withdrawals;

(c) aquifer water levels;

(d) rainfall data; and

(e) hydrologic modeling.

2. The District will also evaluate the Minimum Flow every five years as part of the regional water supply planning process. This evaluation will include the use of hydrologic modeling.

3. If the Minimum Flow is being met based on the annual evaluation or the evaluation performed as a part of the regional water supply planning process, then no further actions are required beyond continued monitoring.

4. If the annual evaluation indicates the flow is below the Minimum Flow, or if the flow is projected to fall below the Minimum Flow within 20 years based on the evaluation performed as a part of the regional water supply planning process, the District will conduct a causation analysis to evaluate the potential causes of impacts on the Homosassa River System. 

5. Based on the causation analysis, the District will re-evaluate the Minimum Flow for the Homosassa River System, or adopt a recovery or prevention strategy consistent with the provisions of Section 373.0421(2), F.S.

(d)(c) The District will reevaluate the Minimum Flow by December 2029 within six years of adoption of this rule.

(18) through (21) No change.

Rulemaking Authority 373.044, 373.113, 373.171 FS. Law Implemented 373.036, 373.042, 373.0421 FS. History–New 10-5-74, Amended 12-31-74, Formerly 16J-0.15, 40D-1.601, Amended 10-1-84, 8-7-00, 2-6-06, 4-6-06, 1-1-07, 11-25-07, 2-18-08, 3-2-08, 5-12-08, 5-10-09, 3-23-10, 3-28-10, 7-12-10, 8-2-10 (8), 8-2-10 (15), 10-16-12, 3-20-13(16), 3-20-13(17), 6-20-16, 3-15-18, 6-19-18, __.

 

NAME OF PERSON ORIGINATING PROPOSED RULE: Southwest Florida Water Management District

NAME OF AGENCY HEAD WHO APPROVED THE PROPOSED RULE: Southwest Florida Water Management District Governing Board

DATE PROPOSED RULE APPROVED BY AGENCY HEAD: October 22, 2019

DATE NOTICE OF PROPOSED RULE DEVELOPMENT PUBLISHED IN FAR: November 27, 2019