The amendments establish minimum flows pursuant to Section 373.042, F.S., for the Lower Hillsborough River, Sulphur Springs and the Tampa Bypass Canal, all located in Hillsborough County, Florida. These water bodies are listed on the District’s ...

 

WATER MANAGEMENT DISTRICTS
Southwest Florida Water Management District

RULE NO: RULE TITLE
40D-8.041: Minimum Flows
PURPOSE AND EFFECT: The amendments establish minimum flows pursuant to Section 373.042, F.S., for the Lower Hillsborough River, Sulphur Springs and the Tampa Bypass Canal, all located in Hillsborough County, Florida. These water bodies are listed on the District’s minimum flow and levels priority list for establishment of minimum flows. These minimum flows will be used in the District’s permitting and resource management and development programs.
SUMMARY: The amendments establish minimum flows for the Lower Hillsborough River ranging from 20-24 cubic feet per second depending on the time of year and climatic conditions. The amendments establish minimum flows for Sulphur Springs ranging from 10-18 cubic feet per second depending on the time of year, water level elevations in the Hillsborough River Reservoir and tide stages. The amendments also establish a minimum flow of 0 cubic feet per second for the Tampa Bypass Canal at Structure 160.
SUMMARY OF STATEMENT OF ESTIMATED REGULATORY COSTS: No Statement of Estimated Regulatory Cost was prepared.
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.
SPECIFIC AUTHORITY: 373.044, 373.113, 373.171 FS.
LAW IMPLEMENTED: 373.036, 373.0361, 373.042, 373.0421 FS.
IF REQUESTED WITHIN 21 DAYS OF THE DATE OF THIS NOTICE, A HEARING WILL BE SCHEDULED AND ANNOUNCED IN FAW.
THE PERSON TO BE CONTACTED REGARDING THE PROPOSED RULE IS: Karen A. Lloyd, Assistant Deputy Counsel, Office of General Counsel, 2379 Broad Street, Brooksville, FL 34604-6899, [phone], extension 4651

THE FULL TEXT OF THE PROPOSED RULE IS:

 

40D-8.041 Minimum Flows.

(1) Minimum Flows for the Lower Hillsborough River.

(a) No change.

(b) The Minimum Flows for the Lower Hillsborough River are based on extending a salinity range less than 5 ppt from the Hillsborough River Dam toward Sulphur Springs.  The Minimum Flows for the Lower Hillsborough River are 20 cubic feet per second (“cfs”) freshwater equivalent from July 1 through March 31 and 24 cfs fresh water equivalent from April 1 through June 30 at the base of the dam as adjusted based on a proportionate amount that flow at the United States Geological Survey Gauge No. 01203000 near Zephyrhills, Florida (“Gauge”) is below 58 cfs.  The adjustment is that for each one cfs that Hillsborough River flow at the Gauge is below 58 cfs, when 20 cfs freshwater equivalent is otherwise required, the Minimum Flow is adjusted by reducing it by 0.35 cfs; when 24 cfs freshwater equivalent is otherwise required, the Minimum Flow is adjusted by reducing it by 0.40 cfs.  For purposes of this paragraph  40D-8.041(1)(b), F.A.C., freshwater equivalent means water that has a salinity concentration of 0.0 ppt for modeling purposes. Effective August 7, 2000 the Minimum Flow for the Lower Hillsborough River shall be at the rate of flow of ten cubic feet per second (cfs) at the base of the dam as measured at the Rowlett Park Drive bridge gauging station.  Through December 31, 2007, the City shall be required to supply this Minimum Flow from the Reservoir when the surface water elevation is above 22.5 feet NGVD at USGS Gauge 02304500.  Because the storage of water within the Reservoir is critical to the public health, safety, and welfare of those dependent on the City potable water supply, this flow requirement may be met by diverting flow from sources other than the City’s Reservoir.  The City shall provide this flow from sources other than the City’s Reservoir, when the surface water elevation is below 22.5 feet NGVD at USGS Gauge 02304500 and it is feasible to provide the flow without compromising public health, safety or welfare.  This Minimum Flow has been determined based on the loss of historical hydrologic functions, the existing changes and structural alterations in and along the river and its watershed pursuant to subsection 373.0421(1), F.S., and the dependence of viable ecological communities downstream of the dam on flows from the Hillsborough River and Sulphur Springs.  Following completion of the District and City study described in paragraph 40D-80.073(4)(d), F.A.C., the Minimum Flow shall be re-established, as necessary, based on the results of the study.

(2) Minimum Flow for Sulphur Springs – The Minimum Flow for Sulphur Springs is based on minimization of salinity incursions into the Upper Sulphur Springs Run (“Upper Run”) from the Lower Hillsborough River (“LHR”) and to moderate temperature levels within the manatee protection zone of the LHR.

(a) As of October 1, 2012, the City of Tampa shall maintain a Minimum Flow for Sulphur Springs of:

1. 18 cfs, as measured at the United States Geological Survey Sulphur Springs Gauge No. 02306000 at Sulphur Springs, Florida, or;

2. 13 cfs when water levels in the Hillsborough River reservoir fall below 19 feet NGVD; and

3. 10 cfs during low tide stages in the LHR, provided that salinity incursions from the LHR into the upper spring run do not occur.  Salinity incursions shall be defined as when salinity values in the upper spring run as measured at the United States Geological Survey Gauge Sulphur Springs Run at Sulphur Springs, Florida (#023060003) are greater than 1 ppt than the concurrent salinity value in the spring pool as measured at the United States Geological Survey Gauge Sulphur Springs Run at Sulphur Springs, Florida (#023060000) for a period of greater than 1 hour.

(b) Notwithstanding paragraph 40D-8.041(2)(a), F.A.C., above, and beginning the effective date of this rule, when spring flow is available, a Minimum Flow of 18 cfs shall be required if the temperature of either surface or bottom waters in the LHR near the Spring Run’s outlet is below 15º C.

(c) The City of Tampa may propose to the District modifications to the weirs and gates located within the upper and lower spring run that affect the flow rates and salinity levels in the Upper Run and the LHR. The District shall evaluate the modifications to determine whether the flow resulting from the operating capabilities of the modifications and modeling simulations of the resulting salinity incursions into the Upper Spring Run achieve the salinity goal of the Minimum Flow for Sulphur Springs.  If the District determines that flows different from the Minimum Flows ("Different Flows") will achieve the salinity goal and otherwise protect the resources of the Upper Spring Run, the District, upon request by the City, will recommend to the Governing Board revision of the Minimum Flow to reflect the Different Flow.

Pursuant to the District priority schedule for establishment of minimum flows and levels required by Section 373.042, F.S., the District will establish a Minimum Flow for Sulphur Springs by December 31, 2001.

(3) The Minimum Flow for the Tampa Bypass Canal at structure 160 shall be 0 cfs.

(3) through (5) renumbered (4) through (6) No change.

Specific Authority 373.044, 373.113, 373.171 FS. Law Implemented 373.036, 373.0361, 373.0395, 373.042, 373.0421 FS. History– Readopted 10-5-74, Amended 12-31-74, Formerly 16J-0.15, 40D-1.601, Amended 10-1-84, 8-7-00, 2-6-06, 1-1-07,________.

NAME OF PERSON ORIGINATING PROPOSED RULE: Karen A. Lloyd, Assistant Deputy Counsel, Office of General Counsel, 2379 Broad Street, Brooksville, FL 34604-6899, [phone], extension 4651
NAME OF SUPERVISOR OR PERSON WHO APPROVED THE PROPOSED RULE: Southwest Florida Water Management District Governing Board
DATE PROPOSED RULE APPROVED BY AGENCY HEAD: August 28, 2007
DATE NOTICE OF PROPOSED RULE DEVELOPMENT PUBLISHED IN FAW: September 21, 2007