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 upper segment of the Braden River from Linger Lodge to Lorraine Road. This water body is listed on the District’s minimum flow and levels priority list for establishment of minimum flows. The minimum flows will be used in the District's permitting and resource management and development programs.
SUMMARY: The District has identified seasonal low, medium and high flow periods for the Braden River. Short-term minimum flow compliance standards were developed for each of these periods using a “building block” approach. The Minimum Low Flow for the low flow period (Block 1, May 7 through June 19) is the natural flow minus 15% at the Braden River USGS gage near Lorraine.
For the Minimum High Flow for the high flow period (Block 3, June 20 through October 24), is a stepped flow reduction of 19% and 10% of the historic flows, with the step occurring at the 15% exceedance flow (54 cfs) at the Braden River USGS gage near Lorraine.
For the medium flow period (October 25 to May 6) it was determined that changes in habitat availability for fish and macroinvertebrates determined the Minimum Medium Flow. The Minimum Medium Flow is established as the flow less 11% at the Braden River USGS gage near Lorraine.
Five and ten year means and medians are proposed as long-term compliance standards.
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, (352)796-7211, extension 4651

THE FULL TEXT OF THE PROPOSED RULE IS:

40D-8.041 Minimum Flows.

(1) through (7) No change.

(8) Minimum Flows for the Braden River.

(a) The Minimum Flows are to ensure that the minimum hydrologic requirements of the water resources or ecology of the natural systems associated with the river are met.

(b) Minimum Flows for the Braden River at the USGS Braden River near Lorraine Gage USGS # 02300032 (“near Lorraine Gage”) are set forth in Table 8-14 below. The long-term compliance standards set forth in Table 8-15 are established based on the application of the Minimum Flows to the lowest anticipated natural flow conditions. Minimum Flows for the Braden River are both seasonal and flow dependent. Two standards are flow based and applied continuously regardless of season. The first is a Minimum Low Flow threshold of 7 cfs at the near Lorraine Gage. The second is a Minimum High Flow threshold of 54 cfs at the near Lorraine Gage. The Minimum High Flow is based on changes in the number of days of inundation of floodplain features. There are also three seasonally dependent or Block specific Minimum Flows. The Block 1 and Block 2 Minimum Flows are based on potential changes in habitat availability for fish species and macroinvertebrate diversity. The Block 3 Minimum Flow is based on changes in the number of days of connection with floodplain features.

Table 8-14 Minimum Flow for Braden River at USGS Braden River near Lorraine Gage
Period	Effective Dates	Where Flow on Previous Day Equals:	Minimum Flow Is
Annually	January 1 to December 31	≤7 cfs >7cfs and <54 cfs 54 cfs	7 cfs Seasonally dependent see Blocks below Previous day flow minus 10%
Block 1	May 7 to June 19	≤7 >7 cfs	7 cfs previous day flow minus 10%
Block 2	October 25 to May 6	≤7 >7 cfs and <54 cfs 54 cfs	7 cfs previous day flow minus 11% previous day flow minus 10%
Block 3	June 20 to October 24	≤7 cfs >7 cfs and <54 cfs 54 cfs	7 cfs previous day flow minus 19% previous day flow minus 10%

Table 8-15 Compliance Standards for Braden River near Lorraine Gage
Minimum Flow	Hydrologic Statistic	Flow (cfs)
Annual Flow	10-Year Mean 10-Year Median 5-Year Mean 5-Year Median	31 3 26 2
Block 1	10-Year Mean 10-Year Median 5-Year Mean 5-Year Median	5 1 2 0
Block 2	10-Year Mean 10-Year Median 5-Year Mean 5-Year Median	20 3 10 1
Block 3	10-Year Mean 10-Year Median 5-Year Mean 5-Year Median	65 23 43 7

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, 4-6-06, 1-1-07, 11-25-07,_________.