RULE NO: RULE TITLE
40D-8.041: Minimum Flows
40D-8.624: Guidance and Minimum Levels for Lakes
40D-8.626: Minimum Aquifer Levels in Hillsborough County North of State Road 60, and Pasco and Pinellas Counties
PURPOSE AND EFFECT: To establish minimum flows and levels for the Southern Water Use Caution Area for the Most Impacted Area, the upper Peace River and Lakes Jackson, Letta, Lotela and Little Lake Jackson on the Highlands County Ridge and Lakes Clinch, Eagle, McLeod and Wales in Polk County.
SUMMARY: Minimum flows proposed for the upper Peace River to ensure that the minimum hydrologic requirements of fish and natural systems associated with the upper segment of the river are met and not jeopardized by withdrawals. The upper segment of the river includes that area between Bartow and Zolfo Springs. The minimum flows are based on the hydrologic requirements of biological communities associated with the upper Peace River system, as well as considering non-consumptive uses including fishing, wildlife observation, general recreation, aesthetic enjoyment, canoeing and boating. The minimum flows will be supported by District water development projects.
The District also proposes minimum low and minimum high lake levels, as well as the ten-year flood, and high and low guidance levels for Lakes Jackson, Letta, Lotela and Little Lake Jackson on the Highlands County Ridge and Lakes Clinch, Eagle, McLeod and Wales in Polk County. The High Minimum Lake Level is the elevation that a lake's water levels are required to equal or exceed ten percent of the time on a Long-term basis. The Minimum Lake Level is the elevation that the lake's water levels are required to equal or exceed fifty percent of the time on a Long-term basis. The High and Low Guidance Levels and the Ten-year Flood Guidance Level are advisory guidelines for lakeshore development of, including water dependent structures and operation of water management structures.
A minimum aquifer level is proposed for the coastal portion of the Southern Water Use Caution Area in southern Hillsborough, Manatee and northern Sarasota counties. The minimum aquifer level is to stabilize regional ground water level declines so that long-term management efforts can slow the rate of regional saltwater intrusion in the area.
SUMMARY OF ESTIMATED REGULATORY COSTS: A Statement of Estimated Regulatory Cost, final draft dated March 14, 2006, has been prepared addressing the impact of the proposed minimum flows and levels, and the rules proposed simultaneously in Chapters 40D-2 and 40D-80, F.A.C., to implement the minimum flows and levels within the Southern Water Use Caution Area (the “SWUCA SERC”). The items to be addressed in a Statement of Estimated Regulatory Cost as set forth in Section 120.541(1)(c), F.S., are included in the SWUCA SERC. The SWUCA SERC is available upon request to the District.
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, 373.0395, 373.042, 373.0421, 373.086 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 General 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 (3) No change.

(4) Minimum Flows for upper Peace River.

(a) Over the last several decades there has been a significant decline in flow in the upper Peace River, especially during the dry season. One of the major contributing factors is the elimination of baseflow as a result of ground water withdrawals that have lowered the potentiometric surface of the upper Floridan aquifer. In addition, surface-water drainage alterations, reduction in surface storage, long-term cyclical declines in rainfall and karst openings in the riverbed have played significant roles in reducing flow in the upper Peace River.

(b) The minimum flows are to ensure that the minimum hydrologic requirements of fish and natural systems associated with the river are met and not jeopardized by withdrawals. At this time only Minimum Low Flows are being established. It is anticipated that mid- and high-minimum flows will be established once the controlling factors that affect those flows are better understood.

(c) The Minimum Low Flows for the upper Peace River are set forth in Table 8-8 below. The Minimum Low Flows are established based on the lowest acceptable flow under the lowest anticipated flow conditions. This is determined by providing for the hydrologic requirements of biological communities associated with the upper Peace River system, as well as considering non-consumptive uses including fishing, wildlife observation, general recreation, aesthetic enjoyment, canoeing and boating. This determination uses professional experience and judgment to identify key habitats and hydrologic requirements for specific biotic assemblages. This approach results in establishing Minimum Low Flows for the upper Peace River based on maintaining the higher of the water elevations needed for fish passage (0.6 feet or 7.2 inches) or the lowest wetted perimeter inflection point (as much stream bed coverage as possible for the least amount of flow) as set forth below. A ninety-five percent annual exceedance occurs when the flow is greater than the Minimum Low Flow at least ninety-five percent of the days, or 350 days, of a calendar year.

Table 8-8 Minimum Flows for the upper Peace River
Location/Gage	Minimum Flow (cubic feet per second)
Bartow / USGS Bartow River Gage No. 02294650	Annual 95% exceedance flow of 17 cfs
Ft. Meade / USGS Ft. Meade River Gage No. 02294898	Annual 95% exceedance flow of 27 cfs
Zolfo Springs / USGS Zolfo Springs River Gage No. 02295637	Annual 95% exceedance flow of 45 cfs

(d) Compliance – The Minimum Low Flow is achieved when the measured flow rate is at or above the Minimum Low Flow for three consecutive years. Once the Minimum Low Flow has been achieved for three consecutive years, the Minimum Low Flow is not met when the measured flow rate is below the Minimum Low Flow for two out of ten years commencing the year after achievement. If the two years below the minimum flow occur anytime before the ten year period is complete, the upper Peace River is deemed below its Minimum Low Flow and the three consecutive years above the Minimum Low Flow is again required for compliance. Once the ten-year period is complete, the period will roll forward one year each year.

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,________.

40D-8.624 Guidance and Minimum Levels for Lakes.

(1) through (12) No change.

(13) Levels for lakes established during or after August 7, 2000, are set forth in the following table. After the High Minimum Lake Level and Minimum Lake Level elevation for each lake is a designation indicating the Method used, as described in subsection 40D-8.624(7), F.A.C., to establish the level. Compliance with the High Minimum and Minimum Lake Levels is determined pursuant to paragraphs (6)(b) and (7)(b) above. Guidance Levels established prior to August 7, 2000, are set forth in Table 8-3 in subsection 40D-8.624(14), F.A.C., below.

Table 8-2 Minimum and Guidance Levels Established During or After August 7, 2000. Levels are elevations, in feet above the National Geodetic Vertical Datum of 1929.
Location by County and Basin	Name of Lake and Section, Township and Range Information	Ten-Year Flood Guidance Level	High Guidance Level	High Minimum Lake Level	Minimum Lake Level	Low Guidance Level
(a) – (h) No change.
(i) In Highlands County Within the Peace River Basin ~~RESERVED~~	Jackson Lake S-30 T-24S R-29E	104.1	102.6	102.4 (Cat 3)	101.3 (Cat 3)	100.2
	Letta Lake S-31 T-33S R-29E	100.5	99.5	99.5 (Cat 3)	98.4 (Cat 3)	97.1
	Little Jackson Lake S-06 T-35S R-29E	104.1	102.6	102.4 (Cat 3)	101.3 (Cat 3)	100.2
	Lotela Lake S-26 T-33S R-28E	108.5	107.5	106.8 (Cat 3)	105.7 (Cat 3)	105.0
(j) – (y) No change.
(z) In Polk County Within the Peace River Basin ~~RESERVED~~	Clinch Lake S-31 T-31S R- 8E	107.4	105.5	105.5 (Cat 3)	104.4 (Cat 3)	103.1
	Eagle Lake S-01 T-29S R-25E	131.3	129.6	129.0 (Cat 3)	127.9 (Cat 3)	127.2
	McLeod Lake S-07 T-29S R-26E	133.3	129.4	129.4 (Cat 3)	128.3 (Cat 3)	127.0
	Wales Lake S-01 T-30S R-27E	114.1	ND	107.7 (Cat 3)	106.6 (Cat 3)	ND
(aa) – (cc) No change.

(14) Guidance Levels established for lakes prior to August 7, 2000, are set forth in the following table:

Table 8-3 Guidance Water Levels adopted prior to August 7, 2000
Location of Impoundment by County and Basin	Ten-Year Flood Guidance Level in Feet Above Mean Sea Level (msl)	High Level in Feet Above Mean Sea Level (msl)	Low Level in Feet Above Mean Sea Level (msl)	Extreme Low Level in Feet Above Mean Sea Level (msl)
(a) – (h) No change.
(i) In Highlands County Within the Peace River Basin LAKES Sec Twsp Rng
~~Jackson, Lake~~ ~~30 34S 29E~~	~~103.20~~	~~103.00~~	~~100.00~~	~~98.00~~
~~Letta, Lake~~ ~~31 33S 29E~~	~~100.00~~	~~100.00~~	~~97.00~~	~~95.00~~
~~Little Lake Jackson~~ ~~6 35S 29E~~	~~103.20~~	~~103.00~~	~~100.00~~	~~98.00~~
~~Lotela, Lake~~ ~~26 33S 28E~~	~~106.60~~	~~108.50~~	~~105.00~~	~~104.00~~
(j) – (y) No change.
(z) In Polk County Within the Peace River Basin
~~Clinch, Lake~~ ~~31 31S 28E~~	~~108.00~~	~~106.75~~	~~104.00~~	~~102.50~~
~~Eagle Lake~~ ~~1 29 25E~~	~~131.00~~	~~130.75~~	~~128.50~~	~~126.50~~
~~Lake McLeod~~ ~~7 29 26E~~	~~133.10~~	~~132.00~~	~~129.50~~	~~128.00~~
~~Wales, Lake~~ ~~S01 T30 R27~~	~~114.10~~	~~112.50~~	~~110.00~~	~~108.00~~
(aa) – (cc) No change.

Specific Authority 373.044, 373.113, 373.171 FS. Law Implemented 373.036, 373.0361, 373.0395, 373.042, 373.0421, 373.086 FS. History–New 6-7-78, Amended 1-22-79, 4-27-80, 10-21-80, 12-22-80, 3-23-81, 4-14-81, 6-4-81, 10-15-81, 11-23-81, 1-5-82, 3-11-82, 5-10-82, 7-4-82, 9-2-82, 11-8-82, 1-10-83, 4-3-83, 7-5-83, 9-5-83, 10-16-83, 12-12-83, 5-8-84, 7-8-84, 12-16-84, 2-7-85, 5-13-85, 6-26-85, 11-3-85, 3-5-86, 6-16-86, Formerly 16J-8.678, Amended 9-7-86, 2-12-87, 9-2-87, 2-18-88, 6-27-88, 2-22-89, 3-23-89, 9-26-89, 7-26-90, 10-30-90, 3-3-91, 9-30-91, 10-7-91, 7-26-92, 3-1-93, 5-11-94, 6-6-96, 2-23-97, 8-7-00, 1-8-04, 12-10-04, 6-05-05 ________.

40D-8.626 Minimum Aquifer Levels ~~in Hillsborough County North of State Road 60, and Pasco and Pinellas Counties~~.

(1) Hillsborough County North of State Road 60, and Pasco and Pinellas Counties ~~Salt Water Intrusion Minimum Aquifer Levels~~. Salt Water Intrusion within this area has not been regional in nature, but is of localized concern in some coastal areas. The District has chosen the North Pinellas, Southwest Pasco and Northwest Hillsborough Counties region as the priority area for the establishment of Salt Water Intrusion Minimum Aquifer Levels (“SWIMAL”) to prevent regional seawater intrusion because of the availability of data and the potential for future intrusion. The SWIMALs for the Upper Floridan aquifer shall be established as follows:

(1) through (3) renumbered (a) through (c) No change.

(2) SWUCA Salt Water Intrusion Minimum Aquifer Level.

(a) The District has determined that ground water withdrawals in the SWUCA have contributed to water level declines that advance saltwater intrusion. The coastal portion of the SWUCA in southern Hillsborough, Manatee and northern Sarasota counties (the Most Impacted Area or MIA) is a priority area for the establishment of minimum aquifer levels because of its proximity to the saltwater interface and the large effect on interface movement caused by lowering of the potentiometric surface in this area. The Salt Water Intrusion Minimum Aquifer Level (SWIMAL) is established to stabilize regional water level declines so that long-term management efforts can slow the rate of regional saltwater intrusion in the MIA. This is based on an average value to address the regional nature of the problem and avoids the potential for localized lowering of a minimum level.

(b) The SWIMAL over the surface of the MIA is 13.1 feet (National Geodetic Vertical Datum of 1929 or NGVD 1929). The SWIMAL is derived using the method set forth in (2)(c) below.

(c) The reference period for which the SWIMAL is calculated is the period 1990 through 1999. Ten wells from within or adjacent to the MIA (Table 8-5), are used to determine the minimum level. The annual average elevation for each of the years 1990 through 1999 is established utilizing monthly water level data for each of the wells. The annual averages over the period are then used to calculate the decadal average for the period. The 1990-99 average Upper Floridan aquifer potentiometric surface of the MIA is constructed by calculating the average of these annual average values weighted spatially using the Thiessen polygon methodology. The resulting Minimum Level over the surface of the MIA is 13.1 feet (National Geodetic Vertical Datum of 1929).

Table 8-5: Wells utilized to determine the Salt Water Intrusion Minimum Aquifer Level.

Site Number	Sequence Number	Site Name
564	0	KIBLER DEEP
87		ROMP 123 Hawthorn/Ocala HAWTHORN/OCALA
10914	0	ROMP 50 TAMPA/OCALA
10883	0	ROMP TR 10-2 TAMPA
287	0	ROMP TR 7-1 TAMPA
10926	0	ROMP TR 7-4 Suwannee/Ocala SUWANNEE/OCALA
10920	0	ROMP TR 8-1 Upper Avon Park PARK
10909	1	ROMP TR 9-3 Ocala/Avon Park
561	0	SARASOTA 9 DEEP
456	0	VERNA T 0-4

(d) Implementation of The SWUCA Salt Water Intrusion Minimum Aquifer Level – The SWIMAL shall be used to gauge the status of the ground water resource with respect to saltwater intrusion in the region. Determining the status of the rate of movement of the saltwater interface shall be based on comparison of the average Floridan aquifer water level over the MIA with the Floridan aquifer minimum level over ten‑year moving windows of time. The ten‑year average water level for a particular year shall be calculated as the average water level for that year and the previous nine years. The process of calculating the ten-year average is the same as described in paragraph (c) above for calculating the minimum level.

(e) Compliance – The objective of the District's management efforts is for the ten‑year moving annual average water level to fluctuate in a range at or above the minimum level. The minimum level is achieved if the ten‑year moving annual average water level has fluctuated at or above the minimum level for a minimum of five consecutive years. Once the minimum level is achieved, the minimum level is no longer met when the ten-year moving annual average water level falls below the minimum level for more than two consecutive years. Then, the five consecutive years above the minimum level is again required for compliance.

Specific Authority 373.044, 373.113, 373.171 FS. Law Implemented 373.036, 373.0361, 373.0395, 373.042, 373.0421, 373.086 FS. History–New 8-7-00, Amended________.