40D-8.021. Definitions

The terms set forth herein shall have the meanings ascribed to them unless the context clearly indicates otherwise, and such meanings shall apply throughout these rules. The terms defined in Rule 40D-1.102, F.A.C., shall also apply throughout Chapter 40D-8, F.A.C., and the terms defined in this Rule 40D-8.021, F.A.C., apply throughout the District rules except that where there is a conflict or a difference between Rule 40D-1.102, F.A.C. and this Rule 40D-8.021, F.A.C., the definition in this Chapter 40D-8, F.A.C., will control.

(1) “Current” means a recent Long-term period during which Structural Alterations and hydrologic stresses are stable.

(2) “Guidance Levels” means water levels, determined by the District using the best available information and expressed in feet relative to National Geodetic Vertical Datum (of 1929), or in feet relative to the North American Vertical Datum (of 1988), used as advisory information for the District, lake shore residents and local governments, or to aid in the management or control of adjustable structures. Established Guidance Levels include the Low Level and the High Level.

(3) “Historic” means a Long-term period when there are no measurable impacts due to withdrawals and Structural Alterations are similar to current conditions.

(4) “Hydrologic Indicators” means those biological and physical features, which are representative of previous water levels as listed in Section 373.4211(20), F.S.

(5) “Long-term” means an evaluation period used to establish Minimum Flows and Minimum Water Levels, determine compliance with established Minimum Flows and Minimum Water Levels, and assess withdrawal impacts on established Minimum Flows and Minimum Water Levels that represents a period which spans the range of hydrologic conditions which can be expected to occur based upon historical records, ranging from high water levels to low water levels. In the context of an average water level, the average will be based upon the historic expected range and frequency of levels. Relative to Minimum Flow and Level establishment and compliance, the best available information, selected through application of reasonable scientific judgement, that is sufficiently representative of Long-term conditions will be used.

(6) “Minimum Flow” means the flow for a surface watercourse at which further withdrawals would be significantly harmful to the water resources or ecology of the area and which may provide for the protection of non-consumptive uses.

(7) “Minimum Level” means the Long-term level of surface water, water table, or potentiometric surface at which further withdrawals would be significantly harmful to the water resources of the area and which may provide for the protection of nonconsumptive uses. Such a level shall be expressed as an elevation, in feet relative to National Geodetic Vertical Datum (1929) or in feet relative to the North American Vertical Datum (1988) and includes Minimum Wetland Levels, High Minimum Lake Levels, Minimum Lake Levels, and Minimum Aquifer Levels.

(8) “P10” means the percentile ranking represented by the elevation of the water surface of a lake or wetland that is equaled or exceeded 10 percent of the time as determined from a Long-term stage frequency analysis.

(9) “P50” means the percentile ranking represented by the elevation of the water surface of a lake or wetland that is equaled or exceeded 50 percent of the time as determined from a Long-term stage frequency analysis.

(10) “P90” means the percentile ranking represented by the elevation of the water surface of a lake or wetland that is equaled or exceeded 90 percent of the time as determined from a Long-term stage frequency analysis.

(11) “Structural Alteration” means human alteration of an inlet outlet of a lake or wetland that affects water levels.

Rulemaking Authority 373.044, 373.113, 373.171 FS. Law Implemented 373.036, 373.0361, 373.042, 373.0421, 373.086, 373.216, 373.219, 373.223, 373.229, 373.413, 373.414, 373.416 FS. History–New 6-7-78, Amended 1-22-79, Formerly 16J-8.02, Amended 8-7-00, 1-8-04, 2-18-08, 9-27-21.