40C-8.021. Definitions

Unless the context indicates otherwise, the following terms shall have the following meanings.

(1) “Black Water Creek” means that watercourse designated Black Water Creek within the Wekiva River Hydrologic Basin as defined by Rule 40C-41.023, F.A.C.

(2) “Determined minimum surface water flow” means a flow, expressed in cubic feet per second combined with a temporal element. The temporal element may be specifically expressed as a duration and return interval or may be generally expressed as a hydroperiod category.

(3) “Determined minimum surface water level” means an elevation in feet NGVD combined with a temporal element. The temporal element, for purposes of this chapter may be specifically expressed as a duration and return interval or may be generally expressed as a hydroperiod category.

(4) “Intermittently exposed” means a hydroperiod category where surface water is present throughout the year except in years of extreme drought. In most lakes this category does not typically support emergent vegetation and would be characterized as open water or floating-leaved deep marsh. Water levels causing inundation are expected to occur more than ninety percent of the time over a long term period of record.

(5) “Intermittently flooded” means a hydroperiod category where the substrate is usually exposed, but surface water is present with variable frequency and duration. Water levels causing inundation are expected to occur on average approximately once every ten years or more. Years may intervene between periods of inundation. On recharge lakes (sandhill type lakes), the dominant vegetation growing at this elevation can change as soil moisture conditions change, from a dominance of upland species to wetland species or the reverse. Duration of inundation is on the order of several months. Water levels are expected to inundate less than two per cent of the time over a long term period of record.

(6) “Long term” or “long term period of record” means at least a 30 year continuous period.

(7) “Minimum frequent high” means a chronically high surface water level or flow with an associated frequency and duration that allows for inundation of the floodplain at a depth and duration sufficient to maintain wetland functions.

(8) “Minimum infrequent high” means an acutely high surface water level or flow with an associated frequency and duration that is expected to be reached or exceeded during or immediately after periods of high rainfall so as to allow for inundation of a floodplain at a depth and duration sufficient to maintain biota and the exchange of nutrients and detrital material.

(9) “Minimum average” means the surface water level or flow necessary over a long period to maintain the integrity of hydric soils and wetland plant communities.

(10) “Minimum frequent low” means a chronically low surface water level or flow that generally occurs only during periods of reduced rainfall. This level is intended to prevent deleterious effects to the composition and structure of floodplain soils, the species composition and structure of floodplain and instream biotic communities, and the linkage of aquatic and floodplain food webs.

(11) “Minimum infrequent low” means an acutely low surface water level or flow with an associated frequency and duration which may occur during periods of extreme drought below which there will be a significant negative impact on the biota of the surface water which includes associated wetlands.

(12) “NAVD” means North American Vertical Datum of 1988.

(13) “NGVD” means National Geodetic Vertical Datum of 1929.

(14) “P25” means the percentile ranking represented by the elevation of the water surface or the flow of the spring or surface water that is equaled or exceeded 25 percent of the time as determined from a long-term water level or flow time series.

(15) “P50” means the percentile ranking represented by the elevation of the water surface or the flow of the spring or surface water that is equaled or exceeded 50 percent of the time as determined from a long-term water level or flow time series.

(16) “P75” means the percentile ranking represented by the elevation of the water surface or the flow of the spring or surface water that is equaled or exceeded 75 percent of the time as determined from a long-term water level or flow time series.

(17) “Permanently flooded” means a hydroperiod category where water covers the land surface throughout the year in all years. Vegetation, if present, is composed of aquatic macrophytes.

(18) “Phased Restriction” means the level or flow (based on the past 30 consecutive day average level or flow) at which a water use shortage phase (Phase I-IV as defined by Rule 40C-21.251, F.A.C.), is declared and its associated restrictions imposed.

(19) “Seasonally flooded” means a hydroperiod category where surface water is typically present for extended periods (30 days or more) during the growing season, resulting in a predominance of submerged or submerged and transitional wetland species. During extended periods of normal or above normal rainfall, lake levels causing inundation are expected to occur several weeks to several months every one to two years.

(20) “Semi-permanently flooded” means a hydroperiod category where surface water inundation persists in most years. When surface water is absent the water table is usually near the land surface. In many lakes with emergent marshes this water level is near the lower elevation that supports emergent marsh or floating vegetation and peat substrates, or other highly organic hydric substrates. This characterization may not be true for herbaceous wetlands around sandhill type lakes, which often have emergent vegetation that follows declining water levels to below the lower elevation of peat substrate. Water levels causing inundation are expected to occur approximately eighty percent of the time over a long term period of record. Exposure of these ground elevations is expected to re-occur, on average, about every five to ten years for extended periods (several or more months) during moderate droughts.

(21) “Temporarily Flooded” means a hydroperiod category where surface water is present or the substrate is flooded for brief periods (up to several weeks) approximately every five years. Plants of upland and wetland species are characteristic. The composition of the vegetation at this water level is dependant upon whether the flooding predominantly occurs in the growing season, whether seepage from higher elevations is pronounced, and the nature of the soil. Lake water levels are expected to equal or exceed this elevation five per cent of the time or less over a long term period of record.

(22) “Typically saturated” means a hydroperiod category where for extended periods of the year the water level should saturate or inundate. This results in saturated substrates for periods of one-half year or more during non-flooding periods of typical years. Water levels causing inundation are expected to occur fifty to sixty per cent of the time over a long term period of record. This water level is expected to have a recurrence interval, on the average, of one or two years over a long term period of record. Obligate wetland plant species are expected to be predominate near this water level.

(23) “Wekiva River” means that watercourse designated Wekiva River within the Wekiva River Hydrologic Basin as defined by Rule 40C-41.023, F.A.C.

Rulemaking Authority 373.044, 373.113 FS. Law Implemented 373.042, 373.103, 373.415 FS. History–New 9-16-92, Amended 8-17-94, 6-8-95, 3-19-02, 6-25-14, 1-30-19, 9-28-21.