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As part of the analyses conducted to derive nutrient standards for streams, the Department evaluated the available nutrient data for regional differences and ultimately developed a regionalization criteria for the stream nutrient standards. Nutrient Watershed Regions are drainage areas over which the stream nutrient thresholds in paragraph 62-302.531(2)(c), F.A.C., apply.For purposes of interpreting the numeric nutrient criteria (NNC) in paragraph 62-302.530(47)(b), F.A.C., under paragraph 62-302.531(2)(c), F.A.C., a 'stream' is defined as a predominantly fresh surface waterbody with perennial flow in a defined channel with banks during typical climatic and hydrologic conditions for its region within the state. During periods of drought, portions of a stream channel may exhibit a dry bed, but wetted pools are typically still present during these conditions. Streams do not include: (a) non-perennial water segments where fluctuating hydrologic conditions, including periods of desiccation, typically result in the dominance of wetland and/or terrestrial taxa (and corresponding reduction in obligate fluvial or lotic taxa), wetlands, or portions of streams that exhibit lake characteristics (e.g., long water residence time, increased width, or predominance of biological taxa typically found in non-flowing conditions), or tidally influenced segments that fluctuate between predominantly marine and predominantly fresh waters during typical climatic and hydrologic conditions; or (b) ditches, canals and other conveyances, or segments of conveyances, that are man-made, or predominantly channelized or predominantly physically altered; and 1) are primarily used for water management purposes, such as flood protection, stormwater management, irrigation, or water supply; and 2) have marginal or poor stream habitat or habitat components, such as a lack of habitat or substrate that is biologically limited, because the conveyance has cross sections that are predominantly trapezoidal, has armored banks, or is maintained primarily for water conveyance. The NNC Implementation Document (http://www.flrules.org/Gateway/reference.asp?No=Ref-02905) provides additional information describing the information and data needed to determine the applicable freshwater criteria (i.e., stream, springs, lakes, or narrative). |