The Determination of Minimum Flows for Sulphur Springs, Tampa

DRAFT
northern shore of the upper spring run (Figure 2-5C). Plants that are common along this
reach include leatherfern (Acrostichum danaeifolium), cattail (Typha domingensis),
elderberry (Sambucus canadensis), and brazilian pepper (Schinus terebinthefolius).
Other species that occur along the northern shore of the upper run include groundsel
tree (Baccharis halimifolia), string lily (Crinum americanum), peppervine (Ampelopsis
arborea), rosary pea (Arbrus precatorius), softstem bulrush (Scirpus tabernaemontani)
and giant bulrush (Scripus californicus). There are no shoreline plants established along
the southern bank of the upper spring run, as a retaining wall reaches to the water's
edge.
The banks of the lower spring run (below the weir) are steep with scattered concrete
rubble. Vegetation along this reach of the run is dominated by leatherfern, brazilian
pepper, with some string-lilly, Ceaser weed (Urena lobata) and climbing aster (Aster
caroliniana). With the exception of brazilian pepper, the plants along both the upper and
lower spring run are native wetland species that are common along the tidal freshwater
and oligohaline reaches of southwest Florida rivers (Clewell et al. 2000).
3.7.3 Benthic macroinvertebrates
3.7.3.1 1997 Macroinvertebrate survey
Historic data for macroinvertebrates in the Sulphur Springs system are limited, but
informative. On November 19, 1997, staff from SWFWMD and FDEP did a qualitative
sampling of the benthic macroinvertebrates in Sulphur Springs run. Macroinvertebrates
were sampled by sweeps of a D-frame dip net (600 micron mesh) from unvegetated
portions of the channel bottom, shoreline plant communities, and small woody snags in
the spring run. Flow from the spring pool was at a rate of 41 cfs, and as described in
Section 2.3, this collection occurred during a several-year period when withdrawals
were limited to only a few days in April of 1997. On the day of sampling, dissolved
oxygen concentrations measured at one profile in the middle of the spring run were 5.2
mg/l; pH was 6.94; and surface and bottom salinity values were near 1.6 ppt. The
collection occurred during a high flow event from the Hillsborough River Reservoir and
the lower Hillsborough River was fresh near the mouth of the spring run.
Taxonomic identifications were performed by staff from the FDEP. A list of
macroinvertebrate taxa collected from the spring run is provided in Appendix B, along
with species that were collected in later years by the Florida Fish and Wildlife
Conservation Commission. The invertebrate species collected in 1997 included
freshwater taxa and a number of euryhaline species common to tidal creeks and coastal
springs. The crustacean fauna was characterized by amphipods, isopods, decapods, a
cumacean and a mysid species that are common to tidal creeks and other low salinity
habitats. Though not quantified, the amphipods and isopods seemed particularly
abundant. Although these species are most common in low salinity waters, most can
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