Water Quality Assessment Report - Florida Department of ...

segments where the impairment is due to a pollutant regulated by the Clean
Water Act and the pollutant has contributed to the decline or extirpation
of a federally listed threatened or endangered species, as indicated in
the Federal Register listing the species; or waterbody segments verifi ed as
impaired that are included on the EPA’s 1998 303(d) list as high priority.
The waterbody segments identifi ed as high-priority areas for TMDL
development are as follows: Klosterman Bayou Run Tidal (waterbody
identifi cation number [WBID] 1508) for DO, fecal coliforms, and nutrients
(chlorophyll a), on 303(d) list; Stevenson Creek Tidal (WBID 1567)
for DO and nutrients (chlorophyll a); St. Joe Creek (WBID 1668A) for
DO and nutrients (historical chlorophyll), on 303(d) list; and Pinellas Park
Ditch No. 5 (WBID 1668B) for DO and nutrients (chlorophyll a), on
303(d) list. All of the remaining parameters causing impairment for the
WBIDs placed on the Verifi ed List have been assigned medium priority for
TMDL development.
Summary of Ground Water and Springs
Assessment Findings
This section summarizes the results of an assessment of the availability
and quality of potable ground water supplies, the impact of ground
water on surface water resources, and resource priorities in the Springs
Coast Basin. Due to the signifi cant interaction between ground water and
surface water via springs in most planning units in the basin, ground water
is likely to infl uence surface water quality. The assessment uses planning
units consistent with the surface water assessment and water quality data
from a combination of databases maintained by the Department and the
SWFWMD springs monitoring program.
Basinwide Observations of Elevated Parameter Concentrations
Elevated nitrate levels in the basin are well documented by SWFWMD
work. These studies have shown that, overall, elevated nitrate levels
are present in springs and are attributed to pollutant sources in their
springsheds, primarily inorganic sources such as fertilizers.
Ammonia (dissolved, measured as N) values from Floridan aquifer
system wells and springs are typically very low, except where very localized
sources—such as concentrated animal-feeding operations or malfunctioning
septic or sewage systems—are present. Ammonia typically converts to
nitrate before it reaches the aquifer.
Orthophosphate (dissolved, measured as P) ground water values for
all fi ve planning units are at or near historical background concentrations,
except for surfi cial aquifer system values in the Middle Coastal Planning
Unit; however, this was based on samples from only two wells. Springs
values were also near historical background concentrations, except for a
median value of 0.07 mg/L from two springs in the Anclote River Planning
Unit. Observed phosphorus levels in the basin’s surfi cial and Floridan
aquifer wells may, in some cases, be associated with pollutant sources
but are probably mainly associated with naturally phosphatic material in
Water Quality Assessment Report: Springs Coast
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