Middle St. Johns - Florida Department of Environmental Protection

Water Quality Assessment Report: Middle St. Johns
97
Water Quality Summary
Figure 3.6, a composite map of the planning unit, shows waters on the
1998 303(d) list, the Planning List and Verified List, and potential pollution
sources. Water quality data from 61 monitoring stations were used for
assessment (Appendix F).
Table 3.8 summarizes the water quality assessment status of all waterbody
segments in the planning unit.
Of the 29 waterbody segments in the Lake George planning unit, 15
have at least some type of data in the planning and/or verification periods,
but in may cases the data was insufficient for assessment of segments under
the IWR. Thirteen segments have sufficient data for assessment, and of
these 6 are verified impaired for at least 1 parameter assessed, none are
on the Planning List as potentially impaired, and 7 meet standards for all
parameters assessed.
Listed below are the verified impaired segments in the planning unit,
and the parameters for which they impaired.
St. Johns River Above Ocklawaha River Nutrients (chlorophyll a)
Lake Margaret
Mercury in fish
Lake George
Nutrients (TSI), selenium
St. Johns River Below Lake George
(2893A1) Nutrients (chlorophyll a)
St. Johns River Below Lake George
(2893A2)
DO, nutrients
(chlorophyll a)
Grasshopper Lake
Mercury in fish
Lake George is impaired for elevated levels of nutrients. Moderately
eutrophic, the lake receives nutrient loading from both human-made
and natural sources. Periodic algal blooms occur (Alvarez, Lehman, and
Associates, 1991). This watershed is surrounded by metropolitan areas in
the uplands of the west (Ocala) and to the south-southeast of the basin
(Orlando and DeLand). Lake George is especially vulnerable to pollutants
because the river water slows as it drains into the large, shallow lake,
increasing the retention time of the water (Alvarez, Lehman, and Associates,
1991). Segments of the St. Johns River upstream and downstream of
Lake George are also impaired for nutrients.
The DOH has issued a health advisory recommending limited consumption
of largemouth bass, bowfin, gluegill sunfish and gar from Grasshopper
Lake because of elevated levels of mercury.
Permitted Discharges and Land Uses
Point Sources. There are 14 total permitted point source dischargers
in the Lake George planning unit. Of these, 12 are domestic wastewater
facilities and 2 are industrial wastewater facilities. Discharges range
from 0.0990 to 0.0043 mgd, and none is NPDES-permitted. The facilities
discharge to percolation ponds, drainfields, or holding ponds. The
facility with the largest discharge is the Welaka Wastewater Treatment
Plant (0.0990 mgd), which discharges into the St. Johns Basin above