Middle St. Johns - Florida Department of Environmental Protection

Water Quality Assessment Report: Middle St. Johns
157
Table 4.2 (contined)
Planning
Unit
Lake
George
Unit
Lake
George
Unit
Lake
George
Unit
Lake
Jesup
WBID
Waterbody
Segment
2893A2 St. Johns
River
Above Lake
George
2893A2 St. Johns
River
Above Lake
George
2916B
Grasshopper
Lake
Waterbody
Type
1998
303(d)
Parameters
of Concern
Parameters
Identified
Using
the 2002
Impaired
Surface
Waters Rule
Priority for
TMDL
Development *
Projected
Year for TMDL
Development *
Comments
Stream DO Medium 2008 Planning period: 37/112
values below DO criterion;
verified period: 21/73 values
below DO criterion. DO
met verification threshold
of IWR and nutrients are the
causative pollutant. 200 DO
values, median 5.68 mg/L,
mean 5.69 mg/L, range
0.28–9.23 mg/L.
Stream
Lake
Nutrients
(Chlorophyll
a)
Mercury in
Fish
2981 Lake Jesup Lake Nutrients Nutrients
(TSI)
Medium 2008 Colimitation of N and P based
on a TN/TP median of 17
(120 values) in the planning
period and a median of 16
(80 values) in the verified
period. Planning period:
3 Chlorophyll a annual
means exceeded 20 μg/L
(1992, 1993, 1999), 123 TN
values, median 1.19 mg/L,
124 TP values, median 0.07
mg/L; verified period: 1
Chlorophyll a annual mean
exceeded 20 μg/L (1999),
83 TN values, median 1.132
mg/L, 80 TP values, median
0.07 mg/L.
Medium 2011 Mercury in Fish met verification
threshold of IWR. Fish
tissue levels in 20 samples
averaged 1.55 ppm in 2000.
High 2004 Colimitation of N and P based
on a TN/TP median of 16
(1077 values) in the planning
period and a median of 18
(829 values) in the verified
period. Planning period: 10
TSI annual means exceeded
60 (1991–2000); verified
period: 7 TSI annual means
exceeded 60 (1996–2002).
198 TN values, median
2.47 mg/L. 1279 TP values,
median 0.15 mg/L.