2.7.8. Deep Creek

2.7.8.1. About Deep Creek

Figure 2.33
Figure 2.34 The Deep Creek Tributary (WBID 2549 and 2589).
  • East of the St. Johns at Palatka
  • Primary Land Use: Forested, Row Crop Agriculture
  • Current TMDL reports: Dissolved Oxygen – 2589
  • Verified Impaired 2016 (final): Iron (2589 med)
  • WBID Area: 60.5 sq. mi.
  • Beneficial Use: Class III F (Recreational – Freshwater)

2.7.8.2. Data sources

Data were downloaded from the FL STORET website (DEP 2010e) and filtered based on the stations (DEP 2010f) in Deep Creek WBIDs 2549 and 2589 (DEP 2014d) shown above. The filtered dataset was used to generate Table 2.9.

2.7.8.3. Discussion

Water quality data for Deep Creek are shown in Table 2.9. Deep Creek is a tributary of the LSJR that drains the eastern banks around Hastings and Spuds, and thus receives substantial agricultural inputs, such as nutrients. Concentrations of total nitrogen were elevated (Figure 2.35) but not above the recently updated WQC (DEP 2015d; DEP 2016e; DEP 2016k); however, levels of total phosphorus were significantly above the recommended WQC (Figure 2.36), and fluctuate seasonally. Non-point source rainwater runoff is likely the major cause of the elevated nitrogen/phosphorus concentrations in this area. Likewise, chlorophyll-a concentrations fluctuate, with relatively elevated levels in the summer months (Figure 2.37). Chlorophyll-a has been removed from the recent verified impaired list, as the annual geometric mean chlorophyll-a concentrations have not exceeded the WQC (20 μg/L) more than once over the past three years. Dissolved oxygen concentrations in these areas reflect these conditions, with lower dissolved oxygen concentrations observed in the summer months (Figure 2.38). In addition to nutrients, organic matter, temperature, and community structure (i.e., number and types of plants and animal species), among other biotic factors, may contribute to the lower dissolved oxygen concentrations in these tributaries. As a consequence of the above factors/conditions, a draft TMDL report for dissolved oxygen was published in 2009 (Magley 2009d) for WBID 2589 (Sixteen Mile Creek). Elevated concentrations of cadmium, copper, nickel, and silver have been detected in Deep Creek, as compared to the Class III WQC for metals.

Table 2.9 Water quality data for Deep Creek.
Water QualityConcentrationSampling
ParameterCriteria (FW)LowAverageHighSamplesPeriod
Dissolved Oxygen (mg/L)34% sat. (~3.0)05.5820.865981997 - 2016
Total Nitrogen (mg/L)<1.540.271.4617.864161997 - 2015
Total Phosphorus (mg/L)<0.1200.312.299801997 - 2016
Chlorophyll-a (µg/L)<2009.15193.43581997 - 2016
Arsenic (µg/L)≤5002.217.043021997 - 2016
Cadmium (µg/L)≤0.300.111.282921997 - 2016
Copper (µg/L)≤9.301.8314.784121997 - 2016
Lead (µg/L)≤3.200.627.792011997 - 2016
Nickel (µg/L)≤5201.7834.82731997 - 2016
Silver (µg/L)≤0.0700.191.653101997 - 2016
Zinc (µg/L)≤1200.316.849.684031997 - 2016
Fecal Coliform (log #/100 mL)<2.61.882.52.7742002 - 2009
Turbidity (NTU)<290.237.281465441997 - 2016
Note: Hardness-dependent freshwater criteria for cadmium, copper, lead, nickel, and zinc were generated based on a hardness concentration of 100 mg/L.
FW = freshwater; SW = saltwater (marine). Values denoted with (*) indicate a proposed criterion, which has not yet been adopted.
Values denoted with (†) are reference values based on EPA criteria (EPA 2010b), but the water body is not regulated by this standard.

 

Figure 2.34
Figure 2.35 The yearly total nitrogen concentration in Deep Creek. All data are presented as a box-and-whiskers plot with green boxes indicating the median ± 25% (middle 50% of the data) and horizontal lines indicating median values. Blue whiskers indicate minimum and maximum values in the data set.
Figure 2.35
Figure 2.36 Yearly total phosphorus concentrations in Deep Creek. All data are presented as a box-and-whiskers plot with green boxes indicating the median ± 25% (middle 50% of the data) and horizontal lines indicating median values. Blue whiskers indicate minimum and maximum values in the data set.
Figure 2.36
Figure 2.37 Monthly chlorophyll-a concentration (g/L) in 1997 through 2008 in Deep Creek.
Figure 2.37
Figure 2.38 The monthly dissolved oxygen concentrations (data from 1977 to 2014) in Deep Creek. Data are presented as a box-and-whiskers plot with green boxes, indicating the median ± 25% (middle 50% of the data) and horizontal lines indicating median values. Blue whiskers indicate minimum and maximum values in the data set.