2.7.14. Greenfield Creek About Greenfield Creek

Figure 2.46
Figure 2.47 Greenfield Creek (WBID 2240A/B).
  • West of the Intracoastal Waterway
  • Primary Land Use: Residential
  • Current TMDL reports: Fecal Coliform with BMAP (2010), Mercury
  • Verified Impaired 2016 (final): None
  • WBID Area: 2.9 sq. mi.
  • Beneficial Use: Class III F (Recreational – Freshwater) Data sources

Result data were downloaded from the FL STORET and WIN websites (DEP 2010f; DEP 2018h) and filtered based on the stations (DEP 2010g) in Greenfield Creek WBID 2240A (marine) and 2240B (freshwater) (DEP 2014c) shown above. The filtered dataset was used to generate Table 2.15. Discussion

Water quality data for Greenfield Creek are shown in Table 2.15. Average phosphorus levels were historically higher than the recently updated WQC (DEP 2015c; DEP 2016e; DEP 2016k), but data from 2017 and 2018 indicate that average concentrations of phosphorus and dissolved oxygen were within acceptable limits.  Limited recent sampling suggest that chlorophyll-a concentrations are decreasing.  However, only limited data are available in WIN and in STORET for these parameters, and these measurements are all taken from the marine portion of Greenfield Creek (2240A).  Dissolved oxygen had been removed from the verified impaired list (DEP 2016j) in Greenfield Creek. Greenfield Creek was verified impaired for mercury (DEP 2016j), but this has been addressed in the statewide mercury TMDL already in place (DEP 2013c).

A TMDL report (Wainwright and Hallas 2009a) was released to address fecal coliform, and a BMAP for Greenfield Creek (DEP 2010a) was legally adopted in August 2010. It describes sources of fecal coliform in the watershed, and completed and ongoing activities conducted by state and local agencies that are anticipated to reduce fecal coliform loading in the tributary. The Greenfield Creek watershed does not contain any permitted point sources for industrial wastewater. It contains the Girvin Road Landfill, which has been inactive since 1992; this landfill received not only solid waste, but sludge from the Neptune Beach Sewage Treatment Plant. The watershed also contains numerous outfalls for stormwater discharge. The last Annual Progress Report for this BMAP was published in 2016 and listed 20 active, ongoing projects underway by FDOT and JEA to address the BMAP in the Greenfield Creek watershed (DEP 2017c). FDEP reported improvement in the frequency of fecal coliform exceedances in the freshwater segment of Greenfield Creek, but the last fecal coliform measurements in Greenfield Creek before 2018 date back to 2008.  Recent measurements indicate ongoing issues with fecal coliform concentrations. Additional information about fecal coliform in the tributaries can be found in Section 2.6 and Table 2.2.

No recent measurements were available in WIN or STORET between 2016 and 2018 for the following parameters:

  • Arsenic
  • Lead
  • Zinc
  • Cadmium
  • Nickel
  • Copper
  • Silver

Historical water quality data for these parameters in Greenfield Creek are available in previous versions of the River Report.

Table 2.15 Water quality data for Greenfield Creek.

 Water QualityAverage and Number of Samples º
Dissolved Oxygen (mg/L)≥34% sat. (≥3.0) FWNot availableNot available7.10
(0 of 15 samples)
≥4.0 SWNot available4.87
(0 of 4 samples)
(5 of 14 samples)
Total Nitrogen (mg/L)<1.54Not availableNot available0.92
(0 of 11 samples)
Total Phosphorus (mg/L)<0.12Not available0.07
(0 of 4 samples)
(0 of 12 samples)
Chlorophyll-a (µg/L)<20 FWNot availableNot available2.42
(0 of 7 samples)
<5.4 SWNot available6.58
(3 of 4 samples)
(1 of 5 samples)
Fecal Coliform (CFU/100 mL)<400Not availableNot available760
(10 of 26 samples)
Turbidity (NTU)<29 SWNot available8.45
(0 of 4 samples)
(0 of 12 samples)
Note: Hardness-dependent freshwater criteria for cadmium, copper, lead, nickel, and zinc were generated based on a hardness concentration of 100 mg/L.
° = Number of samples below Water Quality Criteria for Dissolved Oxygen; Number of samples above Water Quality Criteria for all other parameters.
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.