2.7.3.1. About Big Fishweir Creek
- West of Downtown, South of I-10
- Primary Land Use: Residential
- Current TMDL reports:
Fecal Coliform with BMAP, Mercury - 2020 Verified Impairment for
Dissolved Oxygen (2280B) and Nutrients (Chlorophyll-a) (2280B)
- Current TMDL reports:
- WBID Area: 3.7 sq. mi.
- Beneficial Use: Class III F / M
(2280A Recreational – Freshwater, 2280B Recreational – Marine)
- Beneficial Use: Class III F / M
2.7.3.2. Data sources
Data were historically downloaded from the FL STORET website (DEP 2010f), with recent data downloaded from WIN WAVES (DEP 2022f). Data were filtered based on the stations in the Big Fishweir Creek WBID 2280, 2280A (freshwater), and 2280B (saltwater/marine) (DEP 2023b) shown above. The filtered dataset reflects water column concentrations and was used to generate Table 2.8.
2.7.3.3. Discussion
Water quality data for Big Fishweir Creek are shown in Table 2.8. Average total phosphorus concentrations in the freshwater reach (WBID 2280A) have been higher than the WQC for 2020-2022 (not sampled in marine reach WBID 2280B 2020-2022). The marine reach (2280B) was listed as Impaired for Dissolved Oxygen and Nutrients (Chlorophyll-a) in 2020, and excessive nutrient concentrations were identified as the cause for reduced dissolved oxygen levels (DEP 2020a). FDEP has placed a medium priority for the development of a TMDL to address these impairments. The freshwater segment of Big Fishweir Creek was added to the FDEP study list for dissolved oxygen (DEP 2020f). The freshwater segment is considered impaired for dissolved oxygen based on the number of exceedances for the sample size, but the causative pollutant has not yet been identified. Big Fishweir Creek marine reach (2280B) was listed as Impaired for high levels of iron; FDEP cannot rule out the possibility of anthropogenic sources (DEP 2016h; DEP 2020e).
A TMDL report (Wainwright and Hallas 2009a) was released in 2009 to address Fecal coliform, calling for an 87% reduction of sources, and Big Fishweir Creek is no longer listed as impaired for Fecal coliform as a result (DEP 2016f) (Note: the data analyses in the TMDL are based on different criteria than that used in this report). Subsequently, a BMAP to address this issue was legally adopted (DEP 2009b). Additional information about fecal coliform in the tributaries can be found in Section 2.6 and Table 2.3. Fecal indicator bacteria measurements continue to show average bacterial concentrations higher than the WQC. In 2018, FDEP piloted microbial source tracking strategies in selected impaired waterbodies. They found that the strategies used could be used to narrow down areas suspected of containing sources that actively contribute fecal indicating bacteria to water in order to identify and remediate them, but this work is resource-intensive. Big Fishweir Creek was found to have known sources of untreated human waste present (DEP 2019a). In 2020, Big Fishweir Creek was added to FDEP’s study list to monitor the response in fecal indicator bacteria levels (specifically, E. coli in the freshwater portions and Enterococcus in the marine portions) to ongoing restoration activities taking place in both the freshwater and marine segments as part of the BMAP (DEP 2020f).
The US Army Corps of Engineers commissioned a study of the sediment and water in Big Fishweir Creek that took place in October 2019 to provide information regarding dredging activities within the creek (USACE 2020a). This study found that sediments throughout most of Big Fishweir Creek contained heavy metals, and the levels of lead, chlorinated pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and dioxins were high enough to exceed FDEP’s Sediment Quality Assessment Guidelines (DEP 2021g).
No recent measurements were available in WIN between 2020 and 2022 for the marine reach (WBID 2280B) for the following parameters: Total Nitrogen, Total Phosphorus, Chlorophyll-a, Arsenic, Cadmium, Copper, Iron, Lead, Nickel, Silver, Zinc, Turbidity.
Historical water quality data for Big Fishweir Creek are available in previous versions of the River Report.
Table 2.8 Water quality data for Big Fishweir Creek.
Water Quality | Average and Number of Samples º | |||
---|---|---|---|---|
Parameter | Criteria | 2020 | 2021 | 2022 |
Dissolved Oxygen (mg/L) | ≥34% sat. (≥3.0) FW | 4.22 (7 of 25 samples) | 5.63 (3 of 24 samples) | 4.36 ± 0.38 (7 of 26 samples) |
≥4.0 SW | 7.22 (0 of 6 samples) | 5.63 (3 of 24 samples) | 6.60 ± 0.50 (1 of 10 samples) |
|
Total Nitrogen (mg/L) | <1.54‡ | 1.18 (0 of 3 samples) | 0.79 (0 of 2 samples) | 1.19 ± 0.20 (1 of 5 samples) |
Total Phosphorus (mg/L) | <0.12‡ | 0.16 (2 of 3 samples) | 1.15 (2 of 3 samples) | 0.17 ± 0.05 (3 of 5 samples) |
Chlorophyll-a (µg/L) | <20‡ FW | 2 (0 of 6 samples) | 1.27 (0 of 4 samples) | 0.79 ± 0.29 (0 of 4 samples) |
Arsenic (mg/L) | ≤50 | Not Available | Not Available | 1.40 (0 of 1 samples) |
Cadmium (µg/L) | ≤8.8 SW | Not Available | Not Available | 0.01 (0 of 1 samples) |
Copper (µg/L) | ≤3.7 SW | Not Available | Not Available | 0.60 (0 of 1 samples) |
Iron (mg/L) | ≤0.3 SW | Not Available | Not Available | 0.89 (0 of 1 samples) |
Lead (µg/L) | ≤8.5 SW | Not Available | Not Available | 0.54 (0 of 1 samples) |
Nickel (µg/L) | ≤8.3 SW | Not Available | Not Available | 1.25 (0 of 1 samples) |
Silver (µg/L) | ≤0.92 SW | Not Available | Not Available | 0.01 (0 of 1 samples) |
Zinc (µg/L) | ≤86 SW | Not Available | Not Available | 12.5 (0 of 1 samples) |
Fecal Indicator Bacteria (E. coli) (CFU/100 mL) | E. coli <410 FW | 1350 (23 of 29 samples) | 1840 (20 of 28 samples) | 1299 ± 350 (14 of 22 samples) |
E. coli <410 SW | 779 ± 44 (4 of 4 samples) |
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Enterococci <130 SW | 263 ± 117 (3 of 4 samples) |
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Turbidity (NTU) | <29 | 3.87 (0 of 3 samples) | 4.95 (0 of 4 samples) | 4.14 ± 0.62 (0 of 5 samples) |
° = 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.