Hudson Bayou Condition Report for 2020

Pass
Rating icon - Chlorophyll a Rating icon - Total Nitrogen Rating icon - Total Phosphorous Rating icon - Dissolved Oxygen Saturation

4 out of 4 indicators were rated as PASS.

All four indicators must pass for the creek to be rated as PASS.

Learn more about how this report is created

  • Size: 2,406 acres
  • Location: North Sarasota County
  • Discharges into: Sarasota Bay

For more information, please see: Sarasota Bay Water Quality Management Plan (2012)

View county-wide water quality trends »

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Hudson Bayou

Hudson Bayou
Visit the Hudson Bayou water resource page »

Water Chemistry Ratings | Freshwater Portion of the Creek

Creek Conditions Ratings are based on comparing nitrogen, phosphorus, chlorophyll and dissolved oxygen to water quality guidelines or regulations. Florida law defines a maximum allowable concentration of nitrogen, phosphorus, and chlorophyll a, and a minimum allowable concentration of dissolved oxygen in these streams. Learn more about these ratings and how they are calculated »

Data for the following WBIDs is averaged when compiling the data below:
  • 1953A
Chart Legend
  • Trend Line
  • Annual Mean
  • Threshold
Pass

Chlorophyll a

Score: Pass
Units: mg/L Year
2020		 Historical
period of record
High 0.0339 0.1568
Mean 0.0012 0.0012 0.01192602
Low 0.0003 0.0002
No. of Samples 24 593

Five-year Rolling Average

  • Annual Mean
Pass

Nitrogen, Total

Score: Pass
Units: mg/L Year
2020		 Historical
period of record
High 2.02 17.52
Mean 0.9689 0.909 0.84417638
Low 0.492 0.0018
No. of Samples 24 496

Five-year Rolling Average

  • Annual Mean
Pass

Phosphorus, Total

Score: Pass
Units: mg/L Year
2020		 Historical
period of record
High 1.40 4.05
Mean 0.3598 0.433 0.36227154
Low 0.148 0.047
No. of Samples 24 567

Five-year Rolling Average

  • Annual Mean
Pass

Dissolved Oxygen Saturation

Note: Low DO saturation also may be naturally influenced by inflows from nearby wetlands or groundwater sources.
Score: Pass
Units: percent (%) Year
2020		 Historical
period of record
High 94.6874 144.70
Mean 48.96 52.96 28.41647
Low 1.1583 1.1583
No. of Samples 24 553

Five-year Rolling Average

  • Annual Mean

BOD, Biochemical oxygen demand

Units: mg/l Year
2020		 Historical
period of record
High 10.20 13.10
Mean 1.24 1.01 1.59442
Low 1.00 0.50
No. of Samples 24 547

Five-year Rolling Average

  • Annual Mean

Color

Units: PCU Year
2020		 Historical
period of record
High 220.00 400.00
Mean 84.25 72.52 32.66827
Low 55.00 20.00
No. of Samples 24 570

Five-year Rolling Average

  • Annual Mean

Escherichia coli

Units: MPN/100ml Year
2020		 Historical
period of record
High 24196.00 24196.00
Mean 1612.56 1290.01 3661.20029
Low 97.00 41.00
No. of Samples 24 226

Five-year Rolling Average

  • Annual Mean

Nitrogen, Ammonia + Ammonium as N

Units: mg/L Year
2020		 Historical
period of record
High 0.267 0.65
Mean 0.04 0.05 0.10846883
Low 0.008 0.00
No. of Samples 24 591

Five-year Rolling Average

  • Annual Mean

Nitrogen, Kjeldahl

Units: mg/L Year
2020		 Historical
period of record
High 1.90 13.80
Mean 0.76 0.78 0.86469764
Low 0.25 0.00
No. of Samples 24 566

Five-year Rolling Average

  • Annual Mean

Nitrogen, Nitrite + Nitrate as N

Units: mg/L Year
2020		 Historical
period of record
High 0.435 3.72
Mean 0.17 0.12 0.25133293
Low 0.021 0.004
No. of Samples 24 566

Five-year Rolling Average

  • Annual Mean

pH

Units: None Year
2020		 Historical
period of record
High 7.64 9.10
Mean 7.27 7.4 0.30448
Low 6.70 6.20
No. of Samples 24 615

Five-year Rolling Average

  • Annual Mean

Salinity

Units: PSS Year
2020		 Historical
period of record
High 3.2445 25.30
Mean 0.34 0.37 2.20806
Low 0.1234 0.04
No. of Samples 24 609

Five-year Rolling Average

  • Annual Mean

Specific conductance

Units: umho Year
2020		 Historical
period of record
High 5897.49 54000.00
Mean 694.32 846.33 9419.02209
Low 257.963 0.445
No. of Samples 24 531

Five-year Rolling Average

  • Annual Mean

Temperature, water

Units: deg F Year
2020		 Historical
period of record
High 91.40
Mean 73.64 7.23721
Low 53.87
No. of Samples 0 508

Five-year Rolling Average

  • Annual Mean

Turbidity

Units: NTU Year
2020		 Historical
period of record
High 60.00
Mean 3.73 4.56492
Low 1.00
No. of Samples 0 462

Five-year Rolling Average

  • Annual Mean
Other Measures of Creek Health:

Water Chemistry Ratings | Tidal Portion of the Creek

Creek Conditions Ratings are based on comparing nitrogen, phosphorus, chlorophyll and dissolved oxygen to water quality guidelines or regulations. Florida law defines a maximum allowable concentration of chlorophyll a and a minimum allowable concentration of dissolved oxygen in these streams. Florida has no regulatory thresholds for nitrogen or phosphorus in tidal creeks so trends are used to rate the creeks. Learn more about these ratings and how they are calculated »

Data for the following WBIDs is averaged when compiling the data below:
  • 1951
  • 1953
Chart Legend
  • Trend Line
  • Annual Mean
  • Threshold

Chlorophyll a

Units: mg/L Year
2020		 Historical
period of record
High 0.1
Mean 0.003 0.00998153
Low 0.0003
No. of Samples 0 136

Five-year Rolling Average

  • Annual Mean
×

Chlorophyll a

The rating for Chlorophyll a is determined by comparing the annual arithmetic mean of its sampled values to fixed target and threshold values. The annual arithmetic mean is shown in the graph at left, as compared to its established target and threshold values.

An arithmetic mean is used for Chlorophyll a for consistency with the Surface Water Quality Standards, Florida Administrative Code 62-302.532, Estuary-Specific Numeric Interpretations of the Narrative Nutrient Criterion.

Pass

Nitrogen, Total

No trend was observed after performing a trend analysis.
Score: Pass
Units: mg/L Year
2020		 Historical
period of record
High 1.9
Mean 0.8692 0.30960692
Low 0.34
No. of Samples 0 159

Five-year Rolling Average

  • Annual Mean
×

Nitrogen, Total

Pass

Phosphorus, Total

Trend analysis shows a weak decreasing trend.
Score: Pass
Units: mg/L Year
2020		 Historical
period of record
High 1.3
Mean 0.3192 0.24114893
Low 0.05
No. of Samples 0 171

Five-year Rolling Average

  • Annual Mean
×

Phosphorus, Total

Dissolved Oxygen Saturation

Note: Low DO saturation also may be naturally influenced by inflows from nearby wetlands or groundwater sources
Units: percent (%) Year
2020		 Historical
period of record
High 128.7
Mean 42.27 26.31395
Low 0.70
No. of Samples 0 236

Five-year Rolling Average

  • Annual Mean
×

Dissolved Oxygen Saturation

BOD, Biochemical oxygen demand

Units: mg/l Year
2020		 Historical
period of record
High 5.4
Mean 1.69 1.08161
Low 0.50
No. of Samples 0 113

Five-year Rolling Average

  • Annual Mean

Color

Units: PCU Year
2020		 Historical
period of record
High 125.0
Mean 30.85 22.45551
Low 5.00
No. of Samples 0 234

Five-year Rolling Average

  • Annual Mean

Nitrogen, Ammonia + Ammonium as N

Units: mg/L Year
2020		 Historical
period of record
High 0.9
Mean 0.02 0.13069734
Low 0.00
No. of Samples 0 219

Five-year Rolling Average

  • Annual Mean

Nitrogen, Kjeldahl

Units: mg/L Year
2020		 Historical
period of record
High 1.9
Mean 0.72 0.30120653
Low 0.16
No. of Samples 0 217

Five-year Rolling Average

  • Annual Mean

Nitrogen, Nitrite + Nitrate as N

Units: mg/L Year
2020		 Historical
period of record
High 0.7
Mean 0.08 0.15332272
Low 0.00
No. of Samples 0 179

Five-year Rolling Average

  • Annual Mean

pH

Units: None Year
2020		 Historical
period of record
High 8.4
Mean 7.65 0.46212
Low 6.38
No. of Samples 0 228

Five-year Rolling Average

  • Annual Mean

Salinity

Units: PSS Year
2020		 Historical
period of record
High 34.7
Mean 17.52 10.05493
Low 0.35
No. of Samples 0 216

Five-year Rolling Average

  • Annual Mean

Specific conductance

Units: umho Year
2020		 Historical
period of record
High 53,000.0
Mean 32678.21 12919.18969
Low 46.582
No. of Samples 0 309

Five-year Rolling Average

  • Annual Mean

Temperature, water

Units: deg F Year
2020		 Historical
period of record
High 94.2
Mean 75.28 8.23757
Low 51.80
No. of Samples 0 234

Five-year Rolling Average

  • Annual Mean

Turbidity

Units: NTU Year
2020		 Historical
period of record
High 42.0
Mean 4.69 4.40629
Low 0.27
No. of Samples 0 233

Five-year Rolling Average

  • Annual Mean
Other Measures of Creek Health:

Oysters

Because they are immobile and will tolerate a fairly wide salinity range, eastern oysters (Crassostrea virginica) are valuable as an indicator of the relative health of aquatic ecosystems in the tidally-influenced portions of coastal creeks. Sarasota County has established an oyster monitoring program to track the location, types, and status of oyster reefs. Data from this monitoring program is shown below. Learn more about Oysters »

Loading oyster site map...
Most Recent Sarasota County Oyster Monitoring Program Data
Icon Site ID Year Dead Live Total % Live
1 HUD2 2020 13 263 276 95

Impervious Features

Hudson Bayou is located within the Sarasota Bay Watershed. View details about the Sarasota Bay Watershed »

Rain that falls on land that is in a natural state is absorbed and filtered by soils and vegetation as it makes it way into underground aquifers. However, in developed areas, "impervious surfaces" impede this process and contribute to polluted urban runoff entering surface waters. These surfaces include human infrastructure like roads, sidewalks, driveways and parking lots that are covered by impenetrable materials such as asphalt, concrete, brick and stone, as well as buildings and other permanent structures. Soils that have been disturbed and compacted by urban development are often impervious as well. Learn more about Impervious Features »

The Sarasota County Stormwater Environmental Utility (SEU) mapped impervious surfaces in the County in 2013. A map showing impervious surfaces can be viewed using the Water Atlas Map Viewer tool.

47% of the land area within the Hudson Bayou Basin is covered by impervious surfaces

Impervious Surface Coverage by Type

Land Use / Land Cover

Hudson Bayou is located within the Sarasota Bay Watershed. View details about the Sarasota Bay Watershed »

Land use within a creek's watershed has a major effect on its water quality. In general, less development means better water quality. Land Cover/Land Use classifications categorize land in terms of its observed physical surface characteristics (e.g. upland or wetland), and also reflect the types of activity that are taking place on it (agriculture, urban/built-up, utilities, etc.). Florida uses as its standard a set of statewide classifications which were developed by the Florida Department of Transportation. Learn more about Land Use and Land Cover »

Acreage and Percentage within each Land Use / Land Cover Category for Hudson Bayou Basin
Land Use Classification 1990 1995 1999 2005 2011 2014 2017 2020 Trend
Urban & Built-up 2,22492.4% 2,24493.3% 2,24393.2% 2,26093.9% 2,26093.9% 2,24993.5% 2,26093.9% 2,25993.9% Land Use Trend Sparkline
Upland Forests 160.7% 90.4% 90.4% 00% 00% 00% 00% 00% Land Use Trend Sparkline
Water 241% 251% 261.1% 261.1% 271.1% 271.1% 271.1% 271.1% Land Use Trend Sparkline
Wetlands 160.7% 130.5% 130.5% 100.4% 100.4% 100.4% 100.4% 100.4% Land Use Trend Sparkline
Transportation and Utilities 1265.2% 1154.8% 1154.8% 1094.6% 1094.6% 1205% 1094.5% 1104.6% Land Use Trend Sparkline
Land Use Chart