Hudson Bayou Condition Report for 2011

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

2 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 »

Dive Deeper!
Explore Water Quality Trends Watershed Management Plans Water Quality Contour Maps

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
2011		 Historical
period of record
High 0.015 0.0378
Mean 0.0015 0.0015 0.00409568
Low 0.0003 0.0003
No. of Samples 72 229

Five-year Rolling Average

  • Annual Mean
Pass

Nitrogen, Total

Score: Pass
Units: mg/L Year
2011		 Historical
period of record
High 1.817 1.817
Mean 0.9117 0.8041 0.30311992
Low 0.661 0.082
No. of Samples 24 137

Five-year Rolling Average

  • Annual Mean
Caution

Phosphorus, Total

Score: Caution
Units: mg/L Year
2011		 Historical
period of record
High 4.05 4.05
Mean 0.5366 0.4739 0.46893858
Low 0.203 0.15
No. of Samples 72 236

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
2011		 Historical
period of record
High 144.70 144.70
Mean 54.19 54.61 34.61429
Low 4.40 4.20
No. of Samples 80 284

Five-year Rolling Average

  • Annual Mean

BOD, Biochemical oxygen demand

Units: mg/l Year
2011		 Historical
period of record
High 9.01 9.01
Mean 1.24 1.01 1.24396
Low 0.50 0.50
No. of Samples 72 217

Five-year Rolling Average

  • Annual Mean

Color

Units: PCU Year
2011		 Historical
period of record
High 65.00
Mean 43.6 14.68181
Low 20.00
No. of Samples 0 10

Five-year Rolling Average

  • Annual Mean

Nitrogen, Ammonia + Ammonium as N

Units: mg/L Year
2011		 Historical
period of record
High 0.34 0.587
Mean 0.08 0.1 0.11708216
Low 0.024 0.0004
No. of Samples 72 234

Five-year Rolling Average

  • Annual Mean

Nitrogen, Kjeldahl

Units: mg/L Year
2011		 Historical
period of record
High 1.57 1.74
Mean 0.75 0.69 0.29579868
Low 0.46 0.00
No. of Samples 72 235

Five-year Rolling Average

  • Annual Mean

Nitrogen, Nitrite + Nitrate as N

Units: mg/L Year
2011		 Historical
period of record
High 0.387 0.681
Mean 0.1 0.1 0.15414587
Low 0.008 0.004
No. of Samples 72 235

Five-year Rolling Average

  • Annual Mean

pH

Units: None Year
2011		 Historical
period of record
High 7.85 9.10
Mean 7.66 7.64 0.33684
Low 7.23 6.64
No. of Samples 30 194

Five-year Rolling Average

  • Annual Mean

Salinity

Units: PSS Year
2011		 Historical
period of record
High 0.51 7.00
Mean 0.36 0.36 0.5673
Low 0.21 0.04
No. of Samples 30 167

Five-year Rolling Average

  • Annual Mean

Specific conductance

Units: umho Year
2011		 Historical
period of record
High 1035.00 54000.00
Mean 739.0 904.93 14163.68306
Low 436.00 0.445
No. of Samples 30 191

Five-year Rolling Average

  • Annual Mean

Temperature, water

Units: deg F Year
2011		 Historical
period of record
High 82.094 91.40
Mean 73.23 72.42 8.04366
Low 65.75 53.87
No. of Samples 20 165

Five-year Rolling Average

  • Annual Mean

Turbidity

Units: NTU Year
2011		 Historical
period of record
High 10.50 38.00
Mean 3.08 3.24 2.79089
Low 1.26 1.00
No. of Samples 72 235

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
Pass

Chlorophyll a

Score: Pass
Units: mg/L Year
2011		 Historical
period of record
High 0.0 0.1
Mean 0.0013 0.0032 0.00976926
Low 0.0003 0.0003
No. of Samples 36 145

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
2011		 Historical
period of record
High 1.5 1.9
Mean 0.9129 0.8611 0.30365489
Low 0.648 0.34
No. of Samples 12 125

Five-year Rolling Average

  • Annual Mean
×

Nitrogen, Total

Caution

Phosphorus, Total

Trend analysis shows a weak increasing trend.
Score: Caution
Units: mg/L Year
2011		 Historical
period of record
High 1.3 1.3
Mean 0.5683 0.337 0.24695159
Low 0.222 0.05
No. of Samples 36 185

Five-year Rolling Average

  • Annual Mean
×

Phosphorus, Total

Caution

Dissolved Oxygen Saturation

Note: Low DO saturation also may be naturally influenced by inflows from nearby wetlands or groundwater sources
Score: Caution
Units: percent (%) Year
2011		 Historical
period of record
High 69.4 128.7
Mean 31.88 39.04 26.11442
Low 4.00 0.70
No. of Samples 40 281

Five-year Rolling Average

  • Annual Mean
×

Dissolved Oxygen Saturation

BOD, Biochemical oxygen demand

Units: mg/l Year
2011		 Historical
period of record
High 2.8 5.4
Mean 1.09 1.69 1.06992
Low 0.50 0.50
No. of Samples 36 127

Five-year Rolling Average

  • Annual Mean

Color

Units: PCU Year
2011		 Historical
period of record
High 125.0
Mean 23.7 22.74227
Low 5.00
No. of Samples 0 121

Five-year Rolling Average

  • Annual Mean

Nitrogen, Ammonia + Ammonium as N

Units: mg/L Year
2011		 Historical
period of record
High 0.2 0.9
Mean 0.07 0.02 0.13128757
Low 0.039 0.00
No. of Samples 36 232

Five-year Rolling Average

  • Annual Mean

Nitrogen, Kjeldahl

Units: mg/L Year
2011		 Historical
period of record
High 1.2 1.9
Mean 0.59 0.72 0.30118157
Low 0.337 0.16
No. of Samples 36 231

Five-year Rolling Average

  • Annual Mean

Nitrogen, Nitrite + Nitrate as N

Units: mg/L Year
2011		 Historical
period of record
High 0.6 0.7
Mean 0.29 0.09 0.16174015
Low 0.168 0.00
No. of Samples 36 193

Five-year Rolling Average

  • Annual Mean

pH

Units: None Year
2011		 Historical
period of record
High 7.6 8.4
Mean 7.13 7.64 0.45081
Low 6.40 6.40
No. of Samples 15 233

Five-year Rolling Average

  • Annual Mean

Salinity

Units: PSS Year
2011		 Historical
period of record
High 14.8 34.7
Mean 2.73 18.35 9.90436
Low 0.63 0.35
No. of Samples 15 204

Five-year Rolling Average

  • Annual Mean

Specific conductance

Units: umho Year
2011		 Historical
period of record
High 24,309.0 53,000.0
Mean 5024.59 31111.31 13627.00058
Low 1252.00 46.582
No. of Samples 15 314

Five-year Rolling Average

  • Annual Mean

Temperature, water

Units: deg F Year
2011		 Historical
period of record
High 77.9 94.2
Mean 73.09 75.38 8.37347
Low 68.036 51.80
No. of Samples 10 225

Five-year Rolling Average

  • Annual Mean

Turbidity

Units: NTU Year
2011		 Historical
period of record
High 8.5 42.0
Mean 4.0 4.77 4.44269
Low 2.10 0.27
No. of Samples 36 248

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 2011 74 176 250 70

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