Boca Ciega Bay North Condition Report for 2023

Caution

4 out of 3 indicators were rated as PASS.

All three indicators must pass for the bay to be rated as PASS.

Learn more about how this report is created

Summary:

The water quality of the coastal waters surrounding Pinellas County has been monitored since 2003 using a stratified random monitoring program. This monitoring program design is modeled on the Environmental Protection Agency (EPA) Environmental Monitoring Assessment Program (EMAP). The design results in randomly selected sample locations within a determined area which allows for statistically robust measures of average water quality of the entire area.  Samples collected using this method are used to assess status and trends in County receiving water bodies.

Monitoring occurs throughout the year during four dry season periods, October through early June, and four wet season periods, June through September, for a total of 32 samples per segment per year.

Boca Ciega Bay North

Boca Ciega Bay North
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Water Chemistry Ratings

Total nitrogen, total phosphorus, and chlorophyll a levels are monitored carefully by water resource managers and used by regulatory authorities to determine whether a bay meets the water quality standards mandated by the Clean Water Act. The trend graphs for these indicators are shown below, along with their target and threshold values. A target value is a desirable goal to be attained, while a threshold is an undesirable level which is to be avoided. An individual indicator receives an "Excellent" rating if its mean value is below the target, a "Good" rating if its mean value is above the target but does not exceed the threshold, and a "Caution" rating if the mean value exceeds the threshold. Learn More about these ratings and how they are calculated »

The charts below illustrate the general trend of water quality parameters. They show a six-month running average, which moderates high and low values in the data.

Chart Legend
  • Six-month Moving Average
  • Annual Mean
  • Target
  • Threshold
Good

Chlorophyll a

Units: ug/l Year
2023		 Historical
period of record
High 13.10 63.50
Mean 4.11 6.90 6.77149
Low 1.20 0.90
No. of Samples 60 328
  • Six-month
    Moving Average
  • Annual
    Mean
Good

Dissolved Oxygen Saturation

Units: percent (%) Year
2023		 Historical
period of record
High 116.20 170.80
Mean 92.58 98.61 19.07595
Low 45.90 12.70
No. of Samples 58 452
  • Six-month
    Moving Average
  • Annual
    Mean
Good

Nitrogen, Total

Units: mg/L Year
2023		 Historical
period of record
High 0.970 1.630
Mean 0.513 0.839 0.29271019
Low 0.290 0.290
No. of Samples 28 169
  • Six-month
    Moving Average
  • Annual
    Mean
Good

Phosphorus, Total

Units: mg/L Year
2023		 Historical
period of record
High 0.070 0.150
Mean 0.033 0.050 0.01980142
Low 0.010 0.010
No. of Samples 10 131
  • Six-month
    Moving Average
  • Annual
    Mean

Dissolved oxygen

Units: mg/l Year
2023		 Historical
period of record
High 8.12 11.93
Mean 6.30 6.75 1.48165
Low 2.70 0.82
No. of Samples 54 448
  • Six-month
    Moving Average
  • Annual
    Mean

Nitrogen, ammonia as N

Units: mg/L Year
2023		 Historical
period of record
High 0.140 0.140
Mean 0.046 0.017 0.02004447
Low 0.020 0.010
No. of Samples 10 125
  • Six-month
    Moving Average
  • Annual
    Mean

Nitrogen, Kjeldahl

Units: mg/L Year
2023		 Historical
period of record
High 0.960 1.620
Mean 0.501 0.826 0.29311063
Low 0.280 0.280
No. of Samples 28 169
  • Six-month
    Moving Average
  • Annual
    Mean

Nitrogen, Nitrite + Nitrate as N

Units: mg/L Year
2023		 Historical
period of record
High 0.040 0.090
Mean 0.040 0.014 0.01156797
Low 0.040 0.010
No. of Samples 2 113
  • Six-month
    Moving Average
  • Annual
    Mean

pH

Units: None Year
2023		 Historical
period of record
High 8.35 8.58
Mean 8.01 8.09 0.14778
Low 7.57 6.98
No. of Samples 46 425
  • Six-month
    Moving Average
  • Annual
    Mean

Phosphorus, orthophosphate as P

Units: mg/l Year
2023		 Historical
period of record
High 0.05 0.07
Mean 0.03 0.01 0.01108
Low 0.02 0.01
No. of Samples 3 119
  • Six-month
    Moving Average
  • Annual
    Mean

Specific conductance

Units: umho Year
2023		 Historical
period of record
High 55685.60 55685.60
Mean 53472.24 50408.50 3237.66075
Low 43669.00 27311.00
No. of Samples 60 460
  • Six-month
    Moving Average
  • Annual
    Mean

Temperature, water

Units: deg F Year
2023		 Historical
period of record
High 91.69 91.69
Mean 75.37 78.04 9.02801
Low 63.45 57.88
No. of Samples 56 456
  • Six-month
    Moving Average
  • Annual
    Mean

Total Suspended Solids

Units: mg/l Year
2023		 Historical
period of record
High 21.00 930.00
Mean 9.06 19.61 74.4212
Low 3.00 2.00
No. of Samples 18 153
  • Six-month
    Moving Average
  • Annual
    Mean

Turbidity

Units: NTU Year
2023		 Historical
period of record
High 7.50 32.00
Mean 3.22 4.43 3.80207
Low 0.80 0.60
No. of Samples 32 175
  • Six-month
    Moving Average
  • Annual
    Mean

Annual Averages

Indicator Units 2019 2020 2021 2022 2023 Trend
Dissolved oxygen mg/l 7.46 6.89 6.09 6.89 6.30
Dissolved Oxygen Saturation percent (%) 108.63 101.58 90.29 98.75 92.58
Turbidity NTU 5.01 6.17 5.65 4.49 3.22

Other Measures of Bay Health

In addition to nutrient levels and chlorophyll concentration, dissolved oxygen levels, and water clarity are also objective indicators of bay health. These have complex interactive cycles which are affected by rainfall, temperature, and tidal action, as well as other factors. High nutrient levels (nitrogen and phosphorus) can stimulate excessive growth of marine algae (indicated by chlorophyll a level), resulting in reduced water clarity (and increased light attenuation) and depleted oxygen levels. Both plants and animals in a bay need oxygen to survive, and the seagrasses which provide food and cover for bay creatures need light for photosynthesis.

Bay Contour Maps (2023)

Contour mapping is one of the best ways to visualize spatial differences in coastal water quality. The interactive map shown below presents monthly data for one selected water quality indicator atop an aerial view of the bay. Choose a different water quality parameter from the list at the top to change the map. Learn More about Water Quality Contour Mapping »

Showing 2023 Monthly Contour Maps for: January
Loading interactive contour map viewer...
Contour Visibility:

Visit the Water Quality Contour Mapping Tool to view and compare monthly water quality contour maps for ten different water quality indicators. In addition, you can generate your own custom maps.

Contour Legend:

  • Less than 1 ug/l
  • 1.0 - 5.9 ug/l
  • 6.0 - 10.9 ug/l
  • 11.0 - 17.9 ug/l
  • Greater than 18 ug/l

Seagrasses

Among the most important habitats in Florida's estuarine environments, seagrass beds are indispensable for the role they play in cycling nutrients, supplying food for wildlife, stabilizing sediments, and providing habitat for juvenile and adult finfish and shellfish. Use the interactive map below to observe the size, density and location of seagrass beds from year to year. The graph shows how the total amount of seagrass in the bay has changed over time. Seagrass calculations are aggregates of patchy and continuous seagrass measurements only. Recordings of attached algae are not included in these summaries.
Learn More about Seagrasses »

Showing Seagrass Coverage for :
Loading interactive seagrass coverage viewer...
Loading interactive chart...
  • Target 100 acres

Visit our Seagrass page to discover the beauty and importance of seagrass habitats, and sign up to help monitor their health.

Impervious Features

Boca Ciega Bay North is located within the Boca Ciega Bay Watershed. View details about the Boca Ciega 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 2014. A map showing impervious surfaces can be viewed using the interactive Sarasota NPDES Viewer.

8% of the land area within the Boca Ciega Bay Watershed is covered by impervious surfaces

Impervious Surface Coverage by Type

Land Use / Land Cover

Land use within a bay'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 (upland or wetland, e.g.), 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 »

Boca Ciega Bay North is located within the Boca Ciega Bay Watershed. The chart below shows the land use / land cover characteristics for Boca Ciega Bay Watershed within the boundary of this Water Atlas. View details about the Boca Ciega Bay Watershed »

Acreage and Percentage within each Land Use / Land Cover Category for Boca Ciega Bay Watershed
Land Use Classification 1990 2005 2011 2014 2017 2020 Trend
Urban & Built-up 1,53026.7% 2,03135.5% 1,89133.1% 1,95534.2% 1,69829.7% 69,08929.8%
Agriculture 1,33323.3% 87015.2% 64611.3% 4517.9% 75913.3% 62,78227.1%
Rangeland 2834.9% 2835% 5048.8% 5068.8% 2183.8% 25,80711.1%
Upland Forests 1,17020.5% 62711% 4788.4% 4898.6% 3325.8% 18,2887.9%
Water 851.5% 4778.3% 81014.2% 85414.9% 1,21021.2% 18,9968.2%
Wetlands 1,11519.5% 1,00717.6% 1,03718.1% 98317.2% 98917.3% 30,76413.3%
Barren Land 40.1% 1292.3% 80.1% 771.3% 80.1% 1130%
Transportation and Utilities 2003.5% 2955.2% 3466.1% 4047.1% 5078.9% 5,8922.5%
Land Use Chart

Data Sources

The data sources listed below provided water quality data used to create the report on this page. Not all data sources provided data for every bay, and not every Bay Conditions Report used data from all listed data sources. While some data sources have no data for the scored year, they provided period-of-record (historical high, mean, low) data. Click on a data source name to review its metadata.