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Blackburn Bay Condition Report for 2015

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Pass

3 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 overall health of Blackburn Bay deteriorated slightly in 2015. Chlorophyll a increased significantly, particularly in the latter half of the year, with the mean value increasing 79% over 2014. Nitrogen concentration decreased slightly, remaining in the “Good” range, between target and threshold levels. The mean value for phosphorus concentration increased only very slightly, and is still well below the target.

Water Quality: While all three water quality indicators (chlorophyll a, nitrogen, and phosphorus) were rated as pass, chlorophyll a's rating changed from “Excellent” to “Good” because of its large increase in value. The mean for chlorophyll a was calculated as an arithmetic mean and the means for nitrogen and phosphorus were calculated as geometric means (per the Numeric Nutrient Criteria outlined in the Florida Administrative Code, section 62-302.532). The mean chlorophyll a level was 0.0077 mg/l . The mean nitrogen level decreased from 0.4226 mg/l to 0.4059 mg/l. Phosphorus concentrations in the bay have remained relatively constant and low, with a mean in 2015 of 0.0702 mg/l, well below the target (0.170 mg/l) and threshold (0.210 mg/l) levels and earning a score of “Excellent”.

Biotic Indicator: Measurement of the biotic indicator, seagrass, was performed in 2014 by the Southwest Florida Water Management District. Total seagrass acreage in Blackburn Bay was measured to be 344 acres. Seagrass acreage continues to slowly increase, but it is still below the target level of 447 acres.

Bay Location Map

Bays included in this report:

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. Learn More about these ratings and how they are calculated »

The Five-year Trend Graphs 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.

Good

Chlorophyll a

Units: mg/l Year
2015
Historical
period of record
High 0.0252 0.043
Mean 0.0077 0.0051 0.00505424 0.0060000000
Low 0.0012 0.0002
No. of Samples 57 959

Five-year Trend Graph

     
1/1/20111.7050.0017000mg/l
2/1/20112.2650.0019800mg/l
3/1/20112.4550.0021400mg/l
4/1/20118.3350.0036900mg/l
5/1/20113.6150.0036700mg/l
6/1/20112.0750.0034000mg/l
7/1/20113.3750.0036800mg/l
8/1/20116.4050.0043700mg/l
9/1/20118.8750.0054400mg/l
10/1/20115.9650.0050500mg/l
11/1/20114.3250.0051700mg/l
12/1/20112.3450.0052100mg/l
1/1/20122.8950.0051300mg/l
2/1/20123.8950.0047100mg/l
3/1/20123.4250.0038000mg/l
4/1/20124.0850.0034900mg/l
5/1/20121.5450.0030300mg/l
6/1/20121.8950.0029500mg/l
7/1/20125.9550.0034600mg/l
8/1/201216.6550.0055900mg/l
9/1/20126.6650.0061300mg/l
10/1/20126.4950.0065300mg/l
11/1/20127.0340.0074500mg/l
12/1/20121.6240.0074000mg/l
1/1/20134.7050.0071900mg/l
2/1/20132.0750.0047600mg/l
3/1/20132.1550.0040100mg/l
4/1/20131.7350.0032200mg/l
5/1/20132.7050.0025000mg/l
6/1/20133.2550.0027700mg/l
7/1/201311.5650.0039100mg/l
8/1/20136.2850.0046100mg/l
9/1/20137.0850.0054300mg/l
10/1/201310.9450.0069700mg/l
11/1/20138.0150.0078500mg/l
12/1/20134.1250.0080000mg/l
1/1/20142.2450.0064500mg/l
2/1/20141.7750.0056900mg/l
3/1/20141.9750.0048400mg/l
4/1/20144.5350.0037700mg/l
5/1/20141.9250.0027600mg/l
6/1/20142.9750.0025700mg/l
7/1/20144.0150.0028600mg/l
8/1/20143.5750.0031600mg/l
9/1/20144.3540.0035600mg/l
10/1/201418.3840.0058700mg/l
11/1/20144.2850.0062600mg/l
12/1/20144.5350.0065200mg/l
1/1/20152.8450.0063300mg/l
2/1/20152.4350.0061400mg/l
3/1/20152.5940.0058400mg/l
4/1/20152.3750.0031700mg/l
5/1/20151.5540.0027200mg/l
6/1/20151.9950.0023000mg/l
7/1/20153.8650.0024700mg/l
8/1/201520.7250.0055100mg/l
9/1/201513.1450.0072700mg/l
10/1/201518.9750.0100400mg/l
11/1/201512.3540.0118400mg/l
12/1/20158.0250.0128400mg/l
Loading Chart...
Target
0.006 mg/l
Threshold
0.0082 mg/l
Good

Nitrogen, Total

Units: mg/l Year
2015
Historical
period of record
High 1.048 2.205
Mean 0.4059 0.18117654 0.3600000000
Low 0.115 0.055
No. of Samples 57 953

Five-year Trend Graph

     
1/1/2011229.0050.2290000mg/l
2/1/2011259.4050.2442000mg/l
3/1/2011367.0050.2851300mg/l
4/1/2011443.4050.3247000mg/l
5/1/2011415.8050.3429200mg/l
6/1/2011367.0050.3469300mg/l
7/1/2011269.0050.3536000mg/l
8/1/2011401.0050.3772000mg/l
9/1/2011545.8050.4070000mg/l
10/1/2011335.0050.3889300mg/l
11/1/2011337.6050.3759000mg/l
12/1/2011329.4050.3696300mg/l
1/1/2012341.0050.3816300mg/l
2/1/2012385.2050.3790000mg/l
3/1/2012413.0050.3568700mg/l
4/1/2012239.0050.3408700mg/l
5/1/2012245.0050.3254300mg/l
6/1/2012229.0050.3087000mg/l
7/1/2012540.4050.3419300mg/l
8/1/2012566.0050.3720700mg/l
9/1/2012499.8050.3865300mg/l
10/1/2012521.0050.4335300mg/l
11/1/2012360.7540.4528300mg/l
12/1/2012233.0040.4534900mg/l
1/1/2013319.0050.4165900mg/l
2/1/2013289.0050.3704300mg/l
3/1/2013205.0050.3212900mg/l
4/1/2013291.0050.2829600mg/l
5/1/2013351.0050.2813300mg/l
6/1/2013320.0050.2958300mg/l
7/1/2013565.0050.3368300mg/l
8/1/2013546.6050.3797700mg/l
9/1/2013612.8050.4477300mg/l
10/1/2013913.4050.5514700mg/l
11/1/2013863.0050.6368000mg/l
12/1/2013445.0050.6576300mg/l
1/1/2014335.6050.6194000mg/l
2/1/2014407.0050.5961300mg/l
3/1/2014369.2050.5555300mg/l
4/1/2014420.0050.4733000mg/l
5/1/2014321.8050.3831000mg/l
6/1/2014413.0050.3777700mg/l
7/1/2014351.0050.3803300mg/l
8/1/2014506.0050.3968300mg/l
9/1/2014537.5040.4248800mg/l
10/1/2014660.0040.4648800mg/l
11/1/2014443.0050.4850800mg/l
12/1/2014524.2050.5036200mg/l
1/1/2015472.8050.5239200mg/l
2/1/2015349.0050.4977500mg/l
3/1/2015332.5040.4635800mg/l
4/1/2015211.0050.3887500mg/l
5/1/2015332.5040.3703300mg/l
6/1/2015341.0050.3398000mg/l
7/1/2015357.0050.3205000mg/l
8/1/2015810.4050.3974000mg/l
9/1/2015573.6050.4375800mg/l
10/1/2015574.2050.4981200mg/l
11/1/2015465.0040.5202000mg/l
12/1/2015381.0050.5268700mg/l
Loading Chart...
Target
0.36 mg/l
Threshold
0.43 mg/l
Excellent

Phosphorus, Total

Score: Excellent How was this determined?
Units: mg/l Year
2015
Historical
period of record
High 0.20 0.53
Mean 0.0702 0.06733818 0.1700000000
Low 0.05 0.05
No. of Samples 57 960

Five-year Trend Graph

     
1/1/201156.0050.0560000mg/l
2/1/201154.0050.0550000mg/l
3/1/201162.0050.0573300mg/l
4/1/201192.0050.0660000mg/l
5/1/201166.0050.0660000mg/l
6/1/201150.0050.0633300mg/l
7/1/201150.0050.0623300mg/l
8/1/201150.0050.0616700mg/l
9/1/201150.0050.0596700mg/l
10/1/201150.0050.0526700mg/l
11/1/201152.0050.0503300mg/l
12/1/201150.0050.0503300mg/l
1/1/201252.0050.0506700mg/l
2/1/201256.0050.0516700mg/l
3/1/201266.0050.0543300mg/l
4/1/201250.0050.0543300mg/l
5/1/201250.0050.0540000mg/l
6/1/201250.0050.0540000mg/l
7/1/2012142.0050.0690000mg/l
8/1/2012110.0050.0780000mg/l
9/1/201286.0050.0813300mg/l
10/1/201266.0050.0840000mg/l
11/1/201275.0040.0881700mg/l
12/1/201262.5040.0902500mg/l
1/1/201354.0050.0755800mg/l
2/1/201350.0050.0655800mg/l
3/1/201376.0050.0639200mg/l
4/1/201354.0050.0619200mg/l
5/1/201350.0050.0577500mg/l
6/1/201354.0050.0563300mg/l
7/1/201398.0050.0636700mg/l
8/1/201374.0050.0676700mg/l
9/1/201358.0050.0646700mg/l
10/1/2013148.0050.0803300mg/l
11/1/201390.0050.0870000mg/l
12/1/201352.0050.0866700mg/l
1/1/201456.0050.0796700mg/l
2/1/201462.0050.0776700mg/l
3/1/201464.0050.0786700mg/l
4/1/201486.0050.0683300mg/l
5/1/201466.0050.0643300mg/l
6/1/201464.0050.0663300mg/l
7/1/201468.0050.0683300mg/l
8/1/201464.0050.0686700mg/l
9/1/201467.5040.0692500mg/l
10/1/201477.5040.0678300mg/l
11/1/201476.0050.0695000mg/l
12/1/201450.0050.0671700mg/l
1/1/201570.0050.0675000mg/l
2/1/201576.0050.0695000mg/l
3/1/201552.5040.0670000mg/l
4/1/201580.0050.0674200mg/l
5/1/201550.0040.0630800mg/l
6/1/201550.0050.0630800mg/l
7/1/201570.0050.0630800mg/l
8/1/2015142.0050.0740800mg/l
9/1/201568.0050.0766700mg/l
10/1/2015110.0050.0816700mg/l
11/1/201570.0040.0850000mg/l
12/1/201550.0050.0850000mg/l
Loading Chart...
Target
0.17 mg/l
Threshold
0.21 mg/l

Dissolved Oxygen

Units: mg/l Year
2015
Historical
period of record
High 9.20 11.90
Mean 6.3 6.47 1.13545
Low 4.80 1.60
No. of Samples 48 1,004

Five-year Trend Graph

     
1/1/20117.3347.3300000mg/l
2/1/20117.8847.6100000mg/l
3/1/20116.8547.3500000mg/l
4/1/20117.6047.4200000mg/l
5/1/20115.6547.0600000mg/l
6/1/20116.3546.9400000mg/l
7/1/20115.1546.5800000mg/l
8/1/20115.4046.1700000mg/l
9/1/20115.1345.8800000mg/l
10/1/20115.7545.5700000mg/l
11/1/20116.4345.7000000mg/l
12/1/20117.4345.8800000mg/l
1/1/20127.9346.3500000mg/l
2/1/20127.0046.6100000mg/l
3/1/20127.1346.9500000mg/l
4/1/20126.8347.1300000mg/l
5/1/20126.2347.0900000mg/l
6/1/20126.0346.8600000mg/l
7/1/20124.9046.3500000mg/l
8/1/20124.8846.0000000mg/l
9/1/20124.7045.6000000mg/l
10/1/20125.3045.3400000mg/l
11/1/20126.2845.3500000mg/l
12/1/20126.1545.3700000mg/l
1/1/20136.4545.6300000mg/l
2/1/20137.5346.0700000mg/l
3/1/20136.3846.3500000mg/l
4/1/20136.7846.6000000mg/l
5/1/20135.9046.5300000mg/l
6/1/20135.1546.3700000mg/l
7/1/20136.6046.3900000mg/l
8/1/20135.0845.9800000mg/l
9/1/20135.2345.7900000mg/l
10/1/20134.9045.4800000mg/l
11/1/20136.5845.5900000mg/l
12/1/20136.7545.8600000mg/l
1/1/20147.1345.9500000mg/l
2/1/20147.1346.2900000mg/l
3/1/20146.2546.4600000mg/l
4/1/20147.3346.8600000mg/l
5/1/20146.0846.7800000mg/l
6/1/20145.8546.6300000mg/l
7/1/20145.1046.2900000mg/l
8/1/20143.6045.7000000mg/l
9/1/20144.6045.4300000mg/l
10/1/20145.8545.1800000mg/l
11/1/20147.0045.3300000mg/l
12/1/20146.1545.3800000mg/l
1/1/20155.4545.4400000mg/l
2/1/20157.5346.1000000mg/l
3/1/20157.2546.5400000mg/l
4/1/20157.8846.8800000mg/l
5/1/20156.0546.7200000mg/l
6/1/20156.6346.8000000mg/l
7/1/20155.2346.7600000mg/l
8/1/20155.7846.4700000mg/l
9/1/20155.3346.1500000mg/l
10/1/20156.4045.9000000mg/l
11/1/20155.9045.8800000mg/l
12/1/20156.2345.8100000mg/l
Loading Chart...
Target
mg/l
Threshold
0.00 mg/l

Light Attenuation

Units: K(1/m) Year
2015
Historical
period of record
High 2.06 5.03
Mean 0.86 0.86 0.49139
Low 0.24 0.16
No. of Samples 48 842

Five-year Trend Graph

     
1/1/20110.2840.2800000K(1/m)
2/1/20110.7640.5200000K(1/m)
3/1/20110.7440.5900000K(1/m)
4/1/20111.2840.7700000K(1/m)
5/1/20110.5840.7300000K(1/m)
6/1/20110.3840.6700000K(1/m)
7/1/20110.4640.7000000K(1/m)
8/1/20110.6440.6800000K(1/m)
9/1/20111.1840.7500000K(1/m)
10/1/20111.0240.7100000K(1/m)
11/1/20110.8840.7600000K(1/m)
12/1/20110.7840.8300000K(1/m)
1/1/20120.8640.8900000K(1/m)
2/1/20121.0440.9600000K(1/m)
3/1/20120.8940.9100000K(1/m)
4/1/20120.5140.8300000K(1/m)
5/1/20120.4730.7600000K(1/m)
6/1/20120.5040.7100000K(1/m)
7/1/20121.1640.7600000K(1/m)
8/1/20121.1640.7800000K(1/m)
9/1/20121.2540.8400000K(1/m)
10/1/20121.0940.9400000K(1/m)
11/1/20120.8641.0000000K(1/m)
12/1/20120.7141.0400000K(1/m)
1/1/20130.7740.9700000K(1/m)
2/1/20130.9540.9400000K(1/m)
3/1/20130.5140.8200000K(1/m)
4/1/20130.6840.7500000K(1/m)
5/1/20130.6340.7100000K(1/m)
6/1/20130.5540.6800000K(1/m)
7/1/20131.4640.8000000K(1/m)
8/1/20130.9540.8000000K(1/m)
9/1/20131.2340.9200000K(1/m)
10/1/20131.4641.0500000K(1/m)
11/1/20130.9741.1000000K(1/m)
12/1/20130.7341.1300000K(1/m)
1/1/20140.7141.0100000K(1/m)
2/1/20140.4740.9300000K(1/m)
3/1/20140.4730.8000000K(1/m)
4/1/20140.8540.7000000K(1/m)
5/1/20140.7440.6600000K(1/m)
6/1/20140.8240.6800000K(1/m)
7/1/20140.4640.6400000K(1/m)
8/1/20140.6540.6700000K(1/m)
9/1/20140.6840.7000000K(1/m)
10/1/20141.5240.8100000K(1/m)
11/1/20141.0640.8700000K(1/m)
12/1/20140.5640.8200000K(1/m)
1/1/20150.6440.8500000K(1/m)
2/1/20150.7940.8800000K(1/m)
3/1/20150.6440.8700000K(1/m)
4/1/20150.6040.7200000K(1/m)
5/1/20150.5440.6300000K(1/m)
6/1/20150.5240.6200000K(1/m)
7/1/20150.5540.6100000K(1/m)
8/1/20151.6340.7500000K(1/m)
9/1/20151.5340.9000000K(1/m)
10/1/20151.2741.0100000K(1/m)
11/1/20150.8841.0600000K(1/m)
12/1/20150.8041.1100000K(1/m)
Loading Chart...
Target
K(1/m)
Threshold
0.00 K(1/m)

Rainfall

Units: inches/yr Year
2015
Historical
period of record
High 48.21 52.18
Mean 33.57 17.078760538706
Low 2.40
No. of Samples 365 4,615

Five-year Trend Graph

     
1/1/20112.33312.3300000inches
2/1/20110.48280.4800000inches
3/1/20119.66319.6600000inches
4/1/20110.88300.8800000inches
5/1/20112.95312.9500000inches
6/1/20113.32303.3200000inches
7/1/20116.56316.5600000inches
8/1/20118.23318.2300000inches
9/1/20115.03305.0300000inches
10/1/20111.23301.2300000inches
11/1/20111.94301.9400000inches
12/1/20110.21300.2100000inches
1/1/20120.69290.6900000inches
2/1/20120.76290.7600000inches
3/1/20121.56311.5600000inches
4/1/20121.59241.5900000inches
5/1/20122.77312.7700000inches
6/1/201215.993015.9900000inches
7/1/20126.92316.9200000inches
8/1/20129.11319.1100000inches
9/1/20126.08306.0800000inches
10/1/20123.59313.5900000inches
11/1/20120.17280.1700000inches
12/1/20122.29312.2900000inches
1/1/20130.37310.3700000inches
2/1/20131.17231.1700000inches
3/1/20131.48301.4800000inches
4/1/20133.58303.5800000inches
5/1/20131.97311.9700000inches
6/1/201312.093012.0900000inches
7/1/201311.063111.0600000inches
8/1/20138.85318.8500000inches
9/1/20139.93309.9300000inches
10/1/20130.81310.8100000inches
11/1/20130.73300.7300000inches
12/1/20130.14310.1400000inches
1/1/20142.82312.8200000inches
2/1/20141.41281.4100000inches
3/1/20145.26315.2600000inches
4/1/20141.42291.4200000inches
5/1/20144.93314.9300000inches
6/1/20144.64304.6400000inches
7/1/20141.94311.9400000inches
8/1/20143.90283.9000000inches
9/1/20147.35267.3500000inches
10/1/20142.50302.5000000inches
11/1/20143.04303.0400000inches
12/1/20140.31310.3100000inches
1/1/20152.54312.5400000inches
2/1/20153.95283.9500000inches
3/1/20151.51311.5100000inches
4/1/20151.14301.1400000inches
5/1/20156.13316.1300000inches
6/1/20152.04302.0400000inches
7/1/201514.333114.3300000inches
8/1/20153.78313.7800000inches
9/1/20157.98307.9800000inches
10/1/20151.03311.0300000inches
11/1/20151.00301.0000000inches
12/1/20152.78312.7800000inches
Loading Chart...
Target
inches/yr
Threshold
inches/yr

Salinity

Units: PSS Year
2015
Historical
period of record
High 36.10 39.30
Mean 31.46 33.16 4.16278
Low 14.90 5.70
No. of Samples 48 1,004

Five-year Trend Graph

     
1/1/201132.90432.9000000PSS
2/1/201131.98432.4400000PSS
3/1/201134.83433.2400000PSS
4/1/201129.80432.3800000PSS
5/1/201133.88432.6800000PSS
6/1/201135.68433.1800000PSS
7/1/201135.38433.5900000PSS
8/1/201135.63434.2000000PSS
9/1/201129.63433.3300000PSS
10/1/201133.88434.0100000PSS
11/1/201134.23434.0700000PSS
12/1/201133.45433.7000000PSS
1/1/201233.60433.4000000PSS
2/1/201234.15433.1600000PSS
3/1/201235.78434.1800000PSS
4/1/201236.95434.6900000PSS
5/1/201236.05435.0000000PSS
6/1/201235.13435.2800000PSS
7/1/201229.40434.5800000PSS
8/1/201228.65433.6600000PSS
9/1/201230.15432.7200000PSS
10/1/201229.70431.5100000PSS
11/1/201234.73431.2900000PSS
12/1/201234.05431.1100000PSS
1/1/201334.23431.9200000PSS
2/1/201334.38432.8700000PSS
3/1/201333.70433.4700000PSS
4/1/201333.95434.1700000PSS
5/1/201334.75434.1800000PSS
6/1/201335.70434.4500000PSS
7/1/201328.33433.4700000PSS
8/1/201330.18432.7700000PSS
9/1/201324.33431.2100000PSS
10/1/201322.68429.3300000PSS
11/1/201330.85428.6800000PSS
12/1/201332.70428.1800000PSS
1/1/201434.03429.1300000PSS
2/1/201432.85429.5700000PSS
3/1/201434.28431.2300000PSS
4/1/201431.85432.7600000PSS
5/1/201432.93433.1100000PSS
6/1/201435.30433.5400000PSS
7/1/201435.73433.8200000PSS
8/1/201434.68434.1300000PSS
9/1/201434.60434.1800000PSS
10/1/201427.33433.4300000PSS
11/1/201433.15433.4700000PSS
12/1/201430.10432.6000000PSS
1/1/201533.58432.2400000PSS
2/1/201531.20431.6600000PSS
3/1/201532.55431.3200000PSS
4/1/201533.23432.3000000PSS
5/1/201535.15432.6400000PSS
6/1/201535.88433.6000000PSS
7/1/201535.45433.9100000PSS
8/1/201521.93432.3700000PSS
9/1/201526.28431.3200000PSS
10/1/201525.93430.1000000PSS
11/1/201533.10429.7600000PSS
12/1/201533.30429.3300000PSS
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Turbidity

Units: NTU Year
2015
Historical
period of record
High 6.40 39.00
Mean 3.34 3.93 3.37425
Low 1.30 0.20
No. of Samples 57 960

Five-year Trend Graph

     
1/1/20112.8652.8600000NTU
2/1/20114.7053.7800000NTU
3/1/20114.1053.8900000NTU
4/1/201111.9055.8900000NTU
5/1/20112.8255.2800000NTU
6/1/20111.8854.7100000NTU
7/1/20112.6254.6700000NTU
8/1/20112.5254.3100000NTU
9/1/20114.4254.3600000NTU
10/1/20114.6653.1500000NTU
11/1/20114.1253.3700000NTU
12/1/20113.3853.6200000NTU
1/1/20124.1853.8800000NTU
2/1/20125.3654.3500000NTU
3/1/20128.4855.0300000NTU
4/1/20122.7454.7100000NTU
5/1/20121.7854.3200000NTU
6/1/20122.4054.1600000NTU
7/1/20123.4254.0300000NTU
8/1/20123.5053.7200000NTU
9/1/20123.2652.8500000NTU
10/1/20123.3652.9500000NTU
11/1/20125.2543.5300000NTU
12/1/20121.9843.4600000NTU
1/1/20132.5453.3200000NTU
2/1/20135.2853.6100000NTU
3/1/20133.1853.6000000NTU
4/1/20132.3653.4300000NTU
5/1/20136.7853.6900000NTU
6/1/20134.7854.1500000NTU
7/1/20133.5654.3200000NTU
8/1/20133.7854.0700000NTU
9/1/20133.4054.1100000NTU
10/1/20134.6854.5000000NTU
11/1/20134.9254.1900000NTU
12/1/20133.0453.9000000NTU
1/1/20144.7654.1000000NTU
2/1/20141.7653.7600000NTU
3/1/20142.1853.5600000NTU
4/1/201414.0455.1200000NTU
5/1/20142.9254.7800000NTU
6/1/20142.5054.6900000NTU
7/1/20141.8254.2000000NTU
8/1/20143.0854.4200000NTU
9/1/20143.1844.5900000NTU
10/1/20144.8343.0600000NTU
11/1/20142.9253.0600000NTU
12/1/20141.7852.9400000NTU
1/1/20154.1853.3300000NTU
2/1/20153.8253.4500000NTU
3/1/20154.2343.6300000NTU
4/1/20153.8653.4700000NTU
5/1/20152.4043.3800000NTU
6/1/20151.7253.3700000NTU
7/1/20151.8852.9900000NTU
8/1/20154.1253.0400000NTU
9/1/20153.5652.9200000NTU
10/1/20154.4853.0300000NTU
11/1/20152.5843.0600000NTU
12/1/20153.0453.2800000NTU
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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 (2015)

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 »

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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 mg/l
  • 1.0 - 5.9 mg/l
  • 6.0 - 10.9 mg/l
  • 11.0 - 17.9 mg/l
  • Greater than 18 mg/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. Learn More about Seagrasses »

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Target
447 acres

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 »

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

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