Indicators

Nutrients

Total Nitrogen - Discrete

Scatter plot of monthly average total nitrogen over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only nitrogen values obtained from laboratory analyses (triangles) are included in the plot.
Scatter plot of monthly average total nitrogen over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only nitrogen values obtained from laboratory analyses (triangles) are included in the plot.
Seasonal Kendall-Tau Results for - Total Nitrogen
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Significantly increasing trend 109 17 2001 - 2025 0.322 0.2395 0.25912 0.01101 0.0281

Monthly average total nitrogen increased by 0.01 mg/L per year.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Total Phosphorus - Discrete

Scatter plot of monthly average total phosphorus over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only phosphorus values obtained from laboratory analyses (triangles) are included in the plot.
Scatter plot of monthly average total phosphorus over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only phosphorus values obtained from laboratory analyses (triangles) are included in the plot.
Seasonal Kendall-Tau Results for - Total Phosphorus
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Significantly increasing trend 107 17 2001 - 2025 0.012 0.27143 0.00627 0.00039 0.0186

Monthly average total phosphorus increased by less than 0.01 mg/L per year.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Quality

Dissolved Oxygen - Discrete

Scatter plot of monthly average dissolved oxygen over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only dissolved oxygen values measured in the field (circles) are included in the plot.
Scatter plot of monthly average dissolved oxygen over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only dissolved oxygen values measured in the field (circles) are included in the plot.
Seasonal Kendall-Tau Results for - Dissolved Oxygen
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field No significant trend 1119 31 1995 - 2025 7.2 -0.04825 7.34801 -0.016 0.1392

Dissolved oxygen showed no detectable trend between 1995 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Dissolved Oxygen - Continuous

Scatter plot of monthly average dissolved oxygen over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average dissolved oxygen over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results - Dissolved Oxygen
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
YRMAP1 No significant trend 267617 10 2015 - 2025 7.00 -0.04 6.93 -0.01 0.4884
P11 No significant trend 131 7 2002 - 2012 6.37 0.04 6.54 0.02 0.4884

No detectable change in monthly average dissolved oxygen was observed at two locations.

Map showing location of dissolved oxygen continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of dissolved oxygen continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Dissolved Oxygen Saturation - Discrete

Scatter plot of monthly average dissolved oxygen saturation over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only dissolved oxygen saturation values measured in the field (circles) are included in the plot.
Scatter plot of monthly average dissolved oxygen saturation over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only dissolved oxygen saturation values measured in the field (circles) are included in the plot.
Seasonal Kendall-Tau Results for - Dissolved Oxygen Saturation
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field No significant trend 183 17 2002 - 2025 75.6 -0.0935 73.60381 -0.34809 0.3327

Dissolved oxygen saturation showed no detectable trend between 2002 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Dissolved Oxygen Saturation - Continuous

Scatter plot of monthly average dissolved oxygen saturation over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average dissolved oxygen saturation over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results - Dissolved Oxygen Saturation
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
YRMAP1 No significant trend 273885 10 2015 - 2025 87.50 0.08 86.25 0.25 0.326
P11 No significant trend 126 7 2002 - 2012 79.93 0.09 79.97 1.09 0.7119

No detectable change in monthly average dissolved oxygen saturation was observed at two locations.

Map showing location of dissolved oxygen saturation continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of dissolved oxygen saturation continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Salinity - Discrete

Scatter plot of monthly average salinity over time. If the time series included ten or more years of discrete observations, significant (blue) or non-significant (magenta) trend lines are also shown. Discrete salinity values derived from grab samples analyzed in the field (circles) or the laboratory (triangles) are both included in the plot.
Scatter plot of monthly average salinity over time. If the time series included ten or more years of discrete observations, significant (blue) or non-significant (magenta) trend lines are also shown. Discrete salinity values derived from grab samples analyzed in the field (circles) or the laboratory (triangles) are both included in the plot.
Seasonal Kendall-Tau Results for - Salinity
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
All Significantly decreasing trend 1252 31 1995 - 2025 11 -0.15102 13.38403 -0.2225 0.0011

Monthly average salinity decreased by 0.22 ppt per year.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Salinity - Continuous

Scatter plot of monthly average salinity over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average salinity over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results - Salinity
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
YRMAP1 Significantly increasing trend 284295 10 2015 - 2025 14.60 0.28 11.88 0.42 3e-04
P11 No significant trend 136 7 2002 - 2012 10.05 0.06 11.52 0.15 0.6499

At one program location, monthly average salinity increased by 0.42 ppt per year. No detectable change in monthly average salinity was observed at one location.

Map showing location of salinity continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of salinity continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Temperature - Discrete

Scatter plot of monthly average water temperature over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only water temperature measurements taken in the field (circles) are included in the plot.
Scatter plot of monthly average water temperature over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only water temperature measurements taken in the field (circles) are included in the plot.
Seasonal Kendall-Tau Results for - Water Temperature
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field No significant trend 1245 31 1995 - 2025 22 -0.0128 22.18306 -0.00955 0.6147

Water temperature showed no detectable trend between 1995 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Temperature - Continuous

Scatter plot of monthly average water temperature over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average water temperature over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results - Water Temperature
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
YRMAP1 No significant trend 309064 10 2015 - 2025 22.80 0.11 22.91 0.06 0.1403
P11 No significant trend 136 7 2002 - 2012 26.22 0.13 25.96 0.10 0.496

No detectable change in monthly average water temperature was observed at two locations.

Map showing location of water temperature continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of water temperature continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

pH - Discrete

Scatter plot of monthly average pH over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only pH values measured in the field (circles) are included in the plot.
Scatter plot of monthly average pH over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only pH values measured in the field (circles) are included in the plot.
Seasonal Kendall-Tau Results for - pH
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Significantly decreasing trend 751 31 1995 - 2025 7.64 -0.20867 7.98375 -0.01786 0

Monthly average pH decreased by 0.02 pH units per year.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

pH - Continuous

Scatter plot of monthly average pH over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average pH over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results - pH
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
YRMAP1 No significant trend 282641 10 2015 - 2025 7.6 0.09 7.55 0.01 0.2568

No detectable change in monthly average pH was observed at one location.

Map showing location of ph continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of ph continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Clarity

Turbidity - Discrete

Scatter plot of monthly average turbidity over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only turbidity values measured in the laboratory (triangles) are included in the plot.
Scatter plot of monthly average turbidity over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only turbidity values measured in the laboratory (triangles) are included in the plot.
Seasonal Kendall-Tau Results for - Turbidity
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No significant trend 593 26 1995 - 2025 2.5 0.08445 1.79891 0.01504 0.3945

Turbidity showed no detectable trend between 1995 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Turbidity - Continuous

Scatter plot of monthly average turbidity over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average turbidity over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results - Turbidity
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
YRMAP1 Significantly decreasing trend 296386 10 2015 - 2025 6 -0.22 12.55 -0.4 0.0056
P11 Insufficient data to calculate trend 37 4 2009 - 2012 2 - - - -

At one program location, monthly average turbidity decreased by 0.40 NTU per year. There was insufficient data to fit a model for one location.

Map showing location of turbidity continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of turbidity continuous water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Total Suspended Solids - Discrete

Scatter plot of monthly average total suspended solids (TSS) over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only TSS values obtained from laboratory analyses (triangles) are included in the plot.
Scatter plot of monthly average total suspended solids (TSS) over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only TSS values obtained from laboratory analyses (triangles) are included in the plot.
Seasonal Kendall-Tau Results for - Total Suspended Solids
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No significant trend 49 10 2009 - 2025 3.24 -0.00877 4.06369 0.00786 0.7404

Total suspended solids showed no detectable trend between 2009 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Chlorophyll a, Uncorrected for Pheophytin - Discrete

Scatter plot of monthly average levels of chlorophyll a, uncorrected for pheophytin, over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed chlorophyll a (triangles) is included in the plot.
Scatter plot of monthly average levels of chlorophyll a, uncorrected for pheophytin, over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed chlorophyll a (triangles) is included in the plot.
Seasonal Kendall-Tau Results for - Chlorophyll a, Uncorrected for Pheophytin
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No significant trend 68 13 2001 - 2025 2.8 0.05035 1.50098 0.01111 0.9342

Chlorophyll a, uncorrected for pheophytin, showed no detectable trend between 2001 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Chlorophyll a, Corrected for Pheophytin - Discrete

Scatter plot of monthly average levels of chlorophyll a, corrected for pheophytin, over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed chlorophyll a (triangles) is included in the plot.
Scatter plot of monthly average levels of chlorophyll a, corrected for pheophytin, over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed chlorophyll a (triangles) is included in the plot.
Seasonal Kendall-Tau Results for - Chlorophyll a, Corrected for Pheophytin
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Significantly decreasing trend 146 19 2002 - 2025 3.60685 -0.31104 5.33533 -0.15458 0

Monthly average chlorophyll a, corrected for pheophytin, decreased by 0.15 µg/L per year, indicating an increase in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Secchi Depth - Discrete

Scatter plot of monthly average Secchi depth over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Secchi depth is only measured in the field (circles).
Scatter plot of monthly average Secchi depth over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Secchi depth is only measured in the field (circles).
Seasonal Kendall-Tau Results for - Secchi Depth
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Significantly decreasing trend 242 14 2001 - 2025 -0.8 -0.32413 -0.35633 -0.035 0.0081

Monthly average Secchi depth became deeper by 0.04 m per year, indicating an increase in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Colored Dissolved Organic Matter - Discrete

Scatter plot of monthly average colored dissolved organic matter (CDOM) over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed CDOM (triangles) is included in the plot.
Scatter plot of monthly average colored dissolved organic matter (CDOM) over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed CDOM (triangles) is included in the plot.
Seasonal Kendall-Tau Results for - Colored Dissolved Organic Matter
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Insufficient data to calculate trend 31 7 2001 - 2025 28 - - - -

There was insufficient data to fit a model for colored dissolved organic matter.

Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Yellow River Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.