# Numeric Nutrient Criteria Development for the Tolomato-Matanzas Estuary
Florida Department of Environmental Protection Division of Environmental Assessment and Restoration Joy Jackson August 31, 2010

# Tolomato -Matanzas Estuary 

# Geographical and Physical Description

 

## Located in St Johns and Flagler Counties.
 

## Much is in the GTMNERR. Other natural areas: Guana River Wildlife MA, Guana River, Twelve Mile Swamp CA, Anastasia St Park, Moses Creek CA, Matanzas St Forest, Faver St. Park, Pellicer Creek CA, Princess Place Preserve
 

## Land uses in the watershed are primarily upland forest, and wetlands; major urban area is the City of St. Augustine, St Augustine Beach.
 

## Two major inlets – St Augustine and Matanzas.

# Tolomato-Matanzas Estuary 

# Geographical and Physical Description cont.
 

# Mean depth ~2 m  

# Tidal range 1.25 m  

# Freshwater residence times 5
– 22 days  

# Watershed area = 1,024 km2  

# Estuary area is~44km2.  

# Ratio of watershed to estuary is 23:1.

# Tolomato -Matanzas Estuary 

# Sources of Nutrients
 

# ~80% of overall watershed is forests, wetlands, and surface water; ~15 % urban  

# Urban stormwater , septic tanks, silviculture, agriculture, shoreline erosion, groundwater, and atmospheric deposition.  

# St Johns is the second fastest county in State (2000 census)  

# Point source discharges (7 NPDES domestic wastewater facilities) **Watershed Land Use**

# Tolomato-Matanzas Estuary 

# Biological Summary  

# The principle habitat types in the TME are salt marshes , and mollusk/oyster reefs.  

# Vast stretches of nearly contiguous marsh, oyster habitat, and minimally developed upland strand in the TME, much of it publicly owned and under conservation management, is one reason why NOAA and the State of Florida established the GTMNERR.  

# The estuary supports a wide diversity of species: 358 bird, 41 reptiles, 21 amphibian, 303 fish, and 580 plants.  

# There have been minor losses to due to dredge and fill activities in areas around St. Augustine.

# Tolomato-Matanzas Estuary 

# Checklist of Eutrophication Symptoms Response variable Observed historically? Observed currently? Explanation Source Low DO (hypoxia/anoxia) Yes Yes Caused by natural factors, especially the high oxygen demand by decomposing bacteria in the highly organic saltmarsh systems. Steward and Miller, pers. comm. 2010 Reduced clarity Yes Yes Naturally high turbidities and high tidal scouring contribute to sporadic reductions in clarity. The naturally low clarity (from tripton ) contributes to the lack of seagrass in this region of Florida. Steward et al. 2010a Increased chlorophyll a concentrations Yes No Slightly increasing temporal trend from 1986- 2009 but annual averages well below the threshold for impairment in the IWR of 11 μg/l. Steward et al 2010a Phytoplankton bloom No No Short residence times, High tripton levels may help control phytoplankton densities. Vertical mixing by tidal stirring may control phytoplankton blooms in some estuaries. Steward et al 2010a Cloern 1991 Problematic epiphyte growth N/A N/A - - Problematic macroalgal growth No No - - SAV community changes or loss N/A N/A Large tidal amplitude and naturally high turbidity have prevented SAV establishment. Steward et al 2010a Emergent or shoreline vegetation community changes or loss Yes Yes Impacts to shoreline habitats, associated with maintenance of inlets and navigation channels, mosquito control, and recreational boating activities, have historically occurred, but are spatially limited. Haydt and Frazel 2003 Oyster reef community changes or loss Yes Yes Oyster reef communities have been negatively impacted by erosion, primarily due to wind and boat wakes and sediment loads due to runoff and tidal scouring. It should be noted that denser oyster populations, with larger, meatier individuals, were found in areas with higher nutrient concentrations. Haydt and Frazel 2003 Dix and Phlips 2009
Impacts to benthic community Unknown Unknown - - Fish kills Yes Yes Fish kills reported January 2010 due to cold stress Fish kill (red and black drum) reported August 2010 in San Sebastian Creek (St. Augustine, Matanzas basin); cause unknown FFWCC 2010

# Tolomato-Matanzas Estuary 

# Water Quality
 

# Water quality in the Tolomato - Matanzas Estuary is generally good.  

# Shorter residence times and greater flushing around inlets (Upper and Lower Matanzas River) tends to improve water quality. Analytes Data Yrs n Data Min Median Max Range TOLOMATO RIVER - - - - - - total nitrogen (mg/L as N) 16 140 0.13 0.59 1.82 mid - lo total phosphorus (mg/L as P) 16 139 0.02 0.09 1.24 mid trichromatic uncorrected chlorophyll - a (ug/L) 16 135 0.01 5.12 27.32 mid - lo trophic state index 16 138 -2.39 44.74 60.76 mid - lo UPPER MATANZAS RIVER - - - - - - total nitrogen (mg/L as N) 15 126 0.01 0.47 1.46 low total phosphorus (mg/L as P) 15 124 0.02 0.07 0.61 mid trichromatic uncorrected chlorophyll - a (ug/L) 15 119 0.01 4.67 23.79 mid - lo trophic state index 15 124 -2.96 40.84 57.14 low LOWER MATANZAS RIVER - - - - - - total nitrogen (mg/L as N) 16 134 -0.02 0.5 1.16 low total phosphorus (mg/L as P) 16 134 0.02 0.07 0.27 mid trichromatic uncorrected chlorophyll - a (ug/L) 16 127 0.01 5.06 22.01 mid - lo trophic state index 16 133 -0.85 41.8 61.71 mid - lo 

## Source: http://sjrwmd.com/watershedfacts/factsindex.html

# Tolomato-Matanzas Estuary 

# Approach to criteria development

 

# Nutrient criteria were developed to maintain the existing conditions that are supportive of healthy, well - balanced populations of flora and fauna.

 

# Relatively low nutrient and chlorophyll a levels,  

# Lack of long-term increasing trends in nutrient and chlorophyll a concentrations,  

# Lack of widespread biological impacts associated with nutrients,  

# Due to this natural spatial variation, the first step in the derivation of appropriate nutrient criteria was to divide area into more homogeneous sub - regions.

# Tolomato-Matanzas Estuary 

# Estuary Segmentation
 

# Segmentation based on spatial analysis of TN, TP, Chla , salinity, turbidity, and TSI.  

# Tolomato River: Palm Valley Bridge south to St Augustine Inlet  

# N. Matanzas River: St. Augustine Inlet south to Ft Matanzas Inlet  

# S. Matanzas River: Ft Matanzas Inlet south to High Bridge0 5 10 15 20 25 30 35 40Salinity (ppt)

Site 

### Salinity Dry Wet High Bridge St. Augustine Inlet Matanzas Inlet Tolomato median: 31.9 ppt 

### 1986 – 2009 period of record N. Matanzas median: 33.5 ppt S. Matanzas median: 31.5 ppt

0 2 4 6 8 10 12 14 16 18Turbidity (ntu)

Site 

### Turbidity Dry Wet High Bridge Matanzas Inlet St. Augustine Inlet Palm Valley Bridge S. Matanzas median: 7.8 ntu N. Matanzas median: 7.5 ntu Tolomato median: 9.4 ntu Tidal node point 

# Tolomato-Matanzas Estuary

# Spatial distribution of TN, TP, and Chl-a (μg/L) means and medians 1986- 2009

0 2 4 6 8 10 12 14 16CHLAC μg/l)

Site Chlorophyll a (corrected) Dry Wet 0 0.05 0.1 0.15 0.2 0.25 0.3TP (mg/l)

Site Total Phosphorus Dry Wet

High Bridge 0 0.2 0.4 0.6 0.8

1 1.2 1.4 1.6 1.8 2TN (mg/l)

Site Total Nitrogen DRY Wet Palm Valley Bridge Matanzas Inlet St. Augustine Inlet High Bridge 

### S. Matanzas median: 0.49 mg/L mean: 0.50 mg/L 

### N. Matanzas median: 0.41 mg/L mean: 0.43 mg/L 

### Tolomato median: 0.53 mg/L mean: 0.58 mg/L



### S. Matanzas median: 0.083 mg/L mean: 0.10 mg/L 

### N. Matanzas median: 0.072 mg/L mean: 0.087 mg/L 

### Tolomato median: 0.084 mg/L mean: 0.098 mg/L



### S. Matanzas median: 3.9 mg/L mean: 4.6 mg/L 

### N. Matanzas median: 3.1 mg/L mean: 3.4 mg/L 

### Tolomato median: 4.3 mg/L mean: 5.0 mg/L Mean ± s.d .

Mean ± s.d .

Mean ± s.d . Tidal node point

# Tolomato - Matanzas Estuary 

# Approach to criteria development cont. - Multiple Lines of Evidence
 

# Reference Period  

# Chl a – TN & TP Regression Models  

# General Models  

# Geometric Means

# Tolomato - Matanzas Estuary 

# Reference Period

 

# Good spatial and temporal coverage; supports good trophic state (<50 TSI), healthy aquatic life, fully supports designated use.
 

# At least 5 consecutive years or longer to avoid bias from extreme events (e.g., drought, hurricanes).
 

# Data from 2000- 2009 was considered most temporally and spatially complete and subject to less bias from episodic events.
**Segment Chla (μg/L)**  **TN (mg/L) TP (mg/L)**  Tolomato 4.5 (5.3) 0.52 (0.56) 0.085 (0.096) N. Matanzas 3.1 (3.5) 0.37 (0.41) 0.073 (0.083) S. Matanzas 4.3 (5.0) 0.45 (0.49) 0.089 (0.103) 

### Tolomato - Matanzas Estuary, reference period results–1 st 

### line of evidence: Annual median (mean),

# Tolomato - Matanzas Estuary 

# Chla -TN, TP Regressions
 

# All data from full period is organized into annual averages, monthly averages, and avg. wet season monthly data sets.
 

# If model had strong correlation and significance, it was used to predict median concentrations based on reference period Chla medians.

**Segment Target Chla**  **(μg/L) TN**  **(mg/L) r**  **p TP**  **(mg/L) r**  **p** Tolomato 6.4 0.62 0.63 .028 0.110 0.68 .014 N. Matanzas 4.0 0.46 0.72 .008 0.095 0.81 .002 S. Matanzas 6.3 0.61 0.87 .0002 0.120 0.82 .001 

### Tolomato - Matanzas Estuary, linear regression results–2 nd 

### line of evidence: Maximum wetseason median (1986–2009; all months).

# Tolomato - Matanzas Estuary 

# General Models

 

# Steward and Lowe 2010  

# Uses relationship between hydraulic loading (mean depth/water residence times) and nutrient loading limits for mesotrophic Florida systems.  

# Dettmann 2001  

# Predicts TN based on trophically desirable TN loading limit. S. Matanzas Tolomato

-

### 0.5 0.5

1 1.5

2 2.5

-

### 0.5 0 0.5 1 1.5 2 2.5 3 

### log q s 

### (z/τw

### ; m/yr)log TN load limit (g/m2/yr) 

### 95% upper CI LML 

### N. Matanzas

- 

### 2.0 - 

### 1.5 - 

### 1.0 - 

### 0.5 0.0 

### 0.5 1.0 1.5

- 

### 0.5 0.0 0.5 1.0 2.0 2.5 3.0 

### log q s 

### (z/τw

### ; m/yr)log TP load limit (g/m2/yr) 

### N. Matanzas S. Matanzas Tolomato 2.0 95% upper CI LML 

# TN

TP

# Tolomato-Matanzas Estuary Numeric Nutrient and Chlorophyll Recommendations: Concentrations and Loads
Segment Chla (μg/L) TN (mg/L) TP (mg/L) Tolomato segment 4.5 (5.3) 0.52 (0.56) 0.085 (0.096) N. Matanzas segment 3.1 (3.5) 0.37 (0.41) 0.073 (0.083) S. Matanzas segment 4.3 (5.0) 0.45 (0.49) 0.089 (0.103) 

## Tolomato - Matanzas Estuary, concentration limits: Annual median (mean), 2000–09.

Segment TN: kg/yr TP: kg/yr Tolomato segment 76,727 11,264 N. Matanzas segment 237,074 43,792 S. Matanzas segment 208,025 37,142 

## Tolomato - Matanzas Estuary loading limits (ca. 2004 loadings) for TN and TP.

### Segment TN: kg/yr TP: kg/yr Tolomato segment 76,727 11,264 N. Matanzas segment 237,074 43,792 S. Matanzas segment 208,025 37,142 

## Tolomato-Matanzas Estuary loading limits (ca. 2004 loadings) for TN and TP 

# Tolomato-Matanzas Estuary Numeric Nutrient and Chlorophyll Recommendations: LoadsFDEP Total Phosphorus (μg/L)
Segment Existing Long Term Geometric

Mean Maximum Allowed Long term Geometric Mean Annual Geometric Mean for a Network of Stations (2 of 5

year exceedance rate) Annual Geometric Mean for a Single Site (2 of 5 year exceedance rate) N. Matanzas 0.074 0.082 0.102 0.109 S. Matanzas 0.092 0.101 0.119 0.120 Tolomato 0.087 0.096 0.116 0.119 FDEP Total Nitrogen (mg/L) Segment Existing Long Term Geometric Mean Maximum Allowed Long term Geometric Mean Annual Geometric Mean for a Network of Stations (2 of 5 year exceedance rate) Annual Geometric Mean for a Single Site (2 of 5 year exceedance rate) N. Matanzas 0.382 0.420 0.493 0.501 S. Matanzas 0.445 0.489 0.540 0.556 Tolomato 0.528 0.581 0.662 0.681 FDEP Chlorophyl a (mg/L) Segment Existing Long Term Geometric Mean Maximum Allowed Long term Geometric Mean Annual Geometric Mean for a Network of Stations (2 of 5 year exceedance rate) Annual Geometric Mean for a Single Site (2 of 5 year exceedance rate) N. Matanzas 2.95 3.24 4.03 4.18 S. Matanzas 3.96 4.35 5.87 6.06 Tolomato 4.19 4.60 6.05 6.15 

# Tolomato-MatanzasEstuary Numeric Nutrient and Chlorophyll Recommendations: Annual Geometric Means

# Tolomato -Matanzas Estuary 

# SUMMARY

 

# There is considerable evidence to demonstrate that the nutrient regime in the Tolomato - Matanzas Estuary is not adversely affecting the biological communities. A reduction in nutrients would not lead to recovery of oysters or tidal marshes, or improve the condition of other biological resources in the bay.  

# FDEP therefore proposes nutrient concentration targets that reflect the current conditions as reported from 2000 to 2009 water quality monitoring data.

# Tolomato - Matanzas Estuary 

# Next Steps

• 

# Provide additional comments on estuary report to: Joy Jackson • 

# Phone 850 - 245 - 8074 • 

# Email: Joy.Jackson@dep.state.fl.us
• 

# Finalize estuary reports.
• 

# Information concerning nutrient criteria development posted to DEP website: http://www.dep.state.fl.us/water/wqssp/nutrients/estuarine.htm