# Presentation: 513271

## NUTRIENT CONCENTRATION, DISTRIBUTION AND TRANSPORT FROM THE EAST COAST CANALS TO BISCAYNE BAY AND WATER-QUALITY TRENDS AT SELECTED SITES IN SOUTH FLORIDA

- South Florida Ecosystem Program

## INTRODUCTION

- Biscayne Bay Is An Oligotrophic Subtropical Estuary Which Provides Habitat To A Variety Of Plant And Animal Life
- Nutrient-laden Discharges From East Coast Canals Threaten Ecological Health Of Bay (Biscayne Bay SWIM Plan)
- Ecosystem Restoration Plans Diversion Of Discharges To Biscayne Bay To Re-establish Natural Flow To Everglades National Park

## INTRODUCTION(CONTINUED)

- Anthropogenic Activities Are Major Source Of Nutrients And May Result From Urban And Agricultural Runoff
- Adverse Effects Of Excessive Nutrients
- Eutrophication
- Algal Blooms
- Phytoplankton Growth
- Decreased Light Penetration Harmful To Submerged Aquatic Vegetation
- Hypoxia/anoxia

## PROJECT OBJECTIVES

- Determine Method For Estimating Loads From Canals To Bay
- Characterize Nutrient Concentration And Distribution In The East Coast Canals
- Evaluate Sampling Methods In Order To Document Most Representative Manner Of Sample Collection
- Determine Long-term Trends at Selected Sites in South Florida

## DESCRIPTION OF PROJECT

- Samples Collected Upstream Of Gated Control Structures At East Coast Canals During Periods Of Flow
- Depth-integrated And Point Or Grab Samples Collected
- Depth-integrated Samples Collected By Equal-Width-Increment (EWI) Using Weighted Bottle Since Velocities < 2.0 Ft/sec
- Instantaneous Discharge Determined for Each Sampling Event

## DESCRIPTION OF PROJECT (CONTINUED)

- Samples Analyzed For:
- Total Organic Nitrogen
- Total Ammonia
- Total Nitrite And Nitrate
- Total Phosphorus
- Total Orthophosphate
- Kjeldahl Nitrogen (Calculated)
- Total Nitrogen (Calculated)

## LOCATION OF SAMPLING SITES

- <date/time>

## DESCRIPTION OF PROJECT(CONTINUED)

- Depth-integrated Samples Collected By Equal-Width-Increment (EWI) Method
- Stream Width Subdivided Into Equal Width Intervals With Sampling Vertical Associated With Each Interval
- Vertical With Highest Velocity Is Selected And Sampler Is Raised And Lowered At Constant Rate So Bottle Is Not Overfilled When Returned To Surface

## DESCRIPTION OF PROJECT(CONTINUED)

- Depth-integrated Samples (Continued)
- Same Transit Rate Used In All Verticals But Sample Volume May Be Different
- Samples Composited In Churn Splitter
- Samples Collected In Amber Polyethylene Bottles And Chilled To 4 Degrees  Centigrade And Sent To Lab

## FIGURE SHOWING EWI SAMPLING

- <date/time>

## DESCRIPTION OF PROJECT(CONTINUED)

- Point Or Grab Samples
- Collected At 0.5 Or 1.0 Meter Below Water Surface in Middle of Stream
- Niskin Bottle Or Van Dorn Sampler

## SNAPPER CREEK AT S-22 LOOKING UPSTREAM

- <date/time>

## SNAPPER CREEK AT S-22 DOWNSTREAM

- <date/time>

## SAMPLES COMPOSITED IN CHURN AT BRIDGE UPSTREAM OF S-22

- <date/time>

## SAMPLES COLLECTED WITH VAN DORN SAMPLER AT SNAPPER CREEK  S-22

- <date/time>

## DESCRIPTION OF PROJECT(CONTINUED)

- Nutrient Concentrations In East Coast Canals:
- Total Organic Nitrogen Ranged From 0.20 To 1.7 Mg/l And Median Was 0.75 Mg/l
- Ammonia Ranged From 0.01 To 1.5 Mg/l And Median Was 0.10 Mg/l
- Nitrate Ranged From .001 To 4.38 Mg/l And Median Was 0.18 Mg/l

## DESCRIPTION OF PROJECT(CONTINUED)

- Nutrient Concentrations (Continued)
- Total Nitrogen Ranged From 0.31 To 4.7 Mg/l And Median Was 1.47 Mg/l
- Total Phosphorus Ranged From .004 To 0.31 Mg/l And Median Was 0.02 Mg/l
- Orthophosphate Ranged From <.001 To 0.26 Mg/l And Median Was .005 Mg/l

## DESCRIPTION OF PROJECT(CONTINUED)

- Five Sites (G58, G93, S-26, S-27, And S-123) Had Ammonia Concentrations That Exceeded The Miami-Dade DERM Standard Of 0.5 Mg/l
- Maximum Total Phosphorus Concentration Of 0.31 Mg/l At G58 (Arch Creek) Was Above Recommended EPA Upper Limit Of 0.10 Mg/l To Control Eutrophication

## DESCRIPTION OF PROJECT(CONTINUED)

- Nutrient Distribution In East Coast Canals Based On Land Use Categories
- Agricultural (S-20f, S-20g, S021, S21a)
- Urban (G-58, G-93, S-22, S-25, S-25b, S-26, S-27, S-28, S-29, S-123)
- Wetland (S-20)

## MEDIAN TOTAL ORGANIC NITROGEN CONCENTRATIONS WERE HIGHEST IN WETLAND AND URBAN AREAS

- <date/time>

## MEDIAN CONCENTRATIONS OF TOTAL AMMONIAWERE HIGHEST IN URBAN AREAS

- <date/time>

- MEDIAN CONCENTRATIONS OF TOTAL AMMONIAWERE HIGHEST IN URBAN AREAS

## MEDIAN NITRATE CONCENTRATIONS WERE HIGHEST IN AGRICULTURAL AREAS

- <date/time>

## MEDIAN TOTAL PHOSPHORUS CONCENTRATIONS WERE HIGHEST IN URBAN AREAS

- <date/time>

## DESCRIPTION OF PROJECT(CONTINUED)

- Comparison Of Grab With Depth-integrated Samples For Total Nitrogen And Total Phosphorus
- Wilcoxon Signed Rank Test – Exact Form Of The Test Statistic
- Comparison Between Grab Samples At 0.5 Meter Depth And EWI Samples
- Comparison Of Grab Samples At 1.0 Meter Depth And EWI Samples
- Comparison Of Grabs At 0.5 Meter Depth And 1.0 Meter Depth

## DESCRIPTION OF THE PROJECT(CONTINUED)

- Statistical Interpretation Of Differences Between Grab Samples And Depth-integrated Samples
- Total Nitrogen
- No Significant Differences Between Grabs And Depth-integrated Samples (P<.025)

## DESCRIPTION OF PROJECT(CONTINUED)

- Statistical Interpretation Of Differences (Continued)
- Total Phosphorus
- Three Sites (25%) Showed Significant Differences Between Grabs At 1.0 Meter Depth And Depth-integrated Samples
- One Site (33%) Showed Differences Between Grabs At 0.5 Meter Depth And Depth-integrated Samples

## DESCRIPTION OF PROJECT(CONTINUED)

- Water-Quality Cross-section Surveys
- Document Water-Quality Homogeneity In The East Coast Canal System
- At Several Sites Temperature, Dissolved Oxygen, pH, And Specific Conductance Measured  Beneath Surface And At 2-foot Intervals To Streambed
- Dissolved Oxygen Was Only Parameter Showing  Variation In Cross-section

## DESCRIPTION OF PROJECT(CONTINUED)

- Water-Quality Cross-section Survey At Snapper Creek At S-22
- Temperature, Dissolved Oxygen, pH, Specific Conductance Measured From 1.0 Foot Below Surface Every 2 Feet To Streambed
- Total Nitrogen And Total Phosphorus Samples Collected Every 2 Feet To Above Streambed

## DESCRIPTION OF PROJECT(CONTINUED)

- Water-Quality Cross-section Survey (Continued)
- Discharge Of 414 Cfs During Measurements
- Suspended Sediment Sample Collected By EWI And By Grab

## DISSOLVEDOXYGENDECREASEDWITHDEPTH

- <date/time>

- DISSOLVEDOXYGENDECREASEDWITHDEPTH

## TOTALNITROGENAND TOTALPHOSPHORUSINCREASED WITH DEPTH

- <date/time>

- TOTALNITROGENAND TOTALPHOSPHORUSINCREASED WITH DEPTH

## DESCRIPTION OF PROJECT(CONTINUED)

- Suspended Sediment Sample Collected By EWI Method Was 3.0 Mg/l And By Grab Method Was 1.0 Mg/l
- Depth-integrated Samples Collected By EWI Probably More Accurately Reflect Phosphorus Concentration Than Those Collected As Grabs

## DESCRIPTION OF PROJECT(CONTINUED)

- <date/time>

- DESCRIPTION OF PROJECT(CONTINUED)

- Relation Between Grab And Depth-integrated Samples
- Line Of Organic Correlation (LOC) Describes Relation Between Two Variables. No Reduction in Variance of Estimated Values

## DESCRIPTION OF PROJECT(CONTINUED)

- Grab Samples Underestimate Phosphorus Concentration Compared To EWI Samples
- S-21 (0.5)  Grab = 0.25EWI + .00625
- S-21 (1.0) Grab = 0.2973EWI + .0057
- S-25b (1.0) Grab = 0.8255EWI - .0018
- S-28 (1.0) Grab = 1.093EWI - .008

## DESCRIPTION OF PROJECT(CONTINUED)

- <date/time>

- DESCRIPTION OF PROJECT(CONTINUED)

- Determination Of Constituent Loads

## DESCRIPTION OF PROJECT(CONTINUED)

- <date/time>

- DESCRIPTION OF PROJECT(CONTINUED)

- Discharge Computed Corresponding to Each Sampling Event
- Fundamental Equations

## DESCRIPTION OF PROJECT(CONTINUED)

- Linear Regression Analysis To Develop Predictive Models
- Load Was Dependent Variable
- Discharge Was Explanatory Or Predictor Variable
- Best Model Based On Highest R-squared And Lowest Predicted Error Sum Of Squares (PRESS)
- R-squared Averaged 0.87 For Nitrogen Models And 0.76 For Phosphorus Models

## DESCRIPTION OF PROJECT(CONTINUED)

- Log-linear Model Called Estimator Used At Miami Canal S-26
- Used For Load Estimation By NAWQA
- Continuous Discharge Data
- Minimum Of 50 Samples For Period Of At Least 2 Years
- Minimum Variance Unbiased Estimator (MVUE) For Elimination Of Bias From Log Space To Real Space And Adjusted Maximum Likelihood Estimator (AMLE) For Censored Data

## DESCRIPTION OF PROJECT(CONTINUED)ESTIMATOR

- <date/time>

- DESCRIPTION OF PROJECT(CONTINUED)ESTIMATOR

## <footer>

- <date/time>

## <footer>

- <date/time>

## DESCRIPTION OF PROJECT(CONTINUED)

- Water-Quality Trends At Two Long-term Discharge Sites In South Florida
- Miami Canal At S-26 (1966 To 1994). Represents Flow Through Agricultural, Conservation and Urban Areas.
- Tamiami Canal 40-mile Bend To Monroe (1967 T0 1993). Represents Overland Sheet flow From Big Cypress National Preserve.

## DESCRIPTION OF PROJECT(CONTINUED)

- Constituents Analyzed For:
- Major Inorganics And Physical Characteristics
- Field Parameters: Specific Conductance, pH, Dissolved Oxygen
- Suspended Sediment
- Nitrogen And Phosphorus Species
- Total Organic Carbon
- Trace Metals
- Fecal Coliform And Fecal Streptococcus
- Phytoplankton

## LOCATION OF SAMPLING SITES

- <date/time>

## TAMIAMI CANAL OUTLETS

- <date/time>

## OUTLET ON TAMIAMI CANAL IN BIG CYPRESS NATIONAL PRESERVE

- <date/time>

## MIAMI CANAL AT S-26

- <date/time>

## DESCRIPTION OF PROJECT(CONTINUED)

- Extraneous Variation in Water-Quality Must Be Removed in Order to Ascertain Anthropogenic Changes on Water-Quality
- Extraneous Variation in Water-Quality Caused by:
- Seasonality
- Discharge

## DESCRIPTION OF PROJECT(CONTINUED)

- ESTREND – A Program For Determining Monotonic Trends In Water-Quality
- Non-parametric Seasonal Kendall Trend (SKT) Test To Remove Extraneous Variation
- SKT Applied To Time Series Of Flow-adjusted Concentrations (Residuals) From Regression Of Concentration With Discharge
- Time Series Of Non-adjusted Concentrations

## DESCRIPTION OF PROJECT(CONTINUED)

- <date/time>

- DESCRIPTION OF PROJECT(CONTINUED)

- Form Of Linear Models
- Conservative Constituents (Dissolved Solids, Cations And Anions)

## DESCRIPTION OF PROJECT(CONTINUED)

- <date/time>

- DESCRIPTION OF PROJECT(CONTINUED)

- Form Of Linear Models (Continued)
- Non-conservative Constituents (Nitrogen And Phosphorus Species, Suspended Sediment, Organic Carbon, Bacteria And Phytoplankton)
- Non-linear Method – Fitting Concentration/discharge Or Log Concentration/log Discharge Relation By LOWESS

## <footer>

- <date/time>

## <footer>

- <date/time>

## SUMMARY

- Nutrient Concentrations Vary In The East Coast Canals Based On Land Use Categories
- No Statistical Differences Between EWI And Grab Samples For Total Nitrogen But 25% Of Sites Showed Differences For Total Phosphorus
- Coefficients Of Determination (R2) For Nitrogen Models Averaged 0.87 And 0.76 For Phosphorus Models
- Long-term Trends At Miami Canal At S-26 And Tamiami Canal Showed Both Improvement And Deterioration In Water-Quality With Time

## WHERE DO WE GO FROM HERE?

- Continued Water-quality Monitoring At Tamiami Canal And Miami Canal At S-26
- Continued Water-quality Monitoring At East Coast Canal Sites

## ACKNOWLEDGEMENTS

- South Florida Water Management District Employees
- George Hwa, Control Room
- Ron Dempsey, Supervisor, Homestead Field Office
- Dawn Browning, Supervisor, Miami Field Office