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South Florida Ecosystem Program

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.

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South Florida Ecosystem Program

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  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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)

  7. LOCATION OF SAMPLING SITES

  8. 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

  9. 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

  10. FIGURE SHOWING EWI SAMPLING

  11. 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

  12. SNAPPER CREEK AT S-22 LOOKING UPSTREAM

  13. SNAPPER CREEK AT S-22 DOWNSTREAM

  14. SAMPLES COMPOSITED IN CHURN AT BRIDGE UPSTREAM OF S-22

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

  16. 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

  17. 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

  18. 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

  19. 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)

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

  21. MEDIAN CONCENTRATIONS OF TOTAL AMMONIAWERE HIGHEST IN URBAN AREAS

  22. MEDIAN NITRATE CONCENTRATIONS WERE HIGHEST IN AGRICULTURAL AREAS

  23. MEDIAN TOTAL PHOSPHORUS CONCENTRATIONS WERE HIGHEST IN URBAN AREAS

  24. 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

  25. 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)

  26. 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

  27. 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

  28. 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

  29. 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

  30. DISSOLVEDOXYGENDECREASEDWITHDEPTH

  31. TOTALNITROGENAND TOTALPHOSPHORUSINCREASED WITH DEPTH

  32. 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

  33. 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

  34. 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

  35. DESCRIPTION OF PROJECT(CONTINUED) • Determination Of Constituent Loads

  36. DESCRIPTION OF PROJECT(CONTINUED) • Discharge Computed Corresponding to Each Sampling Event • Fundamental Equations

  37. 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

  38. 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

  39. DESCRIPTION OF PROJECT(CONTINUED)ESTIMATOR

  40. 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.

  41. 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

  42. LOCATION OF SAMPLING SITES

  43. TAMIAMI CANAL OUTLETS

  44. OUTLET ON TAMIAMI CANAL IN BIG CYPRESS NATIONAL PRESERVE

  45. MIAMI CANAL AT S-26

  46. 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

  47. 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

  48. DESCRIPTION OF PROJECT(CONTINUED) • Form Of Linear Models • Conservative Constituents (Dissolved Solids, Cations And Anions)

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