nutrient concentration, distribution and transport from the east coast canals to biscayne bay and...

NUTRIENT CONCENTRATION, NUTRIENT CONCENTRATION, DISTRIBUTION AND TRANSPORT DISTRIBUTION AND TRANSPORT

FROM THE EAST COAST CANALS TO FROM THE EAST COAST CANALS TO BISCAYNE BAY AND WATER-QUALITY BISCAYNE BAY AND WATER-QUALITY

TRENDS AT SELECTED SITES IN TRENDS AT SELECTED SITES IN SOUTH FLORIDASOUTH FLORIDA

South Florida Ecosystem Program

INTRODUCTIONINTRODUCTION

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

INTRODUCTIONINTRODUCTION(CONTINUED)(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 OBJECTIVESPROJECT 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 PROJECTDESCRIPTION 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 DESCRIPTION OF PROJECT (CONTINUED)(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 SITESLOCATION OF SAMPLING SITES

DESCRIPTION OF PROJECTDESCRIPTION OF PROJECT(CONTINUED)(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


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 SAMPLINGFIGURE SHOWING EWI SAMPLING


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 UPSTREAMSNAPPER CREEK AT S-22 LOOKING UPSTREAM

SNAPPER CREEK AT S-22 DOWNSTREAMSNAPPER CREEK AT S-22 DOWNSTREAM

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

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


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


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


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


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

MEDIAN CONCENTRATIONS OF TOTAL AMMONIAMEDIAN CONCENTRATIONS OF TOTAL AMMONIAWERE HIGHEST IN URBAN AREASWERE HIGHEST IN URBAN AREAS

MEDIAN NITRATE CONCENTRATIONS WERE HIGHEST IN MEDIAN NITRATE CONCENTRATIONS WERE HIGHEST IN AGRICULTURAL AREASAGRICULTURAL AREAS

MEDIAN TOTAL PHOSPHORUS CONCENTRATIONS WERE MEDIAN TOTAL PHOSPHORUS CONCENTRATIONS WERE HIGHEST IN URBAN AREASHIGHEST IN URBAN AREAS


• 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 PROJECTDESCRIPTION OF THE PROJECT(CONTINUED)(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)


• 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


• 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


• 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


Water-Quality Cross-section Survey (Continued)

• Discharge Of 414 Cfs During Measurements

• Suspended Sediment Sample Collected By EWI And By Grab

DISSOLVEDDISSOLVEDOXYGENOXYGENDECREASEDDECREASEDWITHWITHDEPTHDEPTH

TOTALTOTALNITROGENNITROGENAND TOTALAND TOTALPHOSPHORUSPHOSPHORUSINCREASED INCREASED WITH DEPTHWITH DEPTH


• 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


• Relation Between Grab And Depth-integrated Samples

• Line Of Organic Correlation (LOC) Describes Relation Between Two Variables. No Reduction in Variance of Estimated Values

SAMPLES EWI OF AVERAGE

SAMPLE EWI

DEVIATION STANDARD

1 R IF 1- SGN(R) 0, R

if 0 SGN(R) 1, R if 1 SGN(R) T,COEFFICIEN NCORRELATIO

GRABS OF AVERAGE

GRAB

)()(

,

X

X

SS

R

Y

Y

XXS

SRSGNYY

XY

X

Y


• 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


• Determination Of Constituent Loads

TONS/DAY TO FACTOR CONVERSION

IONCONCENTRAT TCONSTITUEN

(CFS) DISCHARGE

(TONS/DAY) LOAD

x X

F

C

Q

L

FCQL


• Discharge Computed Corresponding to Each Sampling Event

• Fundamental Equations

)(2

CULVERTS FOR EQUATIONFLOW ORIFICE

)(2

SPILLWAYS GATED FORFLOW WEIRSUBMERGED

)(2

SPILLWAYS GATED FORFLOW ORIFICE SUBMERGED

hHgACQ

hHgLhCQ

hHgLhCQ

C

WS

gs


• 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


• 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


ESTIMATORESTIMATOR

FUNCTION PERIODIC22

DISCHARGE

TIME DECIMAL

TSCOEFFICIEN

CONSTANT

LOAD

LOGARITHM NATURAL

22lnln

6 TO 1

0

652

432

210

tt

Q

T

L

Ln

ttTTQQLnL

COSSIN

COSSIN


• 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.


• 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 SITESLOCATION OF SAMPLING SITES

TAMIAMI CANAL OUTLETSTAMIAMI CANAL OUTLETS

OUTLET ON TAMIAMI CANAL IN BIG CYPRESS OUTLET ON TAMIAMI CANAL IN BIG CYPRESS NATIONAL PRESERVENATIONAL PRESERVE

MIAMI CANAL AT S-26MIAMI CANAL AT S-26


• 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


• 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


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

)1(1 HYPERBOLIC ,1 INVERSE ,ln LINEAR,)(

DISCHARGE OUSINSTANTANE OR DAILY MEAN

SLOPE

INTERCEPT

IONCONCENTRAT ESTIMATED

)(

QQQQf

Q

b

a

C

QbfaC


• 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

221 )(lnlnLnC QbQba

SUMMARYSUMMARY

• 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?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

ACKNOWLEDGEMENTSACKNOWLEDGEMENTS

• South Florida Water Management District Employees

• George Hwa, Control Room• Ron Dempsey, Supervisor, Homestead Field Office• Dawn Browning, Supervisor, Miami Field Office

nutrient concentration, distribution and transport from the east coast canals to biscayne bay and...

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