Potential Contribution of Potential Contribution of Refuge Canals to P LoadsRefuge Canals to P Loads

Samira DaroubSamira DaroubOctober 30, 2003October 30, 2003

Everglades Research & Education Everglades Research & Education CenterCenter

Storm Storm Treatment Treatment

Areas Areas (STAs)(STAs)

BackgroundBackground

Goal of the STAs to deliver water of P concentration of 10 ppb or lessWater from STAs discharge into WCA canalsQuestion: How will the WCA canal network impact P concentrations of waters released from STAs?

ExperimentsExperiments

WCA canal sediment inventoriesP speciation (fractionation) to determine relative availability of P compoundsP flux studies to determine potential P release into water column (laboratory studies)P transport study- evaluate P dynamics under flow conditions (in-situ)

Canal samplingCanal sampling

STA 2

STA-1W STA-1E

STA 3/4

STA 5

STA 6L39

L40

L7

L6

L38L5Miami Canal

Inventory 1-mile longitudinal increments over 120 miles of canals

20 Cores sampled for P speciation and flux studies

Average Sediment Properties by CanalAverage Sediment Properties by Canal

Canal Bulk

Density (g/cm3)

% Dry Mass

% Organic

Matter

PhosphorusContent (mg/kg)

L7S 1.14 18.2 38.8 932 L39 1.21 24.2 34.6 735

L40S 1.24 25.1 33.1 1071 L6 1.31 37.1 23.1 285 L5 1.20 26.7 28.8 583

L38 1.22 29.1 28.5 1123 MC 1.24 28.0 26.6 1477

MCN 1.32 38.7 14.9 1362 L7N 1.07 12.8 48.1 1282

L40N 1.07 12.6 41.8 1168

Average Values for Canal Sediment (Total Depth)Average Values for Canal Sediment (Total Depth) Canal

Average Sediment

Depth (m)

Average

Width (m)

Length(m)

Canal Bed Area (m2)

SedimentVolume

(m3)

Estimated

P Mass (Kg)

L7S 1.07 55.2 14,725 812,837 869,612 104,353 L39 0.91 42.8 20,921 895,312 813,215 97,586

L40S 0.76 37.4 40,073 1,498,676 1,132,855 260,557 L6 0.54 41.5 11,265 467,412 252,947 32,529 L5 0.82 19.5 8,851 172,666 141,967 21,820

L38 0.64 25.0 20,921 523,541 335,108 100,532 MCN 0.97 31.2 17,220 537,462 520,942 672,016 MC 0.75 22.7 44,901 1,018,903 719,657 79,162

Totals 178,879 5,926,808 4,786,303 1,368,555

L7N 2.45 56.6 10,863 614,865 1,506,782 180,814 L40N 1.78 43.8 6,276 275,098 488,845 112,434

Totals 17,140 889,963 1,995,627 293,248

Phosphorus Fractionation Phosphorus Fractionation And ReleaseAnd Release

Potential Potential

ObjectivesObjectives

Evaluate phosphorus storages in canal sediments.Estimate potential phosphorus mass release and flux rates from canal sediments using experimental microcosms.

STA 2

STA-1W STA-1E

STA 3/4

STA 5

STA 6

L39 L40

L7

L6

L38

L5Miami Canal

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C28

C27

C3

C2

C1

C23

C8

C6C5C4

C7

C9 C25

C10

C24

C12

C22C21

C11

C26

Sampling LocationsSampling Locations

Phosphorus Fractionation SchemePhosphorus Fractionation SchemeInorganic

KCl Pi labile

NaOH Pi Fe and Al phosphates –relatively stable; sensitive to sediment redox changes

HCl Pi Ca & Mg phosphates-stable with exceptions of changes in pH

Organic NaOH Po

humic and fulvic acids – could be mineralized depending on environmental conditions

Recalcitrant PMost stable fraction.

Surface Sediment Phosphorus Storage Surface Sediment Phosphorus Storage Near Existing and Proposed STA’sNear Existing and Proposed STA’s

STA - 1E(L40)

KCl - Pi0%

NaOH - Pi17%

HCl - Pi38%

NaOH - Po18%

Recalcitrant P27%

STA - 1W(L7 and L39)

KCl - Pi0%

NaOH - Pi6%

HCl - Pi51%NaOH - Po

13%

Recalcitrant P30%

TP = 1092 ± 212 mg kg-1 TP = 790 ± 200 mg kg-1

Phosphorus Release Potential (Flux)Phosphorus Release Potential (Flux)Laboratory MicrocosmsLaboratory Microcosms

P FluxP Flux

P Flux from sediments was estimated by two methods

Maximum Flux= Maximum P release rate per unit area; occurs early on when low-P water is contact with sedimentsAverage Flux= Average P release rate per unit area over a 30-day period

Site mean sd mean sd

L40-C22 6.04 2.02 0.488 0.115L40-C12 8.78 1.46 0.619 0.338L40-C24 *22.02 14.17 *0.453 0.164L7-C21 3.02 1.65 0.207 0.050L7-C11 2.41 0.20 0.131 0.021L7-C26 4.07 1.14 0.396 0.291L6-C9 2.66 1.25 0.095 0.022

L39-C25 5.30 0.55 0.776 0.221L39-C10 4.34 1.78 0.309 0.190L6-C7 2.09 0.58 0.076 0.013L5-C5 2.30 0.96 0.162 0.016

L38-C6 2.94 0.32 0.138 0.034L38-C8 2.23 0.55 0.082 0.036L5-C4 2.91 1.49 *0.292 0.293

MC-C28 2.71 1.06 0.266 0.091MC-C27 3.40 0.36 0.206 0.051MC-C3 3.52 1.67 0.188 0.057MC-C2 4.44 1.74 0.643 0.332MC-C1 2.30 0.29 0.104 0.007MC-C23 2.00 0.25 0.086 0.005* Value from second floodwater exchange

Maximum Flux Average Flux

-----------------mg P / m2 / day ---------------

First Floodwater Exchange

Max and Max and Average Average Sediment Sediment

P FluxP Flux

Maximum P Flux Near Existing Maximum P Flux Near Existing and Proposed STA’sand Proposed STA’s

0.01.02.03.0

4.05.06.07.08.09.0

P Fl

ux m

g P/

m2 /d

ay

1st Exchange 2nd Exchange 3rd Exchange 4th Exchange

Floodwater Exchange Cycles

Maximum Flux Rates

STA-1E (L40) STA-1W (L7 and L39)STA's 2, 3 and 4 (L6, L38, and L5) STA's 5 and 6 (Miami Canal)

Hypothetical 24Hypothetical 24--hr P hr P concentration increaseconcentration increase

0.202.92L40S

0.171.43L39

0.201.69L7S

24 hr- P delta C (ppb)

(Avg. Flux)

24 hr- P delta C (ppb)

(Max. Flux)

Canal

Temporal Effects ?Temporal Effects ?

Maximum P Flux Comparison for 2001 and 2002Maximum P Flux Comparison for 2001 and 2002

0.0

1.0

2.0

3.0

4.0

5.0

6.0

Max

imum

P F

lux

(mg

P/m

2/da

y)

L7-C26 L39-C25 L40-C24 L38-C6 MC-C2

Sample Locations

2001 2002

STASTA--1W Flow History for 7/00 Through 5/021W Flow History for 7/00 Through 5/02

STA-1W Discharge Patterns

0

500

1000

1500

2000

2500

3000

3500

4000

06/01/2000 08/30/2000 11/28/2000 02/26/2001 05/27/2001 08/25/2001 11/23/2001 02/21/2002 05/22/2002 08/20/2002

Date

Dis

char

ge (f

t3/s

)

FirstSample Cycle

Second Sample Cycle

Temporal EffectsTemporal Effects

Significant reduction in net P release of core samples from 2001 to 2002 in 4 of the 5 locations.Hypothesized causes

Seasonal variation in labile P poolLabile P source is susceptible to disturbance and could have been removed or translocated due to flow management.

SummarySummarysediment inventory, fractions and fluxsediment inventory, fractions and flux

L7/L39/L40 canals have more organic matter, more readily available P, and higher flux rate.Sediment P flux maybe a significant contributor to the elevation of dissolved P in the conveyance system on a periodic basis under the appropriate conditions (quiescent antecedent conditions)Compliance sampling schedule- seasonal timing and flow distribution into consideration

Transport studiesTransport studies

Evaluate P dynamics in L7/L39 under flow conditions

Estimate magnitude of particulate P re-suspension and transportEvaluate changes in dissolved P

Transport Study sampling locationsTransport Study sampling locationsL7 and L39 canals downstream of STA-1W

STA-1W

Sampling Station 1

Sampling Station 2

Sampling Station 3

G-310

STA 1-W

Sampling Platform Set-upTop View

Flow Direction 55 Gal Drum55 Gal Drum

Steel Cable

Jon Boat (12 ft)ISCO Samplers

ISCO samplers

Sediment

55 Gal Drum

Steel Cable

Side ViewBuoy

Depth 1

Depth 2

Depth 3Anchor

STASTA--1 W Discharge Flow Jan1 W Discharge Flow Jan--Nov. Nov. 20022002

STA 1-W Flow vs Time

0

500

1000

1500

2000

2500

3000

01-Jan-02 02-Mar-02 02-May-02 02-Jul-02 01-Sep-02 01-Nov-02 01-Jan-03

Date

Tota

l STA

Dis

char

ge -

CFS

Flow -All Times

Flow During Sampling

Downstream P Gradient Sampling Downstream P Gradient Sampling Event Starting 7/16/02Event Starting 7/16/02P Species Average vs Distance Downstream from STA 1-W

24 Hour Run 7/16/02-7/17/02

y = 1.0735x + 12.106

y = -0.2194x + 30.043

0

5

10

15

20

25

30

35

40

45

0 2 4 6 8 10 12 14

Distance Downstream from STA 1-W (mi)

Ave

rage

P C

once

ntra

tion

(ppb

)

TDP

PP

Slopes and Intercepts of Regression Slopes and Intercepts of Regression EquationsEquations

Date

TDP Slope ppb/mile

TDP Intercept

ppb

PP Slope ppb/mile

PP Intercept

ppb

7/16/02 -0.219 30.0 1.074 12.1 8/27/02 -0.367 26.7 0.892 13.2 9/10/02 0.257 31.4 -0.108 13.1 10/1/02 -1.295 39.6 0.047 8.9 10/19/02 -0.909 39.8 0.350 9.5 11/4/02 -0.426 43.7 -0.196 14.8 11/18/02 -0.253 36.6 -0.311 14.8

Average -0.459 35.4 0.250 12.4

Particulate P Gradients in L7 as a Particulate P Gradients in L7 as a Function of Cumulative FlowFunction of Cumulative Flow

Downstream Particulate P Gradient in L7 Only vs Cumulative Flow

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

0.0E+00 2.0E+09 4.0E+09 6.0E+09 8.0E+09 1.0E+10 1.2E+10 1.4E+10 1.6E+10 1.8E+10

Cumulative Flow - ft3

Parti

cula

te P

Gra

dien

t - p

pb/m

ile

Flow of 830-1100 CFS

Flow of 1500-2100 CFS

Grab Samples at 548 CFS

Dissolved P Gradients in L7 as Dissolved P Gradients in L7 as Function of Cumulative FlowFunction of Cumulative Flow

Downstream Dissolved P Gradient in L7 Only vs Cumulative Flow

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.0.E+00 5.0.E+07 1.0.E+08 1.5.E+08 2.0.E+08 2.5.E+08 3.0.E+08 3.5.E+08 4.0.E+08 4.5.E+08 5.0.E+08

Cumulative Flow - M3

Dis

solv

ed P

Gra

dien

t - p

pb/m

ile

Included Sampling Events

Excluded Sampling Event (9/10/02)

Summary Summary –– Transport StudiesTransport Studies

The conveyance systems appeared to affect a net reduction of dissolved P and a net contribution of particulate P downstream of STA-1W.The net reduction of dissolved P - results from biological activity in the canals and their floodplains, and appeared to be a function of time-in-season, higher in the summer and lower during spring and autumn.

Summary Summary –– Transport Studies Transport Studies (cont’d)(cont’d)

The net contribution of particulate P - results from the remobilization of biological generated particulate matter that had accumulated in the canal system during the quiescent dry season.As the pumping season progressed, the particulate matter accumulation was subject to washout, so early in the period mobilization was high, and low at the end of pumping period.

Recommendations for Future WorkRecommendations for Future Work

Interaction between canal/floodplain sediments and aquatic systems and water column is important to understand especially during the dry season.Evaluation of the dissolved P removal and contribution mechanisms, and seasonal responses.Expand the P transport study to include L40 downstream of STA-1E.