Implementation and Verification of BMPs for Reducing P ...erec.ifas.ufl.edu/media/erecifasufledu/docs/pdf/soil-water-sci-reports/UF-IFAS...UF/IFAS Annual Report July 9, 2010 6 I. Introduction

Implementation and Verification of BMPs for Reducing P Loading

from the Everglades Agricultural Area

Floating Aquatic Vegetation Impact on Farm P Load

2010 Annual Report

Submitted to the

Everglades Agricultural Area Environmental Protection District And

The South Florida Water Management District By

Samira H. Daroub, Timothy A. Lang,

Manohardeep S. Josan, and Jehangir H. Bhadha

University of Florida, Institute of Food and Agricultural Sciences

Everglades Research and Education Center, Belle Glade, FL 33430

July 2010

UF/IFAS Annual Report July 9, 2010

2

Acknowledgments

This project is primarily funded by the Everglades Agricultural Area Environmental Protection

District. The collaboration and cooperation of the growers in the Everglades Agricultural Area is

duly appreciated. The expert advice from members of the Water Resources and BMP Advisory

Committee has been of great value. Researchers, extension personnel, and SFWMD staff who

assisted with BMP trainings were major contributors to the success of those trainings. This

project is also supported by the Florida Agricultural Experiment Station.


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Table of Contents I. Introduction ........................................................................................................................................... 6

II. Activity A: EAA Farm Canal Survey ................................................................................................... 8

Rationale and Methods ................................................................................................................................. 9

Sediment and Canal Measurements ............................................................................................................ 11

Drainage Water P Concentrations ............................................................................................................... 13

Unit Area P Loads ....................................................................................................................................... 16

Pump to Rainfall Ratios .............................................................................................................................. 19

Prevalent FAV Species ............................................................................................................................... 21

III. Activity B: Farm Pair Selection ...................................................................................................... 22

Methodology ............................................................................................................................................... 22

Farm Pair Descriptions ............................................................................................................................... 24

Correlation Analysis Results ....................................................................................................................... 25

Regression Analysis Results ....................................................................................................................... 26

Summary ..................................................................................................................................................... 27

IV. BMP Education and Extension Services ......................................................................................... 44

V. List of Current Publications ................................................................................................................ 47

VI. Literature Cited ............................................................................................................................... 48


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List of Figures

FIGURE 1. BOX-WHISKER PLOT OF CANAL SEDIMENT THICKNESS (M) OF NINE SELECTED FARMS IN EACH OF THE EAA SUB-BASINS (S5A, S6,

S7, S8). ................................................................................................................................................................. 11

FIGURE 2. BOX-WHISKER PLOT OF CANAL SEDIMENT THICKNESS (M) OF SELECTED FARMS IN EAA BASIN (A) AND EAA SUB-BASINS (B)

BASED ON FARM SIZE. ............................................................................................................................................... 12

FIGURE 3. BOX-WHISKER PLOT OF FWTP (MG/L) OF SELECTED FARMS IN FOUR EAA SUB-BASINS BASED ON THE 10 YEARS OF DATASETS

OBTAINED FROM THE DBHYRO DATABASE. (VALUES, N=4, GREATER THAN 1.0 MG/L WERE TRIMMED IN SAS FOR THE BETTER

REPRESENTATION OF RESULTS). ................................................................................................................................... 14

FIGURE 4. BOX-WHISKER PLOTS OF FWTP (MG/L) OF SELECTED FARMS IN EAA BASIN BASED ON FARM SIZES: A. OVERALL DISTRIBUTION

OF FWTP, B. SUB-BASIN WISE DISTRIBUTION OF FWTP (VALUES, N=4, GREATER THAN 1.0 MG/L WERE TRIMMED IN SAS FOR THE

BETTER REPRESENTATION OF RESULTS). ........................................................................................................................ 15

FIGURE 5. PLOT OF UNIT AREA P LOAD (UAL) OF TOTAL-P FOR 36 SURVEYED FARMS IN THE EAA DURING 2000-2009. UAL VALUES >10

KG/HA (N=3) WERE TRIMMED IN SAS. ......................................................................................................................... 17

FIGURE 6. BOX-WHISKER PLOTS OF UNIT AREA P LOAD (UAL; KG/HA) OF SELECTED FARMS IN EAA BASIN BASED ON FARM SIZES: A.

OVERALL DISTRIBUTION OF UAL, B. SUB-BASIN WISE DISTRIBUTION OF UAL (KG/HA) (VALUES, N=3, GREATER THAN 10 KG/HA

WERE TRIMMED IN SAS FOR THE BETTER REPRESENTATION OF RESULTS). ............................................................................ 18

FIGURE 7. PLOT OF PUMP TO RAINFALL RATIO OF NINE SELECTED FARMS IN EACH OF THE EAA SUB-BASINS OBTAINED FROM THE DBHYRO

DATABASE FOR WATERYEAR 2000-2009. ..................................................................................................................... 19

FIGURE 8. BOX-WHISKER PLOTS OF PUMP TO RAINFALL RATIO (PTR) OF SELECTED FARMS IN EACH OF THE EAA BASIN BASED ON FARM

SIZES: A. OVERALL DISTRIBUTION OF PTR, B. SUB-BASIN WISE DISTRIBUTION OF PTR. .......................................................... 20

FIGURE 9. WATER LETTUCE GROWING IN THE FARM CANALS ..................................................................................................... 21

FIGURE 10. MIX OF RECENTLY CONTROLLED FLOATING AQUATIC WEED SPECIES ............................................................................. 21

FIGURE 11. LOCATION OF THE SELECTED FARM BASINS. ........................................................................................................... 28

FIGURE 12. FARM PAIR 1 BIWEEKLY UNIT AREA LOAD (UAL) OF TOTAL PHOSPHORUS. .................................................................... 32

FIGURE 13.. FARM PAIR 1 BIWEEKLY UNIT AREA VOLUME (UAV). .............................................................................................. 33


FIGURE 15. FARM PAIR 2 BIWEEKLY UNIT AREA VOLUME (UAV). ............................................................................................... 35





FIGURE 20. ALTERNATE FARM PAIR BIWEEKLY UNIT AREA LOAD (UAL) OF TOTAL PHOSPHORUS. ....................................................... 40

FIGURE 21. ALTERNATE FARM PAIR BIWEEKLY UNIT AREA VOLUME (UAV). .................................................................................. 41


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List of Tables

TABLE 1. SUMMARY SURVEYS OF NINE SELECTED FARMS IN EACH OF THE SUB-BASINS S5A, S6, S7, AND S8 INCLUDING SEDIMENT

THICKNESS, WATER DEPTH, AND CANAL WIDTH ............................................................................................................... 13

TABLE 2. SHAPIRO-WILK NORMALITY TEST RESULTS FOR TRANSFORMED MONTHLY AND BIWEEKLY UNIT AREA P LOAD (UAL). ............... 29

TABLE 3. BIWEEKLY UNIT AREA P LOAD (UAL) CORRELATION ANALYSIS OF CANDIDATE FARMS IN THE S5A SUB-BASIN. ......................... 30

TABLE 4. BIWEEKLY UNIT AREA P LOAD (UAL) CORRELATION ANALYSIS OF CANDIDATE FARMS IN S6 SUB-BASIN. ................................. 31

TABLE 5. MONTHLY AND BIWEEKLY REGRESSION ANALYSIS OF FARM PAIR UNIT AREA LOAD (UAL). .................................................. 42

TABLE 6. MONTHLY AND BIWEEKLY ANALYSIS FOR DETECTING DIFFERENCES AT THE 10, 15, AND 20 PERCENT LEVELS. ......................... 43

TABLE 7. SURVEY RESULTS FROM A GENERAL BMP TRAINING WORKSHOP HELD ON APRIL 22, 2010. ............................................... 45


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I. Introduction

The Everglades Agricultural Area (EAA) basin, comprising approximately 250,000 ha of farms

and several small communities south and east of Lake Okeechobee, is located in the geographic

center of the south Florida watershed. The EAA has highly productive agricultural land

comprised of rich organic soils. Sugarcane, vegetables, sod, and rice are grown in the EAA and

annually provide south Florida with jobs and over one billion dollars to Florida‟s economy

(Florida Department of Agriculture and Consumer Services, 2004). The EAA plays an important

role in the Everglades water supply, either directly through agricultural drainage runoff or

indirectly by serving as a conduit for large water transfer from Lake Okeechobee to the Water

Conservation Areas (WCAs). The primary mode of drainage in the EAA is by groundwater

flow, which may be by capillary action through the organic soils, or through fractures in the

marl-soil interface. On-farm water management is achieved by using this groundwater flow and

the level in open field ditches to raise or lower the field water tables. Rainfall is highly seasonal

and frequently intense. Nearly all drainage discharge is achieved by pumping through high

volume, low head axial flow pumps. Drainage water from the EAA, after treatment in Storm

Treatment Areas, is ultimately discharged to the downstream WCAs, Everglades National Park

(ENP), or the South Florida coastal estuaries. Agricultural drainage waters discharged from the

EAA are nutrient-enriched compared to the original flow under which the Everglades evolved.

The EAA basin as a whole is required by the Everglades Forever Act (1994) to achieve P load

reductions of 25% or greater relative to a baseline P load average (derived from 1979 to 1988

monitoring data). Since January 1, 1995, BMP implementation has been mandatory for all farms

that discharge drainage water into SFWMD conveyance canals. The SFWMD monitors EAA


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basin P loads via a network of monitoring stations, i.e. pump stations and structures that border

the EAA. During the fourteen years since BMP program initiation, the EAA basin‟s annual P

load reduction has averaged nearly 50% (SFWMD, 2010). Everglades Agricultural Area farmers

employing BMPs incur additional costs.

Further reductions in farm P loads can be achieved by targeting sediment generation and

transport in the canals to reduce particulate P in the drainage water. Particulate P comprises 40-

60% of the P loads out of EAA farms (Stuck, 1996, Daroub et al., 2005). A major portion of the

particulate P in EAA farm canals originates from in-stream biological growth rather than from

soil erosion (Stuck, 1996, Daroub et al., 2005). Particulate P that contributes significantly to farm

P export has been determined to be, for the most part, recently deposited biological material such

as settled plankton, filamentous algae, and macrophyte detritus. There are several sediment

control practices in the SFWMD-EAA BMP table from which EAA farmers are able to choose

and employ on their farms. One of the sediment control practices is the control of aquatic

vegetation in farm canals. In addition, many growers control to varying degrees the growth of

FAV in their canals. However this practice is seldom claimed on BMP permits because there is

inadequate scientific knowledge regarding its efficacy and implementation methods.

Limiting the growth of floating aquatic vegetation (FAV) in farm canals is a practice that has the

known benefit of improvement in the conveyance of drainage and irrigation waters throughout

the farm. Control of FAV may lead to further reductions in farm P loads by changing the

physical and chemical properties, and transportability of sediments. It is hypothesized that with

better light penetration into canal waters more P may be co-precipitated with Ca and Mg

carbonates and form cohesive sediments that are less likely to be re-suspended and transported

off the farm during drainage events. Production of the less transportable and less labile sediments


8

should result in decreased farm loads Reduced P loads from EAA sub-basins should improve the

performance of STAs, especially those STAs performing at less than expected reduction levels.

This study will quantify changes in sediment composition and drainage water P speciation in

EAA sugarcane farms. It will determine changes in the composition of the P species in canal

waters and overall total P loads as influenced by treatment. This report focuses on the activities

conducted by the IFAS/UF during the time period from July 2009 to June 30th

, 2010 for the

scope of work (SOW) entitled “Implementation and Verification of BMPs to Reduce Everglades

Agricultural Area Farm P Loads – Floating Aquatic Vegetation Impact on Farm P load”. The

objectives of the SOW are:

1. Evaluate FAV management practices in the Everglades Agricultural Area farm canals

for impact on farm drainage water phosphorus load.

2. Evaluate the effect FAV management practices on P speciation of farm drainage

water and on accumulated sediments‟ physico-chemical properties.

3. Use the information from the research for the development of a BMP for managing

FAV to reduce farm P loads. The goal is to provide growers an additional tool in their

efforts to reduce off-farm P loading in the Everglades Agricultural Area.

II. Activity A: EAA Farm Canal Survey

Activity A is defined and stated under Task 1- Research the Impact of FAV in EAA Farm Canals

on Farm P Load- in the approved BMP research SOW: “before final cooperator farms can be

selected, an initial survey of EAA farms is proposed. The survey will provide researchers a

representative range of farm canal characteristics and FAV biomass for farms within a sub-

basin. Eight or more farms in each sub-basin will be selected and visited to obtain information


9

on canal dimensions and layout, estimated average and maximum flow velocities, prevalent FAV

species coverage, FAV management strategies, sediment depths, visual observations of

sediments, canal cleaning schedules, average farm soil depth, and cropping history. Additional

data for drainage water P concentrations, drainage flow, and pumping to rainfall ratio will be

obtained from SFWMD’s BMP permit database. Data will be statistically analyzed to observe

trends and relationships among the farms.”

Rationale and Methods

The EAA has historically been delineated into six sub-basins according to the pump station

system that drained the EAA basin. The original six sub-basins can be reduced to four, since the

pump stations along Lake Okeechobee serve now primarily as irrigation inflow structures to the

EAA (Daroub et al., 2008). The four sub-basins, S-5A, S-6, S-7, and S-8 correspond to outflow

structures that line the south and east periphery of the EAA basin. Nine farms in each of the four

sub-basins were selected to be surveyed according to their sizes: 3 large farms (>1900 acres), 3

medium farms (640-1900 acres), 3 small farms (<640 acres). The purpose of the surveys was to

provide researchers a representative range of farm canal characteristics and floating aquatic

vegetation (FAV) species distribution within a sub-basin. Accumulation of sediments within the

farm canals is a product of the drainage effluent exiting the surrounding farmlands. Average and

maximum flow velocities were estimated by the difference in volumetric rate (m3/s) change

within the canals between pumping and non-pumping periods. Additionally data for drainage

water P concentrations, unit area loads (UAL), and pumping to rainfall ratio (PTR) were also

obtained from SFWMD‟s BMP permit database.

Water depth was measured by a water column measuring pad. Sediment thickness within

individual canals was measured using a calibrated penetrometer and a water column measuring


10

pad. Three separate locations were selected within a single canal, and sediment thickness was

measured along a transect across the canal width. At each transect location two steel rebar were

installed at the edge of the water on each side of the canal. During surveying, a steel cable was

attached to the rebar to anchor a boat used during measurements. Measurements were recorded

at every 2 ft (0.61 m) interval along the transect. The measuring pad was used to record the depth

of the water column (in meters), while the penetrometer was used to record the depth of the

water column + sediment. The average thickness of sediment along each transect from all three

locations was reported as the thickness of the individual farm canal. The annual (2000-2009; 10

years) drainage water P concentrations, UALs, and PTR data were obtained from the SFWMD-

DBHYDRO database. The annual time period corresponds to the SFWMD Water Year (May 1st

to April 30th

).

Selected parameters of all farms surveys are presented using Box-whisker plots. Box plots

provide a schematic graphical summary of important features of a distribution that include the

minimum and maximum range values, upper and lower quartiles, mean and median. This

collection of values is a quick way to summarize the distribution of a dataset. Box plots partition

a data distribution into quartiles, that is, four subsets with equal size. A box is used to indicate

the position of the upper and lower quartiles; the interior of the box indicates the inter-quartile

range, which is the area between the upper and lower quartiles and consists of 50% of the

distribution. Lines, also called whiskers, are extended to the minimum and maximum values in

the dataset. Outliers are represented individually by „ο‟ symbols. The box is intersected by a

crossbar drawn at the median of the data set. The mean is represented by a „◊‟ sign.


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Sediment and Canal Measurements

Summary statistics in the box-whisker plots of sediment thickness (m) of nine selected farms in

each of the four EAA sub-basins are shown in Figure 1. Mean sediment thickness was uniform

across farms surveyed in the sub-basins, ranging from a low of zero for all sub-basins, to 2.5 m

in S5A, 1.8 m in S6, 1.9 m in S7, and 1.8 m in S8 sub-basin. Mean sediment thickness was 0.63

m for the small farms, 0.54 m for the medium farms and 0.48 m for the large size farms (Figure

2A). Sediment thickness for the selected surveyed farms according to farm size in each of the

sub-basins is shown in Figure 2B.

Figure 1. Box-whisker plot of canal sediment thickness (m) of nine selected farms in each of the

EAA sub-basins (S5A, S6, S7, S8).


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Figure 2. Box-whisker plot of canal sediment thickness (m) of selected farms in EAA basin (A) and

EAA sub-basins (B) based on farm size.

B

A


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Table 1. Summary surveys of nine selected farms in each of the sub-basins S5A, S6, S7, and S8

including sediment thickness, water depth, and canal width

Sub-basin Sediment thickness (m) Water depth (m) Canal width (m)

mean STD† mean STD mean minimum maximum

S5A 0.59 0.20 0.82 0.43 6.9 3.0 9.8

S6 0.56 0.08 1.05 0.60 9.0 3.4 17.7

S7 0.58 0.12 1.24 0.75 7.0 3.1 9.8

S8 0.48 0.06 0.94 0.60 8.8 4.3 17.1

Overall 0.55 0.44 1.01 0.62 8.0 3.1 17.7

†STD= standard deviation

Drainage Water P Concentrations

Flow-weighted total phosphorus (FWTP) concentrations distribution for ten years of 36

surveyed farms in the EAA sub-basins are presented in Figure 3. Flow-weighted total

phosphorus concentrations ranged from a low of zero mg/l in S5A and S8 farms to a high of 2.0

mg/l in S6 farms (values greater than 1.0 mg/l were trimmed in SAS for better representation of

results). Sub-basin S5A surveyed farms had the largest mean and median FWTP concentrations

of 0.28 and 0.17 mg/l respectively, whereas S7 sub-basin farms had the lowest mean and median

FWTP concentrations of 0.11 and 0.09 mg/l respectively. Large size farms of the EAA basin

had mean FWTP concentrations of 0.13 mg/l, whereas small size farms had mean FWTP

concentrations of 0.20 mg/l (Figure 4,A-B).


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Figure 3. Box-whisker plot of FWTP (mg/l) of selected farms in four EAA sub-basins based on the

10 years of datasets obtained from the DBHYRO database. (Values, n=4, greater than 1.0 mg/l were

trimmed in SAS for the better representation of results).


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Figure 4. Box-whisker plots of FWTP (mg/l) of selected farms in EAA basin based on farm sizes: A.

Overall distribution of FWTP, B. sub-basin wise distribution of FWTP (values, n=4, greater than

1.0 mg/l were trimmed in SAS for the better representation of results).

A

B


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Unit Area P Loads

The selected surveyed farms in the S5A sub-basin showed the highest P loads (Water year UAL)

and wide variability ranging from 0 kg/ha to 25.6 kg/ha (Figure 5). The mean UAL of 2.1 kg/ha

was at S5A, followed by a mean value of 1.3 kg/ha at S6. The S7 farms had the lowest mean

UAL of 0.76 kg/ha, with a maximum value of 4.0 kg/ha. The mean UAL for the small size farms

was 1.5 kg/ha, whereas the mean UAL of the medium and large size farms were 1.0 and 1.2

kg/ha respectively (Figure 6A). Comparing the UAL of amongst the various farm sizes of EAA-

sub basins, small size farms of S5A, S7, and S8 sub-basins showed the highest variability,

followed by medium and small size farms of S6 sub-basin (Figure 6B). Field water tables in

small farms would appear to be more susceptible to seepage from surrounding farms and

adjoining water conveyance canals. Depending upon the small farm‟s relative elevation to the

surrounding topography, this could lead to high drainage unit area volume and high UAL from

small farms. In addition, small farms may not have the flexibility of storing the water on farm

and may have less capacity to adjust water tables across the farm.


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Figure 5. Plot of unit area P load (UAL) of total-P for 36 surveyed farms in the EAA during 2000-

2009. UAL values >10 kg/ha (n=3) were trimmed in SAS.


18

Figure 6. Box-whisker plots of unit area P load (UAL; kg/ha) of selected farms in EAA basin based

on farm sizes: A. Overall distribution of UAL, B. sub-basin wise distribution of UAL (kg/ha)

(values, n=3, greater than 10 kg/ha were trimmed in SAS for the better representation of results).

A

B


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Pump to Rainfall Ratios

Pump to rainfall ratio is the ratio between rainfall recorded at a location in a farm and the volume

of water pumped off the farm as drainage. There appeared to be little differences in pump to

rainfall ratios between basins (Figure 7). The nine selected farms in the S6 sub–basin appeared to

have more outlier values and skewed distribution. No obvious differences were noted between

farm size for pump to rainfall ratio. Individual box plots by farm size and sub basin are presented

in Figure 8.

Figure 7. Plot of pump to rainfall ratio of nine selected farms in each of the EAA sub-basins

obtained from the DBHYRO database for wateryear 2000-2009.


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Figure 8. Box-whisker plots of pump to rainfall ratio (PTR) of selected farms in each of the EAA

basin based on farm sizes: A. Overall distribution of PTR, B. sub-basin wise distribution of PTR.

A

B


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Prevalent FAV Species

Most of the main farm canals had minimum FAV infestation at the time of observation (early

spring). The dominant species of FAVs that were observed were water lettuce, water hyacinth,

torpedo-grass, filamentous algae, and alligator weed. Late spring surveyed farms had thicker

coverage of FAV, with most of it confined to the canal edges.

Figure 9. Water lettuce growing in the farm canals

Figure 10. Mix of recently controlled floating aquatic weed species


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III. Activity B: Farm Pair Selection

The following provides the justification and analyses used to select the farm pairs for monitoring

for the Best Management Practice (BMP) research project identified in the Scope of Work

(SOW) of the Everglades Agricultural Area Environmental Protection District (EAA-EPD).

Farm pair selections for the research study are required to be submitted for approval by the

SFWMD as stated in the SOW letter of approval dated January 11, 2010. The approval letter

states, “Prior to installation of the monitoring equipment in each farm (Task 1.03) a report with

the proposed eight farms and justification for the pairing shall be submitted to the District for

approval.” This report serves as justification for farm pair selections and was submitted to fulfill

the requirements of the SOW and its accompanying approval letter. According to the SOW four

farm pairs, two each in the S5A and S6 sub basins, are to be selected for the BMP research study.

Criteria for farm pairing as stated in the SOW include:

1. farm size between 640 to 1280 acres with a single exit pump station,

2. similar dimensions of main farm canals,

3. similar land use and cropping history,

4. total P loads from the regulatory database on a monthly or biweekly basis demonstrate

a significant regression relationship of the paired farms, and the residual errors of this

regression are smaller than the expected BMP effect (USEPA, 1993),

5. same irrigation source canal,

6. willingness of the grower to cooperate and incur extra cost for likely need to remove

canal sediments and mechanical harvesting of floating aquatic vegetation at start of

experiment.

Methodology

The pool of candidate farms for each sub-basin was limited. Nine farms from a pool of ten farm

basins were identified as suitable candidates in the S5A sub-basin. In the S6 sub-basin sixteen

farm basins fit the selection criteria for farm size; only eight of the farms were suitable

candidates for the study.


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Before initiating statistical analyses, daily farm basin data (total P concentration, flow, and

rainfall) from the SFWMD BMP permit database were compiled by monthly and biweekly time

intervals and unit area loads (UAL) of phosphorus and unit area drainage volumes (UAV) were

calculated. Distributions of monthly and biweekly unit area loads (UAL) were non-normal. Log

transformations were completed and resulting distributions of transformed data were normal for

most of the farm basins (USEPA, 1997). Two exceptions were farm basin I for both biweekly

and monthly UAL and farm basin A for monthly UAL.

Pearson correlation analyses were conducted on monthly and biweekly log transformed UAL for

farms that met the initial selection criteria of farm size and single exit pump station. After

potential farms were identified and correlation analyses on farm UAL were conducted, IFAS

researchers met with the IFAS Water Resources and BMP advisory committee on January 29,

2010 to select and recommend the best candidate farm pairs. Potential farm basin

growers/owners were contacted and visited by Tim Lang and/or Samira Daroub to check on

suitability of their farm for the study and the willingness of the grower to cooperate for the

duration of the five-year study. The visits were conducted February to April 2010.

Regression analyses were conducted for each farm pair on both the monthly and biweekly data

sets. Regression analyses were programmed in SAS using the PROC REG procedure (SAS,

2008). Rainfall at both the independent and dependent stations was tested in the regression

models. Rainfall at the independent stations was not found to be significant. Rainfall at the

dependent farm basin of a farm pair was included as a covariate in the regression analyses.

Regression results were included in calculations to determine if the duration of the study was

adequate to detect UAL differences after treatment imposition. Hypothetical UAL differences of


24

10, 15, and 20 percent between control and treatment farms were tested using the means and root

mean square errors of regression results from both monthly and biweekly data sets (USEPA,

1993).

Farm Pair Descriptions

Four farm pairs were selected, two pairs in each sub-basin (Figure 11). Farm pair 1 is located in

the S5A sub basin; both farms are adjacent to the West Palm Beach canal approximately 12

miles from S-352. Farm basin A is a 908 acre sugarcane farm with a single pump station that

discharges into the West Palm Beach canal. Farm basin B is an 824 acre sugarcane farm adjacent

to Farm basin A; it also discharges from a single pump station into the West Palm Beach canal.

Biweekly plots of UAL and UAV for farm pair 1 are presented in Figures 12 and 13.

Farm pair 2 consists of two farm basins in the S5A sub-basin, both discharge drainage water

directly to the West Palm Beach canal. Farm basin D is a sugarcane farm of 709 acres that is

located approximately 7 miles from S-352 on the West Palm Beach canal; farm basin C is a

sugarcane farm of 1285 acres located 10 miles down the West Palm Beach canal from S-352.


Farm pair 3 is located in the S6 sub-basin near its northern edge. Farm basin E is a 640 sugarcane

farm with a single discharge pump station that discharges into a secondary canal that feeds into

the larger district canal that runs north from Sam Center road, and which eventually discharges

into the Ocean canal. Farm basin F is a 640 acre sugarcane farm which is located one-half mile

east of farm basin E; farm basin E also has a single pump station for drainage discharge.



25

Farm pair 4 is located in the S6 sub-basin just north of Airport road and Sam Center road. Farm

basin G is a sugarcane farm of 1387 acres located north of Airport road and west of the feeder

canal that runs parallel to Sam Center road. Farm basin H is a 602 acre farm that is located west

across the canal from farm basin G. Both farms have single exit drainage pump stations that

discharge into the feeder canal that parallels Sam Center road. Biweekly plots of UAL and UAV

for farm pair 4 are presented in Figures 18 and 19.

A fifth or alternate farm pair was provided in case one of the four farm pairs becomes

unavailable or unsuitable for inclusion in the study; the farms in the pair are located in the S6

sub-basin adjacent to the Hillsboro canal. Farm basin I is an 1185 acre sugarcane farm that is

located west and adjacent to the Hillsboro canal approximately half way between Lake

Okeechobee to the S6 pump station. Farm basin J is an 811 acre sugarcane farm that is located

east and across the Hillsboro canal from farm basin I. Biweekly plots of UAL and UAV for farm

pair 4 are presented in Figures 20 and 21.

Correlation Analysis Results

Pearson correlation analyses of the biweekly data set of candidate farm basins in the S5A and S6

sub-basins are presented in Tables 3 and 4. Several farms that had significant correlations with

other farms were unavailable for participation in the study. Several farm basins that did not have

drainage water total P data collected at their respective pump station, but rather used a collective

TP concentration for drainage discharge values, were not included in the analyses. Most farm

basins had significant correlations with other farms, but the correlation coefficients were low.

Potential farm pairs were identified by both physical proximity and significant correlation value;

farm pairs were then tested for a significant UAL relationship using regression analysis.


26

Regression Analysis Results

Results of the regression analyses of UAL for the five farm pairs at the monthly and biweekly

time interval are presented in Table 5. Farm pair 2 did not have a significant relationship for

UAL at the monthly time period. All other farm pairs had significant regression relationships for

UAL at the biweekly and monthly time periods.

Means and root mean square errors from the regression analyses were included in an analysis to

determine if the duration of the baseline and treatment periods would provide sufficient

observations to detect differences between control and treatment farm loads at the 10, 15, and 20

percent of the mean load values (Table 6; USEPA, 1993). The equation to test the duration of

control and treatment period is based on comparing the ratio of residual variance (s2) and the

smallest worthwhile difference (d2) with the value to the right side of equation 1:

S2

xy/d2 = (n1n2/n1+n1)(1/(F(1+(F/(n1+n2-2))))) Equation 1

Where n1 and n2 are numbers of observations in the calibration and treatment periods

respectively; and F is the table value for (p = 0.05) at 1 and (n1 + n2 – 3) degrees of freedom.

Estimates of observations per year (biweekly and monthly time periods with drainage loads > 0)

were derived using farm data from the BMP permit database.

At the biweekly time scale, all farms would be able to detect a 15 percent difference with a two-

year baseline period followed by a three-year treatment period. It is assumed that with improved

water and flow measurement that the research study instrumentation will provide, the root mean

square error will be reduced and the regression UAL relationships will be improved sufficiently.

This should allow for more accurate testing of treatment differences. In addition, UAL


27

relationships will be also be tested for individual drainage events which are expected to provide

better regression relationships than those based on a monthly or biweekly time interval.

Summary

Four farm pairs were identified that met the research SOW criteria for inclusion in the five-year

BMP research study. A fifth farm pair was included as an alternate choice in event that one of

the pairs was determined to be unsuitable or unavailable for the research study.


28

Figure 11. Location of the selected farm basins.

WCA 1

WCA 2WCA 3

Lake

Okeechobee

Bolles Canal

STA-1W STA-1E

S8 S7

S-2

S5AS3

STA-6

STA-5STA-3/4

STA-2Holey Land

Ro

ten

be

rge

r

S6

C

S352

S2

0 10 205 Kilometers

J

D

F

E AB

I

GH


29

Table 2. Shapiro-Wilk normality test results for transformed monthly and biweekly unit area P

load (UAL).

Time

Interval

Obs.

(n) W value

P value

Pr < w

Farm Basin A

Biweekly 147 0.9901 0.3945

Monthly 126 0.9777 0.0359

Farm Basin B

Biweekly 136 0.9819 0.0908

Monthly 127 0.9935 0.8341

Farm Basin C

Biweekly 116 0.9881 0.4100

Monthly 107 0.9913 0.7352

Farm Basin D

Biweekly 91 0.9793 0.1573

Monthly 105 0.9874 0.4347

Farm Basin E

Biweekly 125 0.9910 0.6023

Monthly 98 0.9855 0.3609

Farm Basin F

Biweekly 105 0.9839 0.2384

Monthly 88 0.9934 0.9454

Farm Basin G

Biweekly 161 0.9938 0.7384

Monthly 131 0.9917 0.6374

Farm Basin H

Biweekly 187 0.9949 0.7890

Monthly 152 0.9854 0.1099

Farm Basin I

Biweekly 158 0.9806 0.0257

Monthly 115 0.9675 0.0068

Farm Basin J

Biweekly 192 0.9907 0.2537

Monthly 128 0.9838 0.1322


30

Table 3. Biweekly unit area P load (UAL) correlation analysis of candidate farms in the S5A sub-

basin.

Farm a UAL0401 UAL1301 UAL1812 UAL1813 UAL2501 UAL3801 UAL5402 UAL5403 UAL5903

UAL0401 b

1

-

190 c

UAL1301

0.05649 1

0.5826 -

97 130

UAL1812

0.32264 0.16469 1

<.0001 0.0856 -

174 110 247

UAL1813

0.45077 0.15469 0.53589 1

<.0001 0.1066 <.0001 -

179 110 213 246

UAL2501

0.42656 0.14079 0.50279 0.6694 1

<.0001 0.1857 <.0001 <.0001 -

142 90 150 154 163

UAL3801

0.33762 0.40828 0.26025 0.3269 0.41943 1

<.0001 0.0002 0.0023 <.0001 <.0001 -

130 81 135 142 115 226

UAL5402

0.45405 0.25335 0.50572 0.60965 0.70453 0.42803 1

<.0001 0.0294 <.0001 <.0001 <.0001 <.0001 -

140 74 161 156 122 116 180

UAL5403

0.11125 -0.03821 0.45082 0.35266 0.24935 0.15295 0.36642 1

0.2729 0.7859 <.0001 0.0002 0.0191 0.1728 0.0004 -

99 53 103 110 88 81 91 114

UAL5903

0.3929 0.14879 0.25461 0.45337 0.37088 0.22907 0.37458 -0.00418 1

<.0001 0.1569 0.001 <.0001 <.0001 0.0093 <.0001 0.9674 -

156 92 165 172 135 128 132 98 188 a Abbreviated farm ID, eg, 0603 = 50-006-03 b UAL = monthly unit area load of phosphorus (log transformed data) c Number of observations per correlation


31

Table 4. Biweekly unit area P load (UAL) correlation analysis of candidate farms in S6 sub-basin.

Farm a UAL0603 UAL3102 UAL3103 UAL4701 UAL4702 UAL4801 UAL5101 UAL5502

UAL0603 b

1

-

212 c

UAL3102

0.37701 1

<.0001 -

194 464

UAL3103

0.4411 0.57194 1

<.0001 <.0001 -

110 289 344

UAL4701

0.07576 0.66688 0.58101 1

0.4987 <.0001 <.0001 -

82 180 103 202

UAL4702

0.23526 0.57656 0.35627 0.505 1

0.0553 <.0001 0.0008 <.0001 -

67 144 86 146 166

UAL4801

0.39761 0.38923 0.44433 0.32106 0.37599 1

<.0001 <.0001 <.0001 <.0001 <.0001 -

96 180 116 174 142 250

UAL5101

0.37649 0.38436 0.27366 0.16213 0.3825 0.51244 1

<.0001 <.0001 <.0001 0.0306 <.0001 <.0001 -

176 362 255 178 144 216 498

UAL5502

0.38939 0.36311 0.56265 0.51738 0.33189 0.55059 0.22647 1

0.0002 <.0001 <.0001 <.0001 <.0001 <.0001 0.0025 -

85 176 98 162 134 170 176 198 a Abbreviated farm ID, eg, 0603 = 50-006-03 b UAL = monthly unit area load of phosphorus (log transformed data) c Number of observations per correlation


32

Figure 12. Farm pair 1 biweekly unit area load (UAL) of total phosphorus.

0

100

200

300

400

500

600

700

800

900

1,000

Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-09

UA

L (g

P h

a-1)

UAL Farm A (S5A)

0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1)

UAL Farm B (S5A)


33

Figure 13.. Farm pair 1 biweekly unit area volume (UAV).

0

50

100

150

200

250

300

350

400


UA

V (m

m h

a-1)

UAL Farm A (S5A)

0

50

100

150

200

250

300

350

400


UA

V (

mm

ha-1

)

UAL Farm B (S5A)


34


0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1)

UAL Farm C (S5A)

0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1)

UAL Farm D (S5A)


35

Figure 15. Farm pair 2 biweekly unit area volume (UAV).

0

50

100

150

200

250

300

350

400


UA

V (m

m h

a-1)

UAL Farm C (S5A)

0

50

100

150

200

250

300

350

400


UA

V (

mm

ha-1

)

UAL Farm D (S5A)


36


0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1)

UAL Farm E (S6)

0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1)

UAL Farm F (S6)


37


0

50

100

150

200

250

300

350

400


UA

V (m

m h

a-1)

UAL Farm E (S6)

0

50

100

150

200

250

300

350

400


UA

V (

mm

ha-1

)

UAL Farm F (S6)


38


0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1

)UAL Farm G (S6)

0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1

)

UAL Farm H (S6)


39


0

50

100

150

200

250

300

350

400


UA

V (m

m h

a-1

)UAL Farm G (S6)

0

50

100

150

200

250

300

350

400


UA

V (m

m h

a-1

)

UAL Farm H (S6)


40

Figure 20. Alternate farm pair biweekly unit area load (UAL) of total phosphorus.

0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1)

UAL Farm I (S6)

0

100

200

300

400

500

600

700

800

900

1,000


UA

L (g

P h

a-1)

UAL Farm J (S6)


41

Figure 21. Alternate farm pair biweekly unit area volume (UAV).

0

50

100

150

200

250

300

350

400


UA

V (m

m h

a-1)

UAL Farm I (S6)

0

50

100

150

200

250

300

350

400


UA

V (

mm

ha-1

)

UAL Farm J (S6)


42

Table 5. Monthly and biweekly regression analysis of farm pair unit area load (UAL).

Time

Interval

Obs

(n) Intercept UALab Rainb RMSEc Adj R2

Pair 1: Farms A and B

Monthly 114 0.6007 0.5327 ns 0.4416 0.261

Biweekly 108 0.9428 0.3003 0.0015 0.3876 0.241

Pair 2: Farms C and D

Monthly 64 1.3033 ns 0.0775 0.5138 0.288

Biweekly 92 0.7305 0.3449 0.0036 0.5474 0.285

Pair 3: Farms E and F

Monthly 59 0.4441 0.5091 0.0325 0.4357 0.408

Biweekly 94 0.6843 0.4344 0.0021 0.4581 0.346

Pair 4: Farms G and H

Monthly 127 -0.0150 0.8773 0.0264 0.3723 0.589

Biweekly 154 0.9916 0.4444 0.0031 0.4510 0.374

Alt Pair: Farms I and J

Monthly 83 0.6398 0.3539 0.0829 0.3623 0.576

Biweekly 146 0.8920 0.2976 0.0050 0.4289 0.445

a UAL = Unit Area P Load, kg P a-1 (log transformed). b Significant regression coefficient of determination (r2) at P value = 0.001. c RMSE = root mean square error.

Table 6. Monthly and biweekly analysis for detecting differences at the 10, 15, and 20 percent levels.

Note: values in blue text signify adequate duration to detect differences at the respective levels.

ParameterPair 1 UAL

Monthly

Pair 2 UAL

Monthly

Pair 3 UAL

Monthly

Pair 4 UAL

Monthly

Alt Pair UAL

Monthly

s (RMSE with rain covariate) 0.441 0.513 0.435 0.372 0.362

mean 1.420 1.806 1.49 1.860 1.540

d (10% of mean ) 0.142 0.181 0.149 0.186 0.154

Left = s2/d

2 (to detect 10% mean difference) 9.64 8.03 8.52 4.00 5.53

Left = s2/d


Left = s2/d


N1 = number of baseline months 20 20 20 20 20

N2 = number of treatment months 30 30 30 30 30

F value at 1 and N1 + N2 - 3df 4.06 4.06 4.06 4.06 4.06

Right 2.73 2.73 2.73 2.73 2.73

ParameterPair 1 UAL

Biweekly

Pair 2 UAL

Biweekly

Pair 3 UAL

Biweekly

Pair 4 UAL

Biweekly

Alt Pair UAL

Biweekly

s (RMSE with rain covariate) 0.387 0.474 0.458 0.451 0.428

mean 1.661 2.051 1.680 2.173 1.730

d (10% of mean ) 0.166 0.205 0.168 0.217 0.173

Left = s2/d


Left = s2/d


Left = s2/d


N1= number of baseline biweeks 40 40 40 40 40

N2 = number of treatment biweeks 60 60 60 60 60

F value at 1 and N1 + N2 - 3df 3.94 3.94 3.94 3.94 3.94

Right 5.86 5.86 5.86 5.86 5.86


44

IV. BMP Education and Extension Services

Best Management Practices (BMP) workshops have been designed by UF/IFAS faculty to cover

all major areas of the BMP program to insure uniform and successful implementation by EAA

growers. The topics covered includes a review of Rule 40E-63, BMPs for Atrazine and Ametryn,

floating aquatic weed control, BMP table overview, soil testing and plant tissue analysis,

fertilizer application BMPs, rainfall detention, sediment control, and latest research findings.

Three BMP training workshops were conducted from the period of July 1st, 2009 – June 30

th,

2010 with a total of 173 participants from all major companies in the EAA as well as different

agencies including DOACS, USDA-NRCS, PBSWCD, USDA-ARS, and SFWMD. Each

workshop lasted four at least four hours.

Workshop 1. September 22, 2009: 70 participants

Workshop 2. September 24, 2009: 64 participants

Workshop 3. April 22, 2010: 39 participants

BMP Training workshop overview (April 22, 2010):

Overall we received a very favorable response to the BMP training workshop that was held on

April 22, 2010. Out of the 39 participants 29 responded to the surveys. 56% of the surveyors

found that the usefulness of the BMP information was excellent, 37% found it very good and 7%

found it good. 48% of the surveyors found that the speakers that were present were excellent,

38% found them very good, while 14% found them good. Overall, 36% surveyors found the

training material excellent, 61% found it very good, while only 3% found it good. Table 7

represents a summary of the type of questions asked in the survey and their corresponding

responses.


45

Table 7. Survey results from a general BMP training workshop held on April 22, 2010.

Excellent Very Good Good Average Fair Abstain

Usefulness of the BMP information. 15 (56%) 10 (37%) 2 (7%) - - -

The speakers were effective during the training. 14 (48%) 11 (38%) 4 (14%) - - -

Rating of the training material. 10 (36%) 17 (61%) 1 (3%) - - -

Suggestion for improvement.

None

12 (43%)

Add New Topics

2 (7%)

Shorten Training

-

- - Abstain

14 (50%)

New topics that you would like in the future. Explain More Point system

-

Information on Sulfur

-

Water Table Research

-

- None

12 (46%)

Abstain

14 (54%)

Strongly Disagree

Disagree Neutral Agree Strongly Agree

-

The information provided helped me to be aware of the importance of field BMP documentation

1 (3%) 12 (41%) 16 (55%)

The information helped me to better understand the effect of sediments on water quality

1 (3%) 13 (45%) 15 (52%)

The information provided during the BMP training was easy to understand

1 (3%) 19 (66%) 9 (31%)

The information provided during the BMP training was accurate and up-to-date

1 (3%) 2 (7%) 20 (69%) 6 (21%)

All of my questions were adequately answered during the BMP training

1 (3%) 18 (62%) 10 (34%)

Overall, the training is an important educational tool of the BMP program in the EAA and I would recommend it to others

1 (3%) 10 (34%) 18 (62%)


46

Mr. Les Baucum presenting safe use of

Atrazine and Ametryn (04.22.10)

Participants attending the BMP training

workshop at UF-EREC (04.22.10)


47

V. List of Current Publications

Daroub, S. H., Van Horn, S., Lang, T. A., Diaz, O. A. 2010. Long-Term Water Quality Trends in

the Everglades Agricultural Area. GEER symposium proceedings, In Press.

Daroub, S. H, Lang, T. A., Diaz, O. A., Grunwald, S. 2009. Long-term Water Quality Trends

after Implementing Best Management Practices in South Florida. J. Environ. Qual. 38:1683-

1693.

Grunwlad, S., Daroub, S. H., Lang, T. A., and Diaz, O. A. 2009. Tree-based Modeling of

Complex Interactions of Phosphorus Loadings and Environmental Factors”. Sci. of the Total

Environ. 407:3772-3783.

Kwon, H. Y, Grunwald, S., Beck, H. W., Jung, Y., Daroub, S. H., Lang. T. A., Morgan, K. T.

2010. Modeling of Phosphorus Loads in Sugarcane in a Low-Relief Landscape Using Ontology-

based Simulation. J. Env. Qual. In Press.

Kwon, H. Y, Grunwald, S., Beck, H.W., Jung, Y., Daroub, S. H., Lang. T. A., Morgan, K. T.

2010. Ontology based Simulation of Water Flow in Organic Soils Applied to Florida Sugarcane.

Agric. water manag. 97:112-122.

Lang, T. A., Oladeji, O, Josan, M. and Daroub, S. H. 2010. Environmental and management

factors that influence drainage water P loads from Everglades Agricultural Area farms of South

Florida Research Paper. Agric. Ecosys. Environ. In Press.


48

VI. Literature Cited

Daroub, S.H., T.A. Lang, O.A. Diaz, M. S. Josan. 2008. Annual Report submitted to Florida

Department of Environmental Protection. Everglades Research and Education Center.

Institute of Food and Agricultural Sciences. University of Florida. July 2008.

Daroub, S.H., T.A. Lang, O.A. Diaz, M. Chen, and J.D. Stuck. 2005. Annual Report submitted to

Florida Department of Environmental Protection. Everglades Research and Education

Center. Institute of Food and Agricultural Sciences. University of Florida. June 2005.

FDACS. 2004. Florida department of consumer services annual report. http://www.florida-

agriculture.com/pubs/pubform/pdf/FDACS_Annual_Report_2004.pdf.

Stuck, J.D. 1996. Particulate phosphorus transport in the water conveyance systems of the

Everglades Agricultural Area. Ph.D. dissertation submitted to the University of Florida

Department of Agricultural and Biological Engineering, Gainesville, Fla.

McBride, G. B. 2005. Using statistical methods for water quality management, Issues, problems

and solutions. Wiley Interscience, John Wiley & sons, New Jersey.

SAS Institute, 2008. SAS system for Windows. Version 9.2. SAS Institute, Cary, NC.

SFWMD. 2010. South Florida Environmental Report. South Florida Water Management District,

West Palm Beach, FL.

USEPA. 1993. Paired watershed study design. USEPA Fact Sheet 841-F-93-009.

USEPA, 1997. Linear regression for nonpoint source pollution analyses. USEPA Fact Sheet 841-

B-97-007.

http://www.florida-agriculture.com/pubs/pubform/pdf/FDACS_Annual_Report_2004.pdf

http://www.florida-agriculture.com/pubs/pubform/pdf/FDACS_Annual_Report_2004.pdf


49

Samira Daroub

University of Florida/IFAS

Everglades Research and Education Center

Belle Glade, FL 33430 | T: (561)-993-1500| [email protected]

http://erec.ifas.ufl.edu

mailto:[email protected]

Documents

Implementation and Verification of BMPs for Reducing P ...erec.ifas.ufl.edu/media/erecifasufledu/docs/pdf/soil-water-sci-reports/UF-IFAS...UF/IFAS Annual Report July 9, 2010 6 I. Introduction