Implementation and Verification of BMPs for Reducing P Loading from the Everglades Agricultural Area:

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1 Implementation and Verification of BMPs for Reducing P Loading from the Everglades Agricultural Area: Floating Aquatic Vegetation Impact on Farm Phosphorus Load 2012 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 July 2012

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3 Acknowledgments This project is primarily funded by the Everglades Agricultural Area (EAA) Environmental Protection District, a special district representing landowners within the EAA Basin, that was created for the purpose of ensuring environmental protection by means of conducting scientific research on environmental matters related to air and water and land management practices and implementing the financing, construction, and operation of works and facilities designed to prevent, control, abate or correct environmental problems and improve the environmental quality in the EAA. 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 and to the continuing excellent results of the EAA basin s BMP program. This project is also supported by the Florida Agricultural Experiment Station. 3

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5 Project Personnel Name Samira Daroub, PhD Timothy Lang, PhD Manohardeep Josan, PhD Jehangir Bhadha, PhD Vivianna Nadal, MS Irina Ogelvich, BS Suzanna Gomez, BS Michael Korbly, AA Title Principal Investigator Project Manager QA/QC Officer and Lead Scientist Lead Scientist Head Chemist Chemist Grad Student/Laboratory Technician Field and Laboratory Technician Abbreviations BMP DDb WDb DOP EAA ENP EPA EPD EREC FAV FLREC IFAS LOI OM PP SAV SFWMD SOP SRP STA TDP TP TSS UF WCA Best Management Practice Dry Bulk Density Wet Bulk Density Dissolved Organic Phosphorus Everglades Agricultural Area Everglades National Park Environmental Protection Agency Environmental Protection District Everglades Research and Education Center Floating Aquatic Vegetation Fort Lauderdale Research and Education Center Institute of Food and Agricultural Sciences Loss on Ignition Organic Matter Particulate Phosphorus Submerged Aquatic Vegetation South Florida Water Management District Standard Operating Procedure Soluble Reactive Phosphorus Stormwater Treatment Area Total Dissolved Phosphorus Total Phosphorus Total Suspended Solids University of Florida Water Conservation Area 5

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7 Table of Contents Acknowledgments... 3 Project Personnel... 5 Abbreviations... 5 Summary Introduction Farm Descriptions Farm Canal Sediment Surveys Materials and Methods Results Physical and Chemical Characterization of Canal Sediments Sediment Analyses Results Floating Aquatic Vegetation: Speciation, Coverage and TP Content FAV Sampling Procedure and Analyses Results Assessment of FAV in Farm Canal Pairs Water Quality Monitoring Water Sampling Procedures Laboratory Analyses Ambient Farm Canal Water Monitoring Results Farm Canal In Situ Monitoring Farm Canal In Situ Monitoring Results Farm Drainage Water BMP Training Workshops References Appendix List of Appendix Tables List of Appendix Figures

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9 List of Tables Table 1. Summary of farm canal sediment depths in meters surveyed in November Table 2. Physical and chemical properties of sediments collected on November 2011 from the eight farms Table 3. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for May Table 4. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for June Table 5. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for August Table 6. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for October Table 7. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for January Table 8. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for April Table 9. Summary statistics of phosphorus species concentrations of ambient canal waters for farm pairs in S5A sub-basin from November 2010 through April Table 10. Summary statistics of phosphorus species concentrations of ambient canal waters for farm pairs in S6 sub-basin from November 2010 through April Table 11. Summary statistics of ambient canal water ph, calcium, and total suspended solids for S5A and S6 sub-basin farm pairs from November 2010 to April Table 12. Summary statistics of hourly in situ water quality measurements collected from October 2011 through April Table 13. Summary statistics of drainage water phosphorus concentrations of farm pairs in the S5A sub-basin from November 2010 through April Table 14. Summary statistics of drainage water phosphorus concentrations of farm pairs in the S6 sub-basin from November 2010 through April Table 15. Summary statistics of drainage water ph, calcium, and total suspended solids in S5A and S6 basin farms from November 2010 to April Table 16. Spearman correlation coefficients of biweekly farm drainage data Table 17. Speakers, affiliations, and presentations for BMP training workshops held in WY List of Photos Photo 1 Floating aquatic vegetation (duck weed) being collected from one of the farm canals.. 38 Photo 2. Datalogger, auto-sampler, refrigerator, and drainage water composite sample collection Photo 3. Orthophosphate (top) and total phosphorus (bottom) analyses being conducted on SEAL Auto Analyzer Photo 4. Calibration of Hydrolab MiniSonde left, and Ca analyses using atomic absorption spectrophotometer, right Photo 5. Images of selected speakers from BMP training sessions held at the EREC in September 2011 and April

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11 List of Figures Figure 1. Map of the Everglades Agricultural Area and farm locations Figure 2. Aerial map of farms 0401 and 2501 with pumphouse and canal transect locations Figure 3. Aerial map of farms 1813 and 6117 with pumphouse and canal transect locations Figure 4 Aerial map of farms 3102 and 3103 with pumphouse and canal transect locations Figure 5. Aerial map of farms 4701 and 4702 with pumphouse and canal transect locations Figure 6. Sediment profile of main canal of farm 0401 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water Figure 7. Sediment profile of main canal of farm 2501 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water Figure 8. Sediment profile of main canal of farm 1813 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water Figure 9. Sediment profile of main canal of farm 6117 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water Figure 10. Sediment profile of main canal of farm 3102 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water Figure 11. Sediment profile of main canal of farm 3103 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water Figure 12. Sediment profile of main canal of farm 4701 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water Figure 13. Sediment profile of main canal of farm 4702 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water Figure 14. Comparison of FAV in main canals of farms 3102 and (Left) Changes in mass of dried FAV and average TP concentration of FAV over time. (Right) Changes in percent FAV coverage and mass of P in FAV over time Figure 15. Comparison of FAV in main canals of farms 4701 and (Left) Changes in mass of dried FAV and average TP concentration of FAV over time. (Right) Changes in percent FAV coverage and mass of P in FAV over time Figure 16. Comparison of FAV in main canals of farms 0401 and (Left) Changes in mass of dried FAV and average TP concentration of FAV over time. (Right) Changes in percent FAV coverage and mass of P in FAV over time Figure 17. Comparison of FAV in main canals of farms 6117 and (Left) Changes in mass of dried FAV and average TP concentration of FAV over time. (Right) Changes in percent FAV coverage and mass of P in FAV over time Figure 18. Distribution of total P (TP) concentrations in canal water grab samples collected from November 2010 through April Figure 19. Ambient canal water average P speciation concentrations and percent total P by farm from November 2010 through April Figure 20. Distribution of total P (TP) concentrations in drainage water samples collected from November 2010 through April Figure 21. Drainage water average P speciation concentrations and percent of total P by farm from November 2010 through April

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13 Summary This document is the second annual report which presents the status of work completed up to April 30, 2012 for the project titled Implementation and verification of BMPs to reduce Everglades Agricultural Area farm P loads: floating aquatic vegetation impact on farm P load. This project report describes the eight project farms (four farm pairs) that are being monitored within the S5A and S6 sub-basin. Under the approved 2010 scope of work modification, the following activities have been conducted: (1) bathymetric surveys of farm main canals conducted in November 2011, (2) dry season sediment analyses of farm main canals collected in November 2011, (3) water quality analyses of ambient main canal and farm drainage water monitoring: total P (TP), total dissolved phosphorus (TDP), particulate phosphorus (PP), soluble reactive phosphorus (SRP), dissolved organic phosphorus (DOP), total suspended solids (TSS), total dissolved calcium (Ca), and ph, (4) bimonthly qualitative and quantitative assessment of floating aquatic vegetation biomass from each farm s main canal, (5) monitoring of farm canal drainage flow rates, canal elevations, rainfall, and farm drainage volume during drainage events, and (6) monitoring of additional water quality parameters using in situ multi-parameter sondes: canal water temperature, oxidation reduction potential, and specific conductivity. In addition to these activities, regular maintenance and calibration of field and laboratory equipment, along with quality control and assurance are also conducted by our team. Preliminary investigations into simple regression relationships between paired farms for parameters associated with farm P load revealed that correlations were high for rainfall, drainage volume, and P load. The highest correlations were observed when data was compiled at the biweekly time scale. More complete regression models will be developed once the current wet season ends and the collected data are compiled. An important aspect of the EAA Master Permit SOW is the training of farm personnel in BMP implementation techniques. Two BMP training workshops were conducted during the reported period: October 2011 and April 2012 for growers in the EAA with a total of over 200 participants. Feedback received via evaluations collected after trainings was positive and was used to modify and improve training topics, content, and speaker selections. 13

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15 Introduction Located in the geographic center of the South Florida watershed, the Everglades Agricultural Area (EAA) basin comprises approximately 250,000 ha of farms and several small communities south and east of Lake Okeechobee. The EAA has highly productive agricultural land comprised of rich organic muck 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 transfers from Lake Okeechobee to the Water Conservation Areas (WCAs). The primary mode of drainage in the EAA is by shallow subsurface 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 subsurface flow and the water level in open field ditches to raise or lower field water tables. Rainfall is highly seasonal and frequently intense. Drainage discharge is achieved by pumping with high volume, low head, axial-flow pumps. Drainage water from the EAA, after treatment in Stormwater Treatment Areas, is ultimately discharged to the downstream WCAs, Everglades National Park (ENP), or the South Florida coastal estuaries. The EAA basin as a whole is required by the Everglades Forever Act (EFA) of 1994 and its revision of 2003 to achieve phosphorus (P) load reductions of 25% or greater relative to a baseline P load average (derived from 1979 to 1988 monitoring data) that is adjusted for rainfall distribution and amount. In addition, the EFA requires EAA landowners, through the EAA Environmental Protection District (EPD) to sponsor farm-scale research in Best Management Practices (BMPs). Thus, the University of Florida's Institute of Food and Agricultural Services (UF/IFAS) has conducted comprehensive research on BMP effectiveness and implementation since 1995 under the EAA-EPD BMP Master Permit Scope of Work. BMP implementation has been mandatory since 1995 for all farms that discharge drainage water into South Florida Water Management District (SFWMD) conveyance canals. The SFWMD monitors EAA basin P load via a network of monitoring stations, i.e. pump stations and control structures that border the EAA. During the sixteen years since BMP program initiation, the EAA basin s annual P load reduction has averaged nearly 50%; the highest being recorded in 2011 at 79% TP load reduction compared to the baseline period (SFER, 2012). Some of the BMPs that are currently 15

16 implemented are divided into three categories: nutrient control, water management, and particulate matter and sediment control. Within each of these three categories there are numerous individual practices that farmers can implement to either minimized movement of P off-site, minimize the volume of drainage water discharge, or minimize the movement of particulate matter and canal sediments. Further reductions in farm P loads may be achieved by targeting P containing sediments and particulates that are generated in farm canals and transported off-farm during drainage events. Particulate P comprises 40-60% of the P loads discharged from EAA farms (Stuck, 1996, Daroub et al., 2005). Approximately 50% 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 implement on their farms (SFER, 2012). One of the sediment control practices is the control of aquatic vegetation in farm canals. In addition, most growers control to varying degrees the growth of floating aquatic vegetation (FAV) in their canals. However, there is inadequate scientific knowledge regarding this practice s efficacy and its proper implementation methods. Limiting the growth of FAV in farm canals is a practice that has the known benefit of improving the conveyance of drainage and irrigation waters throughout the farm. Control of FAV biomass growth may lead to further reductions in farm P load by changing the physical and chemical properties (and transportability) of sediments generated in a farm canal (Murphy et al., 1983; Reddy et al., 1987; Danen-Louwerse et al., 1995). It is hypothesized that with better light penetration into the canal water column more P will be co-precipitated with Ca and Mg carbonates and form cohesive, denser sediments that are less likely to be re-suspended and transported off the farm during drainage events. In addition, lower P loads from EAA farms should help the performance of Stormwater Treatment Areas (STAs), more so for those STAs performing at less than expected outflow concentrations. This project titled Implementation and verification of BMPs to reduce Everglades Agricultural Area farm P loads: Floating aquatic vegetation impact on farm P load, which started in Fall 2010 will quantify changes in sediment composition and drainage water P 16

17 speciation in EAA sugarcane farms associated with FAV management. It will determine changes in the composition of the P species in canal waters and overall total P loads as influenced by FAV. This report is the second annual report document since the inception of this project, and focuses on the activities conducted by the IFAS/UF during the time period from May 1, 2011, to April 30, The specific objectives of the project 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 of FAV management practices on P speciation of farm drainage water and on farm canal sediment physical and chemical properties. 3. Use the information from the research for the development of a BMP for managing FAV to further lower 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. Several research projects involving EAA farms have identified FAV as a source of readily transportable sediments and particulate P. No studies have been conducted to isolate and measure the effects of limiting FAV growth in farm canals on sediment properties and farm P load. In addition, several studies in the Everglades have found that sediments accumulated in newly constructed wetlands are organic with low bulk density, but that calcium phosphates may play a significant role in P storage. Studies have shown that precipitation of P with Ca may occur in hard waters when FAV is eliminated and submerged aquatic vegetation (SAV) and other algal species are present in the water column (Reddy et al., 1987; Danen-Louwerse et al., 1995). This research project attempts to quantify the effects of two different canal FAV management practices on farm P load, drainage water P speciation, and canal sediment physical and chemical properties. The scope of work for this project was approved by the SFWMD in January Farms included in the project were selected by project personnel and the Water Resources and BMP advisory committee, an advisory committee comprised of representatives of EAA growers. Selection of three farm pairs was approved by the SFWMD in August 2010, while the final farm pair was approved by SFWMD in September Statistical analysis of the study data will be conducted using SAS (SAS, 2008). The main study is a paired watershed design with repeated measures over time (USEPA, 1993). 17

18 Incorporation of multiple covariates into ANCOVA models has been suggested for paired watershed data analysis (Hewlett and Peinaar, 1973; Loftis et al., 2001; Bishop et al., 2005). Drainage flow, canal level, canal head difference, velocity, rainfall and other data collected will be included in the regression analysis as covariates if significant. Covariates will be used to explain the significance of the treatment regression equation, the significance of the overall regression (calibration and treatment period), the difference in the slopes of the calibration and the treatment regressions, and the difference between the intercepts of the calibration and treatment regressions (if the slopes are the same). At a minimum a bivariate plot of paired observations together with the calibration and treatment regression equation, and a plot of deviations as a function of time during the treatment will be presented. An estimate of the percentage change based on the mean TP predicted and TP observed values will be estimated as an approximate of performance. There are two treatments: nearly complete FAV management and typical FAV management in farm canals. The analyses will use regressions to compare P load parameter responses to treatment between paired farms. The data may also be pooled and analyzed by sub-basin. 18

19 Figure 1. Map of the Everglades Agricultural Area and farm locations. Map courtesy of SFWMD. 19

20 Farm Pair 1 Figure 2. Aerial map of farms 0401 and 2501 with pumphouse and canal transect locations. Farm Descriptions Farm Pair 1 comprises two sugarcane farms located in the S5A sub basin: Farm 0401 and farm 2501 (Figure 2). The farms are adjacent to one another and are located on the southwest side of the West Palm Beach canal approximately 12 miles from the Lake Okeechobee outflow structure S-352. Both farms receive irrigation water from and discharge their drainage waters directly into the West Palm Beach canal. Farm 0401 is a 908 acre sugarcane farm with a single exit discharge pump station that contains one electric and one diesel pump. The majority of the drainage pumping is achieved via the electric pump. The diesel pump is utilized only after extreme rainfall events and in case of electrical failure. In the spring of 2011 Farm 0401 grew sweet corn in approximately 40% of the cropping area; in the spring of 2012 Farm 0401 grew sweet corn on approximately 16% of the farm. After harvest of spring sweet corn acreage remained fallow (Appendix Table A1). 20

21 Farm 2501 is an 824 acre sugarcane farm that lies adjacent north and west to Farm basin It has a single discharge station containing two diesel pumps. In the spring of 2011 Farm 2501 grew sweet corn in approximately 16% of the cropping area; in the spring of 2012 Farm 2501 grew sweet corn on approximately 4% of the farm. After harvest sweet corn acreage remained fallow during the summer (Appendix Table A1). Farm Pair 2 Figure 3. Aerial map of farms 1813 and 6117 with pumphouse and canal transect locations. Farm Pair 2 consists of two sugarcane farms in the S5A sub-basin: farm 1813 and farm 6117 (Figure 3). The farms are adjacent to one another and located on the northeast side of the West Palm Beach canal approximately 12 miles from Lake Okeechobee outflow structure S-352. Farm 1813 receives irrigation water from and discharges drainage water directly into the West Palm Beach canal; farm 6117 receives irrigation water from and drains excess water into a northsouth secondary canal that is connected to the West Palm Beach Canal approximately one mile south of farm 6117 discharge structure. 21

22 Farm 1813 is a sugarcane farm of 594 acres with a single exit pump station containing a single diesel powered pump. Sweet corn was grown on approximately 16% of the farm s cropped area in the spring of After harvest the sweet corn acreage was kept fallow until sugarcane was planted in November 2011 (Appendix Table A2). Farm 6117 is a sugarcane farm of 781 acres; it is drained by a single diesel pump, which discharges into a secondary canal that connects to the West Palm Beach canal. The distance from the pump station to the West Palm Beach canal is approximately one mile. Sugarcane occupied all the cropped fields in this farm from November 2010 through March 2012; snap beans were planted in 10% of the acreage in spring of 2012(Appendix Table A2). Farm Pair 3 Figure 4 Aerial map of farms 3102 and 3103 with pumphouse and canal transect locations. Farm Pair 3 is located in the S6 sub-basin just north of the intersection of Airport Road and Sam Center Road. The pair consists of two sugarcane farms: Farm 3102 and farm 3103 (Figure 4). Both farms receive irrigation water from and discharge into a tertiary district canal that eventually connects with the Hillsboro Canal via the Ocean Canal. 22

23 Farm 3102 is a 1387 acre sugarcane farm that is bordered to the south by the Airport road extension and to the north by SR80. This farm has a single exit pump station containing three diesel pumps for drainage. Sweet corn was planted on approximately 53% of the acreage during the spring season 2011; beans and leaf vegetables were planted in 10 to 20% of the total farm acreage during spring 2012 (Appendix Table A3). Farm basin 3103 is a 602 acre sugarcane farm that is located west across the canal from farm basin 3102 and has Hatton Highway as a western boundary and Airport Road as its southern boundary. It has a single exit pump station containing one diesel powered pump. Leaf vegetables were planted on 25% of the cropped acreage from January through May Vegetable acreage was fallow for the month of May 2011 and was flooded starting in June of In fall of 2011 beans and corn were planted on approximately 25% of the farm. In Spring 2012 sweet corn was planted on approximately 25% of the farm (Appendix Table A3). Farm Pair 4 Figure 5. Aerial map of farms 4701 and 4702 with pumphouse and canal transect locations. 23

24 Farm Pair 4 is located in the S6 sub-basin near its northern boundary and consists of two sugarcane farms: farm 4701 and farm 4702 (Figure 5). Both farms receive irrigation water from and discharge into an east-west secondary district canal that eventually connects with the Hillsboro Canal via the Ocean Canal. Farm 4701 is a 630 sugarcane farm with a single diesel discharge pump station with a single diesel powered pump that discharges drainage water into a tertiary canal that feeds into the secondary district canal that runs north from Sam Center road, and eventually discharges into the Ocean canal at Sam Center Road and SR880. Sugarcane occupied all the cropped fields on this farm from November 2010 through April 2012 (Appendix Table A4). Farm 4702 is a 640 acre sugarcane farm which is located one-half mile east of farm basin Farm 4702 has a single pump station with a single diesel pump for drainage discharge. Sugarcane occupied all the cropped fields on this farm from November 2010 through March In April 2012 rice was planted on 50% of the farm (Appendix Table A4). Farm Canal Sediment Surveys Farm canal surveys are conducted to assess individual farm canal dimensions (length, width, area), the thickness of sediments present in the canals, and their physical and chemical characteristics. Surveys are conducted twice a year to monitor changes in sediment thickness or composition. This report summarizes results from the survey conducted in November The next canal surveys will be conducted in June 2012 and Nov Materials and Methods Water depth to sediment surface was measured by a neutral buoyancy water column measuring pad, which is a circular (10 inches) wooden pad attached to a graduated staff. The pad-staff is slowly submerged in the canal until the pad gently touches the sediment surface with minimal disturbance. Sediment thickness at each 2 ft lateral increments within each transect of individual canals was measured by subtracting the water column measuring pad value from its corresponding calibrated penetrometer value. Three separate transect locations were selected within a single canal, and sediment thickness was measured along a transect across the canal width. Transect A was closest to the pump station, transect B was in the middle of the canal, while transect C was confined at the back end of the canal. These three locations were adjacent 24

25 to where grab water samples are collected. At each transect location two iron rebars were installed at the edge of the water on each side of the canal. During surveying, a steel cable is attached to the rebar to anchor a boat used during measurements. Along a transect measurements were recorded at 2 ft (0.61 m) intervals. A measuring pad was used to record the depth of the water column; a graduated 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. Results The overall average thickness of canal sediments for all eight farms and along all three transects was 0.61 m (2.0 ft; summarized in Table 1). As expected the thickest section of sediment accumulation was confined to the center of the canals. In general, no differences in sediment thickness were observed between the three transects A, B, C (or from closest to the pump station to furthest away from the pump station). Farm 1813 had the highest mean sediment thickness of 0.75 m (2.3 ft) while 2501 had the least mean sediment thickness 0.51 m (1.7 ft) (Table 1). In transect A the highest sediment thickness was observed in farm 6117 at 1.95 m (6.4 ft), while in transect B the highest sediment thickness was observed in farm 1813 at 1.55 m (5.1 ft), and in transect C the highest thickness was also observed in farm 6117 at 2.57 m (8.4 ft). Schematics of sediment profiles for all transects are shown in Figures 6 to 13. The underlying canal sediment can potentially adsorb or release P depending on canal water P concentration and water-sediment interface conditions. 25

26 Table 1. Summary of farm canal sediment depths in meters surveyed in November Farm ID Mean Std Dev N Minimum Maximum Median 1 Overall Transect A Transect B Transect C Overall= average of three transects (A,B,C) 26

27 stage height (m) A canal width (m) channel bottom sediment surface stage height (m) B channel bottom sediment surface canal width (m) stage height (m) C channel bottom sediment surface canal width (m) Figure 6. Sediment profile of main canal of farm 0401 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water. 27

28 stage height (m) A channel bottom sediment surface canal width (m) 1.5 stage height (m) B channel bottom sediment surface canal width (m) stage height (m) C channel bottom sediment surface canal width (m) Figure 7. Sediment profile of main canal of farm 2501 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water. 28

29 thickness (m) A channel bottom sediment surface canal width (m) thickness (m) B channel bottom sediment surface canal width (m) thickness (m) C channel bottom sediment surface canal width (m) Figure 8. Sediment profile of main canal of farm 1813 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water. 29

30 stage height (m) A channel bottom sediment surface canal width (m) stage height (m) B channel bottom sediment surface canal width (m) stage height (m) C channel bottom sediment surface canal width (m) Figure 9. Sediment profile of main canal of farm 6117 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water. 30

31 stage height (m) A channel bottom sediment surface canal width (m) stage height (m) B channel bottom sediment surface canal width (m) stage height (m) C channel bottom sediment surface canal width (m) Figure 10. Sediment profile of main canal of farm 3102 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water. 31

32 stage height (m) B channel bottom sediment surface canal width (m) stage height (m) C channel bottom sediment surface canal width (m) stage height (m) C channel bottom sediment surface canal width (m) Figure 11. Sediment profile of main canal of farm 3103 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water. 32

33 stage height (m) A channel bottom sediment surface canal width (m) stage height (m) B channel bottom sediment surface canal width (m) stage height (m) C channel bottom sediment surface canal width (m) Figure 12. Sediment profile of main canal of farm 4701 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water. 33

34 stage height (m) A channel bottom sediment surface canal width (m) stage height (m) B channel bottom sediment surface canal width (m) stage height (m) C channel bottom sediment surface canal width (m) Figure 13. Sediment profile of main canal of farm 4702 at three transects, A, B, and C, surveyed in November (Note: 1 m = 3.12 ft). Blue line corresponds to height of water. 34

35 Physical and Chemical Characterization of Canal Sediments Sediment characterization of the eight farms was conducted in November Intact sediment cores (approximately 25 cm depth) were collected from the middle of the three transects along main farm canal of each farm. The sediments were collected on November 2-3, 2011 using a piston type, in-house constructed, sediment sampling device. The sediment sampler used polycarbonate tubes of 7.0 cm diameter and 50 cm length. Sample cores were transported to the laboratory on the same day of collection, sectioned into 0-2.5cm and cm core lengths respectively, and stored at 4⁰C. Sediment sampling locations were recorded using a hand held GPS device. Sample preparation and analyses were conducted at the Soil Quality laboratory located at the Everglades Research and Education Center located Belle Glade, FL. Properties analyzed were sediment, organic matter (OM), total P (TP), wet bulk density (WDb) and dry bulk density (DDb). Sediment Analyses Sediment core sections were mixed thoroughly before taking any sub-samples for chemical analyses. All of the material present in the sediment cores was included in the analyses. For TP analyses, known weights of wet sample were ashed at 550 o C for four hours in a muffle furnace and were grounded in a pestle and mortar before analyses (Andersen, 1974). Results are reported on an oven dry-weight basis. Both wet and dry bulk densities were performed on the sediments without any sieving or pre-treatments using EREC-SOP Bulk Density (adapted from Soil Survey Laboratory Methods Manual, 2004). Organic matter and ash content were determined using EREC-SOP Organic Matter (adapted from Soil Survey Laboratory Methods Manual, 2004). Total P was determined using EPA method (EPA, 1993). Results A summary of the results are reported in Table 2. Overall the mean OM and TP content of the sediments from all eight farms were 42.9 ±11 % and 1075 ±395 mg/kg respectively. Both, OM and TP concentrations were similar to those observed during the February 2011 sampling event. While comparing the two depth horizons (0-2.5 and cm) we found that the mean OM was similar in the cm and the cm layer at 43.2 ±10 % and 42.6 ±12% respectively; while TP was slightly higher in the cm horizon at 1149 ±482 mg/kg, 35

36 compared to 995 ±272 mg/kg observed at cm depth. Over the entire 5 cm sediment profile (regardless of depth horizons), Farm 3103 had a mean OM and TP concentration of 37.2 % and 1380 mg/kg respectively; Farm 3102 had 40.9 % and 979 mg/kg; Farm 2501 had 36.9 % and 925 mg/kg; Farm 0401 had 41.8 % and 956 mg/kg; Farm 4702 had 57.0 % and 928 mg/kg; Farm 4701 had 34.5 % and 939 mg/kg; Farm 6117 had 46.5 % and 1188 mg/kg; Farm 1813 had 48.5 % and 1280 mg/kg. 36

37 Table 2. Physical and chemical properties of sediments collected on November 2011 from the eight farms. Farm ID 1 Transect Depth OM WDb DDb (cm) (%) (g/cm 3 ) (g/cm 3 ) TP (mg/kg) 0401 A A B B C C A A B B C C A A B B C C A A B B C C A A B B C C A A B B C C A A B B C C A A B B C C OM = organic matter; WDb = wet bulk density; DDb = dry bulk density; TP = total phosphorus 37

38 Floating Aquatic Vegetation: Speciation, Coverage and TP Content An overall assessment of FAV was conducted approximately every two months with the intention of identifying the species composition, coverage within the main canals, and the TP content of the plant biomass. In this report we include the data collected from May 2011 to April 2012 (total six sampling events). Two representative samples were collected from each farm. Sampling locations were selected at each farm based on spatial coverage of FAV. FAV Sampling Procedure and Analyses A one-meter-square floating PVC retainer is placed on the FAV biomass to be sampled. All FAV within the square is harvested and placed in mesh bags to drain. Total fresh weight is recorded after draining. The entire sample mass is air dried to constant weight with forced air at 50 C. The weight of the dry sample mass is recorded, and the mass is ground to less than 1 mm in a cyclone mill. The ground material is blended well and stored in an airtight container until analysis. Samples were analyzed for water content and TP. Percent moisture content was calculated based on difference between wet mass of FAV versus oven dry mass, while the dry grounded biomass was analyzed for TP using method (USEPA, 2003) on an Inductively Coupled Plasma Mass Spectroscope (IFAS, Analytical Research Lab, Gainesville, FL). The total P in individual farm FAV biomass was calculated as the product of the dry FAV biomass P concentration (mg/kg) times the mass of FAV (kg) present in the canals based on the percent coverage. Photo 1. Floating aquatic vegetation (duck weed) being collected from one of the farm canals. 38

39 Results Following is a summary of the FAV characterization and TP content of FAV biomass from six sampling trips (May 2011 through April 2012): May 2011 Farm 0401: Overall 70% cover, mostly water lettuce and a bit of filamentous algae and duckweed. Farm 2501: Overall 50% cover mostly filamentous algae and water lettuce. Farm 1813: Overall very clear canal. No appreciable FAV. Farm 6117: Overall 30% mostly duck-weed and little water lettuce. Farm 3102: Overall about 40% of the canal was covered with FAV, dominated by water-lettuce mostly confined to the pump area and in the E-W section of the canal. N-S canal was clean. Farm 3103: Overall 10% of the canal showed presence of FAV, mostly confined to the canal edges, including filamentous algae, torpedo grass, and water lettuce. Farm 4701: Overall 30% cover of filamentous algae and torpedo grass. Farm 4702: Overall 5% confined mostly along the canal edges comprising of water lettuce. Table 3. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for May Farm Water [TP] of TP in Farm Sample description ID content (%) dry FAV (mg/kg) FAV Mass (kg) water lettuce and filamentous algae filamentous algae duck-weed and water lettuce 1813 No FAV coverage water lettuce water lettuce, filamentous algae, and torpedo grass filamentous algae and torpedo grass water lettuce 39

40 June 2011 Farm 0401: Overall 40% cover mostly water lettuce and a bit of filamentous algae and duckweed. Farm 2501: Overall 5% cover mostly filamentous algae and water lettuce. Farm 6117: Overall 40% mostly duck-weed and little water lettuce. Farm 1813: Overall very clear canal. No appreciable FAV present. Farm 3102: Overall about 40% of the canal was covered with FAV, dominated by water-lettuce mostly confined to the pump area and in the E-W section of the canal. N-S canal was clean. Farm 3103: Overall 10% of the canal showed presence of FAV, mostly confined to the canal edges, including filamentous algae, and torpedo grass. Farm 4701: Overall 1% cover of filamentous algae and torpedo grass. Farm 4702: Overall 5% confined mostly along the canal edges comprising of water lettuce and torpedo grass. Table 4. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for June Farm Water [TP] of TP in Farm Sample description ID content (%) dry FAV (mg/kg) FAV Mass (kg) water lettuce and filamentous algae filamentous algae and water lettuce duck-weed 1813 No FAV coverage water lettuce and torpedo grass water lettuce, and torpedo grass filamentous algae, and torpedo grass water lettuce and torpedo grass 40

41 August 2011 Farm 0401: Overall 60% cover mostly water lettuce (70%) and a bit of filamentous algae (30%) Farm 2501: Overall 40% cover mostly water lettuce and filamentous algae. Farm 6117: Overall 10% mostly duck-weed and little water lettuce. Farm 1813: Overall very clear canal. No appreciable FAV. Farm 3102: Overall about 40% of the canal was covered with FAV, dominated by water lettuce. Farm 3103: Overall 40% of the canal showed presence of FAV, dominated by water lettuce. Farm 4701: Overall 10% cover of filamentous algae. Farm 4702: Overall 15% confined mostly along the canal edges comprising of water lettuce. Table 5. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for August Farm Water [TP] of TP in Farm Sample description ID content (%) dry FAV (mg/kg) FAV Mass (kg) water lettuce and filamentous algae filamentous algae duck-weed and water lettuce 1813 No FAV coverage water-lettuce water lettuce filamentous algae water lettuce 41

42 October 2011 Farm 0401: Overall 40% cover mostly water lettuce (50%) and a bit of filamentous algae (50%) Farm 2501: Overall 15% cover mostly filamentous algae. Farm 6117: Overall 10% mostly duck-weed and little water lettuce. Farm 1813: Overall very clear canal. No appreciable FAV. Farm 3102: Overall about 30% of the canal was covered with FAV, dominated by waterhyacinth. Farm 3103: Overall 10% of the canal showed presence of FAV, mostly water hyacinth. Farm 4701: Overall 10% cover of filamentous algae. Farm 4702: Overall 15% confined mostly along the canal edges comprising of water lettuce. Table 6. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for October Farm Water [TP] of TP in Farm Sample description ID content (%) dry FAV (mg/kg) FAV Mass (kg) water lettuce and filamentous algae filamentous algae duck-weed and water lettuce 1813 No FAV coverage water hyacinth water hyacinth and duckweed filamentous algae water lettuce 42

43 January 2012 Farm 0401: Overall 20% cover mostly water lettuce (50%) and a bit of filamentous algae (50%) Farm 2501: Overall 15% cover mostly filamentous algae. Farm 6117: Overall 30% mostly duck-weed and little water lettuce. Farm 1813: Overall very clear canal. No appreciable FAV. Farm 3102: Overall about 30% of the canal was covered with FAV, dominated by water-lettuce. Farm 3103: Overall 40% of the canal showed presence of FAV, mostly water lettuce. Farm 4701: Overall 15% cover of filamentous algae. Farm 4702: Overall 10% confined mostly along the canal edges comprising of water lettuce. Table 7. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for January Farm Water [TP] of TP in Farm Sample description ID content (%) dry FAV (mg/kg) FAV Mass (kg) filamentous algae and water lettuce filamentous algae duck-weed and water lettuce 1813 No FAV coverage water lettuce and filamentous algae water lettuce filamentous algae water lettuce 43

44 April 2012 Farm 0401: Overall 50% cover mostly water lettuce (50%) and a bit of filamentous algae (50%) Farm 2501: Overall 70% cover mostly filamentous algae. Farm 6117: Overall 75% mostly duck-weed and little water lettuce. Farm 1813: Overall very clear canal. No appreciable FAV. Farm 3102: Overall about 30% of the canal was covered with FAV, dominated by water-lettuce. Farm 3103: Overall 30% of the canal showed presence of FAV, mostly water lettuce. Farm 4701: Overall 30% cover of filamentous algae. Farm 4702: Overall Clean canal Table 8. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for April Farm Water [TP] of TP in Farm Sample description ID content (%) dry FAV (mg/kg) FAV Mass (kg) water lettuce and filamentous algae water lettuce and filamentous algae water lettuce and duckweed 1813 No FAV coverage water lettuce and filamentous algae water lettuce filamentous algae 44

45 Assessment of FAV in Farm Canal Pairs An assessment of FAV was conducted on farm canal pairs for all the data collected from the beginning of this project to present. Changes in dried mass (kg) of FAV were compared to the average TP concentration contained in the FAV (mg/kg). In addition, the percent FAV coverage in individual farm canals was compared to the total mass of P associated with FAV, (Figures 14 to 17). Between farm pair 3102 and 3103, the highest mass of dried FAV was observed in Farm 3102 in May 2011 at 7013 kg, compared to only 478 kg observed in farm 3103 during the same time (Figure 14). The highest TP concentration contained in the FAV was 4425 mg/kg observed in farm 3103 during October The % coverage of FAV was generally higher in 3102 and the highest mass of P associated with FAV was observed during May 2011 at 18 kg. We expect to see significant changes in % coverage and corresponding mass of FAV, in addition to reduction in mass of TP in individual canals once the treatments have been put into practice following the end of the second year. 45

46 3102 Mass of dried FAV Ave. TP conc. Mass of dried FAV (kg) /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Average TP conc. in FAV (mg/kg) 3102 FAV coverage Mass of P % FAV coverage 1/11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Mass of P in canal (kg) 3103 Mass of dried FAV Ave. TP conc. Mass of dried FAV (kg) /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Average TP conc. in FAV (mg/kg) 3103 FAV coverage Mass of P % FAV coverage 1/11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Mass of P in canal (kg) Figure 14. Comparison of FAV in main canals of farms 3102 and (Left) Changes in mass of dried FAV and average TP concentration of FAV over time. (Right) Changes in percent FAV coverage and mass of P in FAV over time. 46

47 4701 Mass of dried FAV Ave. TP conc. Mass of dried FAV (kg) /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Average TP conc. in FAV (mg/kg) 4701 FAV coverage Mass of P % FAV coverage /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Mass of P in canal (kg) 4702 Mass of dried FAV Ave. TP conc. Mass of dried FAV (kg) /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Average TP conc. In FAV (mg/kg) 4702 FAV coverage Mass of P % FAV coverage /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Mass of P in canal (kg) Figure 15. Comparison of FAV in main canals of farms 4701 and (Left) Changes in mass of dried FAV and average TP concentration of FAV over time. (Right) Changes in percent FAV coverage and mass of P in FAV over time. 47

48 0401 Mass of dried FAV Ave. TP conc FAV coverage Mass of P Mass of dried FAV (kg) /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Average TP conc. In FAV (mg/kg) % FAV coverage /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Mass of P in canal (kg) 2501 Mass of dried FAV Ave. TP conc. Mass of dried FAV (kg) /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Average TP conc. In FAV (mg/kg) 2501 FAV coverage Mass of P % FAV coverage /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Mass of P in canal (kg) Figure 16. Comparison of FAV in main canals of farms 0401 and (Left) Changes in mass of dried FAV and average TP concentration of FAV over time. (Right) Changes in percent FAV coverage and mass of P in FAV over time. 48

49 6117 Mass of dried FAV Ave. TP conc FAV coverage Mass of P Mass of dried FAV (kg) /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Average TP conc. In FAV (mg/kg) % FAV coverage /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Mass of P in canal (kg) 1813 Mass of dried FAV Ave. TP conc. Mass of dried FAV (kg) /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Average TP conc. In FAV (mg/kg) 1813 FAV coverage Mass of P % FAV coverage /11/2011 3/14/2011 5/9/2011 6/27/2011 8/9/ /6/2011 1/23/2012 4/3/ Mass of P in canal (kg) Figure 17. Comparison of FAV in main canals of farms 6117 and (Left) Changes in mass of dried FAV and average TP concentration of FAV over time. (Right) Changes in percent FAV coverage and mass of P in FAV over time. 49

50 Water Quality Monitoring The eight farms (four pairs) are being monitored for water quality since November 2010 There are two conditions when canal waters are sampled: (i) ambient condition (canal water grab samples), and (ii) drainage condition (flow-composited, drainage water samples). Grab water samples are collected regularly from all eight farms main canals at three locations per main farm canal, i.e., A, B, and C. The three grab sampling locations are in proximity of sediment sampling transect locations as shown in the aerial farm maps (Figures 2-5; see Farm Description section for more detail). The sampling location A is located halfway between the main canal length midpoint and the pumphouse, location B is located at the halfway point of the main farm canal, and location C is located halfway between location B and the end of the main canal. The periodicity of grab water sampling was at least two times per month. However, grab water samples are not collected during weeks when a farm was actively discharging drainage water. Drainage water samples were collected on a flow-weighted basis by auto-sampler during drainage events (active pumping of water off the farm). Water Sampling Procedures Ambient canal water samples are collected using an in-house grab sampling technique, which uses a 1.25 L Nalgene bottle harnessed by insulated wire to one end of an aluminum pole. The pole is gently immersed approximately 0.5 m below the canal surface while the sample bottle fills with water. The bottles are immersed upside down so as to prevent any debris from entering the bottle. The bottles are labeled and preserved on ice while being transported to the EREC lab for analyses. Once the samples are collected in field they are transported on ice to the lab in less than 2 hr, where they are immediately filtered and acidified appropriately for the different analyses. Field blanks and field duplicates are collected at every sampling event as per QA-QC guidelines (Quality Manual ver. 7.1, Josan et al., 2010). Drainage water samples are collected daily as a flow-composite sample (Photo 2). The composite sample is collected by auto-sampler using a solar power that is triggered by a data logger set at farm-specific flow discharge volume intervals. Drainage water samples are stored on-site in refrigerated containers until sample collection. Sample collection occurs within hours of the initial drainage water sample collection. 50

51 Laboratory Analyses All water samples are analyzed for total P (TP; Photo 3), total dissolved P (TDP), soluble reactive P (SRP; Photo 3), total suspended solids (TSS), ph, and dissolved calcium (Ca; photo 4). Particulate P (PP) was calculated as the difference between TP and TDP, whereas dissolved organic P (DOP) was calculated as a difference between TDP (after digestion) and SRP. The water samples were filtered through 0.45 µm filter and the filtrate were analyzed for TDP and SRP. For TP and TDP analysis water samples were digested in the presence of concentrated sulfuric acid, ammonium persulfate using method (USEPA, 2003). All samples were analyzed for ortho-p using ascorbic acid method (Murphy and Riley, 1962) using an automated air segmented continuous flow analyzer, Auto Analyzer 3 (AA3) manufactured by Seal. Samples were analyzed in a range between 0.00 and 0.50 mg/ l. Samples with a concentration greater than 0.50 mg/l were diluted to fall in the applicable range. For the WY2012, the respective method detection limits for TP, TDP, and SRP were 0.005, 0.005, and mg/l respectively. Detailed analytical procedures are contained in the Standard Methods for the Examination of Water and Wastewater (APHA, 1998), and EREC Quality Manual Ver (Josan et al. 2010, SOP 28 Rev. 1). For the TSS analysis, a well-mixed water sample (minimum 500 ml, equilibrated to controlled room temperature) was filtered through a pre-weighted standard glass fiber filter and the residue retained on the filter was dried to a constant weight at 105 C. The increase in weight of the filter was recorded and TSS concentrations were calculated on per liter basis. The practical range of the determination is 1 mg/l to 20,000 mg/l. The outlined procure is based on method (USEPA, 2004) and details of the method are available in EREC Quality Manual Ver. 7.1 (SOP 13 Rev. 3). The total suspended solid were calculated using the following equation: TSS ( mg / L) = ( weightofdryfilter + residue + dish weightofdryfilter + dish) Samplevolume The ph of the water samples was determined using a combination glass electrode. The total dissolved Ca levels, hereafter referred as Ca, were analyzed using an atomic absorption spectrophotometer. 51

52 Photo 2. Datalogger, auto-sampler, refrigerator, and drainage water composite sample collection. 52

53 Photo 3. Orthophosphate (top) and total phosphorus (bottom) analyses being conducted on SEAL Auto Analyzer. 53

54 Photo 4. Calibration of Hydrolab MiniSonde left, and Ca analyses using atomic absorption spectrophotometer, right. 54

55 Ambient Farm Canal Water Monitoring Results The P species concentrations during the ambient canal conditions at three set locations on each farm are summarized in Tables 9 and 10. Additionally, the box-plots of TP with matching farm pairs are presented in Figure 18. The boxplots provide the exploratory data analysis along with visual summaries about P concentrations of ambient canal water during the monitoring period. Complete detailed lists of grab water samples results have been presented in Tables A5- A12 in the appendix section. These tables present water quality parameters at each farm location for individual sampling dates for each of the three transects per farm. For example, Table A5 shows the water quality parameters of grab canal water samples collected during each sampling event from November 2010 through April 2012 for farm For farm pair 0401 and 2501 the average TP values were (± 0.043) mg/l and (±0.052) mg/l respectively (Table 9). The highest TP values of and mg/l were observed on 2/23/2011 and 3/16/2011 for the farms 0401 and 2501 respectively. For farm pair 1813 and 6117 the average TP concentration was (± 0.035) mg/l and (± 0.040) mg/l respectively (Table 9). The maximum TP values of and mg/l were observed on 3/12/2012 and 1/4/2011 for the farm 1813 and 6117 respectively. For the farm pair 3102 and 3103 the average TP concentrations values were (± 0.073) and (± 0.049) mg/l respectively. Amongst all of the farms, the farm 3102 showed the widest variability in TP (Figure 18). The maximum TP values of and mg/l were observed on 3/16/2011 and 4/23/2012 for the farm 3102 and 3103 respectively (Table A9). Farm 3102 had higher average SRP concentration (0.059 ± mg/l) than the farm 3103 (0.035 ± mg/l). Farm 4701 had the lower average TP (0.040 ± 0.025) concentrations than that of 4702 (0.056 ± mg/l) (Table 10). Total P concentrations of the grab water samples collected from the farm 4701 exhibited less variability than that of farm 4702 (Figure 18). The maximum TP values of and mg/l were observed on 3/16/2011 and 2/27/2012 for the farm 4701 and 4702 respectively. Farm 4701 had the lowest average SRP (0.005 ± mg/l) concentrations amongst all the farms, with a maximum value of 0.031mg/l observed on 12/6/2011. Bar graphs of ambient canal water average P speciation concentrations and percent total P fraction by farm showed that PP fraction was the dominant fraction observed in ambient canal 55

56 water with the exception of Farm 3102 (Figure 19). The average contribution of PP to the TP in the grab water samples ranged from as low as 31% (0.03 mg/l) for the farm 3102 to as high as 59% (0.025 mg/l) for the farm This behavior resulted in a high SRP contribution (56%) to the TP for the farm 3102 and a lower SRP contribution (16%) for the farm 4701 respectively. Table 9. Summary statistics of phosphorus species concentrations of ambient canal waters for farm pairs in S5A sub-basin from November 2010 through April Farm ID N Variable Mean (mg\ l) Std. dev. Minimum (mg\ l) Maximum (mg\ l) Median (mg\ l) 78 TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP = total phosphorus, TDP = total dissolved phosphorus; PP = particulate phosphorus; SRP = soluble reactive phosphorus, DOP = dissolved organic phosphorus, and Std. dev. = standard deviation; PP = TP TDP and DOP = TDP SRP. The average PP concentrations of the ambient water samples for the farm pair 0401 and 2501 averaged (± 0.027), and (± 0.027) mg/l, representing 38 and 39% of the TP in the water column respectively. For the farm pair 1813 and 6117, the average PP concentrations were (± 0.027) and (± 0.025) mg/l respectively and representing 55 and 48% of the TP. For the farm pair 3102 and 3103 the average PP concentrations were (± 0.055) and (± 0.019) mg/l respectively and representing 32 and 36% of the TP. 56

57 Average DOP concentrations were similar among all the farms with values ranging from to mg/l. The average contribution of the DOP to total P varied from 12% (Farm 3102) to 23% (Farm 0401). A summary of ambient canal water ph, dissolved Ca and TSS is presented in Table 11. For the entire ambient canal water data set, the ph values ranged from 6.9 to 8.9 with an overall average of 8.0 (± 0.4). The Ca concentrations varied from 28.8 to 164 mg/l with an overall average of 71.5 (± 28.8) mg/l. The TSS content ranged from 0.2 to mg/l, with an overall average of 8.6 (± 9.6) mg/l. The TSS content of the farm 6117 was more variable than the other monitored farms (Figure A5), whereas Ca concentrations of the farm 4702 were more variable for the farm 4702 (Figure A6). 57

58 Table 10. Summary statistics of phosphorus species concentrations of ambient canal waters for farm pairs in S6 sub-basin from November 2010 through April Farm ID N 1 Variable Mean (mg\ l) Std. Dev. Minimum (mg\ l) Maximum (mg\ l) Median (mg\ l) 78 TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP = total phosphorus, TDP = total dissolved phosphorus; PP = particulate phosphorus; SRP = soluble reactive phosphorus, DOP = dissolved organic phosphorus, and Std. dev. = standard deviation; PP = TP TDP and DOP = TDP SRP. 58

59 Figure 18. Distribution of total P (TP) concentrations in canal water grab samples collected from November 2010 through April The sign in the box is the mean, horizontal line in the box is the median, the top and bottom of the box represents 75 th and 25 th percentile, whereas the whiskers define the 5 th and 95 th percentile observations, and o sign outside the boxes are outliers. 59

60 PP SRP DOP 0.08 P (mg/l) % P Fraction Farm ID Figure 19. Ambient canal water average P speciation concentrations and percent total P by farm from November 2010 through April

61 Table 11. Summary statistics of ambient canal water ph, calcium, and total suspended solids for S5A and S6 sub-basin farm pairs from November 2010 to April Farm ID N Variable 1 Mean Std Dev Minimum Maximum Median 78 ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS Ca = dissolved calcium (mg\ l), TSS = total suspended solids (mg\ l) and Std. dev.= standard deviation. 61

62 Farm Canal In Situ Monitoring A monitoring program was established in October 2011 to measure water quality parameters that may influence P cycling within farm canals. Hydrolab MiniSonde Series 5 multi-parameter water quality data loggers were used to measure and record temperature, ph, specific conductance (conductivity), and oxidation-reduction potential (ORP) and depth in situ. The MiniSonde units were calibrated according to company specifications and programmed for a seven-day run (programmed to record a measurement every hour). The units were deployed in the center of each of the farm s main canal at transect B at a depth of 0.25 meter above the sediment surface. After the MiniSonde programmed seven day run ends, it was retrieved from the field, and the data were downloaded to a computer and stored in electronic format. A postrun assessment for drift of the instrument s sensors was also immediately conducted. The instruments were then cleaned, maintained, and re-calibrated in the laboratory. The units were returned to the field for deployment during the following week s monitoring cycle. All field and laboratory activities strictly follow relevant Standard Operating Procedures and the National Environmental Laboratory Accreditation Program (NELAP) approved quality manual. Quality control criteria regarding sensor drift and biofouling were as follows: ph <0.2 at ph=7.0 (Fisher Certified Standard: SB C); conductivity < 100 µs/cm at 1413 µs/cm (0.01 M KCl); and redox < 20 mv of Zobell Solution (APHA-Redox Standard: , mv against standard Hydrogen reference electrode at 25 C). Farm Canal In Situ Monitoring Results The summary statistics of hourly in situ water quality measurement are presented in Table 12. In addition, a more detailed summary of in situ monitoring results has been presented in Figures A7-A14 in the appendix section. These figures summarize water quality parameters at the selected farm canal location (B) for individual deployments. For example, Figure A7 shows the daily average water quality parameters measured from October 2011 through May 2012 for the farm The ambient canal water temperature ranged as low as 11.9 C for the farm 4701 to as high as 30.6 C for the farm 2501 (Table 12). The ph values varied from as low as 6.5 in farm 2501 to as high as of 9.7 in the farm The conductivity values ranged from as low as 485 µs/cm in farm 0401 to as high as 1814 µs/cm. The lowest ORP value of -349 mv was observed 62

63 in the farm 3102, whereas the maximum ORP value of 687 mv was observed in the farm The in situ data will be further examined for diurnal and seasonal variations once the monitoring period is over. Additionally these data values can also be used as covariates while conducting the regression studies. Table 12. Summary statistics of hourly in situ water quality measurements collected from October 2011 through April Farm StatisticalParameter Temperature ( C) ph SpCond 1 (µs/cm) ORP 2 (mv) Mean Minimum Maximum Mean Minimum Maximum Mean Minimum Maximum Mean Minimum Maximum Mean Minimum Maximum Mean Minimum Maximum Mean Minimum Maximum Mean Minimum Maximum SpCond= specific conductivity 2 ORP = oxidation reduction potential 63

64 Farm Drainage Water Drainage water concentrations of P species, ph, Ca, and TSS levels are presented in Tables 13 and 14. Overall, the TP concentrations ranged from a minimum of mg\l at farm 4701 to a maximum of mg\l at farm 3102 (Tables 13 and 14). Farm pairs matched well for comparison of drainage water TP with the largest differences in mean TP (0.104 mg\l) observed between farms 3102 and The least difference in mean TP between farm pairs (0.018 mg\l) was observed between farms 4701 and Summary statistics of other P species in farm drainage water are also presented in Tables 13 and 14. Secondary water quality parameter data for farm drainage waters are presented in Table 15. Farm drainage water means for ph Ca, and TSS were similar for all farm pairs; farm pair 0401 and 2501 had the largest difference in mean TSS concentration (12.2 mg\ l) compared to the other three farm pairs. Other differences between farms of a pair were negligible. Initial compilation of farm drainage data was conducted at daily, weekly, biweekly, and monthly time intervals. Higher correlation coefficients and better fitting regression models were observed with the biweekly time interval data set. Biweekly correlation coefficients for rainfall, drainage volume, and P load are presented in Table 16. The lowest correlation coefficients were observed for farm pair 4701 and This was also the farm pair with the least number of drainage events. The other three farm pairs had promising correlation coefficients for all three parameters. Additional regression investigations are being conducted to evaluate additional parameters (ambient canal water data) that may be utilized to develop more robust P load regression models. Additionally visual comparisons of daily load data suggest that for most drainage events, farm pairs had similar TP concentrations of drainage water, rainfall, and drainage volumes. Graphs of daily rainfall, drainage volume, and P load by farm pair are presented in Appendix Figures A16 through A26. Drainage water TP concentration variation by farm is presented in box plot format in Figure 19. The greatest variation in drainage water TP was observed at farms 3102 and 3103; the least variation in TP concentration was observed at farms 4701 and (Box plots of drainage water TDP, SRP, PP, DOP and TSS are presented in Appendix Figures A27 through A31). The P speciation of farm drainage water is affected by many factors. In this study we are investigating possible relationships between P speciation and FAV and canal management. Plots of average drainage water P speciation and percent contribution to total P are presented in Figure 64

65 20. For all farms the contribution of DOP to total P was minimal. Both PP and SRP contributed similarly to total P on the majority of the farms, with TDP contributing slightly more to total P export. Table 13. Summary statistics of drainage water phosphorus concentrations of farm pairs in the S5A sub-basin from November 2010 through April Farm ID N Variable 1 Mean (mg\ l) Std. dev. Minimum (mg\ l) Maximum (mg\ l) Median (mg\ l) 35 TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP = total phosphorus, TDP = total dissolved phosphorus; PP = particulate phosphorus; SRP = soluble reactive phosphorus, DOP = dissolved organic phosphorus, and Std. dev. = standard deviation; PP = TP TDP and DOP = TDP SRP. 65

66 Table 14. Summary statistics of drainage water phosphorus concentrations of farm pairs in the S6 sub-basin from November 2010 through April Farm ID N Variable 1 Mean (mg\ l) Std. dev. Minimum (mg\ l) Maximum (mg\ l) Median (mg\ l) TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP = total phosphorus, TDP = total dissolved phosphorus; PP = particulate phosphorus; SRP = soluble reactive phosphorus, DOP = dissolved organic phosphorus, and Std. dev. = standard deviation; PP = TP TDP and DOP = TDP SRP. 66

67 Table 15. Summary statistics of drainage water ph, calcium, and total suspended solids in S5A and S6 basin farms from November 2010 to April Farm ID N 1 Variable Mean Std. dev. Minimum Maximum Median 35 ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS ph Ca TSS Ca = dissolved calcium (mg\ l), TSS = total suspended solids (mg\ l) and Std. dev. = standard deviation. 67

68 Table 16. Spearman correlation coefficients of biweekly farm drainage data. Farm Pair 1 Drainage Rainfall FWTP P Load Volume 0401 vs vs (<0.0001) (<0.0001) S5A Sub Basin (<0.0001) (<0.0001) S6 Sub Basin (<0.0001) (<0.0001) 3102 vs (<0.0001) (<0.0001) (<0.0001) 4701 vs (<0.0001) (<0.0001) (<0.0001) 1 Number of observations N=37; values in parentheses are significance values (<0.0001) (<0.0001) (<0.0001) (<0.0001) 68

69 Figure 20. Distribution of total P (TP) concentrations in drainage water samples collected from November 2010 through April The sign in the box is the mean, horizontal line in the box is the median, the top and bottom of the box represents 75th and 25th percentile, whereas the whiskers define the 5th and 95th percentile observations, and o sign outside the boxes are outliers. 69

70 P (mg/l) % P Fraction PP SRP DOP Farm ID Figure 21. Drainage water average P speciation concentrations and percent of total P by farm from November 2010 through April

71 BMP Training Workshops Two BMP training sessions were conducted in the past year. Sessions were held on September 29, 2011 and April 19, 2012 respectively. On both occasions there was an excellent turnout of attendees; over 200 participants attended counting both training sessions. Both workshops lasted for over 4 hours and included talks by experts on topics pertinent to the EAA basin and South Florida ecosystem restoration. The evaluations received from participants at the conclusion of both sessions were very positive. The speakers and their presentation titles are listed in Table 17 below. Table 17. Speakers, affiliations, and presentations for BMP training workshops held in WY Speaker Affiliation Presentation Title Samira Daroub, PhD EREC/UF/IFAS Everglades Program Chapter 40E-63, F.A.C. Timothy Lang, PhD EREC/UF/IFAS BMP Research Update: Management of Floating Aquatic Vegetation Manohardeep Josan, PhD EREC/UF/IFAS Sediment and Particulate Control Practices Jehangir Bhadha, PhD EREC/UF/IFAS BMP Program and Performance Overview Les Baucum, MS Regional Agronomic Extension Agent II Wise Use of Pesticides With Emphasis on Atrazine and Ametryn Mabry McCray, PhD EREC/UF/IFAS Nutrient Application and Control Practices Doug Pescatore, MS SFWMD EAA Basin Phosphorus Loads Bill Donovan, PhD SFWMD BMP Verification Methodology Ron Rice, PhD Sugarcane and Rice Extension Agent IV Managing Aquatic Weeds in EAA Farm Canals Lyn Gettys, PhD FLREC/UF/IFAS Managing Aquatic Weeds in Farm Canals Tom MacVicar, MS Private Consultant What s Going On With Lake Okeechobee? Barry Glaz, MS USDA/ARS Canal Point Sugarcane Production and BMPs The BMP Regulatory Program (Rule 40E-63) was explained in detail by Samira Daroub, Professor at EREC. Dr. Daroub covered the history of the BMP rule and the development of its many regulations and requirements. Specific requirements and terms of the rule regarding EAA 71

72 farming operations were explained and discussed with the participants. In addition a synopsis of Everglades restoration and the state of the current efforts was provided. The wise use of Atrazine and Ametryn, two commonly applied sugarcane herbicides was covered by Les Baucum, Hendry County Extension Agent II with IFAS/UF. The importance of safe handling and application of all pesticides, but especially these two indicator pesticides was explained in terms and consequences that the participants could identify. Techniques to minimize risks to environment and applicators were stressed which included anti-siphon check valves, setbacks from water bodies, importance of pesticide labels, meaning of LD50 and half-life, and others. Dr. Timothy Lang, Research Scientist and Project Manager for the FAV impact on farm P loads project, presented an overview of the various undertakings with respect to the ongoing project with the EAA-EPD and the SFWMD, and plans for future work. The final scope of work was presented along with farm selection criterion and some preliminary findings. Dr. Jehangir Bhadha, Research Associate in Soil and Water Science at EREC provided an in depth review of the BMP Program and its recent performance. He reviewed annual EAA basin P loadings and related them to their associated parameters of annual rainfall amount and distribution and rainfall effects on farm drainage water volume and P concentration. Phosphorus fertilizer application and control practices in the EAA were presented by Dr. Mabry McCray, Associate Scientist of Agronomy at EREC. Dr. McCray discussed methods to reduce the negative environmental impacts of P fertilizer application that included calibrated soil testing, banding of P fertilizers, effects of different P sources on P solubility, recommended fertilizer spill prevention protocols, and soil ph and P availability relationships, and sugarcane leaf P analysis and the Diagnostic Recommendation Integrated System (DRIS) was explained. Sediment and particulate control practices were described by Dr. Josan Manohardeep Singh, Research Associate in Soil and Water Science at EREC. Twelve techniques that are commonly employed on EAA farms to minimize sediment generation and transport were presented and discussed. Proper implementation of each technique was emphasized. A thorough presentation of the requirements for the successful verification of BMPs implemented at the farm level was provided by Dr. William Donovan, Senior Scientist at the SFWMD Everglades Regulation Division. Bill covered the methodology that the SFWMD uses 72

73 to verify proper BMP implementation on EAA farms, which included the rationale and documentation requirements for BMP verification. First-hand experience of implementing rainfall detention practices was provided by Mark Howell, environmental and water resources manager of Florida Crystals Corporation. Mark explained the practices and requirements for successful implementation of this integral BMP. He thoroughly discussed pump log requirements, rainfall determinations for pump operations, canal level start and stop elevations, and recognized exception events. The management of aquatic weeds in EAA farm canals was presented by Dr. Ron Rice, Palm Beach County Extension Agent II with the UF/IFAS. The five most prevalent floating aquatic weeds found in EAA farm canals were reviewed and their control practices discussed. Dr. Rice presented methods to minimize the negative impacts of floating aquatic vegetation on water quality and Farm P loads. The critical management of water tables and sugarcane production was clarified by Barry Glaz, Research Agronomist with the USDA at Canal Point, Florida. The relationships between sugarcane water management practices and their effects on crop yield, drainage waters, and soil were presented. Barry s research results from high water table and flooded sugarcane experiments were discussed. Possible management practices for field implementation were suggested and discussed with participants. Mr. Douglass Pescatore, Senior Programmer/Project Manager, SFMWD, gave us an in depth review of annual EAA basin, sub-basin, and farm P loads. Associated parameters were also presented and discussed along with strategies to improve BMP performance at the farm and sub-basin levels. Dr. Lyn Gettys, Weed Scientist at the Fort Lauderdale, UF/IFAS discussed the five most prevalent floating aquatic weeds found in EAA farm canals and also reviewed control practices. Her presentation highlighted some of the methods used to minimize impacts on water quality and farm P loads. Mr. Tom MacVicar, Hydrologist with MFL Associates discussed the relationships between Lake Okeechobee and its surrounding inflow and outflow basins. He also spoke about the historical and future trends of water quality and stage level within Lake Okeechobee, and explored potential treatment options to reduce P levels in the Lake. 73

74 Photo 5. Images of selected speakers from BMP training sessions held at the EREC in September 2011 and April