Submitted to the Everglades Agricultural Area Environmental Protection District And The South Florida Water Management District By

Transcription

1 Implementation and Verification of BMPs for Reducing P Loading from the Everglades Agricultural Area: Floating Aquatic Vegetation Impact on Farm Phosphorus Load 2011 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 2011

2 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. 2

3 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 Title Principal Investigator Project Manager QA/QC Officer and Lead Scientist Lead Scientist Head Chemist Chemist Grad Student/Laboratory Technician Field Technician Abbreviations BD Bulk Density DBD Dry Bulk Density DOP Dissolved Organic Phosphorus EAA Everglades Agricultural Area EPD Environmental Protection District EREC Everglades Research and Education Center FAV Floating Aquatic Vegetation LOI Loss on Ignition PP Particulate Phosphorus SFWMD South Florida Water Management District SRP Soluble Reactive Phosphorus TDP Total Dissolved Phosphorus TP Total Phosphorus TSS Total Suspended Solids WBD Wet Bulk Density 3

4 Table of Contents Acknowledgments... 2 Project Personnel... 3 Abbreviations... 3 Introduction... 7 Farm Monitoring Equipment... 9 Farm Descriptions Farm Canal Surveys Materials and Methods Results Physico-chemical Assessment of Canal Sediments Sediment Analyses Results Floating Aquatic Vegetation: Speciation, Coverage and TP Content FAV Sampling Procedure and Analyses Results Water Quality Monitoring Water Sampling Procedures Water Quality Analyses Results BMP Trainings and Workshops Summary and Future Plans References Appendix

5 List of Tables Table 1. Monthly crop acreages and percent acreages by farm Table 2. Summary of farm canal sediment accumulation in meters Table 3. Physico-chemical properties of sediments collected from the eight farms Table 4. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for January Table 5. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for March Table 6. Drainage water P speciation, ph, Ca concentration, and TSS from November 2010 through April Table 7. Daily drainage water volume, total P concentration and load of the eight farms from November 2010 through April Table 8. Summary of phosphorus species concentrations of canal water grab samples from November 2010 to April Table 9. Summary of ph, dissolved calcium, and total suspended solids of the canal water grab samples from November 2010 through April

6 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) Figure 7. Sediment profile of main canal of farm 2501 at three transects (A, B, and C) Figure 8. Sediment profile of main canal of farm 6117 at three transects (A, B, and C) Figure 9. Sediment profile of main canal of farm 1813 at three transects (A, B, and C) Figure 10. Sediment profile of main canal of farm 3102 at three transects (A, B, and C) Figure 11. Sediment profile of main canal of farm 3103 at three transects (A, B, and C) Figure 12. Sediment profile of main canal of farm 4701 at three transects (A, B, and C) Figure 13. Sediment profile of main canal of farm 4702 at three transects (A, B, and C) Figure 14. Distribution of total P and total dissolved P concentrations in canal water grab samples collected from November 2010 through April Figure 15. Distribution of particulate P and soluble reactive P concentrations in grab canal water samples collected from November 2010 through April List of Photos Photo 1. Intact sediment core collected using the piston-coring apparatus Photo 2. Floating aquatic vegetation sampling on a farm canal Photo 3. Datalogger, auto-sampler, and refrigerator installation for collecting drainage water composite samples Photo 4. Images of the BMP training session held at the EREC on 4/28/

7 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 (1994) to achieve 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. Since January 1, 1995, BMP implementation has been mandatory for all farms that discharge drainage water into 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 fifteen years since BMP program initiation, the EAA basin s annual P load reduction has averaged nearly 50% (SFWMD, 2010). Further reductions in farm P loads can 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). 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 7

8 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, most growers control (to varying degrees) the growth of floating aquatic vegetation (FAV) in their canals. However this practice is seldom claimed on BMP permits because there is inadequate scientific knowledge regarding its efficacy and 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 STAs, more so for those STAs performing at less than expected outflow concentrations. This study will quantify changes in sediment composition and drainage water P 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 treatment. 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 st 2010 to April 30 th, 2011 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 specific 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 of FAV management practices on P speciation of farm drainage water and on accumulated sediment physico-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 8

9 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 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 study was approved by the South Florida Water Management District (SFWMD) in January Farms to be included in the project were selected by project personnel and the Water Resources/BMP advisory committee. Selection of three farm pairs was approved by the SFWMD in August 2010, while the final farm pair was approved by SFWMD in September Following the above timeline, this report outlines the various tasks undertaken between May 1 st 2010 up to April 30 th 2011, along with some preliminary results. Farm Monitoring Equipment The eight cooperator farms (Figure 1) have been instrumented with data loggers that monitor canal levels, pump head revolutions, and rainfall, and trigger an autosampler to collect flow samples on a flow proportional basis. Farm dataloggers communicate by radio telemetry to a base radio station located at the Everglades Research and Education Center. Farm canal levels are monitored by pressure transducers that have been installed in the inflow and outflow canals adjacent to each farm s pump station. Pump speed is monitored by proximity switches that have been installed on the pump heads; speed is recorded by the datalogger in revolutions per minute. Rainfall measurement is being monitored by tipping bucket rain gauge that is connected to the datalogger. Dataloggers calculate drainage flow using the SFWMD approved pump calibration equation for each pump. Drainage flow sampling is achieved by an autosampler that is actuated by the datalogger after a trigger drainage volume has been achieved. Sample trigger volumes have been set after reviewing historical farm daily flow 9

10 volumes; sample trigger volumes were calculated to allow for a maximum of 30 samples per 24 hour period. Flow composite samples are stored in an onsite refrigerator; samples are held at 3⁰ C until collection and transportation back to the laboratory for analyses. 10

11 Figure 1. Map of The Everglades Agricultural Area and farm locations. Map courtesy of SFMWD. 11

12 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. From March through May of 2011 Farm 0401 grew sweet corn in approximately 40% of the cropping area. Sweet corn acreage was fallow during the remaining spring season after sweet corn harvest (Table 1). 12

13 Farm 2501 is an 824 acre sugarcane farm that lies north and adjacent to Farm basin It has a single discharge station containing two diesel pumps. From March through May of 2011 this farm grew sweet corn as a rotational crop on nearly 20% of its total cropped acreage. After sweet corn was harvested in May 2011 the acreage was kept fallow. 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. Both farms receive irrigation water from and discharge drainage water directly into the West Palm Beach canal. 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 13% of the farm s cropped area in the spring of After harvest the sweet corn acreage was kept fallow. 13

14 Farm 6117 is a sugarcane farm of 800 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 April 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. 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 from March through May

15 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 Figure 5. Aerial map of farms 4701 and 4702 with pumphouse and canal transect locations. 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 a tertiary district canal that eventually connects with the Hillsboro Canal via the Ocean Canal. Farm 4701 is a 640 sugarcane farm with a single discharge pump station with a single diesel powered pump that discharges drainage water into a tertiary canal that feeds into the 15

16 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 Farm 4702 is a 640 acre sugarcane farm which is located one-half mile east of farm basin 4701; farm 4701 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 April

17 Table 1. Monthly crop acreages and percent acreages by farm. Farm ID Month/Year Cane Fallow Flooded Corn Beans Leaf Acres % Acres % Acres % Acres % Acres % Acres % 0401 Jan Feb Mar Apr May Jun Jan Feb Mar Apr May Jun Jan Feb Mar Apr May Jun Jan Feb Mar Apr May Jun Jan Feb Mar Apr May Jun Jan Feb Mar Apr May Jun Jan Feb Mar Apr May Jun Jan Feb Mar Apr May Jun

18 Farm Canal Surveys Farm canal surveys were conducted to assess individual farm canal dimensions (length, width, area), the thickness of sediments present in the canals, and their chemical characteristics. Materials and Methods 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 pad. 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 (Figure 2-5). These three locations were relatively close to where grab water samples are routinely collected. At each transect location two steel rebars 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 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. Results The overall average thickness of canal sediments for all eight farms, and along all three transects was 0.61 m (± 0.29). 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 4701 had the highest mean sediment thickness of 0.81 m while 4702 had the least mean sediment thickness 0.49 m (Table 2). In transects A and B the highest mean sediment thickness was observed in farm 4701 at 1.02 and 0.75 m respectively, while in transect C the highest mean sediment thickness was observed in farm canal 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. 18

19 Table 2. Summary of farm canal sediment accumulation in meters. Farm ID Mean Std Dev N Minimum Maximum Median 1 Overall Transect A Transect B Transect C Overall= average of three transects 19

20 thickness (m) thickness (m) thickness (m) A channel bottom sediment surface canal width (m) B channel bottom sediment surface canal width (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). 20

21 thickness (m) thickness (m) thickness (m) channel bottom sediment surface A canal width (m) channel bottom sediment surface B canal width (m) channel bottom sediment surface C canal width (m) Figure 7. Sediment profile of main canal of farm 2501 at three transects (A, B, and C). 21

22 thickness (m) thickness (m) thickness (m) A channel bottom sediment surface canal width (m) B channel bottom sediment surface canal width (m) channel bottom sediment surface 6117-C canal width (m) Figure 8. Sediment profile of main canal of farm 6117 at three transects (A, B, and C). 22

23 thickness (m) thickness (m) thickness (m) channel bottom sediment surface A canal width (m) channel bottom sediment surface B canal width (m) channel bottom sediment surface C canal width (m) Figure 9. Sediment profile of main canal of farm 1813 at three transects (A, B, and C). 23

24 thickness (m) thickness (m) thickness (m) channel bottom sediment surface A canal width (m) channel bottom sediment surface B canal width (m) channel bottom sediment surface C canal width (m) Figure 10. Sediment profile of main canal of farm 3102 at three transects (A, B, and C). 24

25 thickness (m) thickness (m) thickness (m) channel bottom sediment surface A canal width (m) channel bottom sediment surface B canal width (m) channel bottom sediment surface C canal width (m) Figure 11. Sediment profile of main canal of farm 3103 at three transects (A, B, and C). 25

26 thickness (m) thickness (m) thickness (m) channel bottom sediment surface A canal width (m) channel bottom sediment surface B canal width (m) channel bottom sediment surface C canal width (m) Figure 12. Sediment profile of main canal of farm 4701 at three transects (A, B, and C). 26

27 thickness (m) thickness (m) thickness (m) channel bottom sediment surface A canal width (m) channel bottom sediment surface B canal width (m) channel bottom sediment surface C canal width (m) Figure 13. Sediment profile of main canal of farm 4702 at three transects (A, B, and C). 27

28 Physico-chemical Assessment of Canal Sediments Sediment characterization of the eight farms was conducted in November Intact sediment cores (approximately 25 cm long) were collected from three transects along main farm canal of each farm. The sediments were collected on November 2-3, 2010 using a piston type inhouse 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 ph, organic matter (OM), total P, wet bulk density (WBD) and dry bulk density (DBD). Photo 1. Intact sediment core collected using the piston-coring apparatus. 28

29 Sediment Sample Preparation 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 (Anderson, 1974). Results are reported on an oven dry-weight basis. Sediment Analyses Sediment ph, was measured with a glass calomel electrode assembly using 1:2 soil water suspensions (method 9045D, EPA 2004). 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 was determined using EREC-SOP Organic Matter (adapted from Soil Survey Laboratory Methods Manual, 2004). Results A summary of the results are reported in Table 3. Overall the mean OM and TP content of the sediments from all eight farms were 40.6 % and 1039 mg/kg respectively. While comparing the two depth horizons (0-2.5 and cm) we found that the mean OM and TP were slightly higher in the cm depth than in the surface 2.5 cm; OM content and TP was 38.4 (±11.1) % and 915 (±184) mg/kg at the depth, while 42.9 (14.5) % and 1162 (±1587) mg/kg respectively at the cm depth. Over the entire 5 cm sediment profile (regardless of depth horizons), Farm 3103 had a mean OM and TP concentration of 34.5 % and 991 mg/kg respectively; Farm 3102 had 31.8 % and 826 mg/kg; Farm 2501 had 40.2 % and 822 mg/kg; Farm 0401 had 45.0 % and 762 mg/kg; Farm 4702 had 37.9 % and 711 mg/kg; Farm 4701 had 42.0 % and 752 mg/kg; Farm 6117 had 42.3 % and 1010 mg/kg; Farm 813 had 51.9 % and 1141 mg/kg. 29

30 Table 3. Physico-chemical properties of sediments collected from the eight farms. Farm ID 1 Transect Depth (cm) ph OM (%) WBD (g/cm 3 ) DBD (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; WBD = wet bulk density; DBD = dry bulk density; TP = total phosphorus 30

31 Floating Aquatic Vegetation: Speciation, Coverage and TP Content An overall assessment of FAV is conducted 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 January and March 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 2. Floating aquatic vegetation sampling on a farm canal. 31

32 Results Following is a summary of the FAV characterization and TP content of FAV biomass from tow sampling trips (January 2011 and March 2011): January 2011 Farm 0401: Overall 30% cover of water lettuce, and 10 % filamentous algae. Farm 2501: Overall clean; no signs of FAV. Farm 1813: Overall clean; no signs of FAV. Farm 6117: Overall 20% cover with duckweed mostly confined to the area near the culverts. Farm 3102: Overall only about 10% of the canal was covered with FAV, dominated by waterlettuce mostly confined along the edges of the canal. The canal running north-south was clean showing no presence of any FAV. Farm 3103: Overall 3% of the canal showed presence of FAV, mostly confined to the canal edges. Farm 4701: Overall 3% confined mostly along the canal edges comprising of filamentous algae. Farm 4702: Overall 7% cover of water lettuce. Table 4. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for January Farm ID Sample # Water content (%) [TP] of dry FAV (mg/kg) P in Farm FAV Mass (kg) Sample description % water lettuce % filamentous algae % duckweed % duckweed % water lettuce % water lettuce % filamentous algae % filamentous algae % filamentous algae % filamentous algae % water lettuce % water lettuce 32

33 March 2011 Farm 0401: Overall 15% cover mostly water lettuce and a bit of filamentous algae. Farm 2501: Overall 15% cover mostly filamentous algae. Farm 6117: Overall 25% cover mostly near the pump station, duck-weed. Farm 1813: Overall very clean canal. No buildup of FAV. Farm 3102: Overall only about 5% of the canal was covered with FAV, dominated by waterlettuce mostly confined to the pump area and in the E-W section of the canal. N-S canal was clean. Farm 3103: Overall 2% of the canal showed presence of FAV, mostly confined to the canal edges. Farm 4701: Overall 5% confined mostly along the canal edges comprising of filamentous algae. Farm 4702: Overall 2% cover of water lettuce. Table 5. FAV sample composition, water content, TP concentration, and mass of TP in farm canal FAV for March Farm ID Sample # Water content (%) [TP] of dry FAV (mg/kg) P in Farm FAV Mass (kg) Sample description % water lettuce % filamentous algae % filamentous algae % filamentous algae % duck-weed % duck-weed % water lettuce % water lettuce % water lettuce % filamentous algae % filamentous algae % filamentous algae % water lettuce % water lettuce Based solely on the mass of TP generated in the canal as a result of senesced FAV, farm 0401 seemed most affected, while farm 3103 had least amount of TP in FAV biomass during January While the March 2011 sampling event showed farm 6117 had the highest P in farm FAV biomass and farm4702 had the least. These results will be eventually incorporated 33

34 with canal pumping flow rate velocities to derive the net TP loads derived from FAV exiting the farm canals. Water Quality Monitoring Farm canal water has been monitored for water quality since November Two types of canal waters have been sampled; (i) ambient condition canal water grab samples, and (ii) drainage water flow composite samples. Grab water samples have been collected regularly from all eight farm main canals at three locations per farm canal (A, B, C). The three grab sampling locations are situated in the near 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 was located near the drainage pump station, whereas location B was located near the halfway point of the main farm canal reach, and location C was located halfway between location B and the end of the main canal reach. The periodicity of grab water sampling was at least two times per month. Grab water samples were not collected during days when a farm was actively discharging drainage water. Drainage water samples were collected by autosampler during drainage events when the farms were actively pumping water off farm. Water Sampling Procedures Ambient canal water samples were 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 was gently immersed approximately 0.5 m below the canal surface while the sample bottle filled with water. The bottles were labeled and preserved on ice while being transported to the EREC lab for analyses. Field blanks and field duplicates were collected at every sampling event. Drainage water samples were collected as a daily composite sample. The composite sample was collected using a solar powered auto-sampler that was triggered by datalogger at set flow discharge volume intervals. Drainage water samples were stored on site in refrigerated containers until sample collection. Sample collection occurred within 24 hours of the initial drainage water sample collection (Photo 3). 34

35 Water Quality Analyses All water samples were analyzed for total P (TP), total dissolved P (TDP), soluble reactive P (SRP), total suspended solids (TSS), ph, and dissolved calcium. 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. The respective method detection limits for TP, TDP, and SRP were 0.004, 0.004, 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 250 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. This method is based on method (USEPA, 2004) and details of the method are available in EREC Quality Manual Ver. 7.0 (SOP 13 Rev. 3). The total suspended solid were calculated using the following equation: ( weightofdryfilter residue dish weightofdryfilter dish) TSS mg / L Samplevolume The ph of the water samples were determined using a combination glass electrode. The total dissolved Ca levels, hereafter referred as Ca, were analyzed using an atomic absorption spectrophotometer. 35

36 Photo 3. Datalogger, auto-sampler, and refrigerator installation for collecting drainage water composite samples. Results Farm Drainage Water Concentrations of various P species, ph, Ca, and TSS levels for drainage water samples are presented in Table 6. Due to the prevailing dry weather and very limited drainage pumping requirements, we were able to collect a limited number of drainage water samples, therefore results of individual drainage events are presented in this report. During the study period, farm 6117 did not generate any drainage events. Farm 1813 generated two drainage water samples, however the measured TP values of farm 1813 failed the QA\QC control criteria and therefore are not reported. Overall, the TP concentrations ranged from mg/l (farm 4701) to mg/l (farm 3103); the TDP concentrations varied from mg/l (farm 4702) to mg/l (farm 3103) (Table 6). Farm 4701 had the lowest PP concentrations of mg/l, and farm 0401 exhibited the highest PP concentrations of mg/l. For the SRP concentration a minimum value of mg/l was observed at farm 4701, and a maximum of mg/l was observed at farm The drainage water ph values ranged from 7.7 to 8.6 that showed typical EAA farm canal water alkalinity levels (Chen et al. 2006). Similarly, the Ca concentrations varied from 36.2 to 60.6 mg/l. The TSS values ranged from 1.8 mg/l to 33.1 mg/l (Table 6). 36

37 Daily total P loads were also calculated from the drainage flow data (Table 7). The maximum TP load of lbs/ac was observed during the drainage event on 3/30/2011 in farm 3103, whereas the minimum TP load of lbs/ac was observed on 3/30/2011 and 3/31/2011 in farms 4701 and 2501 respectively. The average TP loads of 0.010, 0.004, 0.013, and lbs/ac were observed for the farms 0401, 2501, 3012, and 3103 respectively. Preliminary results suggested that most of the time farm pairs had similar TP concentration of drainage water, but exhibited different TP loads. The dry weather had limited our ability to collect drainage water. Therefore, we anticipate more drainage events during the upcoming wet season will provide a detailed insight into the farm canal drainage TP concentrations and loads. Ambient Canal Water The results of 12 water samplings of ambient canal conditions at three set locations on each farm are summarized in Tables 8 and 9. The distribution of P species with matching farm pairs is presented in the form of Box-plots (Figures 14 and 15). Additionally, the individual sampling event data is also presented in the Appendix A (Table A1-A8). For farm pair 0401 and 2501 the average TP values were (± 0.023) mg/l and (±0.068) mg/l respectively. The highest TP values of and mg/l were observed on 3/2/2011 and 3/16/2011 for the farms 0401 and 2501 respectively. Farm 2501 had a higher TDP, and SRP concentrations than the farm 0401, whereas both farm exhibited similar PP concentrations. For farm pair 1813 and 6117 the average TP concentration was (± 0.033) mg/l and (± 0.049) mg/l respectively. The maximum TP values of and mg/l were observed on 2/9/2011 and 1/4/2011 for the farm 1813 and 6117 respectively. Amongst all of the farms, farm 6117 exhibited the highest TP content and other P species concentrations; however, this farm did not produce any drainage water during the study period. For the farm pair 3102 and 3103 the average TP concentrations vales were (± 0.083) & (± 0.032) mg/l respectively. Amongst all of the farms, the farm 3102 showed wide variability in TP, TDP, and SRP (Figure 14 and 15), and the maximum TP values of and mg/l were observed on 3/16/2011 and 3/30/2011. Farm 3102 had higher average SRP concentration (0.053 ± 0.038) than the farm 3103 (0.024 ± 0.020). 37

38 Total P concentrations of the grab water samples collected from the farm 4701 exhibited more variability than that of farm Farm 4701 had the higher average TP (0.058 ± 0.049) concentrations than that of 4702 (0.042 ± 0.032). The maximum TP values of and were observed on 2/23/2011 and 3/16/2011 for the farm 4701 and 4702 respectively. Farm 4702 had the lowest average SRP (0.006 ± amongst the entire farms, with a maximum value of mg/l. A summary of canal water ph, dissolved Ca and TSS is presented in Table 9. For the entire grab sampling events, the ph values ranged from 7.1 to 8.9 with an overall mean of 8.2. The Ca concentrations varied from 28.2 to 38.2 mg/l with an overall mean of 58.9 mg/l. The TSS content ranged from 0.5 to mg/l, with an overall mean of 8.7 mg/l. 38

39 Total dissolved -P (mg/l) Total-P (mg/l) Farm ID Farm ID Figure 14. Distribution of total P and total dissolved P 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. 39

40 Soluble reactive -P (mg/l) Particulate -P (mg/l) Farm ID Farm ID Figure 15. Distribution of particulate P and soluble reactive P concentrations in grab canal 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 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. 40

41 Table 6. Drainage water P speciation, ph, Ca concentration, and TSS from November 2010 through April Farm ID sampling date 1 TP (mg/l) TDP (mg/l) PP (mg/l) SRP (mg/l) ph Ca (mg/l) TSS (mg/l) /29/ /30/ nd nd nd /31/ /29/ nd nd nd /30/ nd nd /31/ /30/ nd nd nd /31/ /01/ /28/ /29/ /30/ /30/ /30/ TP= total-p, TDP= total dissolved-p, PP=particulate-P, SRP= soluble reactive-p, and DOP= dissolved organic-p. nd= not determined 41

42 Table 7. Daily drainage water volume, total P concentration and load of the eight farms from November 2010 through April Drainage TP conc. TP load TP load Farm ID Sampling date (Gal/ac) (mg/l) (lbs) (lbs/ac) /29/ , /30/ , /31/2011 5, /29/2011 5, /30/ , /31/2011 4, /30/ ,717 nd nd nd /31/ ,668 nd nd nd /30/2011 9, /31/ , /1/2011 5, /28/ , /29/ , /30/ , /30/2011 7, /30/ , nd= not determined 42

43 Table 8. Summary of phosphorus species concentrations of canal water grab samples from November 2010 to April Farm ID N 1 Variable Mean Median Std. Dev. Minimum Maximum (mg/l) TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP TDP PP SRP DOP TP= total-p, TDP= total dissolved-p, PP=particulate-P, SRP= soluble reactive-p, and DOP= dissolved organic-p. 43

44 Table 9. Summary of ph, dissolved calcium, and total suspended solids of the canal water grab samples from November 2010 through April Farm ID N 1 Variable Mean Std. Dev. Minimum Maximum ph Ca (mg/l) TSS (mg/l) ph Ca (mg/l) TSS (mg/l) ph Ca (mg/l) TSS (mg/l) ph Ca (mg/l) TSS (mg/l) ph Ca (mg/l) TSS (mg/l) ph Ca (mg/l) TSS (mg/l) ph Ca (mg/l) TSS (mg/l) ph Ca (mg/l) TSS (mg/l) Ca= total dissolved Calcium; TSS= total suspended solids. 44

45 BMP Trainings and Workshops Two BMP training and workshop sessions were organized since submission of last annual report. The sessions were conducted on September 22, 2010 and April 28, 2011 respectively. On both the occasions we witnessed an excellent turnout of attendees- 106 (on 09/22/2010) and 88 (on 04/28/2011). The workshop sessions lasted for about 5 hours and included talks by numerous speakers on a wide variety of topics. The evaluations received at the end of both the sessions were extremely positive. Some of the talks have been summarized below: Speaker Presentation Title Dr. Samira Daroub Everglades Program Chapter 40E-63, F.A.C. Dr. Timothy Lang BMP Research Update: Management of Floating Aquatic Vegetation Dr. Manohardeep Josan Sediment and Particulate Control Practices Dr. Jehangir Bhadha BMP Program and Performance Overview Mr. Les Baucum Wise Use of Atrazine and Ametryn Dr. Mabry McCray Nutrient Application and Control Practices Mr. Julio Sanchez EAA Drainage Pumps and Pumping Efficiencies Dr. Bill Donovan BMP Verification Methodology Dr. Ron Rice Managing Aquatic Weeds in EAA Farm Canals Mr. Barry Glaz Sugarcane Production and BMPs Mr. Mark Howell Rainfall Detention Practices The BMP Regulatory Program (Rule 40E-63) was explained in detail by Samira Daroub, Associate Professor of Soil Chemistry 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 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 45

46 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 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 Mabry McCray, Assistant Scientist in Soil Science 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. The importance of drainage pumps and their pumping efficiencies and canal flow velocities was covered by Julio Sanchez of TRUFLOW Inc. Mr. Sanchez explained the technical engineering aspects of this crucial component of every EAA farm s BMP program. These aspects included pump calibrations, pump types, pump designs, fuel efficiencies, and the effects of start/stop and slowed running of drainage pumps. 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 to verify proper BMP implementation on EAA farms, which included the rationale and documentation requirements for BMP verification. 46

47 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. 47

48 Photo 4. Images of the BMP training session held at the EREC on 4/28/