We wish to thank Pablo Vital and Johnny Mosley for help with field sampling, and Viviana Nadal and Irina Ognevich for help with laboratory analyses.

1. Datalogger Installation and Workings
<ol>
	<li>Identify a study farm and install a datalogger that triggers an autosampler to collect composite flow samples on a flow proportional basis, which requires monitoring canal levels, pump head revolutions, and pump calibration equation.</li>
</ol>
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56088/56088fig1.jpg" /> 
Figure 1: ISCO sampler used to program auto-sampling proce...

<ol>
	<li>Sims, J. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphorus+loss+in+agricultural+drainage:+historical+perspective+and+current+research.">Phosphorus loss in agricultural drainage: historical perspective and current research.</a> J. Environ. Qual. 27, 277-293 (1997).</li><li>Van Esbroeck, C. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+and+subsurface+phosphorus+export+from+agricultural+fields+during+peak+flow+events+over+the+non-growing+season+in+regions+with+cool,+temperate+climates.">Surface and subsurface phosphorus export from agricultural fields during peak flow events over the non-growing season in regions with cool, temperate climates.</a> J. Soil Water Conserv. 72, 65-76 (2017).</li><li>Bhadha, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphorus+mass+balance+and+internal+load+in+an+impacted+subtropical+isolated+wetland.">Phosphorus mass balance and internal load in an impacted subtropical isolated wetland.</a> Water Air Soil Pollut. 218, 619-632 (2011).</li><li>Eyre, B. D., McConchie, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+implications+of+sedimentological+studies+for+environmental+pollution+assessment+and+management:+Examples+from+fluvial+system+in+north+Queensland+and+western+Australia.">The implications of sedimentological studies for environmental pollution assessment and management: Examples from fluvial system in north Queensland and western Australia.</a> Sediment. Geol. 85, 235-252 (1993).</li><li>Bhadha, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soil+phosphorus+release+and+storage+capacity+from+an+impacted+subtropical+wetland.">Soil phosphorus release and storage capacity from an impacted subtropical wetland.</a> Soil Sci. Soc. Amer. J. , 74 (2010).</li><li>Kenney, W. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-basin,+mass-balance+approach+for+identifying+critical+phosphorus-loading+thresholds+in+shallow+lakes.">Whole-basin, mass-balance approach for identifying critical phosphorus-loading thresholds in shallow lakes.</a> Journal of Paleolim. 51, 515-528 (2014).</li><li>Freebairn, D. N., Wockner, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+study+of+soil+erosion+on+vertisols+of+the+Eastern+Darling+Downs,+Queensland.+Effects+of+surface+conditions+on+soil+movement+within+contour+bay+catchments.">A study of soil erosion on vertisols of the Eastern Darling Downs, Queensland. Effects of surface conditions on soil movement within contour bay catchments.</a> Aust. J.Soil Res. 24, 135-158 (1986).</li><li>Erickson, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Optimizing stormwater treatment practices: a handbook of assessment and maintenance. , (2013).</li><li>Abtew, W., Obeysekera, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drainage+Generation+and+Water+Use+in+the+Everglades+Agricultural+Area+Basin.">Drainage Generation and Water Use in the Everglades Agricultural Area Basin.</a> J. Amer. Water Res. Asso. 32, 1147-1158 (1996).</li><li>Daroub, S. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Best+management+practices+and+long-term+water+quality+trends+in+the+Everglades+Agricultural+Area.">Best management practices and long-term water quality trends in the Everglades Agricultural Area.</a> Cri. Rev. Environ. Sci. Technol. 41, 608-632 (2011).</li><li>Bhadha, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+suspended+particulates+on+phosphorus+loading+exported+from+farm+drainage+during+a+storm+event+in+the+Everglades+Agricultural+Area.">Influence of suspended particulates on phosphorus loading exported from farm drainage during a storm event in the Everglades Agricultural Area.</a> J. Soil Sed. 17, 240-252 (2017).</li><li>Diaz, O. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sediment+inventory+and+phosphorus+fractions+for+water+conservation+area+canals+in+the+Everglades.">Sediment inventory and phosphorus fractions for water conservation area canals in the Everglades.</a> Soil Sci. Soc. Amer. J. 70, 863-871 (2006).</li><li>Reddy, K. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Forms+of+soil+phosphorus+in+selected+hydrologic+units+of+Florida+Everglades.">Forms of soil phosphorus in selected hydrologic units of Florida Everglades.</a> Soil Sci. Soc. Amer. J. 62, 1134-1147 (1998).</li><li>Hedley, M. J., Stewart, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+to+measure+microbial+phosphate+in+soils.">Method to measure microbial phosphate in soils.</a> Soil Biol. Biochem. 14, 377-385 (1982).</li><li>O'Dell, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Method 365.1, Revision 2.0: Determination of Phosphorus by Semi-Automated Colorimetry. , (1993).</li><li>Bhadha, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+aquatic+vegetation+on+phosphorus+loads+in+the+Everglades+Agricultural+Area.">Effect of aquatic vegetation on phosphorus loads in the Everglades Agricultural Area.</a> J. Aqu. Pla. Man. 53, 44-53 (2015).</li></ol>

The autosamplers for drainage water particulate collection were placed near the exiting pump station dataloggers. Power was supplied by 12 V batteries that are charged by solar panels. The autosamplers were controlled by the on-site dataloggers, which turned the autosamplers on when the exit pumps ran, and turned them off when pumping stopped. Openings of the sampler intake lines were positioned 0.5 m above the canal bottom and upflow from the pump station. The intake lines were held in place by installing a metal rebar ...

The fate and transport of suspended particulates has been the subject of numerous studies due to its role in eutrophication, particularly in agricultural systems1,2. A comprehensive evaluation of nutrients contained in particulate matter within an aquatic system is necessary to investigate numerous environmental issues such as, the internal cycling of nutrients and release to the overlying water column3, substrate stability, light availability within the water column, and eventually water quality concerns to downstream ecosystems4. The quantity of phosphorus (P) stored in the particulate form (organic matter or sediments) is typically greater than in the water column5. A study conducted by Kenney et al.6 showed that recent sediments that were deposited in Lake Lochloosa, Florida were between the age range of 1900 and 2006. These younger sediments contained nearly 55 times more P than that which was present in the water column. One approach to characterize the potential impact that particulates may have on a particular system is to conduct a quantitative inventory of phosphorus stored in sediment discharged during drainage events. Collection and analysis of these discharged particulates can help estimate downstream nutrient enrichment impacts on sensitive ecosystems.
Storm events typically represent a small fraction of time, yet may contribute the majority of P load discharge in farm drainage. This is because in order to prevent fields from flooding, a large volume of water is drained over short periods of time. Rainfall intensity and flow rates are vital driving factors that can control the concentration of suspended sediments in overland runoff7. Designing monitoring methods that captures flow-weighted composite water samples would help avoid errors associated with complex, high intensity rain events. During high discharge events like storms, the quick and drastic changes in concentrations may not be representative of the average pollutant concentration for the incremental volume. Therefore, flow-weighted water samples far more accurately represents the concentration of a discharge event as it is a summation of loads over a period of time8. The most common flow-weighted samples are automatically collected discrete or composite samples. By capturing the exported suspended particulates from farm drainage during discharge allows us to quantify the severity of the event on P loading. The method described in this study helps capture the particulates that can later be characterized for various physical and chemical properties. The novelty of sampling drainage discharge using a continuous composite flow method versus grab sampling is that it is a better representation of field conditions over the entire duration of the drainage event. Whereas, grab sampling is a &#8220;snapshot&#8221; in time and may not fully represent the effect of the entire event.
The Everglades Agricultural Area (EAA) in South Florida, USA is a large expanse of the original Everglades that was channelized and drained for farming, commercial, and residential development. Nearly 1,100 million m3 of water is discharged annually from and through the EAA to the south and southeast9. Soils in the EAA are Histosols that commonly contain over 85% organic matter by weight and have less than 35% mineral content10. Canal sediments typically have low bulk density (between 0.14 g cm-3 to 0.35 g cm-3), high organic matter content (between 31 - 35%) and Total P (TP) values ranging between 726 -1,089 mg kg-1 11.
For the purpose of this demonstration, a farm within the EAA was selected. The hydroscape of how water flows within the EAA depends on pumps and gravity. Each farm in the EAA comprises on at least one main canal, and multiple field ditches. The field ditches run perpendicular to the main canal. The pumps typically serve a dual purpose; they deliver irrigation water to the farm, and also discharge drainage water off-site. When the fields need to be drained, water in the main canal is lowered, and water from the field drains into the ditches, driven by a hydraulic gradient. Due to only a slight slope in surface most of the rainfall that occurs on the fields flows through the soil profile in transit to the field ditches.&#160; During irrigation, the system is reversed. There is no network of tile drainage in the EAA. The water table is maintained at a specific height due to a confining layer of limestone bedrock underling the soils.&#160; Water is brought in through the main canals; field ditches are filled, and water is allowed to seep into the soil profile to raise the water table levels in the fields. Typically, demands for irrigation water in the EAA occur during March, April, and May (dry season), with very little drainage discharge. In contrast, the volume of water being discharged between June and October (wet season) is significantly higher. The presence of canal bank berms and ditches allows for minimal surface runoff as a potential source of P loading into farm canals12.
In this visual experiment, we present a novel method of capturing flow-weighted suspended particulates during drainage events that can later be used for physico-chemical characterization such as bulk density, organic matter content, and P fractionation13,14.

<table width="602">
	<tbody>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Datalogger</td>
			<td style="width:83px;">Campbell Scientific</td>
			<td style="width:137px;"></td>
			<td style="width:167px;">model CR1000</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Auto-sampler</td>
			<td style="width:83px;">ISCO</td>
			<td style="width:137px;"></td>
			<td>model 3700</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Pressure transducer</td>
			<td style="width:83px;">KPSI</td>
			<td style="width:137px;"></td>
			<td>model 700</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Tipping bucket rain guage</td>
			<td style="width:83px;">Texas Electronics</td>
			<td style="width:137px;"></td>
			<td>model TR-525</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Potassium Chloride</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">7447-40-7</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Sodium Hydroxide</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">1310-73-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Hydrochloric Acid</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">7647-01-0</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Sulfuric Acid</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">7664-93-9</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Potassium Persulfate</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">7727-21-1</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Ammonium Molybdate Tetrahydrate</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">12054-85-2</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">L-Ascorbic Acid</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">50-81-7</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">100 mg/L Anhydrous Phosphate Standard</td>
			<td style="width:83px;">ERA</td>
			<td style="width:137px;">061</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Antimony Potassium Tartrate Trihydrate</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">28300-74-5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Durapore Membrane Filters</td>
			<td style="width:83px;">Millipore</td>
			<td style="width:137px;">HVLP04700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Whatman #41 Filter Paper</td>
			<td style="width:83px;">Whatman</td>
			<td style="width:137px;">1441-150</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Fixed Speed Reciprocal Shaker E6010</td>
			<td style="width:83px;">Eberbach Corporation</td>
			<td style="width:137px;">E6010.00</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Disposable Culture Tubes</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">14-961-29</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Allegra 25R Centrifuge</td>
			<td style="width:83px;">Becker Coulter</td>
			<td style="width:137px;">U.S. 605168-AC</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Parafilm</td>
			<td style="width:83px;">Bemis Company Inc PM 999</td>
			<td style="width:137px;">13-374-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Oak Ridge Centrifuge Tubes</td>
			<td style="width:83px;">Nalgene</td>
			<td style="width:137px;">3119-0050</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Fisherbrand 20mL HDPE Scintillation Vials with Urea Cap</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">03-337-23C</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Fisherbrand&#160;Natural Polypropylene Jars with White Polypropylene Unlined Cap</td>
			<td style="width:83px;">Fisher</td>
			<td style="width:137px;">02-912-024A</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">0.45 membrane filters</td>
			<td style="width:83px;">Cole-Parmer</td>
			<td>Item # UX-15945-25</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">100 ml digestion tubes</td>
			<td style="width:83px;">Fisher&#160;</td>
			<td>TC1000-0735</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Glass funnels</td>
			<td style="width:83px;">Fisher</td>
			<td>03-865</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Spectronic 20 Genesys</td>
			<td style="width:83px;">Thermo-Fisher</td>
			<td>4001-000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">QuikChem</td>
			<td style="width:83px;">Latchat</td>
			<td style="width:137px;">8500</td>
			<td></td>
		</tr>
	</tbody>
</table>

capturing flow-weighted water and suspended particulates from agricultural canals during drainage events

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage discharge events. Farm canals can be enriched by nutrients such as phosphorus (P) that are susceptible to transport. Phosphorus in the form of suspended particulates can significantly contribute to the overall P loads in drainage water. A settling tank experiment was conducted to capture suspended particulates during discrete drainage events. Farm canal discharge water was collected in a series of two 200 L settling tanks over the entire duration of the drainage event, so as to represent a composite subsample of the water being discharged. Imhoff settling cones are ultimately used to settle out the suspended particulates. This is achieved by siphoning water from the settling tanks via the cones. The particulates are then collected for physico-chemical analyses.

The method described in this study allows us to capture water and particulate matter that is being discharged during pumping events in farms canals. The water and particulates that are collected are flow-weighted, which means that they are representative of the entire duration of the pumping event and not just a onetime snapshot; making it highly representative of the type of material being discharged. The water and suspended particulates can be stored to be analyzed for various physical ...

Watch this Scientific Journal Video about Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events at JoVE.com

Capturing Flow-weighted Water and Suspended Particulates from Agricultural Canals During Drainage Events

Nutrients present in particulate form can contribute significantly to the overall loads in agricultural drainage waters. This study describes a novel method to capture flow-weighted water and suspended particulates from farm canal drainage over the entire duration of the drainage event.

The purpose of this study is to describe the methods used to capture flow-weighted water and suspended particulates from farm canals during drainage ...

The overall goal of this procedure is to provide a novel method for capturing in situ composite flow-weighted farm canal discharge water and suspended particulates during drainage events for their physical chemical characterization. This method will help address the most fundamental step in the field of environmental hydrology, which is collecting a water sample that fully represents a flow event in its entirety. The main advantages of this technique are that it is automated and that it provides a composite sample that is highly representative of typical discharge material present during flow events.This method can provide insight into water quality parameters during routine drainage events as well as during storm events when large volumes of water are discharged over multiple days. Designing monitoring methods that capture flow-weighted composite water samples could help avoid errors associated with complex, high-intensity rain events. Demonstrating the procedure will be research associate, Doctor Timothy Lang, along with field technicians, Pablo and Johnny.After identifying a study farm, install a datalogger near the pump station that triggers an auto-sampler to collect composite flow samples on a flow proportional basis. Use the pressure transducers installed in the inflow and outflow canals, adjacent to the pump station, to monitor the farm canal levels and use the proximity switches installed on the pump heads to monitor the pump speed. To calculate the drainage, use a datalogger and a pump calibration equation for each pump.To program the in situ automated sampler located at the pump station to capture daily composite water samples, first press Enter Program. Then press Program, Flow-based Sampling, Sample every one pulses, 30 composite samples and Sample Volume of 130 milliliters. Press Enter for calibrate sample volume and for Enter Start Time.Then press Program Sequence Complete. Then store the flow-weighted composite samples in an onsite refrigerator at four degrees Celsius until their analysis. To capture suspended particulates, position two, 200 liter PVC settling tanks a few feet from the datalogger to collect farm canal discharge water over the duration of the drainage period.To program the datalogger to collect the particulate samples, press Program, Time-Based Sampling and Sample every two minutes. For composite samples, select 200 and select No for calibrate sample volume and enter start time. Then press Sequence Complete and push Sampling button.Two liters of flow-weighted drainage water will be collected in the settling tanks, every two minutes. As the particulates begin to settle in the tanks, use a hose to siphon off the excess water and transfer the particulates into five-gallon buckets for transport back to the lab for 24-hour equilibration at four degrees Celsius. When the particulates have settled, siphon off the excess water and transfer the particulates into Imhoff settling cones.After one hour, siphon off the excess water one last time and transfer the settled particulates into pre-weighed 500 milliliter screw top jars. Be sure to collect the water below the surface and away from the sides of the cone to reduce the number of aspirated particulates. In this representative experiment, suspended particulates from three farm canals within the Everglade Agricultural Area were collected as demonstrated, and determined to be highly organic, to possess a low bulk density and to be rich nutrients like phosphorous, properties that are highly representative of the water and sediments typically found for the Everglades Agricultural Area soil types and surrounding land use practices.While attempting this procedure, it's important to remember to allow the particulates to fully settle before removing excess water. Following this procedure, other methods like phosphorous fractionation using the Hedley et al. method, can be used to evaluate how much labile versus recalcitrant phosphorous is present in the particulates.After watching this video, you should have a good understanding of how to collect a composite flow-weighted discharge water as opposed to grab sampling. By having a refrigerator onsite, it is possible to preserve the water samples at four degrees Celsius. An added advantage of using this method for collecting water samples is that it is automated and it can be used to capture discharge events associated with storms and hurricanes that can last up to a few days.

capturing-flow-weighted-water-suspended-particulates-from

Research

JoVE Journal

Environment

15.4K visualizações.  University of Florida. The overall goal of this procedure is to provide a novel method for capturing in situ composite flow-weighted farm canal discharge water and suspended particulates during drainage events for their physical chemical characterization. This method will help address the most fundamental step in the field of environmental hydrology, which is collecting a water sample that fully represents a flow event in its entirety. The main advantages of this technique are that it is automated and that it provi...