Microplastics in the Mississippi River and Mississippi Sound

Final Report

Year: 2020 Authors: Cizdziel J.

Led by consumer products, the worldwide demand for plastic continues to grow with global production at nearly 350 megatons in 2017 (Plastics Europe 2018). Unfortunately, careless discarding of plastic and mishandling of the plastic waste stream has resulted in widespread plastic pollution, including the infamous oceanic garbage patches (Lebreton 2018). Further, plastics in the environment weather and degrade as a result of ultraviolet radiation, microorganisms, temperature changes, and mechanical forces (e.g. wave action), yielding smaller and smaller particles called micro- and nano-plastics. Here, we focus on MPs, which have been described as "any synthetic solid particle of polymeric matrix, with regular or irregular shape and with size ranging from 1 ?m to 5 mm, of either primary or secondary manufacturing origin, which are insoluble in water" (Frias 2019).

The occurrence of MPs in the aquatic environment is well documented, with higher concentrations generally found near population centers (Li 2018). MPs have also been detected in remote areas, including the Arctic Ocean (Lusher 2015), deep-sea sediments (Free 2014), and mountain lakes (Cauwenberghe 2013). Given their small size and ubiquitous nature in lakes, rivers, and oceans, their ingestion and impact on aquatic life poses a serious threat, particularly for small suspension-feeding organisms (Auta 2017). Moreover, MPs have been shown to be substrates (vectors) for other contaminants, including persistent organic pollutants such as dichloro-diphenyl-trichloroethane (DDT), both in laboratory studies and in field studies (Teuten 2009; Costa 2017; Tourinho 2019).

Unfortunately, there are often wildly different estimates reported for MP abundances in natural water, even from the same waterbodies, making meaningful comparisons difficult and hindering the utility of real-world MP surveys (Lusher 2017; Lenz 2018; Jiang 2018). Some of these disparate results may be due to inherent variability at the sites, but part of the problem may be the different sampling, sample preparation, and analytical methods used. On one hand, the wide range of approaches to MP analyses is not surprising given that MPs (1) are a diverse class of contaminant encompassing a wide variety of sizes, morphologies, and chemical and physical properties (Rochman 2019), (2) partition into different environmental compartments depending on size, density, biofouling, and other factors (Hartmann 2019), and (3) have only recently (in the last decade) caught the attention of the larger scientific community. On the other hand, MP analytical methods need to become more harmonized to increase the quality and comparability of experimental data.

Two common ways to sample plastic debris suspended in water is through use of a surface or subsurface tow net or by collecting a known volume of water at a specific location (bulk water sampling). Nets are typically used in investigating large areas with results being reported in particles/m3, whereas bulk water sampling is more accurate as a snapshot and is often reported in particles/L. A major drawback to sampling with a net is that it fails to capture particles smaller than the mesh opening (typically 333-?m), and these smaller particles tend to be the most abundant. In contrast, bulk water sampling captures all size fractions of particles in the water. Another advantage of bulk water sampling is the elimination of contamination from sampling equipment such as nylon nets and ropes. However, trawling with a net or bulk water sampling should be considered complementary techniques, covering different parts of the overall MP pollution (Tamminga 2019).

When using a net, the plastics caught in the cod end are typically rinsed out into a container for later processing in the laboratory. Determining the volume of water passing through the net or being pumped through collection sieves is important to accurately calculate MP concentrations. At some point the net and bulk sampling methods converge with the samples being filtered through a sieve or series of sieves to isolate particulates by size fraction(s). Larger particles can be removed by tweezers and analyzed by FTIR or other means. If the remaining solids collected on the sieves or filters are organic-rich they are typically subjected to either enzymatic digestion (Cole 2014) or wet peroxide oxidation, the latter sometimes in the presence of a Fe(II) catalyst (Tagg 2017), to digest labile organic matter and "clean" the plastic surfaces. A final filtering step is used to concentrate the MPs which can then be examined directly on a filter by conventional light microscopy (Masura 2015), stained with Nile Red dye and examined by fluorescence microscopy (Erni-Cassola 2017), or transferred to a spectroscopic window/slide or a suitable filter for chemical imaging by Focal Plane Array (FPA)-?FTIR or Raman spectroscopy (Loder 2015; Tagg 2015; Olesen 2017; Wolff 2019)

Impact of conventional and water-saving irrigation schemes on soybean yield in Big Sunflower River Watershed

Proceedings of the 2020 Mississippi Water Resources Conference

Year: 2020 Authors: Heng T., Feng G., He X., Li F.

Big Sunflower River Watershed (BSRW) is a high-yield agricultural area in the Lower Mississippi river. More than 81% of the total area of the BSRW (approximately 10,488 km2) is agricultural land. Crop yields are often limited by extreme climate events and soil field capacity. Due to these factors, the yield of crops in different regions of BSRW is quite different. For example, in 2013, the soybean yield of Humphreys County, Mississippi was 10.12 bu/acre lower than that of Washington county. Reduction in yield and improving the sustainability of farmland ecosystem is continuous improvement of water use efficiency. However, the model of soybean yield in BSRW has not been calibrated and the effects of different irrigation schemes on soybean yield are rarely reported. In this study, the soil water assessment tool (SWAT model) was calibrated using 20 years (1998-2018) BSRW soybean yield data, then the soybean yield was employed to simulate under non-conventional irrigation schemes. The non-conventional irrigation schemes are the ET-based irrigation method. the amounts of irrigation were set to 50%, 60%, 70%, 80%, 90%, and 100% of crop evapotranspiration (ET). That is, When the soil water storage in 50 cm is lower than the design value of replacement percentage of ET, irrigation was triggered until the irrigation amount reached the ET percentage. The results indicated that soybean yield was positively correlated with ET (R2=0.83). The yield of soybean was 79.23 bu/acre under 80% ET, it was 3.27 bu/acre higher than conventional irrigation. For every 10% increase of ET (50~80%), the average increase of soybean yield is 5.41 bu/acre. Thus this study suggests that the ET irrigation scheduling method can close the gap of soybean yield, so as to make more effective use of irrigation water.

Systematic Water Use Efficiency in Maize-Soybean Rotations: The Impact from Climate Change and Cover Crops

Proceedings of the 2019 Mississippi Water Resources Conference

Year: 2019 Authors: Li Y., Tian D., Feng G., Feng L.

Climate change influence hydrological processes in agricultural systems, which may lead to inefficiency of systematic water use efficiency (sWUE). Cover crops can be potentially considered as a strategy to improve systematic water use efficiency for mitigating the effects from climate change. However, the potential effects of cover crops on sWUE have not been studied under future climate scenarios. In this study, the hybrid Root Zone Water Quality Model version 2 (RZWQM2) model was calibrated using 5 years (2013-2017) field data. The calibrated model was used to simulate historical and future crop yields, evapotranspiration, seepage, and runoff under the cover crop and non-cover crop scenarios in Pontotoc, Mississippi using historical observations and future climate projections under two Representative Concentration Pathways (RCPs) 4.5 and 8.5 from statistically downscaled outputs of ten GCMs (General Circulation Models) from Coupled Model Inter-comparison Project - Phase 5 (CMIP5). The impacts of cover crops and climate change on maize-soybean rotation systems are analyzed using the model simulations under different scenarios. The results indicated that cover crop decreased the annual seepage respectively 13.7% during 2020 to 2049 and 11.4% during 2050 to 2079 under RCP4.5, by 16.1% and 14.7% under RCP8.5. Compared with the no cover crop management, the sWUE under cover crop management were improved respectively by 3.4% during 2020 to 2049 and 1.8% during 2050-2079 under RCP4.5, and by 3.1% during 2020 to 2049 and 1.5% during 2050-2079 under RCP8.5 for maize but not much for soybean. The results of relationships between climate extreme indices and crop model output variables suggest that the practice of cover crops can reduce the negative feedback effect of high temperature and plays a certain buffering role by improving evapotranspiration in extreme weather.

The Spatiotemporal Variation of Groundwater Level and Response to Landuse Change in the Big Sunflower River Watershed

Proceedings of the 2019 Mississippi Water Resources Conference

Year: 2019 Authors: Han Y., Feng G., Ouyang Y., Liu Z., Jenkins J.N.

The Big Sunflower River Watershed (BSRW) groundwater was heavily used for irrigating crops. Cotton, soybean, corn and rice account for 64% of the total area in BSRW and their irrigation water use is 0.5, 0.7, 0.9 and 3.0 feet/acre, respectively. The landuse had a huge change and groundwater levels has been decreased over 1 meter from 2003 to 2013. However, the annual rainfall of BSRW in 2003 and 2013 was similar(52.6 and 54.2 inch). The purpose of this study was to study the spatial variation of groundwater level and the relationship between landuse change and groundwater level variation in 2003 and 2013. We applied the semi-variation function model and Kriging interpolation technique to produce BSRW's groundwater level isogram maps in 2003 and 2013. The differences of groundwater level between 2013 and 2003 were spatially displayed across the BSRW. The landuse map of BSRW in 2003 and 2013 were used to obtain the changes of land use patterns and area. The transition matrix of landuse types with respect to different change range of groundwater depth between 2003 and 2013 will help us to understand the relationship between groundwater level and landuse. Our results showed that the planting area of cotton and corn changed dramatically from 2003 to 2013 and groundwater level in BSRW decreased rapidly from northeast to southwest, sunflower county was the center of groundwater decline. The change trend of planting patterns from cotton to corn and soybean had no obvious relationship with groundwater change, but the change from grass/pasture to woody wetland/forest had an effect on groundwater level change.

Managing the State's Inventory of Dams

Proceedings of the 2019 Mississippi Water Resources Conference

Year: 2019 Authors: Myers D., Watts J.

The Dam Safety Division of the Office of Land and Water Resources (OLWR) within the Mississippi Department of Environmental Quality (MDEQ) is tasked with regulating dams within the state to protect downstream lives and property. The original inventory of dams was completed in the early 1970s prior to the passage of legislation in 1978 creating a state dam safety program. This inventory was updated during the early years of the program but did not undergo any major updates until 2013. To expedite the process of updating the inventory, the program created Geographic Information Systems (GIS) tools to automate many of the steps used to locate and properly classify dams. Information will be presented on the evolution of the state's inventory of dams, the number and beneficial uses of dams, the GIS tools and procedures created, and ongoing efforts to improve and maintain the inventory to better protect the public.

Evaluation of 1-Day–1%AEP Rainfall Depths in Mississippi

Proceedings of the 2019 Mississippi Water Resources Conference

Year: 2019 Authors: Kronkosky B.C.

In Mississippi, the Federal Emergency Management Agency (FEMA), National Flood Insurance Program (NFIP), insures ~64,000 policies that total ~$16M dollars (9/30/2017 FEMA statistics)—in aggregate (since 1978), Mississippi has contributed to ~60,000 insurance claims that have exceeded $3B dollars. In almost all instances NFIP "base flood" flood plains are delineated using 1-day–1% rainfall depths (100-year floodplain). In 2013, the National Oceanic and Atmospheric Admiration (NOAA) released "NOAA Atlas 14—Precipitation-Frequency Atlas of the United States, Volume 9, Version 2,"—the most current source for establishing 1-day–1% rainfall depths for Mississippi (and other neighboring states). In addition to Atlas 14, there are seven other studies, dating as far back as 1917, which define 1-day–1% rainfall depths for Mississippi.

In this investigation, we present a detailed review of these rainfall depths (5 of the 7 studies) using Mississippi county centroids (88 counties). Homogeneous statistical tests are utilized to show differences amongst these estimates, which indicate most estimates are within 10%. It is also shown these studies are bound by each other's standard error, indicating these estimates are statistically indistinguishable (within margin of error). These results suggest 1-day–1% rainfall depths (for Mississippi) have not significantly changed in over 100 year of research, and that methods used 100 years ago produce near identical results as modern-day studies (e.g. Atlas 14).

Attendees will be presented with a breadth review of these historical studies and detailed comparison of their estimates. The objective is to demonstrate that newer research should not necessarily supplement historical practice unless there are significant differences. This calls to question…is newer better, or are we over complicating how 1-day–1% rainfall depths are prepared.

Long-Term Effect of Cover Crop on Water Use Efficiency in Manured and Rainfed Soybean-Corn Rotations

Proceedings of the 47th Mississippi Water Resources Conference

Year: 2018 Authors: Yang W., Feng G., Adeli A., Jenkins J.

Planting winter wheat cover crops in corn and soybean rotations is an effective to improve the effective utilization of soil moisture and enhance water use efficiency. However, the longer-term impact of this practice needs to be further investigated. The hybrid RZWQM-DSSAT model calibrated with 5 yr (2013-2017) field data was used to simulate the effects of this practice on crop evapotranspiration, yield, and water use efficiency under a rainfed condition in no-till corn-soybean cropping system at Mississippi Agricultural and Forestry Experiment Station in Pontotoc Mississippi. The poultry litter (13.4 Mg ha^-1) was applied to corn field with cover crop (CC) and no cover crop (NCC) in May 2014 and 2016. The model was calibrated well in terms of crop yield and biomass, plant N uptake, and soil moisture with percent error (PE) was within ±15%, Nash-Sutcliffe model efficiency (EF) > 0.7, and relative root mean square error (RRSME) < 15%. Longer-term simulations showed that planting a winter wheat cover crop increased corn yield by on average 1,560 kg ha^-1 (12%) and did not change soybean yield. The simulation also indicated that the practice increased annual evapotranspiration by 3.5 cm (9%) in corn years but did not affect evapotranspiration in soybean years. Simulated grain water use efficiency was increased by 17% for corn, and it was not changed in soybean. This study demonstrated that introducing winter wheat cover crops in a corn-soybean cropping system is a promising approach to increase corn water use efficiency in the subtropical agro-ecosystem.

Field Measurements of Irrigation Reservoir Levee Erosion

Proceedings of the 47th Mississippi Water Resources Conference

Year: 2018 Authors: Wren D.G., Ozeren Y., Reba M., Bowie C.

The use of surface water resources for irrigation has increased due to groundwater depletion. In order to reduce dependence on groundwater, irrigation reservoirs and tailwater recovery systems can be used to capture and store water for irrigation. Irrigation reservoir levees are typically constructed from local soils with low cohesion, resulting in levees that are susceptible to erosion by wind-driven waves, necessitating frequent repairs that are an added expense for producers. Motivated by the amount of erosion observed on the levees, a survey was conducted in 2013-2015 to assess the current condition of the levees and attempt to identify common factors for highly eroded sections. It was found that 79% of the 584 homogeneous levee segments contained within 148 surveyed reservoirs had block failures and near-vertical slopes. Despite regional winds with preferential southerly and northerly directions, levees of all orientations were damaged by waves. For the surveyed irrigation reservoir levees, soil type, vegetation, inner slope, and berm presence were found to be poor predictors of the state of impairment. The most important variable associated with levee failure was maximum effective fetch length; levee segments with longer fetches were more likely to have block failures and greater losses of top-width.

Water Availability in the Mississippi Delta: Initial Assessment of Alternative Water-Supply Scenarios

Proceedings of the 46th Mississippi Water Resources Conference

Year: 2017 Authors: Barlow J.R., Haugh C.J.

In an effort to better understand the impacts of different water-management scenarios on water availability and to identify additional monitoring needs in the Mississippi Delta, the U.S. Geological Survey and the Mississippi Department of Environmental Quality are collaborating to update and enhance an existing regional groundwater-flow model. As a result of this collaboration, the model has been updated through 2013 with the most recent water-use data, precipitation and recharge data, and streamflow and water-level observation data. The updated model has been used to evaluate selected alternative water-supply scenarios in order to assess relative impacts to the alluvial aquifer and identify data needs for future groundwater management modeling. Alternative water-supply options assessed to date include: 1) irrigation efficiency; 2) tailwater recovery and on-farm storage; 3) weirs for surface-water augmentation; 4) inter/intra-basin transfers; and 5) groundwater transfer and injection. A relative comparison approach was used to calculate the simulated water-level response due to each scenario. Water-level response is the difference between water-levels simulated by the alternative-supply scenario and those simulated by a base case or "no action" scenario. Water-level response in the alluvial aquifer varied for each scenario based on the location and magnitude of the implemented alternative-supply option. These initial model results will serve as a starting place to develop and assess conjunctive water-management-optimization scenarios as well as improve and enhance current and future monitoring activities within the Delta.

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Estimating water budget components of evapotranspiration, recharge, and runoff for Mississippi and the Mississippi Alluvial Plain

Proceedings of the 46th Mississippi Water Resources Conference

Year: 2017 Authors: Reitz M., Sandord W.E., Senay G.B., Kress W.H.

As water resources become increasingly strained in the US and globally, the development of reliable water availability estimates is needed for making informed water use management decisions. Here we present new 800m annual estimates of water budget components of evapotranspiration (ET), surface runoff, and recharge, produced using various data sources such as soil properties, surficial geology type, stream gage and climate data for 2000-2013. Groundwater-sourced irrigation is included as a component in the local water budget, using data from USGS county-level compilations. The ET and recharge estimates compared favorably when checked against independent field data, and against other ET estimation methods. We show results for the state of Mississippi, and also for the focus area of the Mississippi Alluvial Plain, which has seen significant impacts on water resources due to irrigation and groundwater pumping. Comparisons with USGS groundwater withdrawal data indicate regions where rates of water use may be unsustainable. We summarize results of the water budget estimates for the 2000-2013 timespan for both the state of Mississippi and the Mississippi Alluvial Plain. Finally, we show preliminary results of current work to estimate water budgets on a monthly timescale, through a combination of remote sensing and ground-based data.

MDEQ's Mississippi Comprehensive Ecosystem Restoration Tool

Proceedings of the 45th Mississippi Water Resources Conference

Year: 2016 Authors: Strange T.

As a result of the Deepwater Horizon Oil Spill (DWH), Mississippi is working to restore the health and ensure sustainability of the coastal landscape affected by the spill. To ensure sustainable restoration is achieved, the National Fish and Wildlife Foundation (NFWF) Gulf Environmental Benefit Fund (GEBF) agreed that an ecosystem restoration plan was needed in Mississippi. They approved to fund the development of the Mississippi Restoration Plan. One of primary goals of the Plan is to develop the Mississippi Comprehensive Ecosystem Restoration Tool (MCERT), which is a science-based tool for identifying and examining ecological resources and stressors at a landscape/seascape scale and that allows for improved restoration planning and informed decision making. MCERT represents a suite of geospatial analysis models that provide data products to describe the terrestrial landscape and the marine and water quality conditions in south Mississippi. Two of the MCERT components deal directly with water quality and watershed characterization. The water quality model integrates the Soil and Water Assessment Tool (SWAT). We calculated a 2006-2013 simulation of water, sediment, and nutrient flow in the Pearl, Pascagoula, and Mississippi Coastal basins, as well as indices of change between these and the outputs from an earlier 1987-1994 simulation of the same area to highlight broad indicators of water quality change within the study area using three primary parameters: sediment, nitrogen, and phosphorus at the subwatershed and stream reach level. Stream gauge data from the USGS and observed sediment and nutrient loading data points from the MDEQ are used to calibrate the model to better reflect field conditions. The watershed characterization component of the tool uses derived spatial data, including environmental resource and stressor/threat data, as inputs and aggregates the information to characterize subwatersheds by quantifying the amount, weighting, scoring, and normalizing of the input data. Within each subwatershed, various datasets are assigned values and are adjusted, normalized, and ranked relative to one another. Data inputs include but are not limited to SWAT outputs, dam storage ratios, protected areas, T & E species presence, ecological hubs and corridors, and a landscape development index (LDI). The Mississippi Restoration Team uses these tools to identify hotspots and areas of interest as well as simulate best management practices to quantify restoration scenarios across the landscape. Manipulation of climatic, hydrologic, and land use inputs offers further potential for modeling future scenarios, incorporating both agricultural and non-agricultural management practices, at various spatial and temporal scales.

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Spatial and temporal trends for mercury concentrations in fish from three north Mississippi lakes and human health risk assessment

Proceedings of the 45th Mississippi Water Resources Conference

Year: 2016 Authors: Willett K.L., Cizdziel J.V., Meals K., Brewer S., Thornton C.

Total mercury (Hg) concentrations were determined in the skeletal muscle of 310 fish collected during 2013 and 2014 from three northern Mississippi lakes (Sardis, Enid and Grenada) that are extensively used for fishing and recreation. Largemouth Bass (LMB), Channel Catfish (CC), White Crappie (WC), and Gizzard Shad (GS), that represent a range of trophic levels, were studied. Creel data indicated anglers harvested 372,711 kg of WC, 26,735 kg of CC, and 14,871 kg of LMB, the three most targeted species of fish, from the lakes. Median Hg concentrations (ng/g) were highest in LMB (443, n=64), followed by CC (211, n=72), WC (192, n=101), and GS (49, n=73). Fish-Hg concentrations were lower than those reported in fish >10 years ago, but there were significant differences between lakes consistent across species. Grenada fish-Hg concentrations were higher than those from Enid and Sardis. Because existing consumption advisories for CC are length-based, the lack of a significant relationship between length and Hg concentration indicated that the recommendations may not be protective enough. Furthermore, five different risk assessment paradigms yielded hazard quotient values suggesting that existing fish consumption advisories may be insufficient to protect adults, and especially children, from exposure to Hg.

Characterization of Surface Water Quality in Sunflower River Watershed, Mississippi

Proceedings of the 45th Mississippi Water Resources Conference

Year: 2016 Authors: Ouyang Y., Moran M., Parajuli P., Zhao B.

Characterization of water quality is essential to evaluate river pollution due to natural and/or anthropogenic inputs of point and non-point sources. In this study, surface water quality from three monitoring stations at Big Sunflower River Watershed (BSRW) located in Mississippi during the years from 2013 to 2015 was estimated using the YSI meter and laboratory analysis. Results showed that dissolved oxygen was negatively correlated to water temperature, while total dissolved solid was fairly correlated to water temperature. In general, the concentrations of nitrate-nitrogen (NO_3-N) and total phosphorus (TP) were highest in spring. Our study further revealed that the minimum, mean, and maximum concentrations in the streams were, respectively, 0.019, 2.31, and 6.43 mg/L for NO_3-N, 0.01, 0.08, and 0.16 mg/L for TP, and 2.38, 5.81, and 13.29 mg/L for potassium (K).

Comparison among three methods for suspended-sediment sampling of the Mississippi River at Vicksburg, Mississippi

Proceedings of the 44rd Mississippi Water Resources Conference

Year: 2015 Authors: Welch H.

Depth- and- width- integrated isokinetic sampling techniques have been used to collect suspended-sediment samples in the Mississippi River by the U.S. Geological Survey (USGS) since the early 1970s as part of the National Stream Quality Accounting Network program. Collecting water-quality samples is critical in order to measure and understand chemical and sediment transport, but sampling can be challenging in terms of logistics, cost, and safety. The USGS has established suspended- sediment sampling protocols to ensure that samples are collected in a consistent and uniform way in streams across the country for data comparability and interpretation. However, variants of the traditional method have evolved to account for possible loss of equipment, improved safety to personnel, and potential loss of samples "contaminated" with bed material. Questions have recently arisen regarding the comparability of suspended-sediment data at selected water-quality stations along the lower Mississippi River. Three methods of sample collection have been used since the early 1980s. They include the traditional method, in which the sampler is lowered to the bottom of the channel, and two variants of that method, which consist of either lowering the sampler to 90% of the total stream depth or lowering the sampler to 2 feet from the bottom of the channel. From April through August 2013, the USGS collected suspended-sediment samples along a transect of the Mississippi River above Vicksburg, Mississippi using the three different methods. The collected data will be used to assess if: (1) sample collection techniques are reproducible, (2) data collected using the three different methods are comparable, and (3) the traditional method biases the suspended-sediment sample toward the sand-size fraction.
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The Catalpa Creek Watershed Project and Watershed Demonstration, Research, Education, Application and Management (D.R.E.A.M.) Center

Proceedings of the 44rd Mississippi Water Resources Conference

Year: 2015 Authors: Ingram R.

A significant portion of Mississippi State University's (MSU) campus and property resides within the Catalpa Creek Watershed (referenced by USGS as the Red Bud-Catalpa Creek Watershed, HUC 12 #031601040601, and by MDEQ as MS #8090). This includes important MSU education and research facilities, such as the Mississippi Agricultural and Forestry Experiment Station's (MAFES) South Farm, which is used by numerous departments and programs. Unfortunately, some of MSU's land uses in this watershed may have contributed to the pollution of Catalpa Creek. Total Maximum Daily Load (TMDL) studies that apply to this watershed include those for sediment, nutrients, and pathogens. Each of these TMDLs recommend practices to reduce pollutant amounts to acceptable levels thereby providing improved habitat for the support of aquatic life and allowing for the attainment of applicable water quality standards.

On April 2013, MSU, through the Mississippi Water Resources Research Institute (MWRRI), was designated a Center of Excellence for Watershed Management with the signing of a Memorandum of Understanding (MOU) between the Mississippi Department of Environmental Quality (MDEQ), Region 4 of the U.S. Environmental Protection Agency (EPA), and MSU. The MOU recognized that MWRRI had "demonstrated to the satisfaction of EPA and MDEQ that it has the capacity and capability to identify and address the needs of the local watershed stakeholders" and was charged to "work with colleges and universities in Mississippi to engage students (graduate and undergraduate), faculty and staff from the full suite of disciplines needed to adequately address specific watershed issues" and to "draw upon other local, state, federal resources and expertise".

MWRRI, in its role as a Center of Excellence for Watershed Management, is advantageously positioned to bring resources together from various MSU departments and programs; nongovernmental organizations; and state and federal agencies to address the needs in the Catalpa Creek Watershed. This project will not only put appropriate BMPs on the ground in strategic locations in the watershed to restore water quality and habitat, but also establish a venue for watershed-based demonstrations, research, education, application and management.

Assessment of tailwater recovery system and on-farm storage reservoir efficacies: Quality issues

Proceedings of the 44rd Mississippi Water Resources Conference

Year: 2015 Authors: Omer A.R., Czarnecki J.M.

The Lower Mississippi Alluvial Valley is economically important due to its highly productive agricultural land. However, producers in this region face two predominant environmental issues that are inherently linked to the intensity of the agricultural industry in this region. First, intensive agriculture practices which have resulted in increased surface transport of nutrient-laden sediments, contributing to eutrophication in receiving waters and to the Gulf of Mexico Hypoxic Zone. Second, current water withdrawals from the Mississippi Alluvial Aquifer for irrigation are not sustainable. These issues threatening environmental resources necessitate use of best management practices and groundwater conservation. This research investigates systems of best management practices as water resource conservation methods. Such practices include surface water capture and irrigation reuse systems. Referred to as tailwater recovery systems (TWR), this practice consists of a tailwater recovery ditch which may be paired with on-farm storage reservoirs (OFS). Five case studies of different TWR were monitored for nutrients during a single growing season at: inflow, edge of field, TWR, OFS, and overflow locations. Investigations highlight functionality for nutrient recycling, and descriptions of nutrient loss mitigation. Additional research includes quantification of nutrients lost and captured during rice patty drains into TWR using in-situ nitrate sensors. Although research on these systems continues, initial results from three TWR in 2013 show over 278 million liters of water being recycled applying a mean of 0.96 kg/ha total nitrogen and 0.15 kg/ha total phosphorus. These systems are proving successful in holding water on the landscape, recycling that water, and therefore nutrients. Thereby preventing those nutrients from being lost to downstream waters. This suggests that TWR have much promise for water resource conservation in the Lower Mississippi Alluvial Valley.
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Pathogen Indicator Monitoring in the Ross Barnett Reservoir

Proceedings of the 44rd Mississippi Water Resources Conference

Year: 2015 Authors: Capps P., Surbeck C.

Man-made reservoirs are often used for both water supply and recreation. The Ross Barnett Reservoir in central Mississippi, a 33,000-acre man-made lake, provides drinking water to the city of Jackson, MS, and forty-eight surrounding communities. Further, an estimated 2.5 million people visit the reservoir each year for recreational purposes, including boating, fishing, water-skiing, and swimming. Protecting the water quality in the reservoir is important for these visitors and inhabitants along the shoreline, and for these reasons, the U.S. Environmental Protection Agency has selected it as a Priority Watershed in Mississippi. Presently, there is a concern regarding recent data collected that indicated increasing concentrations of bacteria in the Ross Barnett Reservoir. To detect possible harmful levels of bacteria in recreational waters, pathogen indicator monitoring is used. Sources of pathogens may include stormwater runoff, failing septic systems, lake-bottom sediments, and animals and humans in direct contact with the water. A collaborative study to investigate potential pathogen contamination in the reservoir is underway by the University of Mississippi, the U.S. Geological Survey, and the Mississippi Department of Environmental Quality. The goal of the study is to determine a method of pathogen indicator monitoring that takes less time than the standard 24 hours required by current methods for detecting bacteria. Such a method would improve the swiftness of notification to reservoir users when the water quality is not appropriate for contact. Pathogen indicators and other water-quality data such as water temperature, pH, turbidity, conductivity, dissolved oxygen, nutrients and solar strength, were collected at two recreational sites at the reservoir twice a week for 23 events through the spring and summer of 2013 as part of the collaborative study. Average concentrations for all E. coli, enterococci, and fecal coliform were 264 cfu/100mL, 175 cfu/100mL, and 298 cfu/100mL, respectively. The concentrations of pathogen indicators, nutrients, and values of physical parameters were statistically analyzed to provide insight about contamination sources. This research indicated that two water quality indicators of harmful bacteria levels in the water were turbidity at sites with low water circulation and days following rain events.

Water Quality in Bangs Lake: effects of recurrent phosphate spills to a coastal estuary

Proceedings of the 44rd Mississippi Water Resources Conference

Year: 2015 Authors: Dillon K., Caffrey J., Carmichael R., Holcomb S., Griffin C., Allen J., Jones T., Price K.

Bangs Lake, an estuarine water body in the Grand Bay NERR, has been the site of three industrial phosphate spills from a nearby fertilizer plant since 2005. Due to restricted tidal exchange in Bangs Lake, these events have had long lasting effects on water column phosphate concentrations which may stimulate biological activity and alter the biogeochemical cycling of essential elements within the water column and the sediments. To determine the fate of excess phosphate from the industrial spills, we measured soluble reactive phosphate concentrations in sediment pore water and total particulate phosphate concentrations from sediment cores (0-25 cm depth) from four locations: North Bangs Lake (closest to spill locations), Bangs Lake, and two low impact reference sites (Bayou Cumbest and Bayou Heron). We also conducted phosphate adsorption experiments and measured benthic chlorophyll concentrations with sediments from these sites to determine if the excess PO4 was fertilizing benthic microalgae to determine the fate of this excess PO4. Pore water phosphate concentrations were highest (21 uM) from 10 to 20 cm depths in North Bangs Lake cores however pore water from the surface sections of these cores had much lower phosphate concentrations (<0.5 uM). Pore water from the Bangs Lake cores consistently had elevated phosphate concentrations (2 to 5 uM) throughout the core length while pore water phosphate concentrations from one reference site were much lower (<0.7 uM), likely reflecting background levels. Phosphate adsorption experiments show that surface sediments from North Bangs Lake and Bayou Cumbest rapidly stripped phosphate from solution to final concentrations of <3 uM while surface sediments from Bangs Lake had greatly reduced phosphate adsorption capacity with much higher final concentrations (24 to 32 uM) indicating these sediments are near saturation. In 2013 and 2014, Sediment chlorophyll a concentrations were higher in Bangs Lake compared to the reference site. Sediment chlorophyll a was significantly correlated with extractable phosphate concentration in sediments (r = 0.88). In addition, grow out experiments with amendments of phosphorus to water and sediment samples stimulated the growth of cyanobacteria capable of fixing nitrogen.

USDA-ARS Long-term Agroecosystem Research Network: A new initiative for long-term monitoring, research, and collaboration in the Lower Mississippi Riv

Proceedings of the 44rd Mississippi Water Resources Conference

Year: 2015 Authors: Rigby J.R., Locke M.A.

The Lower Mississippi River Basin is one of the most productive agricultural regions in the country links agricultural practices and associated runoff and nutrient loads from the Upper Mississippi, Missouri, and Ohio basins with the ecology of the Gulf of Mexico. In 2013 the USDA-ARS founded the Long-term Agroecosystem Research (LTAR) network consisting of 18 member locations across the United States to address long-term research and monitoring goals for U.S. agriculture. The Lower Mississippi River Basin (LMRB) is a member location of the network administered by the USDA-ARS National Sedimentation Laboratory. The LTAR network will focus activity on development of agroecosystem observatories with common standards for cross-site monitoring at all locations as well as a set of experiments to address the long-term sustainability of agriculture and the broader agricultural landscape in the U.S. A number of sustainability challenges face the Lower Mississippi River Basin including increased concerns around water quantity and quality issues.
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Water and Environmental Science Programs for Underrepresented Communities in Mississippi

Proceedings of the 44rd Mississippi Water Resources Conference

Year: 2015 Authors: Diaz J.

The goal of this presentation is show current water and environmental science programs developed at Alcorn State University. Alcorn State University - ASU, a Land Grant and Historically Black University located in southwest Mississippi, offers a Bachelor of Science in Agricultural Sciences with emphasis in Environmental Science. This program prepares highly skilled individuals for lifelong environmental career in private and public organizations. Students are trained to understand, investigate, and manage the environment and the many interactions among physical, chemical, biological, economical, and societal components towards a sustainable society. The program consists of 21% social science courses, 24% basic science classes, and 55% applied science subjects. Applied environmental classes include: water quality, concepts of environmental science, geographical information systems applications in natural resources, watershed hydrology, agricultural and environmental law. ASU's Mississippi River Research Center - MRRC is actively involved in mentoring and outreach activities which support the MRRC's mission in reaching out to students and general community as well as training the next generation of minority professionals in science and applied technology areas. Since January 2013, staff and students from the MRRC have prepared and performed eight outreach activities reaching about 200 school students. Through a National Science Foundation grant, the MRRC developed an environmental science activity manual and trained 16 middle-school teachers by providing content and hands on activities in three major themes: water, erosion, and environmental consciousness. Major accomplishments in student involvement include mentoring eight students; hosting two undergraduate students from Oberlin College, OH and University of Florida, FL through the NOAA-NGI Diversity Internship Summer Program; attending six professional meetings; and reaching third place in graduate poster competition in the 71st professional Agricultural Workers in Tuskegee University, Alabama. Currently, the MRRC is leading five projects funded by the State of Mississippi, US Department of Agriculture, US Forest Service, and Monsanto. Projects are focused on evaluating the temporal and spatial water quality variation and the indication of total coliform bacteria and Escherichia coli in four small lakes at ASU; assessing climate change impacts on southern Mississippi watersheds; measuring the acid neutralizing capacity of forest and aquatic ecosystems in Louisiana and Mississippi national forests; understanding factors influencing the adoption, efficiency, and impact of irrigation systems and scheduling methods for irrigation on small and limited resource vegetable and fruit farms in Mississippi; and promoting water quality management techniques for vegetable production. Summary of major project accomplishments will be presented at the conference.
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Quality of water in public supply wells located in the Southeastern Coastal Plain and Coastal Lowlands aquifer systems, Mississippi, 2013

Proceedings of the 43rd Mississippi Water Resources Conference

Year: 2014 Authors: Welch H.L., Barlow J.R.

Groundwater provides over one-third of the water used for public supply in the United States and nearly half of the water used for public water supply in the southeastern United States. In 2013, the U.S. Geological Survey's National Water Quality Assessment Program began studies to provide nationally consistent water-quality data from principal aquifer systems that account for the majority of withdrawals for public supply throughout the United States. Two of these principal aquifers, the Southeastern Coastal Plain and Coastal Lowlands aquifer systems, were selected for sampling in 2013. These aquifer systems are located in the southeastern part of the United States, and each consists of unconsolidated to semiconsolidated sand, silt and clay deposits that thicken and dip coastward. The Southeastern Coastal Plain aquifer system spans approximately 90,000 sq miles and includes parts of 6 states, and the Coastal Lowlands aquifer system spans approximately 98,000 sq miles and includes parts of 5 states. Public-supply wells were selected for sampling using an equal-area grid approach to ensure a spatially unbiased sampling distribution.

Benefits of On-Farm Water Storage Systems in Porter Bayou Watershed

Proceedings of the 43rd Mississippi Water Resources Conference

Year: 2014 Authors: Tagert M.L., Paz J.O., Pote J.W., Kirmeyer R.L.

Since the 1970's, groundwater levels in the Mississippi Alluvial Aquifer have decreased as the number of irrigated acres in the Mississippi Delta has increased. Today, there are roughly 18,000 permitted irrigation wells dependent on water from the Mississippi Alluvial Aquifer, with approximately 50,000 new irrigated acres added both in 2011 and 2012. As concern has grown over groundwater declines and increasing fuel costs to run irrigation pumps, farmers have been implementing more irrigation conservation measures, such as on farm water storage (OFWS) systems. These systems began appearing in the Mississippi Delta in 2010 in conjunction with the implementation of the Mississippi River Basin Healthy Watersheds Initiative (MRBI). OFWS systems typically are surrounded by fields that are padded and piped, directing rainfall and runoff to a tailwater recovery ditch, from where it is then pumped into a pond for storage. Water is pumped from the pond and used for irrigation at a later date. These systems offer farmers the dual benefit of providing water for irrigation and also capturing nutrient rich tailwater for on farm reuse. This presentation will give an update on the project, which has monitored water savings and nutrient levels at two OFWS systems, one each at Metcalf Farm and at Pitts Farm, in the Porter Bayou Watershed, Mississippi. Data collection began in February 2012 and is ongoing, with water samples collected for analysis every three weeks throughout the growing season from March-October and every six weeks through the off season. Cumulative readings were also taken on flow meters to measure water use from the storage pond. The ability of these systems to reduce downstream nutrient concentrations has been mixed, with systems performing better when the tailwater recovery ditch is not full and can contain runoff on site. Thus, better management will improve the nutrient reduction potential of these systems. The water savings potential of these systems has been substantial. Metcalf Farm used 42 and 17 million gallons of water from the storage pond in 2012 and 2013, respectively; Pitts Farm used 60 and 56 million gallons of water from the storage pond in 2012 and 2013, respectively. These amounts reflect savings in groundwater that was not pumped from the Mississippi Alluvial Aquifer.

Assessing new BMPS: efficiencies of a Tailwater Recover System and On-farm Storage Reservoir

Proceedings of the 43rd Mississippi Water Resources Conference

Year: 2014 Authors: Omer A., Kröger R.

The Lower Mississippi Alluvial Valley in Mississippi is economically important due to its highly productive agricultural land. However, producers in this region face two predominant environmental issues that are inherently linked to the agricultural industry. Firstly, intensive agriculture practices which have resulted in increased surface transport of nutrient laden sediments, contributing to eutrophication in receiving waters and to the Gulf of Mexico Hypoxic Zone. Secondly, current water withdrawals from the Mississippi River Valley alluvial aquifer for irrigation during the growing season when precipitation is minimal are not sustainable. These issues threatening environmental resources necessitate best management practices (BMPs) and groundwater conservation. This research investigates BMP systems as water resource conservation methods. Such practices include surface water capture and irrigation re-use systems, referred to as tailwater recovery systems (TWR) and on-farm storage reservoirs (OFS). A single year investigation of two TWRs and one OFS highlighted water holding capacities for irrigation reuse and functionality for nutrient capture as well. Research also included the investigation of the delivery of nutrients and water from a TWR to rice fields during the 2013 growing season, which allowed for the calculation of potential economic savings by a producer pumping surface water rather than ground water. While this research is ongoing, initial investigations indicate that TWRs and OFSs have much promise for water conservation in the Lower Mississippi Alluvial Valley.

Pathogen Indicator Monitoring in the Ross Barnett Reservoir

Proceedings of the 43rd Mississippi Water Resources Conference

Year: 2014 Authors: Capps P., Hicks M., Surbeck C.Q.

Man-made reservoirs are often used for both water supply and recreation. The US Environmental Protection Agency's (EPA) recent National Lakes Assessment survey includes water quality concerns for beneficial uses of such man-made reservoirs. The EPA ranks the Ross Barnett Reservoir watershed as the most important in the state of Mississippi and has selected it as a Priority Watershed. The Ross Barnett Reservoir, a 33,000-acre lake, provides drinking water to the city of Jackson, MS, and forty-eight surrounding communities. Further, an estimated 2.5 million people visit the reservoir each year for recreational purposes, including boating, fishing, water-skiing, and swimming. Substantial residential and commercial developments in Madison and Rankin counties along the 105 miles of reservoir shoreline have the potential to affect water quality in the reservoir. Due to the reservoir's important role as a water-supply source, the protection of the water quality in the reservoir is crucial for human health. A collaborative investigation is underway by the University of Mississippi, the U.S. Geological Survey, and the Mississippi Department of Environmental Quality, to assess pathogen indicator concentrations in the Ross Barnett Reservoir. Sources of the pathogens may include stormwater runoff, failing septic systems, lake-bottom sediments, and humans in direct contact with the water. Data for pathogen indicators and other water-quality parameters such as water temperature, pH, dissolved oxygen, conductivity, nitrate, phosphate, and solar strength, were collected at two recreational sites at the reservoir twice a week for 23 weeks through the spring and summer of 2013. Average concentrations for all E. coli, enterococci, and fecal coliform were 264 cfu/100mL, 175 cfu/100mL, and 298 cfu/100mL, and standard deviations for each were 654 cfu/100mL, 249 cfu/100mL, and 952 cfu/100mL, respectively. The concentrations of pathogen indicators and nutrients, and values of physical parameters will be statistically analyzed to provide insight about contamination sources. A review of past monitoring efforts in other related fresh-water lakes will also be reported.

The Role of Long-term Monitoring In Understanding Phosphate Spills Into A National Estuarine Research Reserve

Proceedings of the 43rd Mississippi Water Resources Conference

Year: 2014 Authors: Cressman K., Woodrey M., Ruple D.

Grand Bay National Estuarine Research Reserve (GBNERR) is an 18,400-acre protected area in southeastern Jackson County, MS. The GBNERR, along with 27 other Reserves, collects long-term environmental data, including water quality, weather and nutrient parameters, following accepted national protocols as part of a System-Wide Monitoring Program (SWMP). In 2005, a phosphate facility on GBNERR's western border released wastewater into Bangs Lake. Data from SWMP were used to help determine the timing and duration of the event. The pH measured by a data logger deployed at the Bangs Lake water quality station dropped to 3.7. Orthophosphate, tested monthly in the water column and usually below the detection limit of 0.01 mg/L, spiked to over 4 mg/L: more than 400 times higher than normal. PO4 concentrations returned to baseline levels after Hurricane Katrina and remained below 0.01 mg/L until September 2012, when Hurricane Isaac led to another release into Bangs Lake. Routine nutrient sampling three weeks after Isaac found phosphate levels over 1 mg/L in Bangs Lake. Phosphate was also high at further distances from the plant. As of December 2013, other stations' water column phosphate concentrations had returned to normal, but phosphate in Bangs Lake remained higher than historical levels. Research by collaborators at nearby institutions has helped fill in details of the magnitude and spatial patterns of the 2012 spill. This work, combined with the long-term context of SWMP data, led to the formation of a Phosphate Working Group, which will continue to explore the ecological effects of this long-term addition of phosphorus to Bangs Lake.

The Effects of Weirs on Vegetation Communities in Agricultural Drainage Ditches of the Mississippi Alluvial Delta

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Shipes C., Kröger R.

Drainage ditches in the Mississippi Alluvial Delta are an essential part of the agricultural landscape of this region. These ditches vary greatly in size, location, and shape, but can aid in mitigation of contaminants from agricultural fields. Historically controlled drainage in the form of slotted or drop pipes, flash board risers, and vegetated drainage ditches have been used to effectively manage nutrients. More recently low-grade weirs have been used as an alternative to traditional controlled drainage structures. Low- grade weirs act to slow water flow, increase residence time, and allow sedimentation. Until recently the relationship between low-grade weirs and the vegetation communities present has not been evaluated. We selected 13 agricultural drainage ditches with weirs present in the Mississippi Alluvial Valley and investigated the vegetation community responses to weirs and weir age. We also selected 4 control ditches with no weirs present to compare our results. Vegetation assessment yielded 41 plant species ranging from obligate wetland plants to facultative upland plants. Simple correlation tests showed a strong positive relationship between weir age and species diversity, and also a positive correlation between total percent vegetative coverage and weir age. Linear regression also showed a positive relationship between weir age and the presence of facultative upland plants and a negative relationship between weir age and the presence of obligate wetland plants. This study shows some interesting trends, but we were limited in our sample size. Future studies should focus on a larger sample size with a wider range of age classes and should take other variables into account such as; vegetation communities upstream, slope of individual ditches, the spatial arrangement of weirs within the ditch system, and association with other weirs within the same ditch system.

The Effects of Weirs on Macroinvertebrate Communities in Agricultural Drainage Ditches of the Mississippi Delta

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Feaga J., Kröger R.

Drainage ditches are an essential part to effective agricultural production by regulating water levels to control the inundation of production acreage. Drainage ditch construction in the Mississippi Delta, was merely a response to the need for access to more fertile soils, which previously was dominated by bottomland hardwood forests, oxbow lakes, and cypress swamps. Various ditches within the Mississippi Delta system contain weirs, which function to limit nutrient export into downstream habitats by reducing flow of water and increasing residence time. Until relatively recently, the biological significance of these agricultural structures to macroinvertebrate communities was not entirely understood. We investigated patterns of communal macroinvertebrate composition within seven agricultural drainage ditches with weirs near Belzoni, Mississippi. We examined macroinvertebrate abundance responses to weir age and distribution patterns with respect to distance from weirs. We then compared these results to results observed in 3 control ditches without weirs. Macroinvertebrates sampled from 7 ditch sites represented 11 distinct taxa with a total abundance of 3,948 individuals. The main contributors to total abundances were Chironomidae (48%), Physidae (30%), and Oligochaeta (20%) with Physidae (43%, n = 876) and Chironomidae (66%, n = 1905) representing the largest relative abundances in treatment and control ditches, respectively. Simple correlation tests showed macroinvertebrate abundances are not significantly influenced by either weir age or distance from weir. Our study suggests further investigation is needed to accurately assess the functional response of macroinvertebrate community composition to weirs. Our study was limited in both sample size and time. These limitations prohibited us from making significant conclusions about our results. We suggest a longitudinal study with a larger sample size across a wider pool of age classes may produce statistically significant results.

Proceedings of the 42nd Mississippi Water Resources Conference

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: .

Soil Media Compositions for Water Quality Improvements and Stormwater Management in Urban Flow-through Facilities

Final Project Report

Year: 2013 Authors: Kröger R., Gallo C., Overbey E.

Nutrient removal and volume reduction capabilities of a range of soil media mixtures in urban flow-through planters were investigated. Eighteen scaled flow-through mesocosms were evaluated for nitrogen and phosphorus removal rates and volume reduction by applying a synthetic stormwater solution over a simulated 2-inch, Type II storm hydrograph. Three replicates of six treatments were tested including four soil mixtures. Significant (p<0.05) reductions in volume for 100% sand, 75% sand, 50% sand content mesocosms compared to the controls, indicating bioretention mixes with higher sand content have greater water retention capabilities. For water quality results, both concentration and load reductions were calculated and compared, where load accounted for volume passing through the mesocosms and therefore more accurately represented water quality results. PO4 load reduction was greater in treatments with less sand (up to 41% reduction). NO₃-N load reduction varied greatly (7% removal to 53% loading). Significant phosphate loading was observed at the peak of the hydrograph (between minutes 60 and 120) compared to the controls, indicating greater flow rates decreased the nutrient removal capabilities of bioretention in the experiment. Preferential flow patterns were observed which potentially led to higher than expected infiltration rates and therefore no observable peak flow reduction.

Comparisons of Indigenous and Selected Bacterial Degrading Pentachlorophenol (PCP) Consortiums for Remediation of PCP Contaminated Groundwater

Final Project Report

Year: 2013 Authors: Prewitt M.L., Borazjani H., Willeford K.

Results from this research are expected to reveal which of 3 consortiums of bioaugmented PCP degrading bacteria will increase PCP degradation in contaminated groundwater. The information that will be gained from this research should lead to customizing remediation methods based on the indigenous microbial community at a contaminated site. Not only could bacterial consortiums be used for PCP degradation, they could also be used to address other water quality issues such as high Biological Oxygen Demand (BOD) that impacts wastewater discharge from industries in Mississippi and nationwide such as the pulp and paper mills, oil spills in the Gulf Coast and excess nitrogen in agriculture runoff.

Ecological Assessment of NRCS's Migratory Bird Habitat Initiative in Reponse to BP's Gulf Oil Spill

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Kaminski R.

Science should guide conservation of natural resources to promote effectiveness, efficiency, and economy of management actions and policy development. Following the Deepwater Horizon Oil Spill in the Gulf of Mexico in April 2010, the Natural Resources Conservation Service (NRCS) established the Migratory Bird Habitat Initiative (MBHI). Working with owners and managers of private croplands, aquaculture ponds, and Wetland Reserve Program easements, NRCS and conservation partners managed thousands of acres of wetlands and agricultural lands in the Mississippi Alluvial Valley (MAV) and Gulf Coast regions to provide wetland and upland habitat inland from potentially oil-impacted coastal wetlands. In fall 2010, scientists and graduate students from Mississippi State University, Arkansas Tech University, and University of Missouri began designing and implementing local and landscape scale surveys to (1) estimate use of MBHI managed wetlands and comparable non-MBHI wetlands by shorebirds, waterfowl, and other waterbirds, and (2) assess relative effectiveness of different MBHI practices for providing habitat and food resources for migrating, resident, and wintering waterbirds. Currently, researchers are working in the MAV in Arkansas, Louisiana, Mississippi, and Missouri and the Gulf Coast Prairies in Louisiana and Texas. Our presentation will summarize estimated bird use and food abundance on MBHI and compared study areas and report future directions for completing the MBHI assessment by 2013. Generally, avian abundance and diversity have been greater on MBHI-managed than other areas, although complexes of managed and other wetlands are providing wetland habitat for waterbirds among seasons. For example, when managed wetlands are dewatered in spring-summer to promote emergent vegetation, wetlands lacking such hydrological management provide habitat for waterbirds. Our study will aid future habitat conservation and adaptive management on private and public lands inland from the Gulf, which is a proactive need considering continued decline of continentally important coastal wetlands.

Support for a Northeast MS Regional Water Management Plan: Updating the Water Budget for the Tombigbee River Basin

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Ramirez-Avila J.J., McAnally III W.H., Tagert M.L.

Researchers from Mississippi State University (MSU) are providing assistance to organize and draft a water management plan for selected northeast Mississippi counties, in the context of an overall basin plan, with the guidance and support of the Tennessee River Valley Water Management District (TRVWMD) and its stakeholders. Updating the MSU water budget for the Tombigbee River Basin developed by McKey and McAnally in 2008 is one of the main tasks included in the statement of work for the study in performance. Research activities to complete the proposed task involves the consecution of new information on withdrawals and discharges; the use of hydrologic calculations to fill in gaps of ungaged streams in the basin and identify potential extreme flows; and the statistical analysis of flow data for use in a risk analysis of extreme flows.

Efficacy of Innovative Surface Water Capture and Irrigation Re-use Technologies as a Best Management Practice: A Multi-seasonal Assessment in the Mississippi Delta Region

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Omer A., Kröger R.

The Mississippi Alluvial Valley is the center for agricultural crop production in the Southeast United States. The necessity for irrigation to maintain maximum yields has led to increased pressure placed on the Mississippi Alluvial Aquifer resulting in a negative balance. As a method of water management, surface water capture and irrigation re-use systems are being implemented into agriculture systems in Mississippi. However, the environmental and economic benefits of these systems have yet to be described and quantified. The main objective of this research is to describe and quantify the potential benefits of surface water capture and irrigation re-use systems for water resource conservation. Four sites located in the Mississippi Delta Region which utilize water capture and irrigation re-use systems will be assessed by monitoring: pumping schedules of re-lift stations, water level of on-farm storage reservoirs and flows of surface water irrigation pumps through irrigation meters. This data will be compared to systems using strictly ground water to understand water saving differences. Three years of data will be used to quantify a water savings budget and assess at a regional scale the contributions of surface water capture to decrease ground water withdrawals. The water savings budget in addition to the potential energy savings will be combined to provide an economic analysis of water capture and irrigation re-use systems. The results of this research will be used to create an economic analysis to provide valuable outreach material for dissemination to Mississippi producers. This potentially will lead to further implementation of water capture and irrigation re-use systems throughout Mississippi.

Modeling Rainfall Runoff using 2D Shallow Water Equation

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Shirmeen T., Jia Y.

Torrential storms often trigger flooding that causes damage in properties and loss of life. In this study a numerical simulation module is developed to enhance the capability of a 2D surface flow model, CCHE2D. Following the procedure for numerical model verification and validation of ASCE, the developed module is tested using both analytical solutions and experiment data.

The analytical solutions of kinematic wave equation for runoff occurring on a sloping plane subject to a constant rainfall of indefinite duration and finite duration were used to compare to the results of the numerical model with good agreements. Runoff processes measured in laboratory experiments were also simulated in this study using the 2D model. The simulated runoff processes and the observed physical processes again showed excellent agreements. These tests indicate that the CCHE2D model is capable of modeling rainfall-runoff and kinematic overland flows.

Crayfish Harvesting: Alternative Opportunities for Landowners Practicing Moist-soil Wetland Management

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Alford A.B., Grado S.C., Kaminski R.M.

Harvest of crayfish (Procambarus spp.) for human consumption in the United States and beyond is considerable, amounting to an annual value of $150-170 million annually in the southern United States alone. Most crayfish harvested for human consumption are cultivated in rice fields in southern Louisiana. Management of emergent vegetation in moist-soil wetlands is similar to cultivation of rice where the seasonal wet-dry cycle of these wetlands encourages the growth of annual plants that produce abundant seeds and tubers for waterfowl forage. Recent aquatic invertebrate studies in moist-soil wetlands suggest that populations of crayfish in these habitats may be large enough to warrant a harvest for human consumption. To estimate the economic potential of crayfish harvests in moist-soil wetlands, crayfish yield was estimated from moist-soil wetlands on public and private lands in the MAV in Arkansas, Louisiana, Mississippi, and Missouri in spring-summer 2009-2011 using typical crayfish harvest strategies practiced in commercial rice-crayfish fields of Louisiana. Average daily yields of crayfish from moist-soil wetlands ranged from 0.08 kg/ha to 23 kg/ha with an overall mean yield of 2.73 kg/ha (n = 42, CV = 21%). Whereas the mean daily yield of crayfish from moist-soil wetlands was >3 times less than the yield expected from a high production rice-crayfish culture system (e.g., 8-10 kg/ha), estimated cost associated with harvest of crayfish from moist-soil wetlands were $529/ha and were lower compared to costs associated rice-crayfish harvest practices which were estimated to be $1,856/ha. However, the estimated break-even selling price for crayfish harvested from moist-soil wetlands was $4.90/kg compared to $2.75/kg estimated for rice-crayfish practices. The estimates of break-even selling prices for crayfish harvested from moist-soil wetlands were higher than the 2012 estimate of $2.75/kg price for single crop production of crayfish in Louisiana. However, in areas where crayfish markets are sparse, such as the North Mississippi Delta, landowners may still realize economic potential from this fishery. Harvesting crayfish from moist-soil wetlands may provide a small profit to landowners but will likely provide additional recreational opportunities and can serve as additional extension vehicles to encourage wetlands conservation throughout the MAV.

Rivers and Community Engagement. Regulatory Frameworks and Practices in Europe and USA.

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Pappalardo G.

Environmental regeneration is not just a matter of natural science. Laypersons, different stakeholders, associations such as NGOs are crucial actors in managing ecosystems, at the grassroots level as well as at the institutional level. Gunderson, Holland et al (1995) describe the relationship between human organizational structures and nature, underlying how Sustainable Development is a process related to Social Learning. Even if the expressions Sustainable Development and Social Learning may have ambiguous meanings related to every different context, it is possible to find some similar issues at the global scale. The U.N. Rio Declaration on Environment and Development (1992) and its updated version Rio+20 show an arising awareness about the crucial role of local communities in taking care of the environment. Moreover, the Nobel Prize in Economic Science Elinor Ostrom (1991) proves the importance of collaborative practices and institutional reframing in order to overcome the Tragedy of the Commons (Hardin 1968).

This paper is aimed at describing and characterizing the process of Community Engagement in watershed management in Europe and USA. First, a critical review of the regulatory frameworks is examined, in order to explain similarities and differences between these two contexts. In Europe, the Convention on Access to Information, Public Participation in Decision-Making and Access to Justice in Environmental Matters (1998) is a milestone on the topic; then, the European Landscape Convention (2000) explains the strong relationship among physical heritage, cultural dimensions and inhabitants' perceptions. Furthermore, the specific Directive in matter of Water (2000/60/EC) is based on the same principles, i.e. broad involvement of the general public and different stakeholders, with different knowledge, values, interests and future perspectives. In U.S.A. the Environmental Protection Agency, with the Clean Water Act (1972) and 40 years of implementation phases, is moving the discussion toward a broader dissemination of participatory practices (Sirianni 2006).

After a comparative analysis of the aforementioned regulations, a multiple case-study research is discussed in order to understand in practice what is engagement, how is it related to watershed management, which are different paradigms and types of community involvement. The cases are selected according to the following characteristics: engagement as an opportunity to define a common vision for the future, starting from history and values of every context; engagement as a way to promote education and responsible behaviors in managing the water; engagement as a moment of dialogue amongst all community members. The outcome of the research is a typology that may operate as a guide in organizing communities that wish to manage ecosystems in a proactive and adaptive way.
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Modeling the Potential for Water Supply from a Constructed Lake in South Mississippi Under Present Climate and Projected Climate Change

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Pote J.W., Wax C.L., Tagert M.L.

The daily volume of water in a 5200 acre lake with a full capacity of 104,000 A-F in a coastal Mississippi location is simulated from 1961-2010. The lake basin is 17,550 acres, a runoff coefficient of 0.7 is used, base flow is set at 3 A-F/d, infiltration rate is set at 12 A-F/d, and outflow is set at 3 A-F/d. Inputs from the present climate regime are precipitation (P) minus potential evaporation (PE). Positive daily P-PE adds water to the lake and daily negative P-PE subtracts water from the lake. Climate change is projected by reducing daily P by 1.57% and increasing daily PE by 9.73%.

Cumulative P-PE for the average of all 50 years, the wettest year (1961), the median year (1993), and the driest year (2000), with and without climate change, is calculated. Factoring in the daily interaction between P and PE and comparing the present and changed climate by graphing the cumulative effect through the year shows that the annual pattern stays relatively the same day-by-day through each of the years and that the modeled climate change does reduce the end result in each of the years. For example, the average curves in both graphs show that under present climate the year ends at 19.77" but with climate change it ends at 13.85", a reduction of 5.32" or about 28% of the extra water. The median year curves show that without climate change the year ends at 24.55" but with climate change it ends at 19.75", a reduction of 4.8" or about 20% of excess water. The wettest year curves show the year ending at 54.65" but with climate change it ends at 48.40", a reduction of 6.55" or about 12% of extra water. The driest year curves show the year ending at -10.93" but with climate change it ends at -15.97, an increase in the year's deficit of 5.04" or about 46%.

Even in light of these potential changes in the average and extreme years, a 50-year daily analysis shows that both without and with climate change, the lake's volume drops no lower than about 97,000 A-F at any point in the period. The conclusion is that the climate of coastal Mississippi will sustain a surface water supply from a lake through known climate variability and proposed climate change in the future.

Design and Construction of Quarry Capture Prevention BMPs on the Buttahatchie River

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Maurer B.J.

Alluvial deposits (Holocen) have made the harvest of sand and gravel profitable in the Buttahatchie River watershed. Historically, excavations in and adjacent to the river have altered the location and stability of the channel. Many inactive, pre-regulation quarries are still found concentrated along the lower 20 km of the main channel. Construction of the Tennessee-Tombigbee Watershed, of which the Buttahatchie River is a tributary, and the resultant head-cutting, have further exacerbated the process of "quarry capture", whereby the river channel changes course into a quarry.

With partners from Mississippi State University, and with support from the US Fish & Wildlife Service, The Nature Conservancy has undertaken a project to develop and implement stabilization BMPs to prevent further quarry capture on the Buttahatchie River. Utilizing LiDAR mapping of the area and modeling of flow patterns, this project will identify points vulnerable to quarry capture, and design and construct appropriate stabilization techniques. Techniques are expected to be both specific to the individual characteristics of each site, and exportable to vulnerable channels in other watersheds.

Construction on the first stabilization project will be completed in the winter of 2013 in Monroe County, Mississippi, and will stabilize 1300 feet of river bank to prevent the river from changing course into several inactive gravel quarries adjacent to the river. This presentation will detail the project design, the selection of BMPs, the construction, and the outcome of the project. The BMPs will include bendway weirs, locked logs, and customized planting installed under very difficult conditions.

Decision analysis for species preservation under sea-level rise

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Linhoss A.C., Kiker G.A., Aiello-Lammens M.E., Chu-Agor M.L., Convertino M., Munoz-Carpena R., Fischer R., Linkov I.

Sea-level rise is expected to dramatically alter low-lying coastal and intertidal areas, which provide important habitat for shoreline-dependent species. The Snowy Plover (Charadrius nivosus) is a threatened shorebird that relies on Gulf Coast sandy beaches for nesting and breeding. Selecting a management strategy for the conservation of this species under sea-level rise is a complex task that entails the consideration of multiple streams of information, stakeholder preferences, value judgments, and uncertainty. We use a spatially explicit linked modeling process that incorporates geomorphological (SLAMM), habitat (MaxEnt), and metapopulation (RAMAS GIS) models to simulate the effect of sea-level rise on Snowy Plover populations. We then apply multi-criteria decision analysis to identify preferred management strategies for the conservation of the species. Two decision analysis techniques are compared: Multiple Attribute Utility Theory and Stochastic Multi-criteria Acceptability Analysis. We investigate four conservation strategies including no action, beach nourishment, nest exclosures, and predator management. Results show that predator management and nest exclosures are the most promising conservation strategies. This is an innovative method for planning for sea-level rise through pairing a linked modeling system with decision analysis to provide management focused results in an inherently uncertain future.

Risk Assessment for Phosphorus Movement in Nutrient Management Planning in Mississippi

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Oldham J.L., Ramirez-Avila J.J., Kingery W.L., Jackson W.

Nutrient Management develops blueprints for using the right amount of the right nutrient source at the right time in the right place. Using poultry litter as a nutrient source in pastures and forages results in increased soil test phosphorus (STP) levels when applications are based on crop nitrogen needs because more phosphorus (P) is provided in each unit of litter than the corresponding unit of grass removes. Increased STP in combination with site-specific soil and field characteristics may lead to P enrichment of surface and ground water. Phosphorus Indices (PI) are state-specific, site-specific algorithms to assess potential P loss that are used in the Nutrient Management Planning (NMP) process. These tools have been developed by individual state Natural Resource Conservation Service (NRCS) agencies under national policy guidance and integrated into the NRCS 590 Nutrient Management Conservation Standard since the late 1990's. Source factors such as STP, and nutrient source and management are used in combination with transport factors including soil characteristics, landscape characterization, and distance to nearest stream in various models to determine relative risk of P movement. Because of the leeway provided to the states, there are numerous versions of PI. Some are quantitative and predict P loss amounts; others, including Mississippi, are qualitative and assign relative risk. With higher risk of P movement to water as determined by PI categories, NMP preparation should assess potential mitigating Best Management Practices adoption. At issue are two recent published southern regional efforts that found differences in PI prediction capacity between state versions, including Mississippi. Individual state NRCS agencies, in cooperation with in-state partners, were asked to update their Nutrient Management Practice Standards in 2012, including reassessment of each state Phosphorus Index. In addition to the in-state standard revision with Mississippi NRCS, Mississippi State University is participating in a multistate effort under the national NRCS Conservation Innovation Grants to coordinate and advance P management in the southern region, ensuring that the PI have been tested based on new guidance in the NRCS 590 standard, and that tools produce more consistent results across physiographic regions in order to promote better consistency between southern state recommendations. This paper provides an overview of NMP, the factors used in the Mississippi Phosphorus Index, and additional efforts regarding NMP process in Mississippi.

Effectiveness of low grade weirs to reduce sediment and nutrients loads in agricultural ditches of the Mississippi Delta

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Ramirez-Avila J.J., Poganski B., Kröger R.

Drainage ditches are an essential component of the agricultural landscape. Ditches mediate the flow of pollutants from agroecosystems to downstream water bodies. Low-grade weirs established along drainage ditches, as an agricultural best management practice, have been evaluated as an effective measure to mitigate nutrient and sediment loads to downstream aquatic systems. A study was performed to estimate sediment and nutrient loading reductions and to determine the cost-effectiveness curve of implementing low grade weirs in agricultural drainage ditches systems in the Mississippi Delta. The study goals were addressed by combining field data collection and computational modeling techniques. Runoff volumes flowing downstream of low grade weirs along different drainage ditch systems during stormflow and irrigation events were estimated by using the Hydrologic Engineering Center - River Analysis System (HEC-RAS 4.1) model. Monitored sediment and nutrient concentrations and the generated runoff flows were used to develop representative rating curves for each low grade weir on each drainage ditch system. Runoff hydrograph flows on each event were routed through the generated rating curves to estimate instantaneous and total sediment and nutrient loads at each location. Loads were compared to determine low grade weirs efficiency inside each drainage ditch and between drainage ditch systems. A second part of the study used the System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN 1.2) to determine the most cost-effective solutions for meeting proposed agricultural runoff water quality conditions. Results from this study will provide more insights to further enhance the nutrient reduction strategy within the Mississippi Delta region.

Variable spatial and temporal impacts of low-grade weirs on the agriculture landscape: evaluating the costs and benefits

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Poganski B., Kröger R., Pierce S.

The use of inorganic fertilizers in agricultural production is widely recognized as a source of nitrate contributing to annual hypoxic zones in the Gulf of Mexico. Ecosystem degradation and impacts on freshwater and marine biota from nutrient contamination of surface waters have motivated research efforts to develop and implement innovative nutrient management practices. Such efforts have become a major priority of many landowners, natural resource conservationists, scientists, and government agencies from a local to national scale. The current experiment investigates how frequency and variable spatial arrangements of best management practices (BMPs) within drainage systems impact water quality leaving the agricultural landscape over time. Preliminary water quality results highlight temporal nutrient trends in agricultural effluent, where concentration spikes were observed during seasons that experience heavy rainfalls and when fertilizer application occurs. Results also showed phosphorus concentrations to be higher in run-off during stormflows rather than during baseflows, while nitrate concentrations in run-off were found to be similar regardless of flow regime. Integrating nutrient reduction data, spatial and temporal variables of best management practices, drainage acreage, and fertilizer inputs will help determine factors that affect nutrient reduction efficiencies and drive the adaptation of management strategies to further enhance pollution mitigation. Investigations of nutrient reduction data and environmental factors highlight the short-term benefits of management practices, which include water conservation, pollution reduction, and ecosystem services. Recognizing that decreasing the loss of water resources and nutrients through BMPs may have additional long-term environmental and monetary benefits to all stakeholders from local to regional scales.

Discerning BMP effectiveness for nutrient reductions in the Mississippi Delta

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Kröger R., Hicks M., Prevost D., Thornton K.

There is a significant impetus within the Mississippi River Basin, at both federal and state levels, to determine the possibility and attainability of nutrient reductions. These questions are being asked at several spatial scales, but ultimately are driven toward the largest spatial scale - Gulf of Mexico hypoxia. The Mississippi approach has been to utilize inter-agency collaboration to identify watersheds where BMP nutrient reductions can be demonstrated and to discern the effectiveness of those BMPs. Harris and Porters Bayous are two HUC 10 watersheds where BMPs have been installed on the landscape, and where tiered water quality monitoring with identical sampling frequencies provides a means for quantifying both reductions in nutrient concentrations and loads. Water quality data is being collected at three tiers. The first Tier (edge of field) is being collected by MSU, while Tiers 2 and 3 are being collected by USGS. Nutrient reductions in concentration, 1-year post BMP implementation are discernible at the Tier 1 scale, but are not yet known at Tiers 2 or 3 due to continued data analysis. Monitoring of multiple watersheds provides environmental variables and landscape characteristics that suggest reasons for the observed reductions. These initial answers provide previously unknown information towards improving in state aquatic ecosystem health as well as critically important BMP attainability estimates to inform Gulf of Mexico restoration recommendations.

Integrated Desalination and Wastewater Treatment Systems

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Kokabian B., Blair M.F., Gude V.G.

Water, energy and environment play a vital role in the sustainability of mankind. Environmental degradation associated with water and energy production/supply processes is the immediate concern faced by many parts of the world. Utilizing wastewater and produced waters as resources to provide for potable water and energy needs could serve as a sustainable alternative to mitigate environmental degradation. Towards this goal, microbial desalination cells allow for efficient wastewater treatment combined with electricity generation and desalination of saline waters. The premise for this research is based on the principles that the bio-electrochemical (BES) systems convert wastewaters into treated effluents while producing electricity and ionic species migration within the system facilitates desalination. A microbial desalination cell (MDC) can be constructed by including an additional saline water chamber in a microbial fuel cell using anode and cathode exchange membranes. Domestic wastewater can serve as a substrate provider while air cathodes can provide oxygen to accept electrons. A new concept to provide in-situ oxygen generation in the cathode section by algae to increase electron mobility (i.e. electric current) in microbial desalination cells is presented in this paper. Treated wastewater in the anode chamber will be allowed to pass through the cathode chamber to serve as CO2 and nutrient rich medium for algal biomass growth and in-situ oxygen generation. This process eliminates current issues encountered in microbial desalination cells such as salt accumulation in treated wastewater, pH drop and rise in anode and cathode chambers and provision of strong electron acceptors such as oxygen. This paper presents the results from experimental studies and energy analysis on the feasibility of algal microbial desalination cells.
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Monitoring fine suspended sediment in streams using high frequency acoustic signal attenuation measurements

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Kajdan T.A., Carpenter Jr. W.O., Chambers J.P., Goodwiller B.T., Surbeck C.Q.

This research focuses on a new device to measure fine suspended sediment particles in rivers and streams using acoustic signal attenuation measurements. The purpose of this device is to create a high frequency signal attenuation system that will be able to measure concentrations continuously without having to physically visit the site in order to obtain the samples. This system will be non-intrusive as well as relatively cost-effective in comparison with the methods that have previously been adopted. Two 20 MHz transducers will be aligned in a pitch-catch configuration at a distance based upon near field effects and noise level caused by the interaction between the transmitting and receiving transducers. The 20 MHz acoustic device will be able to measure particles ranging from 0.2 to 65 µm in size. A vast attenuation database has been created at the National Center for Physical Acoustics (NCPA), located in Oxford, Mississippi, to account for this range of particle sizes. The database includes acoustic signal attenuation measurements of bentonite, kaolinite, illite, and silt, which were used to broaden the sediment range. The database consists of peak-to-peak voltage data that was captured by the receiving transducer during the experiment and displayed and analyzed using LabView 2010. This voltage data corresponds to known particle concentrations. A digital signal processing (DSP) board will be used to process the data obtained from the 20 MHz transducers in the field. The attenuation signal that is measured in the field will be compared with the database so that a sediment concentration can be determined. The 20 MHz acoustic device will be calibrated at the NCPA using the attenuation database. Once the calibration is complete, the 20 MHz acoustic device will be deployed at Harris Bayou, located in Coahoma County, Mississippi. This particular bayou has relatively steady base flow, which is ideal for the acoustic device. The steady base flow of this bayou ensures that the signal produced by the transmitting transducer will not reflect off of the surface of the water causing inaccurate attenuation data. The digital signal processing board will be mounted in the gauging station housing that is currently being used by the United States Geological Survey (USGS). The results that are obtained from the field will be compared with concentrations that the USGS finds from its grab samples.

Solid phase extraction, QuEChERS cleanup, dansylation with LC-MS/MS detection as an improved method for analyzing five estrogens in wastewater

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Gunatilake S.R., Steelhammer S., Kwon J., Xia K., Armbrust K., Rodriguez J.M., Mlsna T.E.

An improved method for the analysis of estriol (E3), estrone (E1), 17α-estradiol (αE2), 17Β-estradiol (ΒE2), and 17α-ethinylestradiol (EE2) in wastewater is described. The method includes sample preparation using solid-phase extraction followed by a "QuEChERS" (Quick Easy Cheap Effective Rugged Safe) cleanup, and a LC-MS-MS detection. Solid phase extraction was carried out using Oasis HLB cartridges and a dispersive solid phase cleanup pack containing MgSO₄, PSA and C-18. The resulting extract was then derivatized with dansyl chloride. Separation was achieved on an Agilent Zorbex Extend C-18, Narrow Bore RR, (2.1 x 100mm, 3.5 µm) column and quantification was accomplished in the positive ion mode using multiple reaction monitoring. The cleanup method is quick, efficient, inexpensive, and requires only 200 ml of water. Reliable linearities were obtained for all the calibration curves (r₂ > 0.995). Calculated matrix effects were less than 12% for all the analytes and hence, matrix matched calibration curves were not needed. The recoveries for the estrogens ranged from 81–103% with a high repeatability (n=3, RSD = 9%) and low limits of quantification (0.6–0.9 ng/L). The method was used to analyze effluent and influent wastewaters in three Mississippi wastewater treatment plants but is broadly applicable for the determination of trace estrogens in any municipal wastewater samples.

Mississippi's Dam Safety Program

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Sigsby N., Myers D.

Created in 1978, the Mississippi Dam Safety program began the task of identifying dams that were High Hazard and working to get those dams repaired. In 1994, Dam Safety Regulations were defined to classify the hazard potential of dams, establish minimum design and construction criteria, to require regular inspections and to have an emergency action plan for all high hazard dams. These regulations were again revised in 2005 and are currently used today.

Created in 1978, the Mississippi Dam Safety program began the task of identifying dams that were High Hazard and working to get those dams repaired. In 1994, Dam Safety Regulations were defined to classify the hazard potential of dams, establish minimum design and construction criteria, to require regular inspections and to have an emergency action plan for all high hazard dams. These regulations were again revised in 2005 and are currently used today.

Source water protection in Mississippi: Just plugging away

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Crawford J., Payne M.

Most of the 3,000 public water system (PWS) wells operating in Mississippi are screened in deep confined aquifers, often overlain with multiple confining layers. Due to this favorable hydrogeologic setting, incidences of groundwater contamination impacting PWSs have not been widely reported in Mississippi. State source water protection efforts have mainly focused on addressing abandoned wells identified in delineated protection areas that may serve as potential conduits for the introduction of contaminants. Unfortunately, the success of these past efforts has been limited due to the sizeable number of abandoned wells in need of plugging and the lack of available funding to help offset the prohibitive cost associated with meeting state regulations.

Most of the 3,000 public water system (PWS) wells operating in Mississippi are screened in deep confined aquifers, often overlain with multiple confining layers. Due to this favorable hydrogeologic setting, incidences of groundwater contamination impacting PWSs have not been widely reported in Mississippi. State source water protection efforts have mainly focused on addressing abandoned wells identified in delineated protection areas that may serve as potential conduits for the introduction of contaminants. Unfortunately, the success of these past efforts has been limited due to the sizeable number of abandoned wells in need of plugging and the lack of available funding to help offset the prohibitive cost associated with meeting state regulations.

The well decommissioning program process began with MSDH's selection of a licensed water well contractor to perform the actual plugging. Accompanying this phase was the decision to contract with MsRWA to coordinate the well abandonment procedure and to assist in prioritizing the plugging of over 200 wells identified thus far. Eleven wells considered moderate risks to contamination (as determined by SWAP) and 13 higher ranked wells have been properly decommissioned and fully funded by the program during 2012. Future plans are to maintain the well decommissioning program provided EPA continues to receive funding from Congress for the capitalization grant.

An Assessment of Private Wells Used for Drinking Water in Mississippi

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Barrett J.

The majority of Mississippians enjoy access to one of the 1200 public water systems in Mississippi. Having access to a public water system provides the citizens with safety and quality of water through the regulatory enforcement of the Mississippi State Department of Health-Bureau of Public Water Supply (MSDH). Mississippi citizens on private wells do not have the luxury of knowing the quality and/or quantity of their water on a regular basis. In this presentation, by comparison of United States Census Data and MSDH data, the areas of Mississippi that have the highest concentrations of citizens on private wells will be derived. Data will be gathered to determine the likely contaminants to private wells in each particular county. This information will highlight the areas that could benefit the greatest from avenues in which private well owners can check the quality of their water as well as inform the surrounding water systems of their capacity to expand.

Occurrence and removal of pharmaceuticals and personal care products in different wastewater plants in Mississippi

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Kwon J., Brown A., Rodriguez J.

Residues of pharmaceuticals and personal care products (PPCPs) have been detected in surface waters. It is well known that effluent from wastewater treatment plants (WWTPs) is a major source of contamination of PPCPs in surface waters. The most frequently detected and toxic PPCPs, according to peer-reviewed articles published in the USA, are carbamazepine, sulfamethoxazole, gemfibrozil, and galaxolide. Three wastewater treatment plants (A, B, and C) in Mississippi, with different treatment technologies, were selected. Influent (law water) and effluent (treated water) were sampled from the three WWTPs over the course of one year. Upstream and downstream samples of the WWTPs were also collected. All the four PPCPs were detected in all influents, with galaxolide and sulfamethoxazole showing the highest concentrations of 4,020 ng/L and 3,905 ng/L, respectively while carbamazepine was detected at the lowest levels (66-348 ng/L). All the PPCPs were detected in all effluents except sulfamethoxazole. Different PPCPs were removed to different extent in the WWTPs, varying from -99% to 100%. Carbamazepine showed the lowest removal (-99% to 30%) and gemfibrozil showed the highest (73% to 100%) in the WWTPs. WWTP A gave lower removal rates than WWTPs B and C for sulfamethoxazole. WWTP A showed higher removal rates than WWTPs B and C for galaxolide. Comparing the concentrations of upstream PPCPs to the downstream, there is an apparent increase in concentrations.

Urban Flow-Through Facilities' Soil Media Compositions for Stormwater Quality and Quantity Improvements

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Overbey E., Gallo E., Kröger R.

An emerging practice for reducing the amount of nutrients and pollutants entering receiving waters is to filter urban stormwater runoff with infiltration based best management practices (BMPs). Small-scale BMPs for urban environments such as rain gardens, bioretention facilities, flow-through planters, and green roofs have been shown to slow peak flows and reduce the amount of nutrients that are washed from impervious surfaces during storm events. These BMP technologies are relatively new in design practice and all aspects of their structural design, potential for nutrient removal, and peak flow reduction is yet to be fully examined. The objective of this study is to provide understanding of different soil compositions in flow-through planters currently used in practice and determine their potential for water quality and quantity improvements. Eighteen 30"x18"x12" aquaria were modified to model flow-through facilities in a practical application using synthetic runoff which contained a 2ppm mixture of nitrogen and phosphorus. Soil mixtures varied across treatments and were composed of different percentages of sand, topsoil and compost. A hydrograph was used to simulate the most intense 4.5 hours of a 2-inch, Type II 24-hour rainfall event and was applied to the aquaria using manually controlled flow rate pumps. The outflow hydrograph was recorded to determine if peak flow was reduced and water quality samples were collected and analyzed to determine if nitrate and phosphate retention differed between soil treatments. Water quality data analyses indicate phosphate retention values ranged from (33-81%) and poor retention of nitrate (4- 23%). Nitrate values showed increases in concentration for some treatments. Preliminary results indicate the need for modification of the study design as higher infiltration rates in soil treatments reduced the residence time expected for the stormwater runoff in these facilities and as a result did not allow for the desired reduced peak flow. Further research is needed to test structural design modifications of flow-through facilities in order to increase their quantity reduction performance.

Introduction to Changing Site Design Standards for Stormwater Management

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Bathi J.R., Rhoads S.

A recent regulatory trend is to base storm water control requirements on the total volume of storm water runoff from a site rather than on runoff rates or a specific pollutant removal rate. This trend is based on a growing body of research which has concluded that volume-based controls accomplish the concurrent benefits of pollutant reduction, peak flow reduction, and base flow protection. The focus on runoff volume as the common currency for best management practices evaluation is gaining wider acceptance across the country. Current regulations in the region demand a high level of stormwater infrastructure to meet the total volume of detention storage required. Instead, the evolving volume based controls have been proving to be less cost intensive with distributed green technologies at the source level. The purpose of this paper is to provide an overview of new volume based standards and rainfall frequency analysis procedures for selecting the appropriate control matrix for an area. In addition, we have summarized commonly used green infrastructure practices, and outlined available computer models for designing and evaluating site level green infrastructure techniques.

Implementing Green Infrastructure through new Policies and Tools

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Gallo W.C., Overbey E.

The underlying theory behind green infrastructure or sustainable stormwater design is that the cumulative impact of many small facilities is greater than that of a few large facilities. This concept depends on the design, installation and management of many more facilities than a traditional pipe and detain ordinance would have created. Instead, a collection of small-scale, vegetated, best management practices are designed to fit seamlessly into the urban fabric to manage smaller storm events close to the source, mitigate nearly every new impervious area, and promote as much infiltration or bio-retention as possible.

For a municipality to move toward a green infrastructure approach requires major changes to how their stormwater ordinance is organized and administered. More facilities, potentially means more submittals, more calculations to check, and more designs to approve. A few municipalities have been grappling with this paradigm shift for the last decade. Their experience indicates that the shift toward green infrastructure requires new tools, which simplify the administrative and design process, and new policies, which ensure the goals of green infrastructure are implemented effectively.

This presentation will explore a few of the specific policies and tools, which have been developed to implement green infrastructure including:

• a pre-development definition which ensures policies will improve watershed protection over time;
• a low application trigger which is central to the concept of managing stormwater at the source;
• a detention requirement, which when combined with a low application trigger, does not impede urban development and also provides a high level of overall flood protection;
• an almost wholesale embrace of small-scale vegetated best management practices (BMPs), which focus on infiltration; and
• a collection of tools specifically designed to facilitate the design, approval, and implementation of small-scale BMPs.

Teaching How Water Works: Informal Science Education through Exhibit Design

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Brzuszek R.

The mission of the Crosby Arboretum, Mississippi State University Extension (located in Picayune, Miss.), is to preserve, protect and display plants and their communities native to the Pearl River Drainage Basin. The Crosby Arboretum's nationally award-winning master plan has designated a portion of its facility for the creation of a small stream swamp forest educational exhibit. Small stream swamp forests are wetlands situated on bottomlands of small streams that are predominated in species type and frequency by black gum (Nyssa biflora) and sweet bay magnolia (Magnolia virginiana). As specified in Mississippi's Comprehensive Wildlife Conservation Strategy by the Mississippi Department of Wildlife and Fisheries (MDWF), small stream swamp forests are considered vulnerable in the state of Mississippi. The proposed swamp forest exhibit will address MDWF priorities through the construction and management of the habitat type, as well as providing a venue for public education and experience in this vulnerable forest.

The Crosby Arboretum Foundation was awarded a grant to create a small stream forest educational exhibit. Graduate students in the Department of Landscape Architecture at Mississippi State University utilized a semester-long class project in spring 2011 to research and design the proposed exhibit. Students conducted a literature search on small streams and related wetlands and visited several in situ small stream swamps in Mississippi. Students recorded environmental data at the natural wetlands to inform the restoration design. Students also conducted an environmental inventory and analysis at the proposed exhibit site that recorded the site's hydrology patterns, plant species, soils and other data. A design charrette, or a collaborative session to determine solution to the design problem, was conducted with wetland specialists and landscape architects to develop the preliminary design. This paper will discuss the method used to develop the exhibit design and will exhibit the drawings for the proposed stream and associated wetland types. Long-term vegetation monitoring will be initiated after construction.

Influence of Spatial Precipitation Patterns on Seasonal Recharge in the lower Mississippi River Alluvial Aquifer

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Dyer J., Mercer A.

Water resources in the lower Mississippi River alluvial valley play a critical role in agricultural productivity due to the widespread use of irrigation during the growing season. Although the region receives abundant precipitation throughout the year, the unknown specifics of meteorological modifications in the region, along with continually changing anthropogenic needs on the groundwater system, makes it difficult for water resource managers to make sound decisions for future water sustainability. Additionally, agriculture in this region is under considerable strain due to diminishing groundwater availability and the non-sustainable trend in irrigation draws from the alluvial aquifer. As a result, it is crucial to correlate local rainfall patterns with aquifer water levels to better determine the spatial and temporal influence of precipitation on regional groundwater levels. This project will address water availability in the lower Mississippi River alluvial aquifer (LMRAA) over northwest Mississippi through an assessment of historical precipitation variability using high-resolution radar-derived precipitation estimates. This information will be used to estimate current and future precipitation availability over the region, which will be compared with regional groundwater observations to determine the level of interaction between rainfall and sub-surface water levels. Results of this project will aid in determining the natural limits to water resource availability, as well as the relationship between regional precipitation and groundwater variability.

Surficial Geology and Soils in the Mississippi Delta: In Search of Infiltration Data

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Mason P., Thompson D.

The water-bearing sands and gravels of the Mississippi River Valley alluvial aquifer (MRVA) underlying Mississippi's Delta region are very prolific and are important to agricultural interests. Significantly, the aquifer's overlying capping layer, or topstratum, is important in understanding the sustainability of this resource. This relatively thin topstratum is a primary controlling factor in determining how much direct recharge from precipitation passes from the surface to the aquifer. This process ultimately plays an important role in recharging this increasingly stressed and heavily utilized aquifer. Concepts and historical research vary regarding the permeability and character of the topstratum. Fisk (1944) described the topstratum as "various combinations of sand, silts, and clays" comprising a "relatively impervious topstratum". Little is known about specific locations in the Delta where direct recharge through the topstratum might be enhanced, restricted, or absent. As a result, previous efforts to simulate the groundwater flow system have postulated various schemes for assigning infiltration. These have included: 1) one uniform infiltration rate, 2) low rates in most areas with moderately low rates in zones controlled by topstratum geology, and 3) moderate to high rates in well-drained soils zones with no infiltration elsewhere. In an effort to clarify and illuminate the level of knowledge regarding this capping interval, systematic research and review of existing literature, surface geological mapping, soils mapping, and pertinent data sets is being undertaken. Some of the available data may be reprocessed or enhanced in order to better identify the various soil parameters, geomorphologic features, and depositional units which are thought to be useful tools in predicting and developing infiltration rates for the MRVA.

Low flow, how low should we go?

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Johnson D.R.

The determination of the minimum flow needed to support aquatic life and meet the needs of the Clean Water Act is a complex issue that has generally been answered with quick and meaningless statistical flows. This paper will examine a number of different methods used to establish low flow, and will compare them to observed flows several rivers in the Mississippi Delta.
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Assessing the Impacts of Future Climate Change on Peak Flows in a Forested Watershed

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Dakhlalla A.O., Parajuli P.B.

Future climate changes, such as precipitation, temperature, and carbon dioxide (CO2) can have dramatic impacts on the hydrological cycle. These climatic changes can also increase the intensity and occurrence of peak flow events, which cause significant damage to agriculture and infrastructure. This study was conducted in the Lower Pearl River Watershed (LPRW) in southern Mississippi, which is dominated by forests and is characterized by its high peak flows. The Soil and Water Assessment Tool (SWAT) was utilized to assess the impact of future climate change scenarios on peak flow frequency and magnitude.

The SWAT model was calibrated and validated for streamflow at five United States Geological Survey (USGS) gage stations (Bogalusa, Columbia, Monticello, Hanging Moss Creek, and Jackson) with good model performance based on the coefficient of determination, Nash-Sutcliffe Efficiency index, and root mean square error statistics. Future climate change scenarios were based on adjusting precipitation, temperature, and CO2 values. Observed daily precipitation and temperature data for the years 1981 to 2010 were used as inputs in a stochastic weather generator model to generate future climate data with the same statistical characteristics as the observed data. The occurrences and magnitudes of extreme peak flow events in the LPRW were analyzed under each climate scenario by developing flood hydrographs. Employing climate scenarios will aid in determining which climatic parameters have the most and least influence on peak flow magnitude and frequency. This study is expected to help in implementing best management practices (BMPs) more effectively in the LPRW that serve to attenuate peak flows.

Development of the Mississippi Irrigation Scheduling Tool-MIST

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Sassenrath G.F., Schmidt A.M., Schneider J., Tagert M.L., van Riessen H., Corbitt J.Q., Rice B., Thornton R.

Increasingly variable and uncertain rainfall patterns together with higher production input costs have led farmers to rely on supplemental irrigation to enhance production. While many irrigation methods have been developed for dry climates, few tools are available for humid, high rainfall areas. Moreover, most scheduling tools require extensive data collection, entry and simulation runs, limiting their practical utility during the production season. We have designed the Mississippi Irrigation Scheduling Tool (MIST) as a web-based, easy to use management tool for crop producers. An estimate of crop water use is made using the modified Penman Monteith to calculate daily evapotranspiration. The "checkbook" water balance method sums the water balance of the soil, plus water from rainfall or irrigation, minus water used by the crop or evaporated from the soil. This method indicates the need for irrigation when the soil water available to the plant falls below that which is readily available for crop growth. To enhance utility, the MIST has been implemented in a web interface, allowing producers to access the information from anywhere through tablet computers or smart phones. To reduce the data entry requirements, the system relies on national databases for automated integration with a water balance model. The system was tested at multiple production sites during the 2011, and 2012 growing seasons. This presentation will give details on the development of input parameters for the water balance calculation, including crop water use and soil moisture, and water balance during the growing season for corn and soybeans. Additional presentations in this session will describe the implementation of the user interface (Rice et al.), calibration and validation of the model (Prabhu et al.), and spatial accuracy of national databases (Thornton et al.). The MIST will provide producers, consultants and other professional colleagues with a reliable, accurate, and easy to use tool for improved water management.

Implementation of the Mississippi Irrigation Scheduling Tool in a dynamic web-based format

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Rice B., Sassenrath G.F., van Riessen H., Schmidt A.M., Tagert M.L.

The Mississippi Irrigation Scheduling Tool (MIST) has been developed to provide a daily calculation of water balance for row crop production. This daily calculation incorporates field specific data on soil type, tillage depth, row spacing, and crop type to make a recommendation on crop water needs. Weather data is automatically downloaded from national and regional databases and used to calculate daily evapotranspiration rate using the Modified Penman-Monteith equations. The first goal of MIST was to make it more accessible to the users. To do this, MIST was implemented as a web application, developed with Java and HTML. Using a web application eliminates the need for the user to download, install and update software. The main difficulty with a web application is making sure that every browser is displaying the web pages correctly since each web browser can interpret code differently. Incompatibilities between web browsers were observed a few times; one of these occurrences was with the font that was being used. Potential incompatibilities are determined by testing the system on multiple web browsers and platforms, though updates in these systems may present problems in the future. All the data is stored within a MySQL database, which currently contains twenty tables each having between three to twenty data columns depending on the data stored. Database security is maintained by restricting server connections to local only. One of the more common SQL attacks is done through SQL injection. Prepared statements are used to prevent these types of attacks. Most of the data are stored in plain English text with a table's data column. Passwords are converted to a MD5 checksum. MD5 checksum is a cryptography based algorithm that allows the storage of data without knowing what the data actually is. This provides security in the event someone is able to obtain access to the database—sensitive information will not be accessible. There are a few different types of user ranks within the interface: admin, manager, consultant, company, and farmer, with each user rank assigned different permissions. To assist in the tedious task of setting up each field within the farm, farmers are allowed to select the border of their field with Google maps. Implementing MIST has been full of challenges and decisions that will be discussed in this paper. Given the widespread adoption of tablets and smartphones, a web application provides equal access to any device that has access to a web browser.

Uncertainty, calibration and validation of the Mississippi Irrigation Scheduling Tool model

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Prabhu R., Lee N., Wadsworth M.C., Sassenrath G.F., Schmidt A.M., Crumpton J., Rice B., van Riessen H.

Implementation and use of a model requires an estimate of its accuracy. The Mississippi Irrigation Scheduling Tool (MIST) is an on-farm decision support tool to assist farmers in irrigating. The accuracy of the model is critical in designing good water management protocols. This research presents the results of the uncertainty analysis of the MIST model, showing the margin of error (uncertainty) of the irrigation advice. The basis for the verification and validation of the model is also given. The MIST calculates the daily soil water balance in a crop field from daily weather measurements, irrigation, and rainfall, accounting for crop type, planting date, soil type, tillage, and other field-specific information. The model output informs farmers of when irrigation is needed. The uncertainty analysis determines the margin of error in the irrigation decision and gives a range within which irrigation is feasible. The current uncertainty analysis also gives essential information on the influence of input parameters on the final irrigation recommendation calculated by the water balance.

The uncertainty calculations were based on Taylor's Series Method for the calculation of the total systematic uncertainty arising from measurement error of variables in the water balance calculation. The errors in measurement were one standard deviation in range, equivalent to an uncertainty with a confidence level of 68.2%. Because the current day's soil water balance depends on the previous day's water balance, the computations are iterative. As equations cascade to calculate the daily water balance, the uncertainties also propagate through the equations. Initially, uncertainty quantifications were performed for two sets of water balance calculations using local weather data. The final uncertainties for the water balance were of the order 3-6%, which is within the acceptable range for error.

The MIST water balance calculations were validated using local weather data consisting of rain days, and significant changes in the solar radiation, relative humidity and wind speed. The final water balance results showed values within acceptable ranges and comparable to in situ measurements of soil moisture. The final relative uncertainty in the water balance value was around 9%, which is in the normal range of margin of error. The current MIST web-based application and uncertainty quantification have been verified and validated for current parameters. The accuracy of the model was shown to be suitable for use by farmers in the Mississippi Delta area, and will help improve water management in crop production systems.

Nutrient and Suspended Sediment Mitigation Through the Use of a Vegetated Ditch System Fitted with Consecutive Low-grade Weirs

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Flora C., Kröger R.

Mississippi is the largest producer of channel catfish (Ictalurus punctatus) in the United States. Channel catfish ponds cover over 20,000 hectares of land, mainly concentrated in the Alluvial Valley of northwest Mississippi. Water management practices to reduce mass discharge from ponds are currently a major point of concern, especially in light of potential regulations through nutrient criteria development. A vegetated ditch fitted with consecutive low-grade weirs is anticipated to be a practical and effective option of reducing nutrients and suspended solids entering downstream receiving systems. This study assesses the effect of low-grade weirs on chemical retention and settling of aquaculture pond effluent in a single drainage ditch. Nine embankment ponds were discharged at 48 hour intervals into a single vegetated drainage ditch fitted with 3 low-grade weirs. Two additional embankment ponds were discharged into the ditch while boards were removed from weirs, thus acting as a conventional ditch. Data were analyzed to quantify the ability of the low-grade weir system to reduce the levels of ammonia, nitrate, nitrite, total inorganic phosphorus, particulate phosphorus, and dissolved inorganic phosphorus. The levels of total suspended solids and volatile suspended solids will be compared across the system. As water passes each weir the nutrient and suspended solid loads should decrease through the system, overall reducing the load entering the downstream receiving systems.

Potential environmental risk of the phosphorus status in soils receiving poultry manure applications in Mississippi

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Ramirez-Avila J.J., Oldham J.L., Kingery W.L., Crouse K.K., Ortega-Achury S.L.

Phosphorus (P) enrichment of surface and ground water involves a combination of source factors such as high soil test phosphorus (STP) levels and site-specific soil and field characteristics that influence P transport by water flow overland and through the soils. Long-term applications of manure have generally increased STP levels to a greater degree than has fertilizer application because manure applied to meet the nitrogen (N) needs of crops provides more P than utilized by crops. Preliminary research found that subwatersheds within the poultry production counties in Mississippi have a high potential for soil and water degradation from manure P and N. An assessment was developed to increase understanding of STP levels in soils of the top 20 poultry production counties in Mississippi. The study performed a descriptive summary and analysis of temporal dynamics of STP in 15,057 soil samples, submitted for forage and pasture crop recommendations, after analysis by the Mississippi State University Extension Service Soil Testing Laboratory for 10 annual periods from 2002-2003 to 2011-2012. There were gradual annual changes in STP level ranges from the first (5 to 3780 lb ac^-1) to the last year (5 to 3980 lb ac^-1). Individual peak STP values of 5990 and 4840 lb ac^-1 were observed in the 2nd and 7th year, respectively. However, mean STP levels increased from 113 lb ac^-1 to 302 lb ac^-1 from the first to the last year with the highest mean STP level of 356 lb ac^-1 in the 7th year. The MSU Extension Service would not recommend additional external P for 69% of the soils sampled in the last year of the dataset; in the first year this value was 38%. These results indicate increased STP in these soils that could contribute P to runoff and leaching flows. Because of the susceptibility of these areas to manure source P leaching and runoff, Best Management Practices should be implemented that manage P source and off-field transport to minimize environmental impacts. Balancing P inputs with crop removal is an essential part of a sustainable practice to controlling P losses. Maintaining moderate STP levels or reducing high STP levels can reduce the potential for transport of P from both particulate and dissolved P. Comprehensive nutrient management plans should be developed and implemented for all poultry production operations for the optimal use of poultry manure.

Numerical Modeling of Sediment-Associated Water Quality Processes in Natural Lakes

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Chao X., Jia Y., Shields Jr. F.D.

Sediment is a major nonpoint source pollutant. It may be transported into surface water bodies from agricultural lands and watersheds through runoff. These sediments could be associated with nutrients, pesticides, and other pollutants, and greatly affect the surface water qualities. Therefore, sediment has been listed as the most common pollutant in rivers, streams, lakes, and reservoirs by the US Environmental Protection Agency (USEPA).

This paper presents the development and application of a three-dimensional water quality model for predicting the distributions of nutrients, phytoplankton, dissolved oxygen, etc., in natural lakes. Three major sediment-associated water quality processes were simulated, including the effect of sediment on the light intensity for the growth of phytoplankton, the adsorption-desorption of nutrients by sediment and the release of nutrients from bed sediment layer. This model was first verified using analytical solutions for the transport of non-conservative substances in open channel flow, and then calibrated and validated by the field measurements conducted in a natural oxbow lake in Mississippi. The simulated concentrations of water quality constituents were generally in good agreement with field observations. This study shows that there are strong interactions between sediment and water quality constituents.

Effects of a native rough fish on water quality

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Goetz D., Kröger R., Miranda L.E.

The smallmouth buffalo (SMB) (Ictiobus bubalus), a large bodied benthivore commonly considered a rough fish, is native to Mississippi. Smallmouth buffalos frequently access floodplain lakes during periods of high water level, and remain isolated within them for extended periods of time after the water recedes. Based on evidence from other benthivore studies we hypothesized that high densities of SMB may contribute to poor water quality conditions. We tested this hypothesis in 0.05 hectare, shallow (<1.5 m) earthen ponds at three stocking densities. Nine ponds were randomly stocked with either a low (15 kg/ha), moderate 85 (kg/ha), and high (315 kg/ha) density and measured for water quality parameters over a ten-week period during the summer of 2012. Results from repeated measures ANOVA suggest SMB at high and moderate densities significantly (p < 0.05) increased chlorophyll, turbidity, total suspended solids, volatile suspended solids, temperature, total inorganic phosphorus, while decreasing dissolved oxygen, and Secchi depth, both through time and across treatments. Several previous studies also attribute high benthivorous fish density to enhanced productivity through feedback mechanisms that keep nutrients and sediments in constant suspension. However, most studies have looked at densities much greater than 315 kg/ha (500 +kg/ha). Our results suggest that effects of SMB even at moderate densities may contribute to degraded water quality conditions in natural habitats such as shallow floodplain lakes.

Spatial distribution of Sediment and Nutrient Loadings from Upper Pearl River Watershed (UPRW)

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Jayakody P., Parajuli P.B., Cathcart T.P.

Deterioration of surface water quality is one of the most concern issues in the U.S. The knowledge of spatial and temporal variability of water quality parameters may help to formulate mitigation plans to improve water quality. This study was designed to investigate temporal and spatial variability of sediment, total nitrogen (TN), and total phosphate (TP) loadings to the surface water through a modeling approach. The Soil and Water Assessment Tool (SWAT) was applied for Upper Pearl River Watershed (UPRW) in central Mississippi. Water samples were collected from Burnside and Lena USGS gauging stations. The SWAT model was calibrated and validated for daily time steps using manual and automatic (SUFI-2) methods from Feb 2010 to May 2011. Preliminary results showed good to very good model performances with the coefficient of determination (R2) and Nash-Sutcliff Efficiency Index (NSE) from 0.6 to 0.8 (flow), 0.3 to 0.6 (sediment), 0.6 to 0.7 (TN), and 0.5 to 0.6 (TP) during both hydrologic and water quality model calibration and validation. Sub-watersheds were ranked based on water quality pollutants loading to prioritize land areas for watershed management operations.

Monitoring and Modeling of Fecal Coliform Bacteria Loads in the Upper Pearl River Watershed

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Parajuli P.B., Jayakody P., Brooks J.P.

Pathogens loading from the non-point sources of agricultural and non-agricultural activities contribute to water quality degradation. Developing Total Maximum Daily Loads (TMDLs) for the pathogens (e.g. fecal coliform bacteria, E. coli) require quantifying bacterial load contribution from potential sources. Quantifying bacterial loads from each source will help in developing pathogenic load reduction strategies to meet applicable water quality standards.

The objective of this research was to monitor fecal coliform bacteria concentrations and quantify bacteria loads from the Upper Pearl River Watershed (UPRW-7,885 km²) in the east-central Mississippi. Analysis of observed fecal coliform bacteria concentrations with stream flows from the watershed will be presented. Preliminary results from the model simulations with seasonal variability of bacteria concentrations will also be presented using appropriate statistics.

A shallow-water equation based one-dimensional dynamic wave model with non-hydrostatic pressure

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Wei Z., Jia Y.

Coastal wave is one of major forces that dominate coastal hydronydamics, sediment transport, morphology and threaten coastal infrastructures. In recent years, the non-hydrostatic technique for solving Reynolds-averaged Navier-Stokes equations has been developed for wave propagation study. It has been shown that this method has a comparable accuracy for wave simulation to Boussinesq-type approaches and a better computing efficiency.

In this paper, a one-dimensional depth-integrated non-hydrostatic pressure wave model for wave propagation, breaking and run-up is developed based on the numerical method proposed by Stelling and Duinmeijer. In this numerical method, the non-conservative form of Navier-Stokes equation is solved for either momentum conservation or energy head conservation by applying different advection approximation methods. The method is, therefore, able to handle rapidly varied water flows (such as wave breaking) in wide range of Froude numbers. When wave run-up is concerned, wetting and drying treatment plays a key role for many numerical models. The wet & dry handling approach in the method is simple, efficient and capable of reserving positive water depth.

In this non-hydrostatic wave model development, the fractional time step method is adopted. The shallow water equations without non-hydrostatic pressure terms are solved for approximation of velocity; a tri-diagonal equation for non-hydrostatic pressure terms is then solved, and the approximate velocity is corrected by non-hydrostatic pressure terms. The free surface elevation is calculated by the depth-averaged continuity equation to satisfy global mass conservation. This model will be validated by an analytical solution and several benchmark wave dynamics test cases; it is anticipated the model can predict wave breaking and run-up processes effectively.

Modeling Sediment and Phosphorus Yields Using the HSPF Model in the Deep Hollow Watershed, Mississippi

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Diaz-Ramirez J., Martin J., McAnally W., Rebich R.A.

The impact of excess nutrient loads on eutrophication of waterbodies, including the increasingly frequent occurrences of harmful algal blooms and hypoxia, is well known and well documented. The Mississippi River/Gulf of Mexico Hypoxia is also a major environmental issue, and a key component of the Gulf Hypoxia Action Plan is the development and implementation of state nutrient reduction strategies. Effective implementation of nutrient load reductions requires that analytical tools be available to accurately estimate loads from watersheds and waterbodies as a function of hydrologic conditions. Hydrologic models have widely been used to accurately estimate outflows from watersheds, and to a lesser degree sediment and nutrient loads. Factors impacting runoff of nutrients are not well understood and as a consequence predictions of nutrient loads are highly uncertain. This research evaluated the ability of the Hydrological Simulation Program—FORTRAN (HSPF) to simulate storm, seasonal, and long-term runoff, sediment, and phosphorus transport at the farm scale in the Deep Hollow drainage area, Mississippi. The main goal was to demonstrate the usefulness of HSPF as a computer tool for future environmental management and planning in the Mississippi Delta region. When analyzing the datasets developed by U.S. Geological Survey, 69 events were selected to setup and evaluate the HSPF model. Model evaluation consisted in splitting the available data in two different time periods, calibration from 1997 to 1998 and validation in 1999. Runoff processes were evaluated using 45 events for calibration and 24 events for validation. In evaluating sediment export processes, 29 and 11 storm events were utilized in calibration and validation periods, respectively. Phosphorus simulations (dissolved and total) were evaluated using 19 and four storm events in calibration and validation periods, respectively. The HSPF model was setup to evaluate runoff, soil erosion, dissolved & total phosphorus to storm, monthly, and annual time scales.

This study concluded that the HSPF runoff model's simulations of storm-by-storm, long term monthly, and annual intervals were very good. In simulating suspended sediment loads, HSPF performance was poor for storm-by-storm analysis. However, long term monthly, and annual suspended sediment load simulations were tracked fair and good, respectively. Simulations of dissolved phosphorus of storm-by-storm and long term monthly intervals were good. Simulated annual dissolved phosphorus loads correlated very good with observed data. Similarly, HSPF performed good in simulating long term monthly total phosphorus loads and showed very good results in modeling annual total phosphorus loads exported from Deep Hollow drainage area.
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Can National Weather Service Spatially Gridded Radar Precipitation Estimates be Used to Overcome Spatial Variability in Mississippi Precipitation Meas

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Thornton R.F., Sassenrath G.F., Schneider J.M., Corbitt J.Q., Schmidt A.M., Crumpton J., Rice B., van Riessen H.

The goal of this research is to determine how reliable National Weather Service (NWS) spatially gridded radar precipitation estimates are in Mississippi. If results are good, the plan is to incorporate this source of rainfall information into the Mississippi Irrigation Scheduling Tool (MIST). Several rain gauge sources are included in the analysis in order to increase the spatial resolution of precipitation across the state of Mississippi. These sources include The Community Collaborative Rain, Snow and Hail Network (CoCoRahs), National Weather Service Cooperative Observers (COOP) and one DREC station. These rain gauge values were obtained for July 1-31 2012. Each rain gauge location is referenced by latitude and longitude, so it can be compared to NWS radar precipitation estimates at the same coordinates.

Summertime precipitation in Mississippi demonstrates a high degree of spatial variability through pop-up afternoon showers and thunderstorms. This research will determine the usefulness of radar-estimated precipitation, the spatial context of which could eliminate the variability problem inherit in point-source measurements. Actual rain gauge values are compared to radar-estimated values through the use of ARCGIS. If it is determined that radar-estimated precipitation is comparable to actual rain gauge data, then this will be incorporated into a tool to aid the Mississippi agricultural community in knowing when to most efficiently irrigate. The analysis will also attempt to find any spatial bias present between the two measurements, resulting in the discovery of any consistent correction coefficients. This, along with other conservation efforts already in place, will potentially help Mississippi farmers to conserve groundwater by supporting recharge of the Mississippi River Shallow Alluvial Aquifer over time.

Effects of vegetation and hydrology on Eh in vegetated agricultural drainage ditches with weirs

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Shoemaker C., Kröger R., Pierce S.

Oxidation-reduction potential (Eh) is an important parameter in predicting biogeochemical reactions occurring in waterlogged soils, including nutrient reduction. Specifically, soil Eh can be used to classify the potential of a system for nitrate reduction, providing a convenient and inexpensive tool for assessing the capacity of primary water bodies for denitrification potential. Continuous automated data loggers were developed, tested, and confirmed for accuracy and precision of Eh measurements. These units were then used to test a vegetated agricultural ditch with weirs in order to assess the influence of hydrology and vegetation on Eh. Six two week testing periods were conducted around two weirs from May-September 2012, with plots above each weir undergoing controlled drainage while plots below each weir functioned as controls subjected to conventional drainage. No differences were observed in the median Eh between vegetated and non-vegetated plots or the median Eh of the location of plot about the weir; however hydrologic changes influenced the range of Eh values regardless of vegetation status. The high levels of temporal and spatial Eh variation inherent in soils make it difficult to determine bulk soil Eh shifts over space and time. A one dimensional moving split window analysis was run to elucidate Eh boundaries by reduction potential. Results of this analysis showed marked shifts of Eh on specific probes, but no overall trends. The standard deviation of probes shifted over time, suggesting the use of controlled drainage coupled with vegetation could increase electrochemical heterogeneity in waterlogged soils. This increase in soil electrochemical heterogeneity may indicate increased denitrification potential as a result of controlled drainage in vegetated ditches.

Spring Microhabitat Oxygen Dynamics of Blue Lake, a Yazoo River Oxbow in Berclair MS

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Andrews C., Kröger R., Miranda L.E.

Shallow oxbow lakes carved in rich alluvial floodplains can support multiple microhabitats that maintain aquatic diversity. Oxbow lakes have a high shoreline to surface area ratio and are often connected to or surrounded by inundated wetlands such as cypress and tupelo brakes, creating within-lake structural habitat variability that may influence biotic composition. Furthermore, these microhabitats fundamentally function in different ways. We studied microhabitat oxygen dynamics of an oxbow lake in the Mississippi Alluvial Valley. Blue Lake has over 8 km of shoreline and is permanently connected to a tupelo brake (approximately 350 ha) inundated with 0.5-1 m of water during the spring, an important time for reproduction. Using hourly diel surface dissolved oxygen (DO) data collected in April-July 2012, we investigate several descriptors of DO dynamics including mean DO, daily DO peaks, rate of DO fall, time of DO peaks, and percent of time above minimum DO thresholds (2 and 5 mg/L). We test differences in spring oxygen dynamics between three habitat types (littoral, pelagic, and brake) using a MANCOVA (p<0.001) and explore the possibility of oxygen refugia in hypoxic systems. Mean temperature along with four DO metrics: mean, minimum, maximum, and range DO showed significant (p<0.05) difference in means and slope between sites. The observed differences promote habitat diversity likely to influence biotic composition and distribution.

Nutrient Reduction Benefits of On-Farm Water Storage Systems in Porter Bayou Watershed

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Tagert M.L., Paz J., Pote J., McCraven K., Kirmeyer R.L.

The Mississippi River Basin contains over 60% of the harvested cropland in the United States, and the Mississippi and Atchafalaya Rivers contribute more than three-fourths of the total nutrient load to the Gulf. Since the 1970's, groundwater levels in the Mississippi Alluvial Aquifer have decreased at a rate of approximately 100,000 acre-feet per year due to increased irrigated acres. Today, there are roughly 18,000 permitted irrigation wells dependent on water from the Mississippi Alluvial Aquifer, with an average addition of approximately 35,000 new irrigated acres per year for the past few years. Adequate supply of good quality water is important to sustaining agriculture, the primary industry in the economically depressed Mississippi Delta. Due to concerns over groundwater declines and increasing fuel costs to run irrigation pumps, farmers have begun implementing irrigation conservation measures, such as creating on farm storage areas to capture irrigation and surface water runoff from the field for later use. These systems offer farmers the dual benefit of providing water for irrigation and also capturing nutrient rich tailwater for on farm reuse. This project includes monitoring of two on farm water storage areas in the Porter Bayou Watershed, Mississippi and has two primary research objectives: a) determine the downstream nitrogen and phosphorous concentrations of effluent from water storage systems and b) quantify the effects of water storage systems on downstream flow levels through a watershed. Data collection began in February 2012, with water samples collected for analysis every three weeks throughout the growing season from March-October. Effluent nitrate and phosphorus levels were significantly lower than the inlet levels at both on farm storage systems.

Development and Application of Numerical Models to Environmental Hydraulics

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Chao X., Zhu T., Jia Y., Altinakar M.

Frequent natural and human activity induced disasters are influencing and degrading our water resources. To prevent and mitigate the damages that these disasters bring to our society in terms of water resources and eco-environmental quality, social and human welfare, life and property losses, and economic development, more effective and robust water resource management plans are necessary. The efforts of developing better research design and management tools have led to rapid advances in numerical modeling and computational simulation methodologies in parallel to the rapidly advancing computer technology. Computational models are effective and efficient tools that can be applied to study surface water flows, contaminant transport and environment impacts. Numerical models, CCHE2D and CCHE3D, developed at the National Center for Computational Hydroscience and Engineering of the University of Mississippi, have been applied to simulate the flow, sediment transport, pollutant distribution and water quality in natural water bodies. This paper briefly describes the CCHE2D & 3D models and demonstrate their capabilities by presenting the results of several study cases, including an oxbow lake in Mississippi, where water quality was degraded by excessive agro-chemicals, a hypothetical chemical spill case in a large lake in Mississippi, a salinity intrusion case in Lake Pontchartrain, LA, and hypothetical impact of radioactive chemicals to water quality in Kerr Reservoir and Lake Gaston, VA. The simulation results were validated using field measurements.

Factors affecting low summer dissolved oxygen concentrations in Mississippi Delta bayous

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Lizotte Jr. R.E., Shields Jr. F.D., Locke M.A., Murdock J.N., Knight S.S.

Streams in watersheds supporting intensive row-crop agriculture are vulnerable to ecological degradation due to non-point source discharge of pollutants such as nutrients. Low gradient streams such as bayous are especially susceptible due to increased water residence time, and often result in poor water quality and chronic low dissolved oxygen (DO) concentrations (hypoxia). The goal of the current study was to assess physical, chemical, and biological components affecting low DO during summer of 2011 in three Mississippi Delta bayous. Three sites were selected within each bayou: upstream channel, lake or open water in the water body mid-section, and downstream channel. Dissolved oxygen was monitored at 40 cm depth every 15 minutes for 6-7 days on alternate weeks. Stream surface water samples collected biweekly were analyzed for nutrient and chlorophyll a concentrations. Minimum daily DO levels were frequently below the State instantaneous minimum DO standard of 4 mg/L. Diel DO fluctuation (the difference between daily maximum and minimum DO concentrations) reflected large 24-h DO ranges (=10 mg/L) across all three bayous. Pearson product moment correlations showed minimum DO concentrations to be negatively correlated with total phosphorus (TP) concentrations across all habitats. Total nitrogen (TN) concentrations and dissolved organic carbon (DOC) concentrations were negatively correlated with minimum DO concentrations only in lake habitats. Diel DO fluctuation was positively correlated with water column chlorophyll a concentrations across all habitats. Upstream diel DO fluctuation was also positively correlated with water depth and TP concentrations while downstream diel DO fluctuation was positively correlated with TP but not water depth. Low summer DO concentrations and changes in diel DO fluctuations were affected by both nitrogen and phosphorus driving summer algal blooms (eutrophic to hypereutrophic conditions) in Mississippi Delta bayous. Organic carbon inputs may exacerbate DO minimums in these nutrient-rich systems. As a result, nutrient reduction in all habitats in conjunction with increased water depth in upstream habitats is necessary to improve summer DO concentrations in Mississippi Delta bayous.

Effects of Low-grade weir on hydraulic patterns of agricultural run-off in the Mississippi Delta

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Brison A., Poganski B., Kröger R.

Agricultural best management practices, in the form of low-grade weirs, have demonstrated the ability to mitigate nutrient and sediment loads to downstream aquatic systems. In a recent study, investigations of impacts of artificial low-grade weirs implemented in drainage ditches reported increased hydraulic residence times, an essential component to enhance nutrient reduction. However, research on the success of weirs is currently limited to controlled experiments rather than naturally occurring storm event conditions. This research investigated the effect of low-grade weirs on hydraulic residence time in several agricultural drainage ditches in the Mississippi Delta. Effects of low-grade weirs was assessed by comparing means of storm events and precipitation totals of varying magnitude within drainage ditches between pre- and post- weir implementation. Preliminary results suggest significantly shorter time to peak values between storm events pre- and post-weir implementation (K=11.522; p<0.05; Kruskal-Wallis) and longer time to base (K=18.566; p<0.05). No significant difference was found between pre-and post- weir time to maximum peak height (K=9.334; p>0.05; Kruskal-Wallis). Further research should account for variable physical dimensions, drainage area of each drainage ditch, and the number and spatial arrangement of weirs implemented to understand how weirs impact hydraulic patterns of drainage.

Detection and mapping of cyanobacterial harmful algal blooms using satellite data in one Louisiana lake and four Mississippi lakes

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Dash P.

Cyanobacteria represent the major harmful algal group in fresh to brackish water environments. Cyanobacterial blooms are aesthetically undesirable since they discolor the water, cause turbidity in recreational facilities and synthesize a large number of low molecular weight compounds which cause taste and odor problems. Of particular concern are a diverse range of toxins produced by cyanobacteria, termed cyanotoxins, which are hazardous to human, animal and aquatic ecosystem health. Recently, a procedure was developed to estimate cyanobacterial concentrations by quantifying chlorophyll a (Chl a) and the primary cyanobacterial pigment phycocyanin (PC) using OCM satellite data over a small lake- Lac des Allemands in Louisiana, USA. This required the development of an atmospheric correction and vicarious calibration methodology for satellite data. Empirical inversion algorithms were developed to convert the OCM Rrs at bands centered at 510.6 and 556.4 nm to concentrations of PC. For the algorithms to be uniformly valid over all areas (or all bio-optical regimes) of the lake, a holistic approach was developed to minimize the influence of other optically active constituents. Similarly, empirical algorithms to estimate Chl a concentrations were developed using OCM bands centered at 556.4 and 669 nm. The best PC algorithm (R²=0.7450, p<0.0001, n=72) yielded a root mean square error (RMSE) of 36.92 µ g/L (PC from 2.75 to 363.5 µg/L, n=48). The best algorithm for Chl a (R²=0.7510, p<0.0001) produced an RMSE of 31.19 µ g/L (Chl a from 9.46 to 212.7 µ g/L, n=48). The results demonstrated the preliminary success of using OCM satellite data to map cyanobacterial blooms in a small lake in Louisiana. In the summer of 2012, five field campaigns were undertaken to four large Mississippi lakes- Lakes Sardis, Enid, Grenada, and the Ross Barnett reservoir in order to obtain a database of photosynthetic pigment concentrations and phytoplankton composition. The objective of this project is to combine multiple satellite data from several sensors such as VIIRS, MODIS AQUA and OCM-2, and developed techniques to quantify cyanobacteria in these four large Mississippi lakes and make the mapped images available through a website for use by water quality managers and general public to rapidly obtain synoptic information on cyanobacterial blooms. Time-series of true color satellite images clearly show the presence of algal blooms. Preliminary analyses of the field data analyzed thus far demonstrate the presence of numerous toxic species of cyanobacteria in these lakes. Preliminary results from this project will be presented.

Factors associated with fate and cycling of nitrogen species in agricultural drainage ditches with implementation of low-grade weirs

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Faust D.R., Kröger R.

The overall objective of this study is to examine factors that may affect the fate and cycling of nitrogen species in agricultural drainage ditches with low-grade weirs installed. Emphasis will be on factors and processes that remove nitrogen from these ecosystems. Particular attention will be paid to factors that have been demonstrated to affect denitrification, as this process results in permanent removal of nitrogen from ecosystems. Three factors that have consistently been implicated in affecting denitrification are nitrate concentration, organic carbon availability, and oxidation-reduction potential. These three factors are the focus under of three specific objective to evaluate effects of these factors on nitrate removal and denitrification potential in sediment pore and overlying water in agricultural drainage ditches. Specific objectives are: 1) Water and sediment samples obtained from ditches at Spruill Farm (Belzoni, MS) will be used in laboratory experiments to determine if organic carbon availability is limiting denitrification potential and whether dissolved or particulate organic carbon is more suitable for denitrification; 2) Results from laboratory experiments will inform conditions used for simulated storm events in experimental v-ditch systems at Mississippi State University's South Farm Aquaculture Facility; 3) Effects of nitrate concentrations, organic carbon availability, and oxidation-reduction potential of sediment pore water and overlying water on nitrogen removal in agricultural drainage ditches at Spruill Farm will then be examined. In addition to best management practices already in use, results from these studies will allow for recommendations to enhance nitrogen removal in agricultural drainage ditch systems.

Evaluating the Variability of Sediment and Nutrient Loading from Crop and Cattle Fields Located in North Mississippi

Proceedings of the 42nd Mississippi Water Resources Conference

Year: 2013 Authors: Guzman S., Salazar G., Diaz-Ramirez J., Schauwecker T.J.

Excess nutrients are known as a primary problem facing Gulf of Mexico estuaries and coastal waters, leading to nuisance algal blooms, depletion of dissolved oxygen, and other water quality impairments. Soil and nutrient losses encourage siltation and eutrophication in Gulf of Mexico waters. Soil and nutrient exported from agricultural fields into water bodies in Mississippi is a major environmental concern by local, state, and federal agencies. This poster presents runoff and sediment & nutrient loads from two fields in north Mississippi: a 8.4-ha cattle drainage area located on the agricultural research property of the Mississippi Agriculture and Forestry Experiment Station (MAFES), adjacent to Mississippi State University (MSU); and a 11.3-ha crop drainage area located in Leflore County. The cattle field is monitored since 2011 by researchers from MSU Departments of Civil & Environmental Engineering and Landscape Architecture. At the outlet of the cattle field, MSU researchers are using a pressure transducer and automatic sampler to monitoring water depth and water quality, respectively. Field data (discharge and sediments & nutrient concentrations) from the crop drainage area were collected by the U.S Geological Survey from 1996 to 1999. The goal of this research is quantify sediment and nutrient loads by storm events yielded from fields managed with crops (soybeans and cotton) and beef production grazing pasture. Currently, we are computing and analyzing sediment and nutrient loads by storm events and planning to show results at the conference.

Hydrologic Regimes of Bottomland Hardwood Forests in the Mississippi Alluvial Valley and Gulf Coastal Plain and the Impact on Red Oak Acorn Production

Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Sloan J., Hatten J.

Red oak (Quercus spp.; Subgenus Erythrobalanus) acorns provide a major food source for many species of wildlife such as ducks, white-tailed deer (Odocoileus virginianus), and wild turkeys. Acorns are also important for the regeneration of these forests. The production of acorns is sporadic and the cause of this is not completely known or understood. Red oaks are prevalent in bottomland hardwood forests throughout the Mississippi Alluvial Valley (MAV) and Gulf Coastal Plain (GCP) and these forests undergo extreme hydrological events annually, from being completely inundated in the winter and spring to very dry in the summer. This study will examine the hydrology and soils of bottomland hardwood systems and the control they have on acorn production. Data has been collected at six sites, covering five states in the MAV and GCP. A well placed at each site was used to measure hydroperiod with an In-Situ Inc. LevelTROLL 300 and an In-Situ Inc. BaroTROLL. With these wells both ground water and surface water were measured. Organic matter input was measured using 10 porcelain sediment tiles at five of the sites and 20 porcelain sediment tiles at one site. Organic matter content of deposited sediment was determined by loss on ignition. Acorn production data was measured at 20 plots per site during the fall and winter of 2011/2012 and will be measured again in the fall and winter of 2012/2013. We will present preliminary hydrology, sedimentation, and organic matter accumulation data collected from September, 2011-February 2012.

MIST: A Web-Based Irrigation Scheduling Tool for Mississippi Crop Production

Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Rice M.B., Crumpton J., Schmidt A., Sassenrath G., Schneider J.

Increased reliance on supplemental irrigation has begun to deplete the alluvial aquifer in the Mississippi Delta region. To alleviate nonproductive overuse of groundwater resources, we are developing a web-based irrigation scheduling tool. The Mississippi Irrigation Scheduling Tool (MIST) uses a water balance approach, calculating evapotranspiration from weather data using standard ET equations. User input is streamlined by relying on automatic integration of soils data and weather information from national databases. MIST is currently being tested in various production management scenarios for corn and soybeans and for different alluvial soils common to the Mississippi Delta. The web interface allows users to input the necessary data that is required to compute the aforementioned formulas. Users then will be able to access the irrigation scheduling information remotely. Using java, jsps, and a SQL database, the web interface attempts to be easy to use for all users. The data that must be entered by a user should be data that is common or easily accessible knowledge to a farmer. Google Maps provides a framework to display and select the features (maps, fields, and wells) via the Internet, minimizing computation resources needed by users. Following completion of testing and validation, the research team is planning a tentative general release for the 2013 growing season.
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