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A Holistic Assessment of the Occurrence of Metolachlor and 2 of its Degradates Across Various Environmental Compartments in 7 Environmental Settings
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Rose C.E., Welch H.L., Coupe R.H., Capel P.D.

The widely used herbicide, metolachlor, is one of the most frequently detected pesticides in surface water and groundwater throughout the United States in both agricultural and urban settings. Metolachlor has also been detected in rain and in the unsaturated zone. The U.S. Geological Survey conducted a study to assess the controlling factors in the transport and fate of metolachlor and its degradates across seven watersheds in California, Indiana, Iowa, Maryland, Mississippi, Nebraska, and Washington during 1997-2007. The occurrence of metolachlor and two degradates (metolachlor ethane-sulfonic acid and metolachlor oxanilic acid) was examined in several environmental compartments within these environmental settings; groundwater, surface water, overland flow, subsurface drains, the unsaturated zone, and the atmosphere. Within these environmental compartments, the occurrence of metolachlor and its degradates primarily is affected by a number of factors including use, management, environmental setting, and physical and chemical properties of metolachlor and its degradates. The fate of metolachlor can be generalized by the environmental compartments. The majority (90%) of metolachlor is taken up by plants, degraded in the soil, or is trapped in/adsorbed to soil. About 10% of the applied metolachlor is volatilized into the atmosphere, and about 0.3% returns by rainfall. Some (0.4%) metolachlor is transported to surface water, while an equal amount (0.4%) is infiltrated into the unsaturated zone and may move downward into groundwater. Generally, groundwater stores less than 0.02% and does not serve as a metolachlor source to receiving surface waters.
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Adapting Portland’s Stormwater Approach to Other U.S. Cities
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Gallo W.C., Overbey E.

The Pacific Northwest, specifically Portland, OR, has become a recognized leader in progressive and creative stormwater management practices in the United States. Its projects have received numerous design awards and recognition based on their innovative approach to manage stormwater for both quality and quantity using primarily small-scale vegetated facilities. Designers throughout the country use Portland as a model of what could be done elsewhere, however there are numerous differences that have to be accounted for.

The presentation will explore the inherent differences between stormwater management in the Pacific Northwest and the rest of the United States, and also the opportunities that can be shared with the rest of the country. The research focuses on Portland's practice of providing a simplified sizing factor for small scale best management practices. The researchers re-created Portland's sizing factors and then modified the variables to reflect a range of locations elsewhere in the United States.

Through this approach, the study highlights just how different, and more complicated, it is to apply small scale best management practices to other parts of the country. However, the differences, while in some instances are quite significant, point to opportunities to design future facilities around the specific needs of each location. This will be demonstrated by illustrating how a built work in Portland could be modified to meet other regions' climatic differences.

Armed with a better understanding of what it means to take the Pacific Northwest's triumphs and apply them to the rest of the country, the study hopes to allow designers to more meaningfully engage clients and engineers in a dialogue about specific issues and opportunities related to adapting Portland approaches to their own watershed.
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An Analysis of Factors Influencing Capacity Development of Public Water Systems in Mississippi
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Barefield A., Tack J.

The Safe Drinking Water Act Amendments of 1996 (SDWA) mandated the implementation of capacity development strategies to avoid the withholding of Drinking Water State Revolving Fund monies. In particular, section 1420 defined the two capacity enhancement foci as (1) ensuring that new community and non-transient water systems demonstrate sufficient financial, managerial and technical capacity to achieve authorization and (2) developing an implementation strategy to assist currently operating water systems with acquiring and maintaining these same capacity components.

As the state's primacy agency, the Mississippi State Department of Health-Bureau of Public Water Supply (MSDH-BPWS) has developed a mandatory survey instrument that contains three sections corresponding to the enumerated capacity development mandates. MSDH-BPWS regional engineers administer this survey to all community and non-transient water systems in the state. MSDH-BPWS also utilizes a portion of Drinking Water State Revolving Fund monies to fund capacity development programs, such as the Peer Review program. The Mississippi State University Extension Service implements this program that utilizes a team of certified waterworks operators from high performing systems to make site visits to poorer performing systems and providing advice and technical assistance in improving capacity development scores.

The purpose of this paper is to assess the effectiveness of the Peer Review program in increasing capacity development scores and to assess a number of other factors that may have significant influence on a particular system's capacity development. An intertemporal binomial dependent variable regression model is constructed to determine the marginal effects of several firm-level managerial and regional socioeconomic factors in influencing the success of public water systems in increasing capacity assessment scores to acceptable levels.
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An Approach for Low Flow Selection in Water Resource Management
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Ouyang Y.

Low flow selections are essential to water resource management, water supply planning, and watershed ecosystem restoration. In this study, a new approach, namely the frequent-low (FL) approach, was developed based on the frequent low category used in minimum flows and/or levels programs. This approach was then compared to the conventional 7Q10 approach for low flow selections prior to its applications, using the USGS flow data from the freshwater environment (Big Sunflower River, Mississippi) as well as from the estuarine environment (St. Johns River, Florida). Unlike the FL approach that is associated with the biological and ecological impacts, the 7Q10 approach could lead to the selections of extremely low flows (e.g., near-zero flows) that may hinder its use for establishing criteria to prevent streams from significant harm to biological and ecological communities. Additionally, the 7Q10 approach could not be used when the period of data records is less than 10 years while this is not the case for the FL approach. Results from both approaches showed that the low flows from the Big Sunflower River and the St. Johns River decreased as time elapsed, demonstrating that these two rivers have become drier during the last several decades with a potential of salted water intrusion to the St. Johns River. Results from the FL approach further revealed that the recurrence probability of low flow increased while the recurrence interval of low flow decreased as time elapsed in both rivers, indicating that low flows occurred more frequent in these rivers as time elapsed. This report suggests that the FL approach, developed in this study, is a useful alternative for low flow selections in addition to the 7Q10 approach.
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Analyzing the Hydraulics of a Biofiltration Swale Using HEC-RAS
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Bassi D., Rivas D., Diaz-Ramirez J., Martin J.

Hydraulic Engineering Center's River Analysis System (HEC-RAS) is a hydraulic model that was developed by the U.S. Army Corps of Engineers to execute 1-D hydraulic calculations. The software is made up of four 1-D river analysis tools that all use the same geometric data that is imputed by the user. It calculates steady flow water surface profile computations, unsteady flow simulation, movable boundary sediment transport computations, and water quality analysis. It comprises of a graphical user interface, data storage and management, and reporting functions. The purpose of this research was to use HEC-RAS to assess a biofiltration swale by calculating the flows, roughness, and sediment loads, as well as evaluating a porous check dam located at the end of the swale. The vegetative swale is a Best Management Practice (BMP) that is located on the South Farm at Mississippi State University. The 50-m long swale contains a rip-rap check dam at the downstream end of the BMP followed by a fiberglass flume. The watershed for the BMP contained cattle pastures and is approximately 8.4 ha. Since summer 2011, flows from storm events were measured using a Son-Tec Flow Meter in the field and water levels were used to measure the gage heights during the events. Rating curves (stage vs. discharge) were developed for the upstream, middle, and downstream (flume) sections of the BMP. Thirteen cross sections of the channel were found using a total station and the geometric data was imputed into HEC-RAS. Water samples were also collected during storm events using an automatic water sampler located at the entrance, middle, and flume sections, and the samples were analyzed in the laboratory for total suspended solids as well as various nutrients. Currently, we're setting up the model and planning to show model results at the conference.

Assessing a Novel Method for Verifying Automated Oxidation-Reduction Potential Data Loggers: Laboratory and Field Tests
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Shoemaker C.M., Kröger R., Pierce S.

Redox potential (Eh) describes the electrical pressure of systems. In waterlogged soils, Eh is an important parameter for regulating the products of biogeochemical cycling. Until recently, Eh was measured at individual points using an electrode attached to a voltmeter. This method can overlook dynamic diel and short term fluxes in the environment. Automated data loggers enable long-term continuous monitoring of Eh in soils; however, no protocol has been developed for testing the accuracy and precision of these loggers. Automated data loggers were tested under a laboratory with known voltages to assess the ability of these units to record Eh precisely and accurately. Voltages of +450 and -450 mV were applied to four loggers with four Eh sensors five times at +450 and -450 mV for each sensor, totaling 40 tests for each board. The average measured voltages varied from each other a maximum of ±8.25 mV and with a maximum range of ±23 mV. The voltage averages of all boards were accurate to ±17.85 mV with a maximum range of ±26 mV. These results indicate that measurements obtained by automated data loggers can be accurate to within a maximum of ±26 mV of the true value. Since soil Eh has a range of over 1000 mV, continuous automated data loggers can be a powerful tool in describing Eh fluxes in waterlogged systems. Additionally, field data obtained from the automated data loggers placed in vegetated and non-vegetated control plots were able to record vegetative diel Eh fluxes over a period of 48 hours. Significant spatial heterogeneity and vegetative influences were observed in Eh values. The loggers thus have the possibility to be used to monitor Eh responses to various management practices and environmental factors.
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Assessing and Modeling Sediment Loads from Stream Corridor Erosion along the Town Creek in Mississippi
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Ramirez-Avila J.J., Langendoen E.J., McAnally W.H., Ortega-Achury S.L., Martin J.L., Bingner R.L.

A research study was developed focused on the identification, assessment, evaluation and prediction of streambank erosion processes within the Town Creek watershed (TCW) in Mississippi. The hypothesis of the study was that streambank erosion is an important mechanism driving sediment supply into the streams and an important portion of the sediment budget for the TCW. A combination of in situ monitoring, geomorphic characterization methods and modeling was performed on different locations along the TCW to quantify the contribution of streambanks to stream sediment loads and better understand the processes of streambank erosion. From the results streambank instability was prevalent and highly erodible materials of streambanks are an important potential source of sediment through the entire watershed. Streambanks predominantly lost materials through gravitational failures and removal of failed sediments by hydraulic forces along the channel headwaters. These geomorphic processes could supply a considerable amount of the estimated 1,000,000 Mg of sediment annually exported from the entire watershed. Headwaters were commonly represented as incised channels near agricultural areas. Annual top streambank retreat occurred up to 2.7 m and contributed annual sediment loads ranged from 0.15 to 28.5 Mg per m-stream. Both assessments were based on repeated measured cross section surveys performed from February 2009 to March 2010. The USDA computational model CONCEPTS (Conservational Channel Evolution and Pollutant transport System) was evaluated on an incised reach of TCW to assess model performance and capability to simulate spatial and temporal changes along the study reach. CONCEPTS accurately predicted the time of occurrence and magnitude of top streambank retreat and failures of streambanks along the modeled reach. Results from field measurements and modeling offered important insights into the relative effects of streambank erosion on the sediment budget for TCW. Reduction of suspended sediment loads should focus on the attenuation of geomorphic processes and stabilization of reaches near agricultural lands at the headwaters within the watershed.

Assessing Water Balance Using a Hydrologic Model
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Duffy S., Parajuli P.

The availability of water within soil is fundamental to the success of agricultural, ranching, and forestry practices. The amount of water than is present within the soil column depends on climate, land use, land management practices, and soil characteristics. The objective of this study is to assess water balance parameters such as surface flow, soil moisture content, and water quality parameters using field studies and the Soil and Water Assessment Tool (SWAT) model simulations.

Two watersheds located in northeast (Town Creek, 1775.2 km2) and central (Upper Pearl River, 7,588 km2) Mississippi were chosen as the focus of this study. Soil samples from four fields of varying land use were collected monthly and analyzed to determine actual soil water content. Theoretical soil water content was predicted by developing two independent computational models using SWAT. The models were calibrated and validated using monthly stream flow data obtained from USGS gauging stations. Field-observed soil water content and model-predicted soil water content was analyzed statistically. Further model-simulated uncalibrated water balance and water quality outputs will be presented.

Assessment of Improved Sensors to Monitor Water Used for Irrigation in the Mississippi Delta
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Burt D.E.

The Mississippi River Valley alluvial (MRVA) aquifer spans seven states in the central part of the U.S. In northwestern Mississippi, the MRVA underlies a rich, agricultural region known locally as the Delta. Nearly all of the water used to irrigate crops in the Delta is withdrawn from the MRVA aquifer. As more and more wells are drilled to irrigate crops, the need to monitor the amount of water being pumped from the MRVA becomes more critical. Using technologies such as data loggers combined with improved sensors, the U.S. Geological Survey has partnered with the Yazoo-Mississippi Delta Joint Water Management District to monitor irrigation wells throughout the Delta.

Vibration and inductance sensors are being tested on a variety of pumping applications to obtain real-time data for the amount of time that pumps are applying water during the growing season. The sensors were evaluated on about 30 test wells during the 2011 growing season to determine their ability to accurately monitor pump usage based on powering up and down and overall run-time. Once pump usage is determined, and pump rates are measured using a non-intrusive flow meter, then a total water volume pumped at each well can be calculated.

Future plans are to calculate total water volume pumped from a network of wells throughout the Delta during the growing season. Selected permitted wells in every county in the Delta for each of the four main crop types—corn, cotton, rice, and soybean—will form the network. This network can then be used to estimate irrigation water use for all other permitted wells in the Delta, aggregated by crop type and county.

Assessment of the Ecological Value of Low-Grade Weirs in Agricultural Drainage Ditches
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Poganski B., Kröger R.

Agricultural best management practices have been a common fixture in farm field landscapes for decades. Unfortunately, little scientific information documents ecological and economic benefits of implementing such practices. Recent literature has highlighted the ability of low-grade weirs placed in agricultural drainage ditches to decrease sediment and nutrient loads to downstream waters by altering ditch discharge rates and hydraulic residence time. Currently, knowledge of how these structures can affect agricultural landscape ecology, from the molecular to ecosystem level, is unknown. The aim of this research is to assess the ecological value of low-grade weirs as effective management practices in agricultural drainage ditches. Ecological value will be appraised based on the diversity and richness of organisms inhabiting such systems. Organismal communities were selected for evaluation because of their critical roles in nutrient cycling and exchange within aquatic food webs. Experimental organisms include aquatic vegetation, microbes, benthic macroinvertebrates, and fish. Sampling events will be conducted during the growing season (May-June) annually for 3 years in agricultural drainage ditches fitted with low-grade weirs in the upper Yazoo River Basin. Conducting the experiment during the specified time period increases the likelihood that water will be present in ephemeral ditches. Organism data will be compared to chemical sediment and water data collected at the study sites provided by an ongoing study that will continue on a parallel temporal scale. Investigating biologically diverse but systematically linked organisms, will not only supplement estimates of the total ecological value of low-grade weirs in drainage ditches, but analysis of individual groups of organisms will aid in predicting mechanistic effects of implementing such structures in heavily cultivated agricultural landscapes.

Beneficial Use at Deer Island: A Decade of Design and Implementation
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Roth W.B., Mears W., Keith D., Ramseur G.

Deer Island, just offshore of Biloxi, Mississippi, provides habitat for native fish and bird species and wintering sites for migratory birds, and the nearshore area is utilized by recreational fishermen throughout the year.

In response to the continual shoreline land-loss at the island, a beneficial use (BU) site at Deer Island was completed in 2003 as a joint effort between the State of Mississippi Department of Marine Resources (MDMR) and the U.S. Army Corps of Engineers (USACE), Mobile District using dredged materials to restore some of the lost habitat. The BU site was designed to restore 52 acres of the island’s intertidal marsh and chenier using 400,000 cubic yards (CY) of dredged material. In 2005, Hurricane Katrina destroyed a significant portion of the restoration area; erosion of the interior marsh area has continued since that time.

Utilizing lessons learned from during and after the construction of the 2003 BU site at Deer Island, new design concepts were developed for the repair and expansion of the site. A containment berm will be constructed along the northern shoreline of the island. Approximately 350,000 CY of dredged material will initially be placed into the existing and new expansion BU areas. The material will be placed at numerous discharge locations within the containment areas to create variation in the finished elevation and to enhance habitat diversity. The western alignment of the containment and control berm will be left open to promote circulation and habitat formation as the dredged materials consolidate. The "open-ended" design will also allow for future expansion of the site.

With the implementation of Mississippi State Law § 49-27-6161, planners, engineers, and contractors participating in design efforts involving excavation of marine sediments in the State now have an obligation to integrate BU of dredged material as a placement option. Proposed BU locations, including Deer Island, along with the sediment testing guidance is presented in the Master Plan for the Beneficial Use of Dredged Material for Coastal Mississippi1 (the Master Plan). Developing and implementing the Master Plan provides a starting point for future maintenance and new work dredging projects in Mississippi, with a global goal to retain this valuable resource within the coastal estuarine environment.
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Best Management Practices in the MS Delta: What Are We Learning?
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Kröger R., Prevost J.D., Cooke T.

Agricultural best management practices (BMPs) can help reduce nutrient and sediment concentrations and loads leaving farm fields, which in turn can reduce negative impacts on downstream aquatic systems. For nearly three decades, significant federal investment in technical and financial assistance has been provided to implement farm BMPs. But few conservation programs attempt to estimate the amount of nutrient and sediment reduction resulting from cost-shared practices, let alone potential positive effect on local or regional water quality. This talk will encompass numerous ongoing and published scientific evaluations of BMPs within the MS Delta and the Lower Mississippi Alluvial Valley (LMAV). A review of BMPs within the LMAV highlighted only 18 articles (9 BMPs) that provided BMP efficiencies that met specific criteria of (a) row-crop agriculture, (b) clay/silt loam soils, (c) slopes 0-5%, and (d) occurred within the LMAV. The majority of the nine key BMPs for the LMAV provided significant nutrient reductions ranging from 15–100%. Field studies of innovative management practices such as low-grade weirs and slotted pipes have provided the very first nutrient reduction efficiency data for these structures in an agricultural field setting. Experimentally, it has been shown that weirs significantly increase nutrient reductions over conventionally drained systems. Field scale data on weirs is showing between 35-60% reductions for nitrate-N between inflow and outflow. Furthermore, the system documented a significant lag-effect that needs to be considered when evaluating BMP efficiencies. Slotted pipes have been quantified for the amount of sediment accumulation behind the structure. Observing sediment accumulation trends, (curvi-linear ; r2 = 0.76) and applying a Von Bertalanffy non-linear model for sediment accumulation through time for the evaluated sites, highlights that highest sediment accumulation occurs with 235 d following installation. These sediment accumulation rates can be translated to sediment volume and mass, and when multiplied by the total phosphorus concentration of the sediment provides a potential for evaluating performance for this specific BMP.
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Calculation of Water Surface Elevation Using HECRAS 4.1.0 for Fixing Tailwater Elevation for Powerhouse Site in Planned 37 MW Kabeli "A" Hy
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Pathak S.R.

Goal of this HECRAS 4.1.0 model analysis is to find out water surface elevations for safe and optimized layout of powerhouse located in left bank of Tamor river with other protective structures like floodwalls at different flood frequencies for planned 37 MW Kabeli "A" Hydroelectric Project. Powerhouse is costly and vulnerable component of any hydropower facility. Its safe location should be prioritized. Any increment in head is related with generation of extra revenue but powerhouse earthwork excavation volume incurs huge part of overall project cost initially. There is some sort of tradeoff between these two parameters to get an optimum design elevation. It is envisioned that 1-D US Army Corp’s HEC-RAS model can simulate flow conditions at different flood frequencies. This project is located in Panchthar and Taplejung districts in Eastern Development Region of Nepal. This project utilizes more than 15 km long loop of Kabeli River formed with Tamor River. Kabeli River, which is a tributary of Tamor river is diverted through a 4326.8 m long D-shaped headrace tunnel having internal finished diameter 5.65 m, discharging diverted water into Tamor River for power generation. The gross head of the project is 116.8 m and the design discharge based on 40 percentile flow set by government for power generation from flow duration curve (FDC) in river is 37.73 m3/s.

Kabeli River is one of the tributaries of Tamor River which itself is a major tributary of Sapta Koshi River basin.The catchment area above the proposed intake site of project is 864 km2 and at powerhouse site is 3930 km2 with elevation ranging from 452 m to 7200 m above mean sea level. In this catchment, monsoon pattern of climate is prevalent. It commences from June to September with heavy rainfall intensity for those four months compared to other months of the year. Rainfall intensity varies in catchment with elevation and runoff is calculated from different methods as powerhouse site is ungaged.

Due to global warming, glacial lake outburst flood (GLOF), known as mountain tsunamies in high Himalayas ( Kanchanjunga range) is highly probable. This zone lies in area with high seismic activity with possibility of GLOF, flooding populated areas and infrastructure downstream. Since glacial/snow hydrology study and data collection is still in nascent stage of development, analysis for design flood elevation has been done without taking into account those effects due to unavailability of data.
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Comparison of Indigenous and Selected Pentachlorophenol (PCP) Degrading Bacterial Consortiums for Remediation of PCP Contaminated Groundwater
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Joshi V.V., Prewitt M.L., Borazjani H., Willeford K.

Pentachlorophenol (PCP) is a very toxic and recalcitrant compound which is commonly used in industrial and agricultural applications such as pesticides, leather tanning, pulp bleaching and wood preservatives. Its extensive use and improper disposal in the environment for more than sixty years has resulted in groundwater contamination, which is a very serious health and environmental issue. Previous studies have reported individual bacterial and fungal species that actively degrade the PCP. However in the environment there are many microorganisms present at sites of PCP contamination and few studies have focused on the microbial community involved in PCP degradation at these sites. Therefore the objective of this work is to compare PCP degradation by the indigenous bacterial community from PCP contaminated groundwater and customized groups of known PCP degrading bacteria. In this study, PCP contaminated groundwater samples will be collected from a former wood treatment site undergoing biosparging remediation. The experimental setup will include treatments of indigenous and known PCP degrading bacteria. Analyses for bacterial identification, gene expression and enzyme activity will be conducted during the degradation of PCP at different concentrations. Molecular identification will be carried out by cloning and sequencing of DNA extracted from these bacteria and real time PCR will be used for gene expression analysis of the PCP degrading genes: pcpB, pcpD, pcpC, pcpA and pcpE. Enzyme activity will be determined spectrophotometrically by monitoring substrate utilization over time. Statistical analysis of the data will be carried out by using the program SAS v. 9.2 to check the significant differences in PCP degradation by these bacterial consortiums. The results of this study should be beneficial for bioremediation of PCP in the environment.

Dating Sediments from Oxbow Lakes in the Mississippi Delta using 239Pu, 240Pu and 210Pb determined by ICPMS: a feasib
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Cizdziel J., Chakravarty P.

Sediments are complex deposits of inorganic and organic matter that can serve as a natural storage system for metals and anthropogenic contaminants. Sediment cores can provide a window on the past because they can go back years, decades, even centuries and serve as environmental proxies. Dating of recent (<100 years) sediments is important in many studies and applications, including determining the source and timing of pollution events, establishing sedimentation patterns, and in reservoir management. Linking sediment "dates" (typically in years) with sediment characteristics or specific chemical constituents is also crucial for examining the effectiveness of both pollution and erosion control measures. Conventional dating techniques which use 210Pb and 137Cs are slow and costly, in part because extended times are needed to measure the radioactive decay emissions from low-activity samples.

In this study, we examined the feasibility of using inductively coupled plasma mass spectrometry (ICP-MS) to: measure global fallout plutonium (Pu) and 210Pb in sediment core samples from Mississippi for dating purposes. Recent advances in mass spectrometry have made it an alternative to radioactive decay spectrometry for determining Pu, and possibly 210Pb, in environmental samples. This study utilized core samples previously collected from strategic locations within the Mississippi Delta region. Select samples were be digested with mineral acids and the Pu and Pb isotopes were selectively removed from the matrix using chromatographic extraction resins, effectively pre-concentrating the elements prior to analysis. Plutonium was determined using isotope dilution mass spectrometry and 210Pb using external standardization. In this talk and associated poster we will discuss the methodology and present our findings.

Develop Hydrological Relationships using a Modeling Approach in Mississippi Delta
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Jayakody P., Parajuli P.B., Sassenrath G.

Agriculture management practices such as tillage and crop rotations alter the hydrological budget of watersheds. Changes happen to surface runoff can be easily identify with the help of intensive USGS stream gage network, available in Mississippi, but changes to ground water table is less understood as inherent difficulties of measurements. The main objective of this research is to develop relationships among evapotranspiration (ET), soil moisture content (SMC) and depth to the ground water table through modelling approach. The SWAT hydrologic and crop models were setup for the Big Sunflower River watershed (BSRW; 7,660 km2) within Yazoo Rive Basin of the Mississippi Delta. Hydrologic calibration and validation was carried out for the period from 1999-2009 using USGS flow data. Crop model was calibrated and validated for the same period by using Corn and Soybean yield data from the USDA experiment stations. Both crop and hydrologic model performances will be evaluated using coefficient of determination (R2), Nash-Sutcliff Efficiency Index (NSE) and Root Mean Square Error (RMSE). Empirical relationships will be developed to predict depth to the groundwater table using model predicted ET and SMC. The relationships developed will be validated with the field observed data and will be used to make groundwater thematic maps for the Mississippi Delta.

Developing rapid methods for dating sediments in Mississippi using ICPMS
Final Project Report

Year: 2012 Authors: Cizdziel J.

Sediment cores from seasonal wetland and open water areas from Oxbow lakes [Beasley (BL), Hampton (HL), Washington (WL), Roundaway (RL), Sky (SL) and Wolf (WL)] in the Mississippi Delta, whose chronology was previously determined by conventional 210Pb and 137Cs age-dating, were analyzed, for the first time, for Pu isotopes (239Pu and 240Pu), and Pb isotopes (206Pb, 207Pb, 208Pb and 210Pb). The primarily purpose was to evaluate the feasibility of using ICPMS as an alternative to radiochemical analyses for fallout-Pu and 210Pb.

For Pu, the mean 240Pu/(239Pu atom ratio was ~0.177 indicating global fallout as the primary and likely source of the Pu. Analyses of an undisturbed sediment core yielded a Pu peak at a depth which is in good agreement with conventional 137Cs and 210Pb dating. Analysis of the Washington Lake sediment core yielded a Pu vs. depth profile that was broad and uncharacteristic of normal sedimentation patterns. It was later found out that the conventional dating technique also yielded data scatter indicative of sediment that was likely disturbed in-situ. Indeed, because sediment can be mixed by natural events after deposition, this demonstrates that ICPMS can serve as a useful tool to simultaneously identify (screen for) sediments that have been disturbed (eliminating costly 210Pb analyses on such cores), and to provide a chronological marker for those that haven't (either alone or in conjunction with conventional dating).

For Pb, total concentrations varied from 1.5 ppm to 12 ppm, with peak levels generally occurring during the 1950's. Isotopic signature plots suggest "natural" Pb (from soil) as the primary source of the lead, with coal and gasoline as slight contributors; however, more study is needed to confirm this. Accurately measuring the 210Pb isotope by ICPMS was problematic. The levels were low and subject to interference from stable isotopes of Pb, possibly by the tail of the large 208Pb peak and/or from polyatomic interference such as 208Pb1H1H. To overcome these barriers, it is recommended to boost the sensitivity, possibly with a jet-face interface, and/or remove the interference using collision cell technology.

Downstream Water Quality and Quantity Impacts Of Water Storage Systems in a Mississippi Delta Watershed
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Tagert M.L., Paz P., Pote J., Kirmeyer R.L.

The Mississippi River Basin contains over 60% of the United States' harvested cropland, 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. There are roughly 13,000 permitted irrigation wells dependent on water from the Mississippi Alluvial Aquifer. Adequate supply of good quality water is vital 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 site storage areas to capture irrigation and surface water runoff from the field for later use. However, while decreases in groundwater levels have been of particular concern to agricultural producers withdrawing from the Mississippi Alluvial Aquifer in recent years, there has also been a push by federal agencies to reduce the Gulf of Mexico hypoxic zone. The Mississippi River/Gulf of Mexico Nutrient Management Task Force, formed in 1997, set a goal to reduce the size of the Gulf hypoxic zone to less than 5,000 km2 by the year 2015. In 2010, the Natural Resources Conservation Service launched the Mississippi River Basin Healthy Watersheds Initiative to support the implementation of conservation practices to reduce nutrient loading in the Basin and improve water quality in the Basin and Gulf of Mexico. This presentation will outline a USDA-funded project that will determine the watershed-scale impacts of water storage systems on water quality and quantity, using the example of Porter Bayou Watershed, Mississippi.
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Effects of Immobilizing Agents on Surface Runoff Water Quality from Bermudagrass Sod Fertilized with Broiler Litter
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Sheng J., Adeli A., Brooks J.P., McLaughlin M.R.

Surface broadcasting is the common method for applying poultry litter on perennial forages, but this application method concentrates nutrients and pathogenic microorganisms at the soil surface where they are vulnerable to runoff water. The potential impairment of surface water from soluble nutrients, particularly N and P, metals such as copper (Cu) and Zinc (Zn), and pathogenic microorganism contained in broiler litter are of concern. Management practices that minimize contaminants in surface runoff water are environmentally desirable. A greenhouse study was conducted using rainfall simulation to determine the effects of immobilizing agents, such as FGD (flue gas desulfurization) gypsum (a residue from coal combustion) and biochar, on manure nutrients and fecal bacteria in runoff from bermudagrass sod. The experimental design was a randomized complete block with seven treatments and three replications. Treatments included a control (no litter), and broiler litter (either wood shavings or rice hulls) at the rate of 9 Mg ha-1, in all combinations with and without FGD or biochar. Rainfall was delivered at an average intensity of 75 mm h-1 with a total of four rain events. Runoff was collected in 250-ml sterile plastic bottles. Runoff samples were immediately transferred to the lab for microbial and nutrient analyses. Nitrate and ammonium were determined on a Lachat. Dissolved reactive P and metals were determined in filtered (0.45 µm filter) runoff samples. Unfiltered runoff samples were digested and analyzed for total nutrient concentrations using ICP). The results indicated that application of broiler litter in combination with FGD gypsum to bermudagrass significantly reduced runoff total dissolved organic C (DOC), total N, dissolved reactive P (DRP), Cu and Zn by 16, 30, 61, 73 and 13%, respectively, compared to broiler litter alone, regardless of litter type. Biochar had no effect on reducing soluble nutrients in surface runoff. Treatments did not affect culturable bacterial levels in runoff. Detailed information will be discussed.

Efficacy of Manufactured Wood Shavings to Mitigate Marsh Land Impacts Associated With Deep Water Oil Spills
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Seale R.D., Borazjani H.

Use of pine shaving to remove oil from seawater and sandy beaches during spill was evaluated. Two identical microcosms capable of simulating tidal waves were constructed. Shavings were applied in three different spill scenarios; 1): over clean sand before tide, 2): over contaminated sands after tide, and 3): over oil covered seawater. Saudi Arabian sweet crude was used for this study. Shavings adsorbed significant amounts of oil in all three cases from oil contaminated water and sands. Shavings spread over the contaminated seawater surface contained the highest amount of oil adsorption from seawater and the least amount of sand contamination. This method of application seems to provide the most efficient and practical approach for quick removal of oil and spent shaving from seawater with minimal contamination of beaches or marshes. The high number of petroleum acclimated bacteria in seawater are able to biodegrade the leftover residual hydrocarbons.

Evaluating a Vegetated Filter Strip in an Agricultural Field
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Young A.

The use of best management practices and low impact development strategies have become common in recent years, leading to the need for the creation of hydrologic models to predict their behavior and effectiveness. A vegetated filter strip at the South Farm Research Park at Mississippi State University was used to test two of these models: the Hydrologic Simulation Program-FORTRAN Best Management Practices Editor (HSPF BMPrac) and the System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN). Water samples were taken during the Spring of 2011 and tested for sediments and nutrients; HSPF was used for computing flows, sediments, and nutrients. The filter strip was not effective at pollutant removal with removal efficiency rates of 68.1, 91.7, 86.3, and 115.4 percent for total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), and dissolved phosphorus (DP) respectively. Calibration of HSPF was successful for TSS with a R2 value of 0.52; nutrients were not as successful with R2 values of 0.11 and 0.43 for TN and TP. HSPF's BMP Practice Editor demonstrated an drastic over prediction of pollutant removal. Modeling of the VFS in SUSTAIN was not a success due to technical failures preventing the model from running.
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Evaluation and Validation of a Decision Support System for Selection and Placement of BMPs in the Mississippi Delta
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Ortega-Achury S., Kröger R., Ramirez-Avila J., Diaz J.

Prevention and reduction of surface water pollution has been a matter of concern for decades, which has promoted the implementation of best management practices (BMPs) to ensure the protection of water resources. A considerable number of structural and non-structural BMPs have been developed to control hydrological processes and enhance pollutant load reduction at field and watershed scales. However, the selection of a specific BMP or the best combination of these practices and BMP placement are major challenges faced by decision makers. Recently, modeling tools have been presented as an effective alternative to support those challenges and to achieve cost-effectiveness in addressing environmental quality restoration and protection needs in different scenarios. USEPA has presented The System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN) model to be used by watershed and stormwater professionals to develop, evaluate and select optimal BMPs combinations, at multiple watershed scales, and to achieve targeted water quality objectives based on cost and effectiveness. This tool incorporates algorithms from the Storm Water Management Model (SWMM), the Hydrologic Simulation Program FORTRAN (HSPF) model and other BMP modeling techniques. In order to evaluate and validate the application of the SUSTAIN model in an agricultural scenario, a case study is developed for a midsize drainage area (307 ha) located in the Mississippi Delta. The agricultural watershed includes a surface drainage ditch in which three low grade weirs have been installed and monitored for water level and pollutants concentrations since July 2010. The objective of this study is to assess the performance and capability of the SUSTAIN model in the context of a real agricultural scenario where BMPs are implemented. The study also attempts to determine the cost-effectiveness curve for the implementation of BMPs in the study area (considering the number of weirs installed as a variable) using total suspended sediments and total phosphorus as control targets.
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Field-Scale Monitoring of Agricultural Ditches as Conduits of Nitrogen, Phosphorus, and Suspended Sediment in Response to Storm Events and Low-Input D
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Pierce S.C., Kröger R., Prevost D., Pierce T.

Runoff from row-crop agriculture is a major source of non-point source aquatic pollution. High concentrations of inorganic nitrogen and sediment-bound phosphorus that are conveyed in agricultural drainage ditches can lead to eutrophication of receiving waters at both local and regional scales. Concerns regarding accelerated eutrophication have led to a concerted effort toward understanding the movement of nutrients across the landscape and the management of agricultural drainages for water quality remediation. This study monitors field-scale movements of nitrate, nitrite, ammonium, dissolved phosphorus, particulate phosphorus and total suspended solids through agricultural ditches over several months preceding and following the implementation of controlled drainage practices including riser boards, slotted pipes, and low-grade weirs. Water samples were collected during baseflow conditions and storm events via grab sampling and different automated techniques. Pre-implementation data collected from January-July of 2011 is summarized below. Preliminary post-implementation data will be presented as it becomes available. Nitrate concentrations showed a high degree of variability both spatially and temporally, varying from approximately 0 to 15 ppm, with values higher in the watershed tending to be slightly higher than outflows. Storm events generally had nitrate concentrations 50% to 100% greater than baseflow concentrations. Nitrite also demonstrated temporal variation, with some samples approaching 1 ppm. Compared to nitrate, however, spatial differences and total variance was low. In contrast to oxidized nitrogen, ammonia concentrations generally ranged from 0.1 to 0.3 ppm regardless of time or location. Dissolved inorganic phosphorus concentrations ranged from approximately 0 to 1.5 ppm, varying nonlinearly with date the sample was collected, but did not appreciably change in response to storm events. Total inorganic phosphorus and turbidity approached an order of magnitude higher in stormwater samples than baseflow samples, with mean total inorganic phosphorus of less than 2 ppm in baseflow samples compared to mean values greater than 10 ppm in stormwater samples. Total suspended sediment concentrations were also significantly higher in stormwater samples than baseflow samples, indicating the likelihood that erosion or sediment resuspension is a major factor in phosphorus transport in agricultural drainage ditches. Preliminary data following implementation of controlled drainage will be compared with this background data set to determine short-term impacts of ditch reshaping on water quality and to estimate the effects of vegetation establishment.
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Financial Sustainability of Water Treatment and Distribution: Using a Public Private Partnership Toolkit to Evaluate Project Costs
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Werner R.A., Surbeck C.

With population growth and an increasing need for water supply and distribution, innovative ways to sustainably finance capital, operation, and maintenance costs of water projects must be found. A Public Private Partnership (PPP) between government and one or more private companies is an underused means of financing such projects. PPPs in the United States are common in the energy and solid waste industries. However, in the water sector, governments have been the entities solely responsible for funding water services. PPPs in water projects would enable a larger variety of capital investments and a balanced share of risk between government and private companies. Further, PPPs enable public services to be provided when there are public budget constraints.

The principal objective of this presentation is to show scenarios in which PPPs are beneficial for funding water projects. The analysis will include data from municipalities in the state of Mississippi, and results from a case study will be reported. The method used will be a toolkit software developed by The World Bank for use in road and highway projects. This existing toolkit, which has been applied to PPP projects worldwide, will be adapted for the water sector. For example, existing input parameters, such as average daily traffic and toll rate per vehicle, will be changed to water-related parameters, such as average daily water use and water use fees per household.

Overall, the goal of a PPP project in the water sector is a sustainable investment for both the government and private entities in terms of balance of risk and financial return on investment.
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Flood Inundation Mapping for the Leaf River at the City of Hattiesburg, MS
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Storm J.

Flood forecasting predicts the eventual elevation of a river at a single location during moderate to extreme hydrologic events. Although this provides an understanding of the expected extremity of the flood, it does not give the general public an understanding of which areas will be affected and to what extent. The U.S. Geological Survey (USGS) Mississippi Water Science Center, in cooperation with the City of Hattiesburg, the Forrest County Emergency Management District, the Mississippi Emergency Management Agency, and the National Weather Service (NWS), is preparing a series of static flood inundation maps for the Leaf River at Hattiesburg, MS, based on a one-dimensional steady flow model calibrated to historic and current hydrologic data. The maps will be accessible to the public on USGS and NWS web pages and will provide flood depths and inundated areas at 1-foot increments of forecasted stage at the real-time USGS stream-gaging station 02473000 Leaf River at Hattiesburg, MS. These maps will provide both the public and city officials the ability for better planning and management during extreme flooding events.

Flooding Concerns on the Lower Pearl River Near Walkiah Bluff, MS
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Roberts A.L.

Walkiah Bluff is located in south Mississippi on the East Pearl River near Wilson Slough and the divergence of the Pearl River into the East and West Pearl Rivers. Approximately 175 residents own homes on or near the East Pearl River near Walkiah Bluff, MS. Flooding often occurs in the Walkiah Bluff area whenever flooding occurs upstream on the Pearl River, thus heightening concerns of local citizens. The Lower Mississippi River Forecast Center (LMRFC) has flood forecasting responsibility in this area, however, Walkiah Bluff is not currently a modeled site.

Historical data from the period of record was utilized to develop flood forecasting guidance tools for the Walkiah Bluff area. Flood events were analyzed to obtain a better understanding of how Walkiah Bluff reacts in relationship to upstream flooding on the Pearl River at Bogalusa, LA and the Bogue Chitto River at Bush, LA. Assessments were also made regarding how the Pearl River at Pearl River, LA reacts in association with upstream flooding at Walkiah Bluff and Bush.

The effects of the Bogue Chitto River on the crest at Walkiah Bluff, MS are complicated due to numerous sloughs and bayous that interconnect the two channels. It is difficult to accurately interpolate any affects from the Bogue Chitto by utilizing a crest to crest curve for Bogalusa to Walkiah Bluff. However, because the crest at Pearl River, LA is based upon water routed from both Bogalusa and Bush, the LMRFC forecast for Pearl River, LA can be utilized along with the crest to crest curve for Walkiah Bluff to Pearl River, LA to essentially back-forecast the crest at Walkiah Bluff. The results of this study are expected to assist in increasing the accuracy and timeliness of LMRFC flood forecasts for Walkiah Bluff citizens.

Formaldehyde Released in Leachate from Medium Density Fiberboard (MDF) Buried in a Simulated Landfill
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Lee M., Prewitt M.L., Borazjani H., Mun S.P.

Formaldehyde, a flammable, colorless, highly reactive gas at standard temperature and pressure, is commonly found in the environment. However, formaldehyde is toxic in high concentrations and causes health issues for human. Approximately 14 million tons of wood waste containing formaldehyde based resins are generated yearly and disposed in large pits and landfills or burned. No regulations however exist for formaldehyde emission from formaldehyde bonded wood waste buried in landfills. More information is needed about the environmental impact of formaldehyde released in water from formaldehyde bonded wood waste buried in landfills. The objectives of this study were to determine a) the amount of formaldehyde released, b) the amount of dissolved oxygen, and c) the microbial enumerations in leachate from MDF buried in a simulated landfill using two board sizes. Simulated landfills were constructed in cylindrical plastic containers (15.24 cm diameter, 22.86 cm high) with alternating layers of 2.54 cm silty clay soil and MDF for a total of five layers. Leachate was sampled on day 0, 7, 14, 21 and 28 for formaldehyde analysis and dissolved oxygen and microbial enumeration were conducted only at the beginning and end of the study. Formaldehyde released in leachate was determined by derivatizing using pentafluorbenzylhydroxylamine and analyzing by gas chromatography with electron capture detection. Preliminary results indicate that formaldehyde released in the leachate was reduced by 99% at the end of the study. The initial pH of the leachate from soil without MDF was 5.87 and increased to 6.18 at the first week's sampling time and remained at approximately 6.22 through week five, while the leachate from soil with added MDF had an initial pH of 4.66 and increased weekly to 6.40 on week 5. Results from this study should provide new information about the fate of wood waste containing formaldehyde disposed in landfills.

Holitoblichi: A Celebration of the North Mississippi Hills
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: English J.R.

Utilizing the Choctaw Indian word for "celebrate" as its name, Holitoblichi intends to celebrate the heritage and inspire the future of the north Mississippi Hills through the stewardship of its unique cultural and natural environment. This project transforms nearly 350 acres adjacent to the new Toyota manufacturing plant in Blue Springs, Mississippi into a regional amenity with a rich array of uses. From stormwater management and bioremediation to stream channel restoration and native habitat revitalization, from experiential learning and community-building facilities to sustainable agriculture and recreation, the project combines many threads into one comprehensive story. Guiding the design are three principles: 1) to express the three components of sustainable development (environment, economy, society) in every aspect of the design; 2) to weave together agricultural, environmental, and industrial and showcase the symbiotic relationships between them; and 3) to evoke a sense of "the new old," pulling culture from the past and the present into an innovative and resilient future. Conceptually, two poles anchor the design: environment and culture. Throughout the space between, the interconnections between the two poles are explored. From practicing agriculture in collaboration with nature to experiencing the blues in the environment that set its tone, Holitoblichi is an example of how a mutually beneficial relationship between man and nature can be cultivated.
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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.

Identifying Fish Guilds Relative to Water Quality and Depth in Oxbow Lakes of the Mississippi Alluvial Valley
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Goetz D., Kröger R., Miranda L.E.

The Mississippi Alluvial Valley (MAV) contains a myriad of oxbow lakes from remnant braided river channels that are constantly being exposed to high nutrient and sediment loads via agricultural runoff. These increased sediment and nutrient loads have deleterious effects on water quality, and potentially have intensified variability in fish assemblages. Recent studies of fish assemblages in oxbow lakes of the MAV have provided strong evidence regarding the driving forces behind fish community organization. Depth and land-use have been identified as key variables influencing fish assemblages. Furthermore, water quality in oxbow lakes is known to vary across environmental gradients though has not been linked to fish community structure, specifically pollution tolerant or intolerant guilds. Preliminary data indicates that diel fluctuations in DO, temperature and pH vary considerably between deep and shallow habitats within the same oxbow lake. Additionally, a dominance by tolerant fish species have been observed in shallow back water areas of deep lakes that harbor a diverse fish fauna, suggesting that stressful environments may harbor tolerant fish species and impede the survival of intolerant species. Measuring diel fluctuations in temperature, pH, and DO and using multivariate statistics to relate fish communities to water quality parameters, will likely determine if distinctly different fish guilds are inhabiting deep and shallow oxbow lakes of the MAV.

Laymen, Experts, NGOs, and Institutions in Watershed Management
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Pappalardo G.

People's activities and behaviors are deeply related with water and ecosystems: the relationship between human communities, their places of life, and nature has always been a challenging issue, like Ian McHarg explains in 1969, inspiring many scholars' works. A question is open: who is part of human communities?

It is possible to identify some groups of people: inhabitants, with their direct experiences of their native lands (laymen); researchers and practitioners, with scientific tools to understand and to design lands (experts); supporters of specific interests and hopes (NGOs); environmental authorities, with their responsibility in managing lands (institutions). They have different knowledge, roles, interests, and expectations and, according to Fisher, everybody should be allowed to participate into the decision-making process about environmental matters.

Elinor Ostrom also underlines the necessity of collaboration between different people and institutions to manage Common Goods, like rivers, rich soil, and hydraulic infrastructures.

Starting from this framework, this paper has an overall goal: to identify how do laymen, experts, NGOs, and institutions work together in managing their places of life. The main question is: how to establish a sort of deal among them, focused on watershed management, to experience collaborative practices able to affect every-day life styles toward a responsible use of resources and better water quality? Even if every context has its own peculiarities, it is useful to learn from different experiences. In Italy, these kinds of deal are experimental practices called River Agreements: they still are not so common, and in Sicily there is an ongoing process to define and to build a River Agreement for the Simeto Watershed. It is a Participatory Action Research (PAR) process, i.e. a deep collaboration between scholars and associations' activists to help local communities (Whyte), and I am directly involved in the process as researcher. So I am studying some Cases in the United States, focusing on Mississippi State, to give an input to the process. The Case Study Method is a useful tool for PAR processes, to help participants in visualizing possible alternatives (Francis).

Through some Case Studies in Mississippi, chosen to answer the main question, this paper also will support the ongoing process in Sicily: it will be translated and shared with other participants through focus groups, public presentations and a web site under construction, as an opportunity for collective learning and education.
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Low-Grade Weirs: An Innovative Best Management Practice for nitrate-N Mitigation
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Littlejohn K.A., Kröger R., Moore M.T., Farris J.L.

Best management practices (BMPs) generally refer to measures that provide some level of environmental protection for downstream aquatic systems. In agricultural watersheds, BMPs aim to improve the water quality of runoff from the landscape by controlling or trapping pollutants that can potentially degrade downstream aquatic ecosystems. Installation of low-grade weirs in agricultural drainage ditches is being evaluated as an innovative, yet cost effective, management practice that decreases nutrient concentrations and loads by increasing the water volume and hydraulic residence time of the ditch. The objective of our study was to assess the nutrient mitigation capabilities of low-grade weirs in artificially constructed ditches (four ditches with weirs and four without weirs). A replicated nutrient runoff event was simulated using a calculated 11-15 mg/L nitrate (NO3-) concentration applied continuously to each ditch for eight hours. Inflow and outflow concentrations and loads were quantified to determine overall NO3- reduction. A significant difference in weir and non-weir ditch volumes (P= 0.006) was observed, as well as a significant difference in observed hydraulic residence times between weir and non-weir ditches (P= 0.029). Similarly, ditches with weirs demonstrated a statistically lower (P= < 0.001) median outflow load (47.9 mg/min) than ditches without weirs (63.2 mg/min). An enhancement of the biogeochemical environment within the ditch was also observed, with a significantly greater NO3- concentration reduction (P= 0.029) during the hypothesized biogeochemical reduction phase of the experiment for those ditches containing weirs. These results highlight the dynamics of low-grade weirs in reducing nutrient concentrations and loads from agricultural landscapes, potentially establishing low-grade weirs as an additional, innovative BMP for nutrient reduction.
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Management Challenges for Deer Creek in the Mississippi Delta
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Killebrew R.

Rivers and central are paramount to surface water ecosystems. Many characteristics differentiate lake ecosystems from running water. Areas with flowing freshwater are called lotic (lotus, from lavo, to wash) and water moves along a slope in response to gravity. Lotic ecosystems are contrasted to lentic (lenis, to make calm) or lake ecosystems. Most lakes are open and have distinct flows into, through, and out of their basins. Throughflows, called water renewal rates, are often variable and slow in lakes but are continuous.

The distinction between running waters and lakes focuses on the relative residence times of the water. The importance of variable but continuous and rapid throughput of water and materials contained within is evident in the biology of most organisms living in running waters. When the energy of flowing water is dissipated, like it does in the transitional zone of reservoirs, the change to lentic characteristics is rapid.

How does one manage a water body that, for most of the year, is neither stream nor lake? Deer Creek in the Mississippi Delta is more like the Dead Sea in many respects. For much of the year it has no outflow and very little inflow. Deer Creek has a very small basin area because it is a perched water body.

This presentation will provide a glimpse into the many challenges of balancing the needs of the water body inhabitants with the needs or desires of the people who live along the water body.
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Management of Coastal Ecosystem Restoration Sites under Increased Climatic Extremes: Effects of Hurricane Katrina on Wetlands Restoration Projects in
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Foster M.A., Battaglia L.L.

Coastal wetland mitigation banks are at the forefront of climate change and are under strict regulatory requirements regarding plant community composition. As effects from climate change intensify, sea level rise and tropical storms may alter the composition of these communities. We measured aspects of plant community structure and diversity at a 382-hectare wetland mitigation bank in southwest Mississippi in 2005-20011. Rapid monitoring assessment with supplemental recording of all species detected was conducted each year at seven pine savanna monitoring plots. The site was in the eye-path of Hurricane Katrina and received over 2.5m of storm surge in August 2005. Multivariate analyses of the understory composition indicated that the high diversity, pre-Katrina community diverged after the storm to a lower diversity subset assemblage. Some recovery through time was evident, although species composition had neither stabilized nor returned to pre-storm conditions by 2011. Richness of savanna forbs dramatically declined following Katrina and has not yet recovered. The assemblages have continued to shift in composition since Katrina, but the eventual state of these systems is not yet known. The reference species composition for a mitigation site is typically strictly defined by regulatory requirements. As a result of tropical storm activity, these coastal ecosystems may be shifting away from fixed reference standards. The likelihood of a major vegetation state change increases as the effects of sea level rise and intensified tropical storm activity become more pronounced along the northern Gulf of Mexico.
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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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Modeling the Potential for Replacing Groundwater with Surface Water for Irrigation by Using On-Farm Storage Reservoirs in the Mississippi Delta
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Thornton R.F., Pote J.W., Wax C.L.

A groundwater conservation strategy is proposed in this research—the use of surface water in lieu of groundwater. This can be achieved through the construction of on-farm surface impoundments, which may be as simple as large ditches which will serve to capture precipitation and tailwater. Previous research shows the effectiveness of using stream water in lieu of groundwater on fields located within one-quarter mile of a stream, and the effectiveness of capturing rainfall in catfish ponds. This research proposes another form of surface water capture—that of on-farm storage reservoirs.

A model was developed for optimizing the size of on-site water retention structures (ditches) to capture rainfall on agricultural fields in the Mississippi Delta. The climatological driver for the model is precipitation minus evaporation, which is then adjusted by a crop coefficient to produce an irrigation demand value based on the age of the crop. The model uses long-term weather records (50 years of daily data) to estimate daily values of these climatological inputs, which are then summed to weeks through the year. Total field irrigation demand, ditch demand, ditch volume, overflow, and ground water used are outputs of the model, calculated according to specified field size and ditch volume. The percentage of required irrigation demand that is met by rain stored in the ditch is calculated weekly for the entire growing season.

Field acreage, runoff coefficient, ditch acreage, and ditch depth are interactive inputs in the model. Outputs of the model recalculate as inputs are changed. Optimization is achieved when groundwater use is minimized, annual overflow is minimized, and the smallest possible amount of the field is used for the ditch. Previous research assessed the impact of crop type and irrigation system on aquifer volume and showed that the aquifer could be reduced in volume by as much as 1,500,000 A-F over the next 50 years under current practices. This study shows that if only 10% of Delta producers adopted on-farm surface water storage for irrigation, that decline in volume in the aquifer could be reduced to 100,000 A-F over the same time period.

Monitoring Success of Mississippi’s Delta Nutrient Reduction Strategies
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Hicks M., Stocks S., Wright J.

Nutrient reduction strategies are being implemented in northwestern Mississippi, an area locally referred to as the Mississippi Delta, in response to Action Plans of the Mississippi River/Gulf of Mexico Hypoxia Task Force and the Gulf of Mexico Alliance, which call for reduction of nutrients to the Gulf of Mexico. As part of the nutrient reduction efforts, it is important to understand and answer several key questions such as what level reductions are achievable and what reductions are required to protect the health of Delta waters. To gain a scientific understanding of these questions, a comprehensive monitoring and data collection plan was developed by a consortia of Federal, State, and local agencies and is being applied throughout the Delta. Monitoring will document changes in nutrient concentrations and loads that occur at each of three nested scales—edge-of-field, in-stream, and outlet of the watershed —following the implementation of a suite of BMPs.

As part of the implementation of the comprehensive plan, the U.S. Geological Survey began monitoring in the spring of 2010 in selected Delta watersheds and will continue for several years to detect changes over time. Two of the watersheds where monitoring is taking place include Harris Bayou and Porters Bayou in the upper part of the Big Sunflower River Bain. Implementation of best management practices (BMPs) is complete in Harris Bayou watershed, and post-implementation monitoring has begun. Pre-implementation monitoring is continuing in Porters Bayou as implementation of BMPs has yet to begin.

Monitoring in these watersheds includes collection of flow and water-quality samples throughout the entire year, during storms and on a regular fixed schedule. To evaluate changes, a before-and-after and a paired-watershed approach are being used. Ecosystem characteristics being monitored and evaluated include, but are not limited to, various physical, chemical and biological properties such as nutrient concentrations, sediment concentrations, dissolved oxygen dynamics, chlorophyll-a concentrations, streamflow, physical habitat, and biological community assemblages.
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Monitoring Success of Mississippi's Delta Nutrient Reduction Strategies—Steele Bayou
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Stocks S., Hicks M.

The Steele Bayou watershed (SBW) in the lower Mississippi Delta of northwestern Mississippi has been subjected to altered land and water resources for decades. Poor stream health in the SBW has been documented by several short-term studies, and the watershed is listed on the Mississippi Department of Environmental Quality section 303(d) List of Impaired Waters with causes of impairment being pesticides, organic enrichment/low dissolved oxygen, nutrients, and siltation. In the SBW, like many other areas in the Delta, there have been and continue to be numerous large and small scale efforts by land owners and State and Federal entities to reduce sediment and nutrient loadings. It is estimated that more than $15 million has been spent in the SBW for various conservation practices, not factoring in unknown private dollars by landowners. It is also estimated that combined Federal, State and private efforts have resulted in up to 50 percent of the Steele Bayou watershed being treated with various conservation practices.

An intensive monitoring network was implemented in 2008 through a multi-agency partnership. This monitoring network was designed to evaluate conditions at three nested scales: edge-of-field, in-stream, and outlet of the watershed. Data collected from the network will help define characteristics of a wide range of physical and chemical properties of water quality and will quantify the changes over time that result from the implementation of conservation measures. Preliminary evaluation of historical data compared to current data from the SBW suggests decreases in both sediment and nutrients. In addition to comparison of data between historical and current values, the current monitoring design will allow for a detailed analysis of loads and trends over time, at edge of field and at several locations along the main stem channel.

Movement of Agricultural Chemicals and Sediment Through the Lower Mississippi River Basin During the 2011 Flood, April through July
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Welch H.L., Aulenbach B.T., Coupe R.H.

Extreme hydrologic events, such as floods, can overwhelm a surface water system's ability to process agricultural chemicals (nutrients and pesticides) and can move large amounts of sediment downstream to larger surface water bodies. The Mississippi-Atchafalaya River basin drains approximately 41% of the conterminous United States and is the largest contributor of nutrients to the hypoxic zone that develops along the inner continental shelf of the Gulf of Mexico each spring. From March through April 2011, the lower Mississippi River basin received more than five times more precipitation than normal, which combined with snow melt from the upper Mississippi River basin, created a historic flood event that lasted from April through July. The U.S. Geological Survey, as part of the National Stream Quality Accounting Network (NASQAN), collected samples from six sites located in the lower Mississippi-Atchafalaya River basin, as well as, samples from the three flow-diversion structures: the Birds Point-New Madrid in Missouri and the Morganza and Bonnet Carré in Louisiana, from April through July. Samples were analyzed for nutrients, pesticides, suspended sediments, and particle size; results were used to determine the water quality of the river during the 2011 flood. Monthly loads for nitrate, phosphorus, pesticides (atrazine, glyphosate, fluometuron, and metolachlor), and sediment were calculated to quantify the movement of agricultural chemicals and sediment into the Gulf of Mexico. Nutrient loads were compared to historic loads to assess the effect of the flood on the zone of hypoxia that formed in the Gulf of Mexico during the spring of 2011.

Nitrogen dynamics within the Big Sunflower River Basin in northwestern Mississippi
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Barlow J.R., Coupe R.H., Kröger R.

Two important water issues in northwestern Mississippi are: (1) the export of nutrients to the Mississippi River and eventually to the Gulf of Mexico, and (2) the availability of water for irrigation and to sustain baseflow in streams. Recently, the Yazoo River Basin in Mississippi was identified as a significant contributor of total nitrogen and phosphorus to the Gulf of Mexico. The Big Sunflower River Basin, located within the Yazoo River Basin, receives large annual inputs of nitrogen from agriculture, atmospheric deposition, and point sources. Recent publications indicate that nitrate, once it enters the surface waters of the Big Sunflower River Basin, acts conservatively and does not undergo significant losses. Stream flow in the Big Sunflower River has been substantially altered by loss of base flow due to declining water levels in the underlying alluvial aquifer. Therefore, instead of being a predominantly gaining stream, the Big Sunflower River is now a predominantly losing stream allowing for surface-water to move through the streambed. Nitrate transported with surface water through the streambed, with its generally low oxygen environment, is susceptible to denitrification, thereby removing nitrate from the system. Over the past 2 years, the USGS, in cooperation with the USACE, has conducted a study to determine the relative roles of in-stream processing and groundwater/surface-water exchange on the transport and fate of nitrate in the Big Sunflower River. Preliminary results from this study indicate that the transport of nitrate in surface water moving through the streambed is removed by denitrification, whereas the in-stream transport of nitrate is relatively conservative.

Nutrient and Suspended Sediment Mitigation Through the Use of a Vegetated Ditch System Fitted with Consecutive Low-Grade Weirs
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 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. The efficiency of consecutive low-grade weirs will be compared in and across the system. The experiment was conducted September 26–October 1, 2011 at the aquaculture facilities at Mississippi State University. Three embankment ponds were discharged at 48 hour intervals into a single vegetated drainage ditch fitted with 4 low-grade weirs. Data will be 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.
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Nutrient Characteristics of Moist-Soil Wetlands in Agriculture Landscapes
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Alford A.B., Kröger R., Kaminski R.M.

In the Mississippi Alluvial Valley (MAV), significant improvements in wetland management strategies have increased the availability of food for wintering waterfowl. Through seasonal drawdown and flooding schedules, moist-soil wetland management encourages growth of annual seed-producing grasses and sedges. Whereas the ecological importance of this conservation strategy is widely known, other environmental benefits, including its effect on water quality, are little understood. To quantify the nutrient exports from these wetlands and therefore explore their potential to improve downstream water quality in the MAV, we implemented a study to compare effluent water quality from runoff events from 5 spatially paired moist-soil wetlands and agriculture fields in Mississippi MAV during October 2010-March 2012. We measured concentrations (mg L-1) of nitrate, NO3-; nitrite, NO2-; ammonium, NH4+; total phosphorus, TP; total dissolved phosphorus, TDP; particulate phosphorus, PP and; total suspended solids, TSS. Mean concentrations of NO3- , TP, PP, and TSS were 91%, 37%, 49%, and 83% lower (P<0.005) in effluent from wetlands than agricultural fields, respectively. Loads (kg) of nutrients discharged from wetlands will be calculated and used to evaluate how moist-soil wetlands in the LMAV aid in meeting Mississippi River and Gulf of Mexico nutrient reduction goals.
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Policy Approaches to Stormwater Facility Sizing and Sustainable Site Design
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Overbey E., Gallo W.C.

A difficult challenge in implementing sustainable stormwater facilities is navigating stormwater policies designed to use complex stormwater models to size large detention basins. The presentation explores unique stormwater facility sizing approaches that have been used and modified for over ten years by landscape architects, architects and civil engineers in Portland, Oregon. Through a survey of design professionals, the research highlights the opportunities for policy to influence where and how stormwater facilities are incorporated into the design process.

The Portland Stormwater Management Manual (SWMM) primarily utilizes two approaches to meet the city's stormwater requirements. The Simplified Approach uses simple sizing factors accompanied by standard design details and specifications to streamline the process. Alternatively, the Presumptive Approach utilizes a unique sizing calculator that allows for maximum design flexibility and control of an array of best management practices. Both of these approaches promote multiple, small-scaled facilities that infiltrate and manage stormwater as close to where it falls as possible.

Results of the survey indicate that design professionals differ on how they utilize sizing tools in the design process. Art based disciplines lean toward the Simplified Approach that allows exploration of multiple solutions early in the design process, while engineers tend to lean toward the more robust Presumptive Approach, allowing refinement of the facility design.

The new and evolving paradigm of sustainable stormwater management can be shaped by policies that are designed specifically for implementation of small-scaled infiltration facilities. By simplifying the sizing process, these tools allow designers to use facilities as an integral part of overall site design. However, simplifying the sizing methodology is not a shortcut for simplifying design of the individual facility which requires careful consideration and refinement to meet specific needs of the site.
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Predicting Nitrogen and Phosphorus Concentrations using Chlorophyll-a Fluorescence and Turbidity
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Andrews C., Kröger R., Miranda L.E.

Agricultural practices and land modification introduce excess nutrient and sediment loads into inland watersheds. Modification of tributary streams and rivers within these watersheds decreases the ability of floodplains to respond to increased loads. Therefore, large amounts of nutrients and sediments are transferred to coastal aquatic systems. Aquatic systems are facing increased nuisance algal growth and premature senescence leading to hypoxic conditions, threatening recreational and commercial fish yields. Furthermore, sedimentation and turbidity create intolerant conditions for aquatic organisms, and can trap phosphorus in these systems. To address these issues, states are developing nutrient criteria for inland waters. As inland water bodies are numerous, the usefulness of such criteria is dependent on efficient monitoring. We investigated the potential use of a handheld chlorophyll-a (chl-a) fluorometer as an estimator of total phosphorus (TP) and total nitrogen (TN) in oxbow lakes of the Mississippi Alluvial Valley. Several adjustments were explored to improve the ability of the fluorometer to accurately represent chl-a. Past studies in Mississippi lakes have shown a poor relationship between TP and chl-a (r2 = 0.18), but a moderate relationship between TN and chl-a (r2 = 0.53). The poor TP-chl-a relationship is partially attributable to naturally high levels of phosphorus and turbidity in the region. We found the relationships between chl-a and nutrient concentrations were improved in oxbow lakes; adding covariates such as turbidity and suspended solids further improved predictability. Estimating TP and TN with in-situ handheld-meter measurements of chl-a supplemented with measures of suspended solids may, in many cases, be adequate for temporal or spatial monitoring of nutrients in oxbow lakes.
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Preliminary Results from a New Ground-Water Network in Northeastern Mississippi
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Manning M.A., Rose C.E., Welch H.L., Coupe R.H.

In 2010, the U.S. Geological Survey established a new groundwater network to better understand the influence of agricultural land use on shallow groundwater quality. The areal extent of the study spans from southwestern Tennessee southward through the middle of northern Mississippi. A 30 well network overlays the basic recharge area that conforms along the eastern outcrop boundary of the Middle Claiborne Group, (Sparta Sand) within Tennessee and Mississippi. Well locations were randomly selected using a grid of 30 polygons generated by a geographical information system (GIS) model. Monitoring- well locations were then selected for each GIS-generated polygon that best fit both agricultural land use, and location to the outcrop area. These areas of outcrop for the Sparta Sand provide a hydrologic connection between the aquifer, and surface-water sources such as rivers, lakes, and rainfall runoff. This study will investigate the shallow groundwater quality of the Sparta waters on the eastern edge of the formation that could be altered by agricultural land use and will document any unfavorable compounds that may be carried into the aquifer.

During the fall of 2010, 15 of the new 30 well network were drilled and established on private properties located in northeastern Mississippi. These new monitoring wells were installed using a rotary drilling-type rig until the first water was identified. Using historical data, potentiometric surfaces were estimated to range from zero (land-surface) to about 30 feet below land surface. During the initial well drilling, the first water was encountered anywhere from 12 to 40 feet below land surface. All of the wells were screened at a 10 foot interval from the bottom of the well. Each well screen was set within mixed marine/deltaic facies consisting mostly of sand to sandy silty clays which are considered consistent with most Sparta Sands. Most of the wells were drilled within an area consisting of a least 60 percent or more local agricultural land-use. The locations were selected because the landowners were interested in the study, allowed accesses to their property, and they possessed land that had active agricultural activities that included corn, cotton, and /or soybeans.

The lower extent of the two-state study area was sampled for groundwater quality from March through April 2011. Water samples were analyzed for a wide range of constituents, including but not limited to trace elements, inorganics, nutrients, dissolved gases, tritium, and a full spectrum of pesticide compounds. The well network will be re-visited annually to monitor water levels, and a subset of five wells will be sampled every other year. Future plans are to re-sample the entire network for water-quality trends on a 10-year rotation. Land-use surveys were conducted within a 500-meter radius of each well to determine the current land use, and to provide a baseline for future land-use changes.

Preliminary Sediment Accumulation and Phosphorus Retention Behind Low Grade Weirs in the Mississippi Delta
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Usborne E., Kröger R.

Agricultural phosphorus (P) loads, carried by surface runoff through ditches, contribute to eutrophication. Low grade rip rap weirs potentially reduce P from entering primary aquatic systems by slowing water flow through drainage ditches, allowing sediments to settle out and P to sorb to soil. Due to the relatively new application of weirs in Lower Mississippi Alluvial Valley drainage ditches, their effects over time are not understood. Weirs have the potential to alter the pH and hydraulic residence time within the ditch system, thereby affecting P retention by ditch soils. Three weirs and a control have been monitored monthly from the time of installation for one year in order to track changes in P bioavailability ratios and sediment deposition rates. Sediment depth was recorded using a permanent reference marker located behind the weir and P fractions were measured on collected sediment samples. Loosely bound P and iron phosphate were considered bioavailable while reductant-soluble P and aluminum phosphate were considered non-bioavailable. Locations that are losing sediment coincide with increasing bioavailability ratios and locations that are accumulating sediment have declining bioavailability ratios. Predicting time periods between soil P saturation and sediment accumulation limits will allow us to inform farm managers of optimal times to dredge ditches for greatest phosphorus retention efficiency.
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Proceedings of the 41st Mississippi Water Resources Conference
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: .

Rainfall Simulation to Evaluate Nutrient Loss from Marietta Soil Amended with Poultry and Cattle Manure
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Read J.J., McLaughlin M.R., Adeli A.

The main waste product produced by the broiler chicken industry is litter (manure and bedding materials), which is typically used as N-P-K fertilizer for pasture and hay crops on the producing farm or nearby farms. Studies in Mississippi indicate the average annual addition of nutrients is approximately 289 kg ha-1 N, 150 kg ha-1 P2O5, and 299 kg ha-1 K2O, assuming all the litter was applied on the ‘average’ 54-ha farm without allowance for buildings, roads, water bodies, or forests. Of the total land area, approximately 474,000 ha is utilized for grazing by livestock, which constitutes another source of manure nutrients. The build up of N and P at the soil surface (0-15 cm) increases the potential for degradation of surface and groundwater resources, but the ultimate fate of much of the manure N and P is not known. This paper presents results of a rainfall-simulation study conducted in the greenhouse using eight, 8-cm deep PVC troughs (0.20 m wide x 1.45 m long) that contained sod of common bermudagrass collected from a Marietta loam soil. The objective was to determine if the combination of cattle feces (dung) and broiler litter increased the potential nutrient load in the surface-water runoff, as compared to broiler litter only. The treatments comprised 130 g litter (~3500 mg N) to six troughs, 24 g dung (~144 mg N) to four of these six; and two un-amended controls. The quantity and quality of soil leachate was determined after five "events" at a rainfall intensity of 75 mm h-1. Results indicated total N loads of 64, 366, and 378 milligrams in the control, broiler litter and litter + dung treatments, respectively, which renders a N-leaching loss of approximately 10% for Marietta soil under these conditions. The majority of leachate N, 40 to 70% across manure-amended troughs, was recovered in the first rainfall event. In general, NH4 was the predominant inorganic constituent recovered in leachate. The quantity of leachate N was similar in the litter and litter + dung treatments, suggesting cattle grazing is not expected to contribute significantly to the N loss in runoff from pasture fertilized with 4.48 Mg broiler litter ha-1. Results will be discussed in relation to managing bermudagrass, broiler litter and grazing to decrease watershed runoff losses of N and P.

Results of Regional SPARROW Models for Selected Watershed in Mississippi
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Rebich R.A.

SPARROW (SPAtially Referenced Regressions On Watershed attributes) models were developed by the U.S. Geological Survey to estimate nutrient inputs (total nitrogen and total phosphorus) to the northwestern part of the Gulf of Mexico from streams in the South-Central United States. These models included drainages in Mississippi: the Yazoo River Basin, the Big Black River Basin, and the South Independent Streams. The models were standardized to reflect nutrient sources and stream conditions during 2002.

Model results indicated that total nitrogen yields in the Yazoo River Basin generally were higher in the lower part of the Basin (an area locally referred to as the Delta) than in the upper part. Although total phosphorus yields generally were higher in the Delta than in the upper part of the Yazoo River Basin as well, yields also were high along the bluff hill area of the Basin prior to entry into the Delta area. The primary source of nitrogen and phosphorus in the Yazoo River Basin was fertilizer. Model results indicated that total nitrogen and total phosphorus yields in the Big Black River Basin were highest in the lower part of the Basin. Wet deposition of total inorganic nitrogen was the largest nitrogen source in the Big Black River Basin; for phosphorus, however, there were no dominant sources. Nitrogen yields generally were highest for areas adjacent to the Mississippi River levee and southern State boundary for the South Independent Streams Basin, whereas phosphorus yields generally were highest for areas adjacent to the Mississippi River levee. The primary source of nitrogen in the South Independent Streams Basin was wet deposition of total inorganic nitrogen; there were no dominant sources of phosphorus.

The SPARROW Decision Support System (DSS) is an online interactive tool created for these and other SPARROW models so that water managers, researchers, and the general public can have access to results for a variety of uses. Users can map loads, yields, concentrations, and sources by stream reach and catchment; track transport to downstream receiving waters, such as estuaries and reservoirs; evaluate management scenarios such as source reductions; and overlay other sources of information such as land use, states, counties, and hydrologic units. The SPARROW DSS is located at: http://cida.usgs.gov/sparrow/index.jsp .
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Rule Curves in Flood Control Reservoirs: A Historical and Procedural Analysis
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Mower E., Miranda L.E.

The U.S. Army Corps of Engineers (USACE) manages 11 million ha of federal land and water including hundreds of multi-purpose reservoirs. Managing the water regime in many of these reservoirs requires establishing seasonal targets in water levels (i.e. rule curves) that are dependent on regional precipitation patterns and water demands from user groups. Rule curves in Northern Mississippi reservoirs were established in 1967 as an answer to increased interest in multi-purpose water storage. Rule curves have been modified in past years attempting to balance various environmental concerns such as emphasis on fish and wildlife management mandated in USACE reservoirs by federal legislation, and water needs such as flood control and agriculture use. The processes and challenges associated with developing and amending rule curves are complicated and generally unknown to most fish and wildlife managers and user groups. Informing managers and user groups about the process required could lead to effective communication, management, research, and collaboration. Thus we sought to review the processes, policies and laws the USACE follows in developing and amending rule curves that govern water levels, focusing on the four large flood control reservoirs in the Upper Yazoo Basin. To this end we reviewed the history of the rule curves, as well federal policies and laws governing them. We obtained our information from a literature review and interviews with agency personnel having current or past involvement in managing these flood control reservoirs. Congressional authorization, feasibility studies and justification studies are some requirements that must be met before a rule curve can be established or modified. National Environmental Policy compliance must be shown, as well as flood risk impacts both upstream and downstream for flood control reservoirs. Magnitude of the rule curve change determines congressional involvement in amending rule curves. Although our results are preliminary, they provide a window into a little-understood but important component of fish and wildlife management in reservoirs.

Runoff Quality Effects of Simulated Conservation Practice Scenarios in a Mississippi Delta's Watershed
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Ramirez-Avila J.J., Ortega-Achury S.L., McAnally W.H., Daiz J.N., Martin J.L.

The APEX (Agricultural Policy Environmental Extender) model was developed for use in whole farm and small watershed management with the capability of detailed field scale modeling and routing by connecting farm/field sized subareas. The ArcAPEX is an ArcGIS based user interface designed to automate the input parameterization of the APEX hydrologic/water quality model. The objective of this study is to evaluate runoff quality effects of alternative conservation practices scenarios for agricultural production in a northeastern Mississippi’s watershed using the APEX model and the ArcAPEX interface. Model evaluation compares the observed runoff sediment and nutrient losses from a USGS gauging station draining an 11 ha watershed in the Mississippi Delta with the simulated results generated by APEX. Initial stage of the study demonstrated a satisfactory capability of the model in simulating runoff and sediment at annual and monthly scales (R2≈0.8), but not at daily scale. Using no calibrated parameters, the model underestimated observed phosphorus loading. This maybe due to the use of the initial phosphorus concentration in soils set as zero. Modeling of conservation practice scenarios are expected to evidence an improvement of runoff quality condition at the edge of the studied watershed. Final results are also expected to compare APEX performance with other developed model(s) for the same location and scenarios.
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Sea Level Rise Visualization and Measurements of Subsidence and Accretion Rates for the Alabama, Mississippi, and Florida Coastlines
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Wilson K.V.

Coastal communities throughout the U.S. are in the initial stages of planning and/or creating climate adaptation plans. Emergency managers, developers, and the general public have a need to understand the potential effect of a rising sea level, whether the land surface is subsiding or accreting, and how these phenomena may influence plans for developing future critical infrastructure and for habitat restoration and conservation.

The Alabama, Mississippi, and Florida Gulf of Mexico Coastal Internet Map Server (http://gom.usgs.gov/slr/index.html) was developed to provide an interactive online tool for the public to visualize the effects of sea level rise along coastal communities. This server was based an existing server which was built principally to display the maximum storm tide crest resulting from Hurricane Katrina (2005). This server quickly and easily projects 1-, 2-, 3-, 4-, 5-, and 6-ft sea level rises onto a 3-meter digital elevation model constructed from Light Detection and Ranging (LiDAR) data procured before Hurricane Katrina for Alabama and Mississippi and after Katrina for Florida from the Alabama line to the east side of the St. Marks National Wildlife Refuge, east of Apalachicola, Florida.

To determine rates of land surface subsidence or accretion due to sea level changes, surface Elevation Tables (SETs) were installed (and readings began) in late 2010 at six sites along the Mississippi and Alabama coasts. Each site has four SETs dispersed within the local area of the site. Three years of data will be collected to provide an estimate of the current rates of subsidence or accretion in the coastal marshes by comparing the leveling rates of vertical displacement to established National Geodetic Survey benchmarks.
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Sediment and Mercury Fate and Path Modeling in Weeks Bay, Alabama
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Sloan-Ziegler J., Camacho-Rincon R., Martin J., McAnally W.

Mercury, a naturally occurring element, is found in water, soil, and air and is released into the environment through natural sources and human activities. Mercury is subject to several physical and chemical processes in aquatic systems that impact its fate, transport, and toxicity to humans and aquatic life. Mercury bioaccumulates though the food chain and can eventually be ingested by humans though fish consumption. Mercury exposure can lead to negative effects such as risks to the nervous system, brain, lungs, heart, kidneys, and immune system.

Knowing the processes that can affect the fate and transport of mercury in waterbodies is fundamental for developing ecological restoration and prevention plans as well as for mitigating the potential threats to humans.

In this study, a mechanistic model based in the Water Quality Analysis Simulation Program (WASP) was implemented to support the analysis and understanding of the fate and transport of mercury in Weeks Bay, Alabama. Preliminary results indicate that the model is capable of representing the transport characteristics of the estuary and is, thus, potentially able to reproduce the long-term transport of mercury in the system. Current observed mercury data is limited; therefore, the current model can be used to aid in the formulation and development of future data collection programs focused on refining, calibrating, and validating the model.

Sediment and Nutrients Loadings from the Upper Pearl River Watershed
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Parajuli P.B.

Sediment and nutrients 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 sediment and nutrients require quantifying pollutant load contribution from each potential source. Quantifying pollutant loads from each source will help in developing pollutants reduction strategies to meet applicable water quality standards. The objective of this research was to monitor sediment and nutrients concentrations and quantify daily, monthly and annual pollutant loadings from the Upper Pearl River watershed (UPRW-7,885 km2) in east-central Mississippi. Analysis of average NCDC rainfall, USGS stream flows, observed sediment, and nutrient data from the watershed will be presented. Preliminary results from the model simulations will also be presented using appropriate statistics.

Sedimentation Processes in Perdido Bay
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Sigsby N.J., McAnally W.H., Sigsby N.

Perdido Bay is an estuarine system located along the Alabama-Florida border in the Gulf of Mexico with an estimated 2900 sq. km watershed and a narrow tidal inlet to the Gulf of Mexico. Water quality and hydrodynamics have been examined in some detail, but very little research has been done on the sedimentation processes of the bay. A systematic sedimentation study will contribute to an improved understanding of the processes of the bay.

An investigation into the sediment classifications, distributions, and discharges will be completed as a major part of this sedimentation study. As a first step, a data collection was performed in July 2011. This survey included water and bed sediment sampling, water quality readings, and velocity measurements. Water quality constituents tested included dissolved oxygen, pH, salinity, temperature, turbidity, and depth. Velocity and discharge calculations were recorded using an Acoustic Doppler Current Profiler. Bed sediment samples will be used for grain size analysis and sediment classification. The water samples collected will be used for total suspended solids analysis. Analysis of the tide levels, salinity and turbidity will be completed for the verification of the existence and location of the turbidity maxima in Perdido Bay.

A thorough literature review will be completed to better understand sedimentation processes, sediment budgets, numerical modeling, and historical data. Using this data, along with data collected on-site, a systematic sediment budget will be developed and a numerical model of sediment transport using EFDC will be developed.

Snapshot Through Time of "The Hole" in the MRVA of the Central Delta (Sunflower and Leflore County)
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Parish P.C.

The data utilized in this presentation will provide snapshots of the decline in water levels in what we affectionately call "The Hole". This will be done through the use of three dimensional maps, hydrographs, and geophysical logs. "The Hole" is an area of depression in the potentiometric surface of the MRVA (Mississippi River Valley Alluvial Aquifer). It is located in the central delta of northwest Mississippi. In large part it is centered in Sunflower and Leflore counties. The purpose of this research is to expand the examination of the growing trend of declining water levels in this area over time. This data collection involves drilling, historical research, and water level data collection. The water level measurements are mainly conducted in the Fall after irrigation season has ended and the Spring before irrigation season begins.

This examination leads us to the question, "Why?". There are many answers to that question which will be discussed in more depth. The geology in and around the delta both creates the possibility of such an aquifer as the MRVA, as well as, hinders its recharge and flow. Deforestation and dewatering of the land in the delta have also caused problems. Incision and dredging of channels in surface water bodies may contribute to the problem. Local domination of certain crops may contribute the trend. All of these areas need to be addressed and examined further.

Soil Moisture and Watershed Assessment to Predict Wildfire Occurrences in the Southeast of United States
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Arias-Araujo E., Diaz-Ramirez J., Cooke W.

Wildfires occurrences are frequent in the Southeast of United States (US) and it has become a major concern in this region. The purpose of this study is to determine the effect that soil moisture (SW) level and basin water- balance values (BWB) have over summer-wildfires occurrences in the Southeast of US which encompasses Texas, Louisiana, Oklahoma, Mississippi, Alabama, Tennessee, Georgia, Florida, South Carolina and North Carolina. Quantifying, analyzing and processing the spatial and temporal distribution of SW and BWB could be an effective method for modeling, managing and preventing potential wildfire occurrences. Most of the studies related with this topic have been done to assess the causes and ecological conditions that aid the beginning of wildfires; however, there has not been found studies that integrate SW and BWB to evaluate and predict the wildfires occurrences. Hydrological models such Soil Water Assessment Tools (SWAT) and Hydrological Simulation Program--Fortran (HSPF) are being used as tools to evaluate, compare and simulate watershed water-flow and SW outputs at specific locations where the density of wildfires occurrences are elevated, medium and low; the purpose of this analysis is to contrast temporally and spatially the three scenarios. To evaluate the complete Southeast of US a simpler soil water-balance model is being utilized because of the large extension of study area. SWAT and/or HSPF require data intensive inputs and extensive parameterization thus these models have limited capabilities to process the complete Southeast region. ArcGIS and MATLAB software have being used to compile, prepare and analyze data. Wildfire data, Digital Elevation Models (DEMs), NASA -Land Information System (LIS) gridded binary (GRIB) data, National Land Cover Data (nlcd), STASTGO soil units (USDA-NRCS), USGS-stream-gauges and NOAA Doppler data (precipitation) is being used in the assessment. The final product will be Graphical user interface (GUI) that permits the modeling and prediction the wildfires occurrences in the southeast of US. This GUI will be distributed and shared with governmental agencies and private organizations associated with Forest and Land management. This project is being funded by National Aeronautics and Space Administration (NASA).
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Sources and Yield of Dissolved Inorganic and Organic Constituents in Headwater Streams of the Upper Gulf Coastal Plain, Mississippi
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Mangum C., Hatten J., Dewey J., Choi B.

Mississippi has more than 8 million hectares of land in active forest management, much of which is in headwater watersheds. Headwater systems contribute water and initiate dissolved material export to downstream fluvial environments. Nutrients, such as nitrogen and dissolved organic carbon (DOC), are constituents that frequently lead to impaired rivers in Mississippi. This study analyzes event data from 4 ephemeral (1.8-3.8 ha) and 1 perennial (32 ha) forested headwater system in Upper Gulf Coastal Plain, Mississippi over a 15 month period. We measured dissolved inorganic and organic constituents in samples collected during storm and baseflow conditions. We calculated the flux of nitrate, dissolved organic nitrogen (DON) and phosphorus with average kilograms per hectares per year yields of 0.48, 7.83 and 0.25 respectively. We also used an end member mixing model to determine the source of water and compared those results with nutrient fluxes during both storm and baseflow conditions. The data show that dissolved constituents are primarily mobilized during the rising limb of storm events. The source of these materials appears to be shallow mineral soil horizons (A horizons). In our presentation we will discuss how the source of water interacts with flux of nitrogen and implications for forest management and downstream environments.
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Sources and Yield of Particulate Organic Carbon and Nitrogen In Managed Headwaters of Mississippi
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Hatten J., Dewey J., Mangum C., Choi B.

Managed, forested headwaters in Mississippi constitute a crucial part of watershed dynamics because they comprise more than 60-80% of stream networks and watershed land areas. Headwater streams contribute particulate forms of organic carbon (POC) and nutrients such as nitrogen (PON) to downstream fluvial environments. Flux of these materials from headwaters is difficult to quantify and few studies have examined their source. In particular, the relationships among origin and export of particulate organic carbon and nitrogen with stream discharge represent significant gaps in our understanding of headwater processes. POC and N serve vital function as a regulator of bacterial productivity, dissolved oxygen concentrations, nutrient cycling, and food web productivity however excess terrestrial input of POC and N can contribute to eutrophication and hypoxia in waters that are deficient in DO. This project augments current research efforts concerning hydrologic and hydrologically-mediated functions in managed, forested headwaters of Mississippi. This study quantifies the yield, source, and transport of POC and N within managed watersheds in order to better constrain the flux of OC, nutrients, and contaminants that bind to OM. Objectives are to (1) quantify exports of sediment, POC , and PON, (2) determine whether C and N are derived from a similar source using stable isotope ratios, and (3) determine whether additional process are occurring at a larger scale. Preliminary data linking suspended sediments to soils from 15 months of sampling across four management intensities will be presented. These data will be of value to forested-watershed managers in their efforts to weight the environmental cost vs. nutrient cycling benefit of organic inputs resulting from silvicultural activities.

Technologies and Methods to Aid the Adoption of PHAUCET Irrigation in the Mississippi Delta
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Powers S.

Conservation is one of the keys to balancing the water budget of the Mississippi Delta's Alluvial Aquifer. As more and more farmed acres in the Delta are being irrigated every year, the use of new and existing conservation practices in the application of that water is imperative. While high value, expensive projects such as the installation of surface water reservoirs and tail water recovery systems demonstrate great groundwater savings potential, there are many other sensible and more economic ways to conserve the Delta's water resources. Among those options is the use of the PHAUCET Irrigation Program. PHAUCET is a computer program originally written by the USDA-NRCS for use with furrow irrigation of row crops using poly pipe. Its primary function is to generate a range of hole sizes for each irrigating set that will increase the uniformity of each round of irrigation. This increased uniformity allows irrigators to more accurately time irrigations, leading to a more easily managed irrigation cycle. With the PHAUCET Program, however, there are a number of variables users must input in order for the program to generate its suggested hole sizes. These variables include the flow rate of the well, hole spacing along the poly pipe, the elevation changes of the poly pipe, poly pipe size, the number of holes for each watered furrow, set lengths, and row lengths. While most of these variables are known to growers, three of them can be more difficult to obtain. Flow rates, elevation changes, and row lengths can all three present problems to growers when they are working to implement the program. This paper will look at different technologies and methods that have the potential to aid users in the collection and use of the lesser known variables.
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The Arkansas Discovery Farms Program
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Daniels M.B., Sharpley A.

Discovery Farms are privately owned farms that have volunteered to help with on-farm research, verification, and demonstration regarding farming's impact on the environment and natural resource sustainability. We currently have six Discovery farms at five counties of the State; including a poultry farm in Washington County, a beef cattle operation in Conway County, a rice-soybean and corn operation in Arkansas County, two adjacent rice-soybean operations in Cross County and a cotton farm in Desha County. We are currently collecting water use and water quality data from individual fields on each of these farms utilizing automated water monitoring stations. These stations include automated ISCO samplers equipped with rain gauges, pressure transducers in conjunction with edge-of-field H-flumes, pipes or weir flow structures. In Washington County, we are monitoring runoff originating immediately near poultry houses due to concerns with spillage during house clean out and dust accumulation from tunnel ventilation. We are also quantifying the nutrient and sediment remedial efficiencies of capturing runoff in a farm pond and an un-grazed filter strip. In Conway County, we are assessing runoff from pastures and the ability of a wetland to capture and assimilate nutrients. In Arkansas County, we are examining three eighty-acre rice fields with different water management practices, a corn field and runoff from 1,200 acres that drains back to an irrigation reservoir. In Cross County, we are monitoring a sixty-five acre rice field under conventional production and a twenty-three acre soybean field under conservation tillage. Finally, in Desha County, we are the effects of conservation tillage and cover crops on nutrient and sediment loss from three eight-acre fields in cotton. However, the Arkansas Discovery Farms program is not just about monitoring but just as importantly, engaging farmers to take ownership in environmental issues facing agriculture. This paper will discuss the development, guidance, principals and goals of the Arkansas Discovery Farm program.
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The Buttahatchie River Stabilization Project
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Maurer B.

The Buttahatchie River watershed is recognized by local and regional scientists, conservationists, and outdoors people for its ecological significance, especially the unique biological diversity found and documented in this system (Mississippi Museum of Natural Science, 2005). Mussel surveys, conducted by O'Neil et al (2004; 69 FR 40084), and the Mississippi Department of Wildlife Fisheries and Parks (2004) have documented viable communities of rare mussel species along several reaches of the Buttahatchie River and some of its major tributaries. In addition, rare and unique fish communities and species have been reported from the Buttahatchie River system (Mississippi Museum of Natural Science, 2005). In an unpublished survey (Hicks 2004) of 23 biological experts in Mississippi, the Buttahatchie River ranked second behind the Pascagoula River out of 14 rivers in Mississippi in terms of priority for conservation and ecological significance (Mississippi Museum of Natural Science, 2005).

However, the lower reaches of the river have undergone wholesale channel adjustments in recent years, including widening, rapid erosion, quarry capture, and excess sediment. Erosion and excess sediment continue to be a problem in this area. The Stability Analysis of the Buttahatchie River by USDA National Sedimentation Laboratory (2005) cites disturbances including meander cutoffs, construction of the Tennessee-Tombigbee Waterway (including the impoundment of the Columbus pool), and gravel-mine capture.

The Buttahatchie River Stabilization Project was completed by The Nature Conservancy and partners in October, 2010 , to demonstrate techniques to reduce non-point source (NPS) pollution within the Buttahatchie River Watershed, specifically NPS resulting from eroding river banks. The project was supported by a Section 319 Grant, and used several Best Management Practices (BMPs) designed to show habitat-oriented options to riverbank stabilization. Located in Lowndes County, Mississippi, the project met several important goals. Most immediately, it stabilized a rapidly eroding river bank and prevented thousands of cubic yards of soil from washing into the river. In the long term it is expected that the river bed in this area will also become more stable, and this will allow for improved habitat for fish, aquatic invertebrates, mussels, and other benthic organisms.

It also created an open-air educational site that demonstrates several useful stabilization BMPs and sets of techniques. This unique setting allows for the comparison of various techniques in one location.

The presentation will describe the individual BMPs, their installation process, and the resulting improvements to the river bank.
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The Fate and Transport of Glyphosate and AMPA into Surface Waters of Agricultural Watersheds
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Coupe R.H., Rose C.E., Welch H.L., Manning M.

Glyphosate [N-(phosphonomethyl)glycine] is a herbicide used widely throughout the world in the production of many crops and is predominately used on soybeans, corn, potatoes, and cotton that have been genetically modified to be tolerant to glyphosate. Glyphosate is used extensively in almost all agricultural areas of the United States. The agricultural use of glyphosate has increased from less than 10,000 Mg in 1992 to more than 80,000 Mg in 2007. The greatest areal use is in the Midwest where glyphosate is applied on transgenic corn and soybeans. Yet the characterization of the transport of glyphosate on a watershed scale is lacking. Glyphosate and its degradate AMPA were frequently detected in the surface waters of 4 agricultural watersheds. The load as a percent of use ranged from 0.009 to 0.86 percent and could be related to 3 factors: source strength, hydrology, and flowpath. Glyphosate use in a watershed results in some occurrence in surface water at the part per billion level, however, those watersheds most at risk for the offsite transport of glyphosate are those with high application rates, rainfall that results in overland runoff, and a flowpath that does not include transport through the soil.
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The Great Flood of 2011 and its Influence on the Mississippi River Valley Alluvial Aquifer: Did the River Recharge the Aquifer or What?
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Byrd C.B.

The flooding along the Mississippi River during the months of April and May, 2011 was among the worst in the last 100 years. According to one source, this flooding event was comparable to the flooding that occurred in 1927 and 1993. Data from five gages that include stations at Memphis, Tennessee down to Vicksburg, Mississippi indicate that an all-time record was set at the gage at Vicksburg, Mississippi, and near-record stages were recorded at the other four stations. Seven states were impacted by the floodwaters, and for the first time in many years, the Morganza Spillway was opened to deliberately flood roughly 4,600 square miles of rural Louisiana so that New Orleans and Baton Rouge could be spared.

With all the record setting stages along the Mississippi River adjacent to Mississippi, one may ask, "What influence did the record-high river stages have on the Mississippi River valley alluvial aquifer (MRVA), which is the shallow aquifer in the alluvial plain (Delta) in the northwest portion of the state?" Unfortunately, the answer is not as straight forward as one may wish.

The Mississippi River is the western boundary for both the Delta and the alluvial aquifer. The depositional history of this river system is very complex, thus the geology of the alluvial aquifer is very complex. As the Mississippi River and its tributaries migrated throughout the alluvial plain, many stream channels were eventually cut off from the main river creating oxbow lakes. Through time, many of these oxbows were filled in with very fine-grained sediments, such as silt and clay. If the fine-grained sediments within an oxbow is of sufficient thickness, a "clay plug" is formed that serves to prevent any flow of water through it. Remnants of these old streams and oxbows are present all along length of the Mississippi River. However, if mostly fine- to coarse-grained sand and gravel was deposited, the river and the MRVA are most likely in very good hydrologic connection.

Water levels were collected during early May (the period of peak flooding) by the Office of Land and Water Resources staff. This data along with water level data collected by the Yazoo Mississippi Joint Water Management District staff during early April and early June were correlated with River stages. Then an analysis of geologic data was combined with the water levels and river stages to try to determine hydrogeologic connection.

The Influence of the Mitchell Rate Structure on Community Drinking Water Consumption and Customer Fairness
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Barrett J.

Public water systems have come to accept standards in relation to rate structures to support their respective drinking water systems without comparing the cost to customer conservation or equity. The current rate structures have been adopted without substantive support for why this is the rate structure to utilize. The Mitchell (single) rate structure is a rate structure that highly promotes fairness among the customer base in relation to the cost of drinking water in comparison to the amount of revenue produced by the customer base. The Mitchell (single) rate structure also triggers conservative drinking water consumption practices amongst different socioeconomic strata. A new rate structure can be an alternative answer to the rising infrastructure cost and drinking water supply concerns. In this presentation, I will look to explain the impacts of the Mitchell (single) rate structure on public drinking water systems and the possible ramifications a new rates structure may bring.
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The Mississippi Nutrient Management Manual: Simplifying Availability of Maintenance-Based Fertilizer Recommendations and Nutrient Best Management Prac
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Oldham L.

Plant nutrient dynamics at the agriculture and environment interface is a societal concern. Injudicious application rates or improper application may have deleterious effects on water or soil quality; however supplemental nutrient applications often maximize agronomic crop production and profitability. Prior to 2007, Mississippians spent about $155 million per year on fertilizers for all uses; dramatic price increases that year nearly doubled fertilizer expenditures. Fertilizer prices have been volatile due to both supply and demand issues since the adjustment. Broiler chicken production is the main animal feeding industry located in the state; the litter produced is valued as a plant nutrient source both in the poultry production region, and other areas in the state. Mississippi State University fertilizer recommendations are chiefly based on the maintenance philosophy of soil testing: providing sufficient phosphorus (P) and potassium (K) fertilizer for the current crop, and controlling soil acidity. The university does not recommend P and/or K if the soil test index is high or very high, except one research-verified exception for cotton. Nitrogen fertilizer recommendations are research-based crop and soil specific, but lack a valid soil test for Mississippi climatic conditions. For many years, specific crop recommendations resided in various outreach platforms, as did recommended Best Management Practices. With combined economic and environmental interests, there was a need to centralize the Mississippi State University Extension Service nutrient recommendation and associated Best Management Practice outreach efforts. The Nutrient Management Guidelines for Agronomic Crops Grown in Mississippi (Manual) was developed for ease of use by crop advisers, farmers, government advisers, and others. The Manual exists both as hard copy, and a dynamic, updatable presence on the Extension Service website. Chapters/subjects include introductions to Nutrient Management, soils of Mississippi, nutrients, soil testing, fertilizers, and lime. Other chapters focus on poultry litter as fertilizer and Best Management Practices for nutrients. Separate appendices include the soil testing based fertility recommendations for forages and annual agronomic crops. In addition, there is a Glossary of nutrient management terminology. The centralization of research-proven recommendations, information, and guidelines should facilitate better management of plant nutrients in the Mississippi environment for many years.
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The National Reservoir Sedimentation Data Base: Background and Purpose
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Römkens M.J., Jones M.M., Gray J.

For many years, the Federal Interagency Subcommittee on Sedimentation (SOS), one of the nine Subcommittees of the USGS Advisory Committee on Water Information (ACWI), has been spearheading the development of a National Data Base concerning the sedimentation status of the Nation's Reservoirs. This data base is of critical importance for a number of issues such as water storage for flood control, sediment storage to reduce sediment movement in watersheds, water supply for irrigation and consumptive use, to maintain recreation functions, etc. Changes in the storage capacity may affect all these functions including the potential of the destabilization of the structures containing the reservoirs. The nation has more than 85000 dams and more than 110000 miles of levees. A large number of these dams are principally earthen dams that were built within the last 60 years, usually with an economic life time of 50 years. Many of them have lost a significant part of their storage capacity due to sedimentation. Decisions need to be made to decommission or rehabilitate these reservoirs and associated dam structures. The presentation will discuss the development of this data base, including the status of the reservoirs, dam failures and their disastrous consequences.

Using Acoustic Measurements as a Surrogate Technique for Measuring Sediment Transport
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Chambers J., Kleinert D., Carpenter B., Goodwiller B., Wren D., Kuhnle R.

The diversity in climate, topography, soil types, and cropping practices within the United States lends itself to numerous soil erosion and water contamination mechanisms. The measurement of sediments transported in waterways using acoustic techniques can provide valuable information which can support both systems for planning and assessment and the development of better erosion control technologies. The collaboration between the NCPA and USDA-ARS-NSL has focused on the development and evaluation of innovative acoustic hardware and measurement techniques to monitor sediment transport. Most current techniques are often prohibitively expensive and not easily adaptable for in-situ measurements. Furthermore, manual techniques are often spatially and temporally coarse, cannot easily monitor particle movement over time and could modify the evaluated particle size distribution since aggregates are often broken up in sample collection and handling. In contrast, acoustic techniques tend to be amenable to in-situ measurement, are less costly, less invasive, and allow for long-term monitoring. The presentation will provide a survey of our work on using acoustics for monitoring sediment transport. This includes near bed, suspended, sand sized particles (100-1000 micron), clays and silts (0.1 – 64 micron diameter particles) which tend to be mixed uniformly throughout the water column along with future plans to investigate kinetic energy impact plates to monitor gravel bedload movement.

Using Dissolved Oxygen Dynamics to Derive Nutrient Criteria: Tried, True, and Troublesome
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Hicks M.B., Paul M.J., Caviness K.

Linking nutrient enrichment to adverse ecological effects involves a series of potential causal pathways and proximal stressors. A common proximal stressor is alteration of dissolved oxygen dynamics due to enriched organic matter loading and decomposition. Predictions associated with nutrient enrichment include both the potential for reduced minimum oxygen concentrations, as well as, increased maximum dissolved oxygen and diel fluctuation. Several states have expressed interest in and used oxygen range as a potential response metric. The U.S. Geological Survey sampled more than 50 low gradient Mississippi streams for the period 2009 to present and analyzed samples for dissolved oxygen and nutrients. Several oxygen characteristics were calculated (min, max, range, mean, sd) and related to concurrent nutrient, chlorophyll, and invertebrate assemblage data. All measures of oxygen showed some relation to nutrient concentrations; however, minimum and central tendency measures were most strongly related. At the same time, invertebrate metrics showed a stronger response to minimum concentration among all other measures.
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Water quality and other ecosystem services from wetlands managed for waterfowl in Mississippi
Final Project Report

Year: 2012 Authors: Kaminski R.M., Alford A.B.

A successful and increasingly applied conservation practice in the Lower Mississippi Alluvial Valley (MAV) to mitigate loss of wetland wildlife habitat and improve water quality has been development and management of "moist-soil wetlands." This conservation practice has the potential to provide ecosystem services critical to restoring wetland functions in the MAV such as reducing dispersal of sediments and nutrients into surrounding watersheds. Moreover, a significant potential exists for native crayfish (Procambarus spp.) harvest in moist-soil wetlands in the MAV. During spring 2011, we estimated average daily yield of crayfish from 18 moist-soil wetlands in Arkansas, Louisiana, Mississippi, and Missouri. Average daily yield in 2011 was 3.64 kg/ha (CV = 33%). This estimate was slightly greater and more variable than the estimated yield from Mississippi wetlands in 2009 (i.e., 1.75 kg ha-1; CV = 16%, n = 9) and wetlands in Arkansas, Louisiana, and Mississippi in 2010 (i.e., 2.18 kg ha-1;CV = 30%, n = 15) . Our estimated daily yield of naturally occurring crayfish from moist-soil wetlands is lower than 10 kg ha-1 which is the average daily yield from commercially operated rice-crayfish ponds in Louisiana. However, our comparisons of operating budgets from the two harvest systems indicated that rice-crayfish systems incur $1455 in direct expenses per hectare whereas crayfish harvest operation in moist-soil wetlands incur $682 direct expenses per hectare. Although fixed expenses are lower in harvest operations from moist-soil wetlands, lower yields increased the break-even selling prices from $2.75 kg-1 in rice-crayfish systems to $6.38 kg-1 in moist-soil harvest systems. These prices, however, are still less than those observed in regions of the Southeastern United States outside of Louisiana. To determine if crayfish harvested from moist-soil wetlands are an acceptable seafood product relative to commercially harvested crayfish, we conducted a consumer acceptability panel in May 2011. We found that crayfish from both sources were well liked and did not differ significantly (p > 0.05) in overall consumer acceptability. In July 2010, we installed water quality monitoring stations at 5 wetlands and 5 agriculture fields. We monitored concentrations of nutrients and sediments exported from these habitats during storm events in December-March of 2010-2012. We determined that wetlands exported significantly less total suspended solids and NO3 than agriculture fields in 2010-2011 whereas all parameters except for NH3 were significantly lower in wetland effluent compared to agriculture fields in winter 2011-2012. We were able to calculate loads (kg ha-1) from wetland habitats during the study years and determined that total annual loads of nutrients were slightly greater than currently assumed loading values of wetlands in Mississippi (i.e., 1 kg ha-1). Quantifying these ancillary ecosystem services of moist-soil wetlands will encourage further establishment and management of these wetlands in the MAV and elsewhere for wildlife and associated environmental and human benefits.

Water Quality in Sardis Lake: A Multi-Variate Statistical Method for Analysis of Temporal and Spatial Trends
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Surbeck C.

Water quality data from rivers, lakes, and other bodies of water are collected by environmental agencies. These monitoring activities occur because of requirements set by regulations, and data are collected in a systematic way for the intended purpose. Monitoring enables agencies to determine whether water bodies are polluted. Much effort is spent for each monitoring event, resulting in hundreds of data points typically used solely for comparison with regulatory standards and then stored for little further use. This presentation shows a data analysis methodology applied to Sardis Lake in north Mississippi that uses a pre-existing dataset to extract more useful information on water quality trends, without new sample collection and analysis. In this presentation, measured lake water quality data are subjected to statistical analyses including Principal Component Analysis (PCA) to deduce changes in water quality spatially and temporally over several years. It was found that the lake water quality as a whole changed temporally by season, rather than spatially. Storm events caused the greatest shifts in water quality, and the shifts were fairly consistent across sampling stations. This methodology can be applied to similar datasets, especially with the recent emphasis by the U.S. EPA on protection of lakes as water sources. Water quality managers using these techniques may be able to lower their monitoring costs by eliminating redundant water quality parameters found in this statistical analysis.
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Water-Conserving Irrigation Systems for Furrow & Flood Irrigated Crops in the Mississippi Delta
Final Project Report

Year: 2012 Authors: Massey J.H.

The goal of this project was to improve irrigation water- and energy-use efficiency in one of the most economically important cropping rotations practiced in the Mississippi delta, the soybean-rice rotation. Combined economic activity for the two crops in the delta can approach $1 billion annually while combined irrigation water use is approximately 1 million A-ft per season. As a result, a modest reduction in the amount of irrigation water used in the soybean-rice rotation could help reduce the current overdraft of the alluvial aquifer. Results from these 2010-2012 on-farm trials indicate soybean irrigation savings using NRCS Phaucet optimization software averaged about 20% compared to non-optimized furrow irrigation while associated energy use reductions ranged from 32 to 20%, respectively. (It is important to note that in order to foster comparison, the soybean fields used in these studies were rectangular in shape; water savings are expected to be greater for more irregular (i.e., hard to irrigate) soybean fields.) Irrigation water used in rice grown using straight-levees with multiple inlets and intermittent flood management averaged 22.1 ± 2.4 A-in/A as compared to 32.4 A-in/A for straight-levee rice using multiple inlets without intermittent flood management. These results indicate that by overlaying an intermittent flood regime on practices that are already familiar to rice producers in Mississippi, rainfall capture is increased and over-pumping is decreased such that overall water use is reduced by ~40% over the standard rice irrigation practices. Field trials comparing rough rice yield and milling quality for up to 15 rice varieties indicated that commercial rice varieties, grown using standard fertility and pest control programs, well-tolerated a carefully-controlled intermittent flooding regime. Each inch of water not pumped from the Alluvial aquifer onto an acre of rice or soybean saves the energy equivalent of ~1 gallon diesel fuel with concomitant reduction in CO2 emissions by ~200 lbs/A. Assuming a current off-road diesel price of $3.20/gallon, a 9 acre-inch (40%) reduction in rice irrigation translates to a savings of ~$20 per acre while a 1.7 acre-inch (20%) reduction in soybean irrigation represents a savings of ~$3 per acre. By reducing irrigation water and associated energy inputs in soybean and rice production, the producer reduces input costs while reliving pressure on the Mississippi River Valley Alluvial aquifer and also reduces carbon emissions.

Water-Conserving Irrigation Systems for Furrow & Flood Irrigated Crops in the Mississippi Delta
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Massey J.H.

The goal of this project was to determine the feasibility of using multiple inlet plus intermittent irrigation to reduce water and energy use in Mid-south rice irrigation. Intermittent rice flooding improves rainfall capture and reduces over-pumping by maintaining rice flood heights at less-than-full levels. Depending on soil conditions, weather, and crop stage, the targeted intermittent pumping pattern allows the flood to naturally subside over a period of five to ten days before re-initiating irrigation, resulting in a fully saturated (not dry) soil surface. Field studies are being conducted at four Mississippi producer locations location in Boliver, Coahoma, and Sunflower counties in the Mississippi River Valley delta. Seasonal water use was measured using flow meters in commercial rice fields ranging in size from ~30 to 70 acres. Rainfall inputs were determined using rain gauges at each field location. Rough rice yield and grain quality determined for the upper and lower portions of each paddy of each field were not different, indicating that intermittent flooding does not result in agronomic losses relative to continuous flood. The studies show that when coupled with multiple inlet irrigation, intermittent rice irrigation uses ~20% less water than multiple inlet irrigation alone and only ~5% more than zero-grade irrigation. Having no slope, zero-grade fields are the 'gold standard' for Mid-south rice production in terms of water use. The advantage of the intermittent flood over zero-grade is that water-logging of rotational crops often associated with zero-grade fields is avoided. Rice is typically grown with soybean in a 1-yr rice, 2-yr soybean rotation. The presentation will also summarize results from using the USDA's Phaucet irrigation optimization program designed to improve soybean irrigation efficiency.
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Water-quality of the Yazoo River During the 2011 Mississippi River Flood
Proceedings of the 41st Mississippi Water Resources Conference

Year: 2012 Authors: Woods M.S., Rose C.E., Coupe R.H.

The Mississippi River was above flood stage at Vicksburg, Mississippi, for much of spring 2011. Water samples were collected during this period on a weekly basis from the Yazoo River near Vicksburg, Mississippi, and analyzed for nutrients, sediment, and pesticides as part of a U. S. Geological Survey study to assess water quality of the Mississippi River Basin. High water affected the water quality of the lower Yazoo River, as the Mississippi River stage rose and fell during the flood. Water-quality changes correspond not only to stagnant or reversed flows and accumulation and backwater effects, but also to different sources of water to the Yazoo River before, during, and after the flood. Before the spring 2011 flooding of the Mississippi River, the Yazoo River water came from two sources: the Delta and the Bluff Hills. Along the upper Yazoo River, flood-control structures at Steele Bayou and Little Sunflower Diversion Canal outlets were closed to prevent flooding in the Delta from the Mississippi River; during this time, the Yazoo River source is primarily from the Bluff Hills. During the flood, when the Mississippi River stage was higher than the Yazoo River stage, the Yazoo River flow was impeded and reversed, and mixing of the Mississippi River into the Yazoo River occurred. The Mississippi River was a major source of water to the Yazoo River near Vicksburg during flooding. For much of the 2011 growing season, the control structures along the Yazoo River were closed, thus causing sediment and nutrients to accumulate behind the flood control structures. As the Mississippi River receded following the flood, the flow control structures were reopened, flushing the stagnant and sediment-laden backwater into the Yazoo River, allowing the streams of the Delta to return to normal flow. Following the flood, the Yazoo River water source was primarily from the Delta. The changes in water-quality on the Yazoo River during the 2011 Mississippi River flood can be attributed to the different water sources caused by the flood.

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