Source: UNIVERSITY OF NEBRASKA submitted to
WSC CATEGORY 1: INFLUENCE OF CLIMATE AND AGRICULTURAL CLUSTERING ON GROUNDWATER CONTAMINATION BY TRACE ORGANICS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1003385
Grant No.
2014-67003-22072
Project No.
NEBW-2014-05314
Proposal No.
2014-05314
Multistate No.
(N/A)
Program Code
A3151
Project Start Date
Aug 1, 2014
Project End Date
Jul 31, 2019
Grant Year
2014
Project Director
Bartelt-Hunt, S.
Recipient Organization
UNIVERSITY OF NEBRASKA
(N/A)
LINCOLN,NE 68583
Performing Department
(N/A)
Non Technical Summary
There is a strong linkage between global water sustainability and agriculture, as currently, agricultural production accounts for nearly 70% of freshwater usage worldwide. There is ample reason to anticipate that in the future, impacts of agriculture on groundwater quality will differ from those of the past as three key influences on the linkage between agriculture and groundwater are currently undergoing rapid transformation. These include (1) climate change; (2) a greater diversity of contaminant compounds, particularly regarding trace organic "emerging contaminants"; and the (3) spatial distribution of animal agriculture, with increased geographic clustering expected as a response to climate change. The goal of this project is to evaluate the direct effects of climate and the indirect effects of climate-induced agricultural clustering on the fate of trace organic compounds originating from production agriculture to better inform policy and decision-making in the face of a changing climate. To meet our research objectives, we have assembled an interdisciplinary team to evaluate physicochemical, biological, and economic factors affecting trace organic compound flux to groundwater using an innovative numerical modeling approach. Our approach takes into account current gaps in our ability to predict the fate and transport of trace organic compounds in the vadose zone. The analysis will be grounded in a unique data set of emerging contaminants in groundwater from a historic USDA testbed in the Northern Great Plains, and we anticipate demonstrating the transferability of this approach to other geographic locations.To date, the assessment of terrestrial climate impacts to agroecosystems has largely focused on direct impacts such as drought, floods and temperature change effects on crops. However, based on previously-published qualitative analyses, it has been predicted that indirect climate change impacts, such as land-use change, may have a more significant effect on trace organics in surface and groundwater than the direct impacts of climate change. It is likely that organic contaminant fate under climate change will likely be difficult to predict due to the competing climate-sensitive processes that may have conflicting implications for contaminant fate and transport - highlighting the need for quantitative studies of trace organic fate under climate change proposed here. We hypothesize that climate change will result in enhanced clustering of crop and animal production in the northern Great Plains due to economies of scale and water supply reliability. We propose to develop models of agricultural production clusters under climate change, and the resulting indirect and direct effects of trace contaminant transport through the vadose zone. A transdisciplinary approach is necessary to elucidate the economic and biophysical processes that will collectively drive future changes in groundwater quality in agroecosystems. Our project team brings together expertise in economics, geosciences, engineering, chemistry, and community and regional planning to address these questions. This proposed project has the potential to significantly reframe climate change impact assessment priorities in agricultural regions.
Animal Health Component
0%
Research Effort Categories
Basic
100%
Applied
0%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1120210202060%
1120210301040%
Knowledge Area
112 - Watershed Protection and Management;

Subject Of Investigation
0210 - Water resources;

Field Of Science
2020 - Engineering; 3010 - Economics;
Goals / Objectives
The goal of this project is to evaluate the direct effects of climate and the indirect effects of climate-induced agricultural clustering on the fate of trace organic compounds originating from production agriculture to better inform policy and decision-making in the face of a changing climate. To achieve this goal, we will pursue work under three research objectives:Objective 1: Determine the likely spatial redistribution of agriculturally intensive land uses in the northern Great Plains under the influence of climate change. We hypothesize that climate change will result in enhanced clustering of crop and animal production due to economies of scale and water supply reliability.Objective 2: Evaluate climate and land use influences on trace organic loading rates to groundwater. We hypothesize that the effects of land use changes associated with human adaptation to climate change, specifically the spatial clustering of intensive agriculture and associated changes in contaminant loading rates, will more profoundly affect trace organic loading rates to groundwater than will direct climate effects (through changing advection rates through the vadose zone and soil chemical conditions).Objective 3: Assess the possible response of agricultural production clusters to future regulation of trace organics. Some veterinary pharmaceuticals - including estrone - and some antimicrobials are currently monitored by the U.S. Environmental Protection Agency for potential future regulation under the Safe Drinking Water Act. We hypothesize that if any future regulatory response includes taxation of currently unregulated compounds such as veterinary pharmaceuticals, the intensity of crop and/or livestock production could fall.
Project Methods
The study location for the project will the Central Platte NRD (2.6 million acres) for the economic modeling and the Nebraska MSEA site for the hydrologic model. We will utilize the record of historic groundwater data from the NE MSEA site, which includes information on water quality parameters including conductivity, pH, HCO3-, Na+, K+, Mg2+, Ca2+, NH4+, NO3, Cl-, SO4-, atrazine, atrazine metabolites, and 13 other pesticides. Available data also includes depth to water and information on local precipitation. Climate model results for a current period (2001 - 2006) and a predictions future climate scenario (2056-2061) are available from simulations generated using GCSM4 and RCP8.5. Climate data is available with 3 hour output over a 24 km grid for the Great Plains. Economic Modeling methods will involve utilizing and expanding a model of the specific industrial cluster in the Central Platte NRD and other adjacent regions of Nebraska to capture additional increases in crop and livestock activity. Of specific interest is how the region's production cluster, which includes biofuel plants as well as animal slaughtering facilities, accelerates the increase in agricultural production that will result from climate change in the Central Platte NRD. The authors of the Malcolm et al. (2012) study, based at the USDA Economic Research Service, have agreed to provide us with specific estimates for crop acreage changes and livestock activity in the localized region encompassing the Central Platte NRD by fall 2014. These estimates are being developed as part of a second-generation study evaluating agricultural adjustment to climate change and will utilize nine alternative global climate models (GCMs) described in Foti et al. (2012). For the economic model, changes in agricultural intensificaiton will be evaluated over a time frame of 2050-2060. Economic modeling will involve expansion of existing models.Hydrologic models for the Nebraska MSEA site will also be largely based on established methods. Initially, experimental results will be generated to quantify contaminant transformation under climate change. Laboratory and analysis methods will follow previoulsy -published protocols by the investigators. Initially, contaminant transport experiments will be conducted in soil cores obtained from the NE MSEA site. Simulations of contaminant transport in the column experiments will be conducted using HYDRUS-1D, a software package widely used to simulate contaminant transport in vadose zone soils. Information from the laboratory-scale experiments and modeling will be used to paramaterize a field-scale model of the NE MSEA site using existing field data set and new laboratory data. The field-scale model will be a 3D model developed using HYDRUS-3D.Assessment of our methods will involve routine laboratory QA/QC procedures for analytical methods and use of proper positive and negative controls. Model calibration and verification will be conducted using the historic data set for the NE MSEA site. Other assessment methods to evaluate the research results will be the peer-review process for journal publications.

Progress 08/01/14 to 07/31/19

Outputs
Target Audience:During the grant period, our target audience was the professional research community, as well as groundwater managers in several states, including Nebraska and Minnesota. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Overall, this project has provided training and professional development for a number of students. The project has provided training for 1 PhD student in Economics, who received his degree and is now employed as an assistant professor of economics at the University of Northern Colorado. A second PhD student completed their degree in Civil Engineering specializing in water resources engineering, and she is currently employed as a postdoctoral teaching fellow in the Department of Civil and Environmental Engineering at Cal Poly in San Luis Obispo, California. Two doctoral students supported by this project are still in progress at the University of Nebraska-Lincoln, specializing in environmental engineering and water resources engineering. They are both in candidacy. The project provided training opportunities for 4 undergraduates students, who were supported through a National Science Foundation REU program grant to S. Bartelt-Hunt. They are all currently pursuing STEM degrees, primarily in engineering at their home institutions. The program also provided training opportunities for 3 scholars through the WARI program at the University of Nebraska-Lincoln, which is supported by the Indo-US Science and Technology Forum. This program supports visits by faculty or PhD students from IIT schools in India to UNL for a period of 3-6 months (PhD students) or up to 1 year (faculty). How have the results been disseminated to communities of interest?The results have been disseminated through peer revewed publications, conference proceedings and presentations, 2 dissertations with 2 additional dissertations in progress, and through presentations to industry groups in Nebraska and Minnesota. The results were also highlighted in an NET radio segment aired in Nebraska. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? We have accomplished the following under the goals of this project. We have developed a three dimensional HYDRUS model of groundwater flow and transport at our study site (the Nebraska MSEA site). We have calibrated and analyzed this model for nitrate, atrazine and we are completing simulations of emerging contaminants. We are evaluating the sensitivity of this model to variability in climate and other parameters. Various Localized Constructed Analogs (LOCA) downscaled climate scenarios under 5 Earth System Models (ESMs) (ACCESS1-0, CCSM4, CESM1-BGC, CanESM2, and FGOALS-g2) for each of 2 RCP scenarios (RCP 4.5, RCP 8.5) were considered. For each climate scenarios, future groundwater recharge was estimated using an inverse method that optimizes soil hydraulic parameters by solving a vadose zone water flow model in Hydrus 1D. Future groundwater elevation will then be estimated using a 3D groundwater flow model in Visual MODFLOW Flex based on groundwater recharge and potential evapotranspiration (ET). To predict atrazine and other trace organics leaching and accumulation under future climate, future atmospheric data (i.e. daily precipitation, potential evaporation rate, and potential transpiration rate) and groundwater elevation are applied to a 3D flow and transport model in Hydrus 3D.The uncertainty in future climate projections will be predicted in years 2057 to 2060 under 5 ESMs for each of two RCP scenarios (RCP 4.5, RCP 8.5). Under each climate scenario, LHS sampling will be used to produce 100 sets of parameters based on the CFD of random parameters. 3-D transport modeling will be applied to simulate atrazine transport for all 100 sets of parameters, following the same procedure for historical modeling as described above. The effect of parameter uncertainty under each climate scenario was assessed by standard deviation of annual atrazine mass or atrazine concentration at certain mesh layers in historical relative to best-fitted historical results. The impacts of climate uncertainty on the accumulation of atrazine mass are evaluated by the standard deviation of average atrazine mass, or change in annual atrazine mass in future relative to historical periods. Antibiotic resistance genes (ARGs) were quantified for the cattle manure, soil, and leachate samples from the soil column tests. A total of 10 columns were operated to cover two soil types (i.e., sandy loam and loam soil), three manure loading rates (i.e., 0, 5, and 25 yr equivalent), and two manure ages (aged and compost). Soil samples were collected from four depths of the column (10, 23, 48, and 72 cm). In addition, cattle manure and leachate samples were collected from multiple time points of the 12-wk test. A total of four genes were quantified for all the samples: the 16S rRNA gene, erm(C), tet(O), and intl1. The results show that the ARG levels in the leachate from the loam soil were very low. In contrast, ARGs were constantly detected in the leachate from the sandy loam soil. For the soil samples, concentration of ARGs remains stable with time at different depth. The measured ARG levels were then used to simulate their transport in the columns using the two sites attachment and detachment model in HYDRUS-1D. Results show that the two sites model fitted the concentration of ARGs in the soil very well (R2 > 0.90). Attachment and detachment coefficients fitted with this model ranged 1.8x10-3 - 8x10-3 and 2.0X10-4 - 2.0x10-3, respectively. In addition to individual genes, shotgun metagenomics were also conducted on the manure, soil, and leachate samples. DNA from the samples was sequenced at the University of Nebraska Medical Center. An average of 8.93 Gb of data were obtained per sample. The DNA sequences have been trimmed, assembled, and annotated. Taxonomic classification was done using KAIJU and revealed that Proteobacteria and Actinobacteria were the dominant bacteria phylum in all samples. Further analyses will be conducted to illustrate the impacts of manure application rate and soil texture on resistomes at different depths of the soil profiles and in the leachate.

Publications

  • Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Simin Akbariyeh, Modeling Fate and Transport of Contaminants in the Vadose Zone: Vapor Intrusion and Nitrate-N Leaching Under Future Climate Scenarios, Doctoral Dissertation, University of Nebraska-Lincoln
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Akbariyeh, S. ; Gomez Pena, C.A. ; Wang, T.; Mohebbi, A.; Bartlet-Hunt, S.; Zhang, J.; and Li, Y., (2019) Prediction of nitrate accumulation and leaching beneath groundwater irrigated corn fields in the Upper Platte basin under a future climate scenario. Science of the Total Environment, doi.org/10.1016/j.scitotenv.2019.05.417
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Liu, C.; Bartelt-Hunt, S.; and Li, Y.; Uncertainties of Atrazine Leaching and Accumulation under Future Climate Scenarios beneath Nebraskas Management Systems Evaluation Area. Invited to present at 2019 American Geophysical Union Fall Conference, December 9-13, San Francisco, CA.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Liu, C.Y.; Li, Y.; Bartlet-Hunt, S. Predict the Transport of Atrazine under Future Climate Scenarios beneath Nebraskas Management Systems Evaluation Area. World Environmental and Water Resources Congress., May 19-23, 2019, Pittsburg, PA
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Liu, CY.; Li, Y.; Bartlet-Hunt, S. Predict the Transport of Atrazine under Future Climate Scenarios beneath Nebraskas Management Systems Evaluation Area. 2019 Water for Food Global Conference, Lincoln, NE, April 29-30, 2019
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2018 Citation: Akbariyeh, S. ; Gomez, C,; Bartelt-Hunt, S.; Li, Y Predicting Nitrate Transport under Future Climate Scenarios beneath the Nebraska Management Systems Evaluation Area (MSEA) site. Indo-US Bilateral Workshop on Water-Food-Energy-Climate nexus: A perspective towards a sustainable future. Banaras Hindu University, Varanasi, India. Nov 13th -20th, 2018
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Junpyo Park, John Anderson and Eric Thompson. Land-Use, Crop Choice and Proximity to Ethanol Plants. (2019) Land, 8, 118; doi:10.3390/land8080118
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Barrios, R.; Gaonkar, O.; Snow, D.D.; Li, Y.; Li, X.; Bartelt-Hunt, S.L. (2019). Enhanced biodegradation of atrazine at high infiltration rates in agricultural soils. Environmental Science: Processes and Impacts, 21: 999  1010, DOI: 10.1039/C8EM00594J
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2019 Citation: Barrios, R.; Bartelt-Hunt, S.; and Li, X. (2019). Influence of manure application on the resistome in the subsurface. Association of Environmental Engineering and Science Professors Biannual Conference, Tempe, AZ, May 13-16, 2019.


Progress 08/01/17 to 07/31/18

Outputs
Target Audience:During this reporting period, our target audience was the professional research community as well as groundwater managers in the state of Minnesota. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two students who have worked on the project have completed their Ph.Ds - one student in Economics and the other in Environmental Engineering. Two other engineering students have worked on the project. The project has provided training for two visiting students from India through an exchance program at the University of Nebraska. How have the results been disseminated to communities of interest?We have made numerous conference presentations and submitted several journal articles for publication in Economics and Environmental journals. We have presented to groundwater managers in the State of Minnesota. What do you plan to do during the next reporting period to accomplish the goals?In the next year, we will apply the 3-D model to predict the transport of various contaminants under various scenarios. Emphases will be to evaluate the indirect impacts of climate change on the contaminant transport. Findings from these models will be compared with the previous modeling of the effects of direct climate change. This will help to validate the central hypothesis of the proposal that indirect factors will have higher impacts than direct climate change factors. For the economic modeling, we plan to augment the model by introducing an energy-water-nutrient recovery system to the agri-cluster. We are in the process of completing our laboratory experiments of antibiotic transport and microbial community changes with changing climate.

Impacts
What was accomplished under these goals? In the previous year, a 3-D model was developed to predict nitrate-N transport in the MESA site under a future climate scenario. In this year, additional simulations were conducted to evaluate the sensitivity of other parameters, including groundwater level change, evapotranspiration rates, and irrigation rates. We found that predicted nitrate-N mass in the field is sensitive to irrigation rates. An accurate estimation of irrigation amount is essential.The previous 3-D HYDRUS model focused on simulating nitrate-N transport in the field. In this project year, the model was extended to predict the transport of other contaminants, including pesticides and emerging contaminants. Currently, the model of atrazine transport is running and under validation. Efforts were devoted to evaluating indirect impacts of climate change on groundwater flow and contaminant transport. First, we explored a more sophisticated way to predict corn yield and fertilizer application under the climate change scenario. Corn yield was simulated using the Hybrid-Maize model, and nitrogen fertilizer application rates were simulated using the Maize-N model. Hybrid-Maize model and Maize-N models consider more realistic conditions for corn growth and nutrient uptake. These models are widely used in agricultural areas. Currently, the output of these models is linked with HYDRUS model to evaluate the sensitivity of fertilizer application on future nitrate-N transport. The second part of this work is to incorporate findings from economic modeling group with the 3-D hydrologic model. Particularly, we are incorporating predicted irrigation rates, manure application rates, and land use into the model. We have completed a laboratory study of the influence of climate on atrazine transport. Results of this study are being submitted to "Environmental Science: Processes and Impacts". The objective of this study was to assess potential changes in atrazine transport to groundwater under climate change scenarios predicted for the Midwestern U.S. The transport and transformation of atrazine in agricultural soils at high infiltration rates associated with increased precipitation intensity was monitored in column experiments. Atrazine behavior was modeled using an advection-dispersion-sorption-degradation transport model. Batch microcosm studies were conducted to examine the effect of moisture content on atrazine degradation. Results showed that although atrazine was applied continuously to the columns, the break-through curves obtained for both soils evaluated showed a pattern characteristic of a pulse input. The rate of atrazine transport at higher infiltration rates was not fast enough to counteract the effect of enhanced degradation. Under future climate change scenarios, where more intense precipitation is likely to result in higher infiltration rates and increased soil moisture, the potential for groundwater pollution from atrazine may be reduced, especially in areas with a long history of atrazine application to soil. The influence of climate on production of atrazine transformation products may be dependent on soil type. Degradation of atrazine in the agricultural soils evaluated led primarily to the formation of hydroxyatrazine (HA) and deethylatrazine (DEA) with increased in HA concentrations observed in sandy soils with low organic carbon.

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Akbariyeh, S.; Bartelt-Hunt, S.L.; Snow, D.D.; Li, X.; Tang, Z.; and Li, Y. Three-Dimensional Modeling of Nitrate-N Transport in Vadose Zone: Roles of Soil Heterogeneity and Ground Water Flux. (2018). Journal of Contaminant Hydrology, 211: 15-25
  • Type: Journal Articles Status: Under Review Year Published: 2018 Citation: Barrios, R.; Akbariyeh, S.; Gani, K.M.; Kovalchuk, M.T.; Park, J.; Li, X.; Li, Y.; Thompson, E.; Rosenbaum, D.; Snow, D.; Tang, Z.; Gates, J.; Bartelt-Hunt, S.L. Climate change impacts the subsurface transport of trace organics originating from agricultural production activities. Submitted to Climate Dynamics
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2018 Citation: Barrios, R.; Gaonkar, O.; Bartelt-Hunt, S.L.; Li, X.; Snow, D.D.; Li, Y. (2018). Influence of climate change on subsurface atrazine degradation and transport. American Chemical Society Spring Meeting, New Orleans, LA, March 18-21,2018.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Bartelt-Hunt, S.L. and Thompson, E. (2017). The influence of agricultural clusters on groundwater quality under climate change. Nebraska Water Symposium, Lincoln, NE October 26-27, 2017
  • Type: Theses/Dissertations Status: Accepted Year Published: 2018 Citation: Park, Junpyo, "Three Essays in Public Economics" (2018). ETD collection for University of Nebraska - Lincoln. AAI10843771. http://digitalcommons.unl.edu/dissertations/AAI10843771
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Akbariyeh, S. ; Gomez, C. ; Barrios, R.; Li, X.; Bartelt-Hunt, S.; Li, Y., Predicting nitrate transport under future climate conditions for agricultural lands. MGWA Fall Conference, St. Paul, MN, November 15, 2017.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Akbariyeh, S. ; Gomez, C. ; Bartelt-Hunt, S.; Li, Y Predicting Nitrate Transport under Future Climate Scenarios beneath the Nebraska Management Systems Evaluation Area (MSEA) site , AGU Fall Conference, New Orleans, December 11-15, 2017.
  • Type: Journal Articles Status: Under Review Year Published: 2018 Citation: Rosenbaum, D. and E. Thompson. Climate Change and the Corn/Cattle/Ethanol Nexus. Submitted February , 2018, to Climate Change Economics


Progress 08/01/16 to 07/31/17

Outputs
Target Audience:During this reporting period, our target audience was the professional research community. Changes/Problems:We do not anticipate any major changes from our initial grant objectives and goals, however, our timeline for our experiments may extend beyond the remaning 12 months in the project. We are conducting experiments over relatively long time scales (1-3 months) in order to observe changes in microbial community structure and contaminant metabolite formation. In addition, we believe that additional time will allow us to fully integrate our economic and water quality models developed for both atrazine and nitrate. We will initiate this model development in September 2017, but additional time will allow us to explore more modeling scenarios. We may request a no-cost extension for this project to allow us to fully evaluate these scenarios and integrate our laboratory data into our models. What opportunities for training and professional development has the project provided?The project has provided reserach training opportunities for two undergraduate students in environmental engineering; 3 graduate students in environmental engineering and 1 graduate student in economics. One PhD student, Simin Akbariyeh, successfully defended her dissertation in April 2017, and a MS student, Cesar Gomez Pena, successfully completed his MS degree in August 2017. How have the results been disseminated to communities of interest?To date, the resutls of this proejct have largely been disseminated through conference presentations, however, we have approximately 5 manuscripts in preparation to be submitted to peer reviewed journals in the next 3-6 months. We anticipate significant increases in peer-reviewed publications from this project in the next reporting period. What do you plan to do during the next reporting period to accomplish the goals?The hydrological model developed up to now only considered the direct impact of climate change on groundwater flow and contaminant transport. In the next phase of the project, we are going to incorporate indirect impacts of climate change on groundwater flow and contaminant transport. Impacts of climate change on land use, corresponding pumping rates, irrigation water application, and crop yield and nitrate-N uptake will be incorporated into the model. In addition, for the economic model, we will link the models we have currently developed with a model of migration of cattle feeding due to climate change. p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Calibri} span.s1 {font-kerning: none} We also plan to make significant progress on the laboratory experiments of contaminant movement in soils, as well as changes in microbial community structure due to climate change.

Impacts
What was accomplished under these goals? Under objective 1, we have initiated laboratory column experiments to evaluate the fate of atrazine in soils from our field site. We are currently completing experiments to evaluate a base case, and then we will conduct additional experiments to evaluate the impact of specific factors influenced by climate (moisture content and infiltration rate) on contaminant transport and microbial community structure. These data will then be incorporated into our numerical model. In addition, we have completed significant work on our numerical model.In the 2016-2017 year, we focused on predicting groundwater recharge, groundwater level, and contaminant transport under future climate scenarios. Future climate data (2050-2060) from the Weather Research and Forecasting (WRF) model, including precipitation, evapotranspiration, and soil moisture contents, was processed to provide as input for the numerical model. WRF is a regional climate change model that downscales climate change prediction from the Community Climate System Model (CCSM4) under the Representative Concentration Pathways (RCP) 8.5 scenario. An inversion modeling approach was first developed to predict groundwater recharge (GR) rate in the Upper Platte basin in Nebraska under future climate scenario. By optimizing soil hydraulic parameters, the inversion modeling approach resulted in reasonable GR values compared with historical data. The predicted GR followed a very similar trend of spatial distribution across the whole basin, however the average GR in the future is decreasing compared to the historical GR data. The maximum GR within the basin decreased more than 50% under future climate change. The predicted GR together with actual evapotranspiration (ETa) was then used to develop a groundwater flow model in the surrounding area to predict groundwater level in the future. A groundwater flow model was first developed and calibrated using historical groundwater monitoring data from the year 1991 to 2014. The calibrated model was then applied to predict groundwater level from 2056 to 2060 based on predicted future GR data, future actual evapotranspiration, and future weather information. Future predictions showed that groundwater level in 2056 will be about 0.5 m lower than 2014, with an overall decreasing trend from 2056 to 2060. The average groundwater level in the area in 2060 will reach about 4.0 m. Finally, the predicted GR together with future climate information was applied to the 3-D vadose zone transport model to simulate contaminant transport. The primary focus was to evaluate the impacts of precipitation, evapotranspiration, and groundwater elevation changes during 2057-2060 on nitrate-N concentration distributions in the vadose zone and the saturated zone. Yearly average precipitation was higher under future climate conditions compared with past climate (1993-1996) and the percentage of precipitation occurring during the growing season increased from 70% to 77% of the total in the future. The changes in precipitation pattern consequently influence soil moisture content and consequently irrigation water requirements. The predicted actual evapotranspiration values are greater under future climate conditions compared with past climate due to increased air temperature, which will cause higher root solute uptake and drier soil conditions. A drier soil condition slows down the nitrification process of urea to nitrate-N and reduced the mass of nitrate-N in the system. Slower mineralization in the system and higher root solute uptake decreased nitrate-N leaching under future climatic condition. In the saturated part of the domain (groundwater), nitrate-N concentration largely depends on groundwater elevation fluctuations. Groundwater elevation was declining under future climate data; therefore, nitrate-N concentration also decreases in groundwater. Under objective 2, we have made significant progress on economic modeling. Corn growing, cattle feeding and ethanol production are inextricably intertwined. Ethanol plants and cattle feeders compete for corn. But increasingly, cattle feeders use ethanol co-products (distillers' grains) as feed alternatives. As climate evolves, it will inevitably affect this amalgam in the agricultural economy. We examine the impact that climate change may have on corn growing, cattle feeding and ethanol production in two ways. First, we examine what happens to cattle feeding and ethanol production costs as climate alters both agricultural productivity and optimal farm allocations. Second, given these impacts, we examine whether it alters incentives for ethanol producers and cattle feeders to cluster together. For the first analysis, we developed a model that links the three industries in this corn/cattle/ethanol sector. The model is first estimated using data from 2016. Then it is altered to account for potential effects of climate change. To do this, we rely on the baseline and climate-altered yield and price predictions of the USDA's latest climate model projections. Deviations from the baseline are then measured in relative terms. These relative deviations are applied to the initial model to see how it impacts producers in the sector. The initial model assumes that an ethanol plant and cattle feeding operation are co-located. In the second phase of the analysis they are separated. We see how the initial results vary with the separation of producers and then see how the relative deviations associated with climate predictions affect profitability when co-location is no longer imposed. The model is fully developed and initial results are consistent with expectations, although they reveal some interesting findings. We have not yet initiated work on objective 3.

Publications

  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: 1. Barrios, R.; Akbariyeh, S.; Bartelt-Hunt, S.L.; Li, X.; Li. Y.; Zhang, Y.; and Gani, K.M. Influence of climate change on trace organic fate in the subsurface. 2017 AEESP Research and Education Conference, Ann Arbor, MI, June 20-22, 2017.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2017 Citation: Akbariyeh, S.; Gomez Pena, C.A.; Barrios, R.; Li, X.; Bartelt-Hunt, S.L., Li, Y. (2017). Impacts of climate change on nitrate transport beneath a center-pivot irrigated corn field. 2017 AEESP Research and Education Conference, Ann Arbor, MI, June 20-22, 2017.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2016 Citation: 1. Akbariyeh, S., Wang, T., Bartelt-Hunt, SL, Li, Y. (2016). Application of Inverse Modeling to Estimate Groundwater Recharge under Future Climate Scenarios. American Geophysical Union Fall Meeting, San Francisco, CA, December 12-16, 2016.
  • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Akbariyeh, S.; Bartelt-Hunt, S.L.; Snow, D.D.; Li, X.; Tang, Z.; and Li, Y. Numerical modeling of nitrate leaching: Interaction of groundwater vertical flux and infiltration of nitrate in a 3-D soil profile. Vadose Zone Journal (in review)
  • Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Simin Akbariyeh Modeling Fate and Transport of Contaminants in the Vadose Zone: Vapor Intrusion and Nitrate-N Leaching under Future Climate Scenarios Doctoral Dissertation, Department of Civil Engineering, University of Nebraska-Lincoln
  • Type: Theses/Dissertations Status: Published Year Published: 2017 Citation: Cesar Gomez Pena "Simulation and Prediction of the Groundwater Level in the Surrounding Area of the Nebraska management system evaluation area site in Central Nebraska" Masters Thesis, Department of Civil Engineering, University of Nebraska-Lincoln


Progress 08/01/15 to 07/31/16

Outputs
Target Audience:During this reporting period, our target audience was the professional research community as well as the general public. We reported results of our research through conference presentations, and we reached the general public through a Nebraska Educational Television (NET) interview. Changes/Problems:One change in our project is the departure of Dr. John Gates from UNL to a position in private industry. Dr. Gates' role on the project was focused on the contaminant transport modeling. These tasks are being completed under Dr. Yusong Li and Dr. Shannon Bartelt-Hunt. Due to a slower than expected start on some of the laboratory work, we are just getting the large scale column experiments started. We anticipate these experiments to occur in the next reporting period as planned in the proposal, however, we are planning to request a one-year no cost extension for this project. What opportunities for training and professional development has the project provided?This project has provided training opportunities for 4 graduate students, including 2 PhD students and 1 MS student in Environmental Engineering, and 1 PhD student in Economics. Additionally, 1 undergraduate student from Sacramento State University has participated on this research project as a summer research intern. How have the results been disseminated to communities of interest?We have made numerous conference presentations including presentations at the annual investigators meeting, as well as research conferences in economics and engineering. Our work was highlighted in a radio interview produced by Nebraska Educational Television and broadcast statewide on Nebraska NPR stations. A link to the story is available at:http://netnebraska.org/article/news/1034250/studying-ties-between-climate-agriculture-and-groundwater-quality. This interview helped us communicate the current status of our project to the public. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, under objective 1, weplanto continue to develop the model linking ethanol, corn production and cattle feeding. This is a spreadsheet-based model that mirrors the interactions between markets. Wearealso developing a linear programming based model that looks at flows of cattle production across the Midwest as climate changes impact economics of specific states. Under objective 2, in the next year, we will first predicate the groundwater recharge rate and groundwater level change under the future climate scenarios. Such information, together with climate data from the WRF model, will be input into the transport model to predict the contaminant distribution during 2050-2060. We will first focus on current contaminants, including nitrate and atrazine. Based on the column experimental results, we will predict the distribution of emerging contaminants using the validated model. Under the laboratory experiments described in Objective 2, we will initiate column experiments with the goal of simulating some of the preliminary climate conditions and infiltration conditions predicted by the model to evaluate their impact on contaminant fate, as well as generating input data that can be used in the model simulations.

Impacts
What was accomplished under these goals? Under objective 1, we are engaged in two research veins with this project. The first is a statistical model that looks at cattle feeding as a function of economic and climate-related variables. We are interested in examining two issues in particular. Once economic variables are controlled for: 1) how will climate change in the form of temperature and rainfall changes affect cattle feeding in Nebraska; and 2) how will climate change impact the distribution of cattle feeding across the Midwest and into Texas and Oklahoma?The second vein of research examines the general equilibrium linkage between corn growing, ethanol production and cattle feeding. The corn sector accounts for density, production yields and proximity to ethanol plants, cattle feeding operations and entry points into the global corn market. Ethanol economics reflect travel costs for inputs and outputs, production costs, input stock prices, output prices and scale economies. The cattle feeding sector accounts for relative input costs and market demands. The model develops general equilibrium among these sectors and examines how climate change may impact that equilibrium. Under objective 2, we are simultaneously engaged in laboratory and modeling studies of contaminant fate under climate change for our field site.In the 2015-2016 year, we focused on validating the 3-D model to simulate the transport of contaminants in the MESA site. Based on a 3-D lithology model of the site, a finite element based numerical model was developed using Hydrus 2D/3D to simulate water flow, root water and nutrient uptake, and leaching of nitrate-N in soils in this field during 1993-1995. During that period, a mixture of urea-ammonium-nitrate was applied onto the center pivot-irrigated corn field as a fertilizer. A urea-ammonium-nitrate sequential first order decay reaction and root uptake of nutrients were incorporated into the advection, dispersion and reaction equation to simulate the transport of urea, ammonium, and nitrate. An atmospheric boundary condition was implemented at the surface, which includes daily precipitation, irrigation and potential evaporation and transpiration rates. A variable pressure head boundary condition was implemented at the bottom boundary to consider the groundwater elevation fluctuations. Simulated vertical profiles of nitrate concentration at multiple locations of the site were compared with the field measurements during the simulation period (1993-1995). We found a reasonably good agreement between the measured and simulated nitrate concentrations for all the 90 samples across the field and in the duration of two years, which indicates that the model is able to capture the most critical processes governing the contaminant transport in the field. Current efforts are focusing on applying the mathematical model to simulate water flow and transport of the contaminants under future climate scenarios. Future climate data (2050-2060) from the Weather Research and Forecasting (WRF) model, including precipitation, evapotranspiration, and soil moisture contents, was processed to provide as input for the numerical model. WRF is a regional climate change model that downscales climate change prediction from the Community Climate System Model (CCSM4) under the Representative Concentration Pathways (RCP) 8.5 scenario. Meanwhile, a comprehensive groundwater flow model is under development in the MESA. Simulated groundwater table change for the future climate scenarios will be input into the transport model for contaminant transport prediction. Additionally, under objective 2, we have initiated batch experiements to investigate sorption and biodegradation of our target contaminants under conditions representative of a future climate scenario. These data are being used as input to a 3D and 1D models of our study site. We are initiating large scale column experiments now to investigate compound fate and microbial community structure changes as a function of climate.

Publications

  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2016 Citation: 1. Akbariyeh, S., Snow, D., Bartelt-Hunt S.L., Li, X., and Li, Y. (2016). Three dimensional modeling of agricultural contamination of groundwater: a case study in the Nebraska Management Systems Evaluation Area (MSEA). Water, Sustainability and Climate Investigators Meeting, Washington D.C., March 9-11, 2016.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2016 Citation: 1. Bartelt-Hunt, S.L. and Thompson, E. (2016). Influence of climate on the fate of trace organics in groundwater. Water, Sustainability and Climate Investigators Meeting, Washington D.C., March 9-11, 2016.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: 1. Akbariyeh, S., Snow, D., Bartelt-Hunt S.L., Li, X., and Li, Y. (2015). Three dimensional modeling of agricultural contamination of groundwater: a case study in the Nebraska Management Systems Evaluation Area (MSEA). American Geophysical Union Fall Meeting, San Francisco, CA, December 14-18, 2015.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: 1. Bartelt-Hunt, S.L. (2015). Influence of Climate on the fate of Trace Organic Compounds in Groundwater. Water, Sustainability and Climate Project Investigators Meeting, National Science Foundation, Washington, D.C., February 9-11, 2015.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: 1. Simin Akbariyeh, Daniel Davidson Snow, Shannon Bartelt-Hunt, Xu Li and Yusong Li, Three Dimensional Modeling of Agricultural Pollutions in Nebraska Management Systems Evaluation Area (MSEA) Site. Nebraska Water Environment Association (NWEA) Fall Conference, Kearney, NE, November 5th, 2015.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2016 Citation: Junpyo Park and Eric Thompson, Crop Choice and Proximity to Ethanol Plants. Water, Sustainability and Climate Investigators Meeting, Washington D.C., March 9-11, 2016.


Progress 08/01/14 to 07/31/15

Outputs
Target Audience:During this reporting period, our target audience was the scientific research community. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project is providing training opportunities for three graduate students. One in the Department of Economics at UNL and two in the Department of Civil Engineering at UNL. One Civil Engineering student is developing the groundwater model and the other is performing laboratory experiments to investigate trace organic behavior under climate change. How have the results been disseminated to communities of interest?To date, our activities have largely centered around model development. We have established the groundwater and economics models. We have not yet disseminated any findings from this study, but we anticipate that will occur during the next reporting period. What do you plan to do during the next reporting period to accomplish the goals?We will simulate contaminant transport behavior using land use data predicted from the model. We will additionally run simulations under climate change scenarios using land use predictions under climate change from the economic models. We will collect data on the behavior of the three model trace organic compounds in batch and column experiments and this data will be incorporated into the model.

Impacts
What was accomplished under these goals? During this first year of the project, we have developed economic and groundwater models to simulate our study area. Our tasks included collecting all available physical and water quality data at the site (see description of data below). These data were distributed between various paper and electronic reports and publications, and we have combined this data into a single electronic data set. In this year, we primarily focused on parameterizing and validating a field-scale model of the MESA site using the existing field data. Massive amount of historical data were collected for the site, including (1) lithology data from 69 wells and 11 test holes; (2) surface soil type, land use, and surface elevation data; (3) groundwater level and flow velocity from 1991 to 1995; (4) precipitation and irrigation data; (5) contaminant concentration measured in wells from 1991 to 1996; and (6) cultivation data. First, a three-dimensional site model, including detailed soil lithology and geologic sections, was developed using Rockworks (RockWare, Inc.) by interpolating the available lithology data. The model geometry from Rockworks, together with lithology types and topography information, were then imported into a finite element based hydrology model Hydrus 3D (PC-Progress s.r.o). The model was successfully applied to simulate water flow and root water uptake during the period of 1991-1996. Currently, the focus is on validating the transport model by simulating historical contaminant transport data. We currently focus on modeling the transport of nitrate and atrazine for model validation. We have finished collecting data for nitrate and have set up an initial nitrate transport model using Hydrus 3D. We have initiated laboratory column experiments to evaluate the fate of three trace organic compounds under climate change. We have built and installed 1-meter columns in the laboratory and have successfully performed column tracer experiments under saturated conditions to evalute column performance. We anticipate beginning contaminant behavior experiments under unsaturated conditions in the next 1-2 months. These activities are in support of Objective 2.

Publications