Seminars

Abstract

Mikaela Cherry: Characterizing hydrology and water quality in the vicinity of a groundwater mound in the High Plains aquifer, south-central Nebraska

PhD candidate in Natural Resources Sciences (Hydrological Science)

Since the development of irrigation canals in the 1930’s a groundwater mound has formed within Phelps County and part of Kearny County in south-central Nebraska. The mound extends more than 2,000 km² laterally with 25-30 m of water table rise relative to pre-development levels. Currently, groundwater nitrate concentrations reflect long-term agricultural production in the vicinity of the mound and in down-gradient areas. Geological data shows thin but laterally extensive confining layers within the aquifer. Elevated nitrate concentrations above 10 ppm at substantial depths suggest that gaps in the confining unit may allow for the transport of nitrate to deeper parts of the aquifer. Groundwater management of this area is controlled by two Natural Resources Districts with differing regulations. Changes in best management practices aim to decrease the amount of nitrate entering the groundwater, but a better understand of the direction and timescale of groundwater flow within the groundwater mound and to surrounding areas will better inform future management in this area

Galen Richards: Nitrate dynamics within nested watersheds of a gaining headwater agricultural stream, Nebraska, USA

MS candidate in Natural Resources Sciences (Hydrological Science)

Bazile Creek is a high-nitrate stream originating in the Bazile Groundwater Management Area of Eastern Nebraska. Bazile Creek is a strongly gaining stream (baseflow index ranging from 56 to 62) and local groundwater has high nitrate concentrations originating from nonpoint sources. The purpose of this study was to determine spatial and temporal variability of baseflow nitrate concentrations in Bazile Creek and its tributaries. Surface-water nitrate samples were collected monthly from July 2018 through September 2019 from nine sites in the watershed. Average surface-water nitrate concentrations between sites ranged from 2.7 mg/L to 15.3 mg/L, and nitrate concentrations were found to be significantly different between sites. Surface-water nitrate concentrations also varied seasonally in the main channel and most tributaries, with nitrate concentrations highest in the winter when discharge was at its lowest. Consistently high nitrate concentrations were observed in two tributaries, suggesting steady inputs of high-nitrate groundwater. The results of this study reveal substantial spatial variation in surface-water nitrate concentrations in the headwaters despite the close proximity of sampling sites. Analysis of watershed land use, soils, and groundwater nitrate proved valuable in determining dominant nitrate delivery pathways. This study also demonstrated that sampling tributaries along with the mainstream channel is beneficial in the identification of targeted best management practices (BMPs) aimed at reducing overall contaminant loading to a watershed.

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Alexa Davis: Examining the 2019 Nebraska Flood

MS candidate in Natural Resources Sciences (Hydrological Science)

In March 2019, a bomb cyclone in the Mid-West United States led to large-scale, extreme flooding in the region. Nebraska was hit particularly hard, with many streams and rivers jumping their banks and remaining elevated for months after the event. Here, we compare nutrient spiraling metrics in four streams in 2018 versus 2019. We found that there was no significant difference in spiraling metrics such as nutrient uptake, uptake velocity and aerial uptake pre and post flood. As climate change is expected to lead to more frequent large-scale and intense hydrological events, studies like this will help understand how these events may impact aquatic ecosystems.

Nawaraj Shrestha: Lakes as monitoring wells in the Nebraska Sand Hills

PhD candidate in Natural Resources Sciences (Remote Sensing)

Lakes in Nebraska Sand Hills are predominantly regulated by the underlying aquifer. The water balance of these lakes are controlled by the precipitation and its subsequent percolation to aquifer, evapotranspiration, and groundwater influx. As the lakes are manifestation of underlying aquifer, monitoring of lakes provides vital insight on the groundwater level. The study uses light detection and ranging (LIDAR) to measure the water surface level and use the spatial interpolation techniques to estimate the groundwater level at unknown locations. We will use time series Landsat image analysis to derive the lakes suitable for monitoring purpose. The suitable lakes will then be used to derive the water level elevation from LIDAR data and subsequently to derive the water table map for the region.

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P. Citlally Jimenez: Engaging with Tradeoffs: Describing How Undergraduates Consider Tradeoffs When Using a Structured Decision-Making Tool to Solve Socio-ecological Issues

PhD candidate in Natural Resource Sciences (Human Dimensions)

Fundamental to the well-being of society is sustainably utilizing ecological goods and services, which necessitates the recognition of tradeoffs when making decisions about socio-ecological issues. Ecology educators play a pivotal role in relating the human-environment interactions that inform these tradeoffs and can encourage students to consider tradeoffs amongst their values to make meaningful decisions about ecological issues in their civic lives. Previous studies have shown students struggle with engaging in tradeoffs amongst conflicting objectives in their decision-making processes, often avoiding tradeoffs or basing decisions on one objective without considering all the objectives they value. Few studies have characterized students’ decision-making practices like tradeoffs strategies during classroom activities. By purposely characterizing how students engage in tradeoffs analysis during their decision-making processes about socio-ecological issues, educators can identify instructional strategies that address student challenges to make decision-making meaningful. A large, multidisciplinary science literacy class employs a structured decision-making (SDM) tool that encourages undergraduates to critically analyze multiple solutions to socio-ecological issues using various sources of scientific information to determine the consequences of alternatives, and purposely engage in a tradeoffs analysis to make a high quality decision. In this preliminary study, we qualitatively explored how students (n.students = 11) engage with tradeoffs in their explanations (n.responses = 66) about the potential consequences of multiple alternatives in satisfying given objectives as they worked through the SDM tool to solve a water conservation issue in fall 2018.

Gabriela Palomo: Temporal Partitioning Of Jaguars And Pumas In The Maya Biosphere Reserve Of Guatemala

PhD candidate in Natural Resource Sciences (Applied Ecology)

IInter-specific competition is important in structuring large carnivore guilds. The coexistence of ecologically sympatric carnivores is potentially facilitated by differences in species behavior and space use which depends on the position each species occupies in the dominance hierarchy. For example, separating temporal activity and space use, competing species reduce opportunities for competitive interactions. Jaguars (Panthera onca) and pumas (Puma concolor), the two largest Neotropical felids, are morphologically sympatric throughout the jaguars’ range where jaguars are socially dominant over pumas and potentially cause pumas to alter their behavior or habitat use. Using data collected from an array of camera traps in three protected areas in the Maya Biosphere Reserve (MBR) in Guatemala, we compared the temporal patterns of jaguar (dominant predator) and puma (subordinate predator) to examine if they temporally segregate. We collected data over 138 days using 78 double-camera trapping stations equating to 3,593 trapping days, obtaining 179 independent records of jaguars (n = 77) and pumas (n = 102). Overall, jaguars were mostly nocturnal and pumas mostly nocturnal and cathemeral. Jaguars showed peaks of activity at 16:00, 21:00, 23:00, and 02:00, and pumas at 07:00 and 22:00 h. Both species alternated their activity patterns across all protected areas which is evidence of temporal segregation. Moreover, our results suggest that jaguars have a distinct nocturnal activity pattern, whereas pumas were mostly cathemeral which could indicate that pumas have a more plastic activity pattern. Our results suggest that coexistence in the MBR between jaguars and pumas is facilitated by temporal segregation. Examining fine-scale temporal interactions between co-occurring carnivores aids in determining the mechanisms by which morphologically similar species differ their use of resources, especially in smaller protected areas where space might be a limiting factor.

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To mitigate drought impacts on crop yield, many vulnerable producers must make risky irrigation decisions affecting their production practices and outcomes. Despite an evident need to make drought mitigation policy changes in many areas across the United States, the when and where to prioritize local and regional investments necessary to avoid production losses from the lack of water security remains unclear. A better understanding of the monetary value of irrigation water, and how it varies across the time and space, may help inform farmers and policymakers about the potential impacts of water shortages and reduce uncertainty in decision making. In our study, we estimate the economic value of water used to produce corn in the central High Plains region during the 2010-2017 period. To assess the value, we use the publicly available data for corn price and for irrigated and non-irrigated yield and incorporate the irrigation requirement adjustments to account for the hydrological balance. The findings suggest that water is valued the most not during the severe drought and not in more arid areas of the study region, but when and where the irrigation can make the largest improvement in average crop productivity. Our results help shed more light on policy changes needed to help mitigate the drought impact on agriculture. Institutional water management changes might be necessary for the states that currently do not practice supplemental irrigation or do not prioritize water sustainability.

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Gabriela Palomo: Debunking the modern wildlife myths and their risk to wildlife conservation

PhD candidate in Natural Resource Sciences (Applied Ecology)

Human-wildlife conflict pose a critical threat to many wildlife species and is one of the most widespread and intractable issues that wildlife biologists and conservation scientists face today. People base their perceptions and attitudes on wildlife on many factors including societal experiences and cultural norms. The perception that certain species are innately evil or harmful to humans or their livelihood can lead to continuous persecution of certain species posing a serious risk to their conservation when individuals are constantly hunted decimating their populations. In this poster, I discuss examples from several countries in which communities have killed a specific species because they believed a myth associated to that specific species. For example, in Guatemala in July 2019 a group of people living in a village in Retalhuleu found a river otter (Nutria longicauda) and killed it by beating it and setting it on fire. The villagers alleged that the otter was a mythical evil creature they fear called “El Win”. Another example involves prairie dogs (Cynomys spp.) in the US. Farmers in South Dakota believe that cows are at risk of breaking their legs when stepping on a prairie dog’s burrow. However, many farmers believe this modern myth because they have heard this happen to others in their town or nearby towns, but they have never experienced it firsthand. Modern myths get passed on orally and are fueled by misconceptions. These myths may pose a risk to wildlife because they increase the possibility of conflict, especially with the increase of urban areas near protected or natural areas. Wildlife scientists can work with the media, social media, schools, or community leaders to help debunk these myths surrounding wildlife. Additionally, these cases must be studied and documented by multidisciplinary groups to assess the risk to wildlife and the pervasiveness of the conflict.

George Limpert: Ensemble Sensitivity Analysis for Targeted Observations of Supercell Thunderstorms

Atmospheric Scientist -- Post-Doctoral Research Associate

The Warn-on-Forecast (WoF) project aims to increase the lead time for tornado warnings from around 13-15 minutes to at least 30 minutes, which is necessary in facilities like hospitals for everyone to take shelter. Instead of issuing warnings on the basis of observed severe weather, high-resolution ensemble forecasts will provide predictions over a few hours of when storms are likely to become severe or tornadic. WoF forecast skill may improve from additional observations in and around potentially severe thunderstorms. However, it is dangerous to collect manned observations in these areas, so this will require the use of novel instrumentation platforms to sample many of these regions. Ensemble sensitivity analysis (ESA) will be used to evaluate where observations in and around a supercell thunderstorm may be most beneficial to improved forecasts of storm severity. This work will employ new techniques for ensemble creation and test whether they can increase the usefulness of ESA for this purpose. New results will also be presented if supercell thunderstorms in different environments may need to be sampled in different locations to achieve the maximum forecast benefit. The implications for novel observing platforms such as unmanned aircraft will be discussed in this presentation.

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Beichen Zhang: Anticipating the Number of Social Unrest Event in India Using Spatial Regression Models

PhD candidate in Natural Resource Sciences (Climate Assessment and Impacts)

In times of instability (social or economic), people tend to show their displeasure against a policy, state decision or movement by participating in protests, demonstrations, riots, and other types of social unrest. Anticipating the number of such events, as well as the place and time, requires a model that can capture the spatial association between the mentioned components. In this project, we try to leverage the power of spatial models to anticipate the number of social unrest events by utilizing various social and economic information. Our main motivation for working in this domain is that anticipating the number of social unrest events at a location will help policy makers and administrators to formulate policies that can either prevent or decrease the likelihood of occurrence of such events in the future. Furthermore, this may help in enhancing the preparedness of government towards tackling such events. In this study we show that using data from a district in southern region of India and applying spatial models, we can derive valuable information that can help with predicting the occurrence and magnitude of social unrest. By applying more information from multiple different locations, we hope the framework will be used in other locations with the same success.

Nafyad Kawo: Optimization of an artificial-recharge–pumping system for water supply in the Maghaway Valley, Cebu, Philippines

PhD candidate in Natural Resource Sciences

A coupled simulation-optimization approach to optimize an artificial-recharge–pumping system for the water supply in the Maghaway Valley, Cebu, Philippines, is presented. The objective is to maximize the total pumping rate through a system of artificial recharge and pumping while meeting constraints such as groundwater-level drawdown and bounds on pumping rates at each well. The simulation models were coupled with groundwater management optimization to maximize production rates. Under steady-state natural conditions, the significant inflow to the aquifer comes from river leakage, whereas the natural discharge is mainly the subsurface outflow to the downstream area. Results from the steady artificial-recharge–pumping simulation model show that artificial recharge is about 20,587 m3/day and accounts for 77% of total inflow. Under transient artificial recharge–pumping conditions, artificial recharge varies between 14,000 and 20,000 m3/day depending on the wet and dry seasons, respectively. The steady-state optimization results show that the total optimal abstraction rate is 37,545 m3/day and artificial recharge is increased to 29,313 m3/day. The transient optimization results show that the average total optimal pumping rate is 36,969 m3/day for the current weir height. The transient optimization results for an increase in weir height by 1 and 2 m show that the average total optimal pumping rates are increased to 38,768 and 40,463m3/day, respectively. It is concluded that the increase in the height of the weir can significantly increase the artificial recharge rate and production rate in Maghaway Valley.

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Lindsay Johnson: Using New Tools to Build an Improved Drought Climatology for Food-Energy-Water System (FEWS) Impacts in New Mexico

PhD candidate in Natural Resource Sciences (Climate Assessment and Impacts)

Drought is a familiar climatic phenomenon in the United States Southwest that is unique amongst other hazards in its complex human-nature interactions beyond just the physical drought events. Due to continued climate variability and change, droughts are expected to become more frequent and/or severe in the future. Decision-makers are charged with mitigating and adapting to these more extreme conditions and to do that they need to understand the specific impacts drought has on regional and local scales, and how these impacts compare to historical conditions. Tremendous progress in drought monitoring strategies has occurred over the past several decades, with more tools providing greater spatial and temporal resolutions for a variety of variables, including drought impacts. Many of these new tools can now be used to develop improved drought climatologies for decision-makers to use in their drought risk management actions. In support of a Food-Energy-Water (FEW) System study for New Mexico, this article explores the use of new drought monitoring tools to analyze data and develop a more holistic drought climatology applicable for New Mexico. The intent is that this improved drought climatology information will provide a better understanding how drought has affected and will affect the FEW Systems across the state, allowing for better management of future drought events and associated impacts.

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George Limpert : A Technique to Track and Predict Convective Planetary Boundary Layer Phenomena to Increase Aircraft Flight Duration

Atmospheric Scientist -- Post-Doctoral Research Associate

Low altitude aircraft can conserve power and achieve longer flight times through static soaring by flying in regions of ascent within convective planetary boundary layer (PBL) circulations. To achieve this, it is necessary to accurately measure and predict the three-dimensional wind within the PBL. Data were collected from the Texas Tech Ka-band mobile radars during a field campaign near Lubbock, Texas in June 2015. These data allow for the identification of areas of PBL convection as well as estimating the three-dimensional wind field through dual-Doppler synthesis. Because dual-Doppler syntheses are rarely available, a variety of proxies for vertical motion that can be derived from single-radar data will be tested to determine whether they provide good estimates and forecasts of vertical motion. These proxies will include a wavelet-based approach to identify convective structures, vertically integrated liquid, azimuthal shear, and along-radial divergence. Prediction will be done by correlating radar data between two times to estimate motion vectors, then extrapolating these motion vectors to produce forecast radar observations. Convective PBL structures are typically short-lived, but longer predictability of these features may allow for improved path planning for low-level aircraft. Results of the usefulness of these proxies for vertical motion and their predictability through extrapolation will be presented.

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Kierstin Blomberg: Modeling Irrigation Impacts on Atmospheric Conditions during the 2012 Historic Drought

PhD candidate in Natural Resource Sciences

Various human activities have been affecting and modifying our environment and atmosphere for thousands of years in a number of ways. One of the more recent forcings identified to have major impacts is land use land cover change (LULCC). A variety of past studies using both modeled and observed data have agreed that since LULCC has a significant impact on the climate, it is important to understand these effects accurately at appropriate scales. It is found that irrigation is one of the more common types of LULCC in the Great Plains and has impacted weather and climate in this region. This study aims to investigate the potential impacts of irrigation on atmospheric conditions, with an emphasis on precipitation, during the historic 2012 drought. This drought was widespread over a large part of the US including the Great Plains and its irrigated regions. Simulations are completed using the Weather Research and Forecasting (WRF) model focusing on conditions during the growing season of 2012.

Emilee Lachenmeier: The Impacts of Irrigated and Rainfed Agriculture on Near Surface Atmosphere: Preliminary Results from GRAINEX

MS candidate in Natural Resource Sciences

Land use/land cover change (LULCC) has long been viewed as a contributing source of climate change. Modification of natural prairie grasslands to irrigated and rainfed agriculture has proven to have significant impacts on regional weather and climate variables including temperature, precipitation and energy fluxes. These impacts can be visible in various parts of the Great Plains. In this presentation, we have analyzed energy flux and soil moisture data collected during the Great Plains Irrigation Experiment (GRAINEX) in the 2018 growing season. The GRAINEX field campaign includes 12 in-situ integrated surface flux systems; three mobile radar units that also conducted radiosonde balloon launches; 74 temporary weather stations; and two integrated sounding systems that launched radiosonde balloons. Balloon launches were conducted every two hours from sunrise to sunset accumulating to 40 radiosonde balloon launches every day. The data were collected during two intensive observation periods (IOPs) in early June (May 30-June 13, 2018) and late July (July 16-July 30, 2018). Flux and surface meteorological observations were continuous from May through July. Impacts of four different land covers, including, irrigated soybean, irrigated corn, non-irrigated soybean, and non-irrigated corn were quantified by analyses of observed data. The data assessed for this study included sensible and latent heat energy, and equivalent temperature (moist enthalpy). In addition, soil moisture and temperature data were also collected and used to determine how root zone soil moisture affected atmospheric boundary layer variables.

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