Nevada Water Resources Research Institute

Abstract

The Beatty Water and Sanitation District reported local groundwater sources with fluoride concentrations four times the EPA guidelines, generating concern for local water authorities. Long-term exposure to fluoride concentrations higher than 1.5 mg/L have negative health impacts on water users. Water defluoridation is complex in rural communities without access to a central public water system or the resources and technical support for water treatment. This project aims to assess the feasibility of scaling up electrocoagulation (EC) technology developed in the past by DRI to reduce fluoride concentration in groundwater using Beatty, Nevada, as a pilot case. The detailed objectives of this proposal are to: (i) identify the effects of initial fluoride concentrations using real groundwater from Beatty, Nevada; (ii) assess the power consumption/requirements of the technology; (iii) investigate routine operation/maintenance requirements and the effect of competing ions; and (iv) characterize by-products.

This project will be completed through the collaboration of two groups at DRI, the Center for International Water and Sustainability (CIWAS) and the Environmental Engineering Laboratory (EEL), and the Beatty Water and Sanitation District (BWSD). AutoCAD will be used to develop the EC prototype based on lab-scale results from previous research. The key parameters that will be considered are: (i) electrode surface area to reactor volume ratio, (ii) current density, and iii) electrode separation. The experimental design will include assessing the effect of parameters such as: (i) initial fluoride concentration; (ii) the presence of competing ions; and (iii) the addition of Moringa oleifera extract. EC prototype testing experiments will be conducted for four weeks with performance data collected every other day in collaboration with BWSD. The sludge/foam by-products generated will be removed at the end of every trial, dried, weighed, and characterized to quantify the amount of waste produced.

Abstract

Western Nevada is vulnerable to extreme winter storms and subsequent floods. Climate change, population growth, and urbanization will exacerbate the impacts of future flood events. More robust methodologies to better understand the future flood events, especially for the extreme ones, are needed. The traditional approach relies on ensembles of climate model simulations, statistical bias correction, downscaling to the local scale, and then to fit the generalized extreme value distribution to derive the quantiles of different recurrence intervals (e.g., 100-year rainfall). Such an approach provides a limited physical understanding of future extreme events, and its veracity cannot be tested. Alternatively, the numerical weather predication model combined with a hydrological model in a hypothetical climate setting can provide narratives of simulations of a historical high-impact event in a future climate. This event-based dynamic modeling approach is referred to as a “storyline.” In this study, we will use a storyline approach to assess the 1997 New Year’s Flood in western Nevada. We will deconstruct this extreme event to its physical driving factors, and then simulate how these factors interact with an altered future climate in driving future hypothetical floods. We will integrate a global climate model simulation with a regional-scale weather model and local-scale hydrological model. This proposed work will potentially provide complementary and more realistic and physically consistent pictures of what the 1997 New Year’s Flood might look like 100 years later.

Abstract

Water resources and their quality are critical to human life and the ecological system. In southern Nevada, nearly 90% of water comes from nearby Lake Mead. In the recent decade, climate change and population growth have altered water chemistry in Lake Mead, and concentrations of heavy metals conceivably increase as the water level recedes due to megadrought. Traditional water monitoring only focuses on a few heavy metals, such as mercury and lead. However, the accumulative effects of other heavy metals cannot be simply ignored, especially as Lake Mead moves toward the direction of a “dead pool.” The accumulative effects of heavy metals can damage the cognitive capacity of young people at an early stage.

To resolve this looming challenge, we propose studying the heavy metals in the water of Lake Mead with the most sensitive multielement radioanalytical technique, Instrumental Neutron Activation Analysis (INAA). After irradiating the samples with thermal neutrons, qualitative and quantitative information about elements can be obtained from the decay spectra recorded by gamma-ray spectrometers. The objectives of the study are to:

(1) Apply INAA to identify heavy metals in Lake Mead and calculate their concentrations up to the parts per billion level.

(2) Investigate the seasonal variation of heavy metal concentrations in Lake Mead and establish the baseline values in various seasons.

(3) Investigate the relationship of isotopes in groundwater downgradient from the Nevada National Security Site to ensure there is no contamination entering Lake Mead.

The data collected will be a guide and future reference for water pollution and environment monitoring for Lake Mead. The results will educate the public about the environmental impact of climate change and human behavior on water quality. Pertinent information will be disseminated to residents via publication.

Abstract

According to the Water Resources Research Act of 1984 (as amended) that created the National Institutes for Water Resources (NIWR), each institute is to arrange for research that fosters the training and education of future water scientists, engineers, and technicians. The goal of the Undergraduate Internship Immersion Program is to attract additional students who may not have considered a water-related STEM career. The program will expose college undergraduates to water-related issues and water-related sciences during their postsecondary education, a time when numerous career options remain in play. The interns will gain direct exposure to active research in water-related earth sciences. Exposure of this kind will increase the skill set of the undergraduate students and the possibility that they may pursue careers in earth sciences. The program will pair undergraduate students from Nevada community and state colleges with DRI scientists for a semester-long paid internship. These students will increase their skill sets and be exposed to a variety of career options that might have not been apparent to them prior to their involvement in this program.

Abstract

Climate conditions and hydrologic processes regulate the functioning and viability of dry forest and woodland ecosystems in southern Nevada. Climate-driven alteration of hydrologic processes toward more water-limited conditions (aridification) is a strong indicator of emergent vegetation dieback and decline. Vegetation decline in this region increases the risk of disturbances, including wildfire, and results in further alterations to hydrologic processes that increase the aridity of natural systems, reduce water quality and quantity, and affect human well-being. Southern Nevada has not yet experienced the widespread vegetation declines that have impacted water resources and ecosystem services in other regions of the southwestern United States, but recent research suggests that these declines are beginning to occur. The proposed work will use existing field instrumentation, detailed ecosystem characterizations, and computational modeling to evaluate climatic and hydrologic aridification for mid- and high-elevation forest and woodland ecosystems in southern Nevada. The first objective of this work will be to use computational land surface modeling to determine to what degree multiple components of regional climate change (long-term meteorological trends, seasonal climate change, and extreme climate events) have reshaped ecosystem water balance processes and partitioning across a diverse set of 26 field-characterized sites in southern Nevada. The second objective of this work will be to identify how the landscape and vegetation structural factors of these sites amplify or dampen climate-driven aridification, identifying the specific characteristics of woodland and forest ecosystems in southern Nevada where emergent ecological declines are most likely to occur. This is critical information for land managers, who can reduce water stress to ecosystems through management interventions but have limited resources and time to do so. Development of outreach to southern Nevada land managers in the form of presentations, meetings, and reports will constitute the third objective of this work. This will help managers identify and prioritize the most vulnerable ecosystems to vegetation decline in their management actions, reducing the effect of ongoing climate change on the hydrology of these ecosystems and the cross-scale hydrologic impacts associated with vegetation decline. In total, this work will develop novel mechanistic insights into the multiple factors shaping aridification in southern Nevada forests and woodlands, and the researchers will work alongside southern Nevada land management groups to improve ecosystem management outcomes and maintain southern Nevada water resources by prioritizing management activities in the most vulnerable forest and woodland locations.

Abstract

The goal of this project is to enhance and work toward operationalizing the use of OpenET, a satellite-based evapotranspiration (ET) based cloud computing and data services platform co-led by DRI, and integrating OpenET data into a national-scale hydrologic model to support the goals of the National Water Census and Water Availability and Use Science Program. The OpenET web application and data services provide equal access to information by all parties, helping stakeholders feel comfortable with the data while promoting a better understanding of the inherent uncertainties with respect to water use and supply planning. The project will further develop and enhance operational software to provide daily ET summaries for irrigated lands for specific watersheds and modeling units. Software for making automated and operational machine-to-machine data queries will be developed and enhanced as part of this project to facilitate the ability for the USGS to operationally download and integrate OpenET data into hydrologic modeling simulations and water-use reports. The specific objectives of this project are to further develop and enhance operational software to provide daily ET summaries for irrigated lands for specific watersheds and modeling units. DRI and the OpenET team will work closely with USGS to continue to advance the SSEBop model, produce 20 years of SSEBop and OpenET Ensemble ET data and summaries for all of the contiguous United States (CONUS), assess the accuracy of ET estimates and new gridded weather data, and evaluate options for long-term collaboration and sustainability of OpenET for operationally estimating and summarizing consumptive water use over all of the CONUS.

Abstract

Across the western United States, rising air temperature, shifts from snow to rain, earlier snowmelt, increased rainfall intensity, and increased interannual variability are changing the timing, intensity, and duration of water inputs (rain, snowmelt) with direct consequences on flood potential, diminished late-season streamflow, and degraded water quality. However, predicting hydrologic response of basin outflows to changing climate remains a challenge in mountainous watersheds where complex interactions occur between snow accumulation and melt dynamics, soil-water partitioning, vegetation water use, recharge, and groundwater circulating to different depths. In addition, the seasonality and steep topography require analysis to be at fine spatial and temporal resolutions. High-performance, physically based, integrated hydrologic models allow for dynamic process representation across these different subcomponents to capture system response to climate perturbation. Recently developed particle tracking codes are used with these detailed hydrologic models to assess source contributions (rain, snow, initial groundwater) and residence time distributions in both evapotranspiration and stream water. The proposed work seeks to use these advanced numerical tools in conjunction with local data, reanalysis products and remote sensing to assess hydrologic vulnerability in Lake Tahoe headwater basins where cascading feedbacks of climate change on snowpack accumulation, water routing, and forest health are already occurring. Vulnerability metrics will describe where and under what climate conditions basin outflows will change in terms of magnitude, sourcing, and residence time distribution (i.e., age). Outflows are defined as streamflow, evapotranspiration, and groundwater discharge to the lake. Research will aid land and water managers in planning for a more sustainable future under climate change. Funding will support an MS graduate student at the University of Nevada, Reno, and build technical capacity in high-performance hydrologic computing at a Nevada institution for use in Lake Tahoe assessment.

Abstract

In the American west, stream and riparian ecosystems serve numerous ecological functions. Many of these systems have been degraded by a combination of natural and anthropogenic processes, and we invest heavily in restoration projects to rehabilitate these ecosystems. Beaver-related restoration (BRR) practices rely on the reintroduction of beavers, or the construction of beaver-dam mimicking impoundments, as a tool for restoration work. These practices are attractive because of the low cost and relative simplicity when compared to engineered restoration practices. However, there are numerous sources of uncertainty in BRR practices: Will beavers build and maintain dams? Will artificial structures hold water through peak flows? How long will structures continue to impound water? How many dams will be constructed on a given reach? There are little data available in the peer-reviewed literature to inform best practices or effective regulation. Post-restoration monitoring is expensive and time consuming, and the numerous uncertainties involved in BRR make it difficult to apply results observed at one site to other scenarios. This proposal seeks to address this problem using a numerical model of sediment transport. A numerical model makes it possible to consider variability over a wide range of spatial and temporal scales, dams can be simulated to breach seasonally or to last 10 years, extensive networks of dams can be simulated and contrasted to sporadic impoundments, and the long-term effect of abandoned dams can be simulated. Successful numerical modeling of these systems can be used to inform both best practices and regulation of BRR, improving the effectiveness of future restoration work.

Abstract

Geochemical tracers have been used to constrain important aspects of spring and underground waters, such as their sources, flow paths, and subsurface mixing. During our pilot study, we measured 53 element compositions, ranging from Li to U, in a suite of 18 springs from the Moapa Valley in southern Nevada. Those springs feed the headwaters of the perennial Muddy River that eventually empties the spring waters into the Lake Mead. The initial results show three types of interelement correlations. Type I: some elements are highly correlated with each other, implying a fundamental connection between the sampled springs. Type II: some elements are highly correlated with each other in most studied springs, with the rest being offset from the main trend. Type III: some elements are not correlated with each other, implying multiple sources for those elements.

Encouraged by our pilot study, we propose to simultaneously measure the compositions of 53 trace elements, from Li to U, in over 30 springs in the Moapa Valley and its upgradient valleys using the iCAPTM Qc ICP-MS at UNLV. We will sample those springs in May and September of 2021 to evaluate possible seasonal and annual variations. With a full suite of element compositions in these spring waters, we plan to (1) characterize their compositional endmembers using Principal Component Analysis and estimate the endmember proportions in each spring, (2) constrain their pathways by matching the endmember compositions in springs with those of local bedrocks, and (3) reevaluate their possible subsurface pathways.

The proposed study will prepare one second-year master’s student, two undergraduate students, and a high school student for a career in water resources fields. We will couple this research activity into a summer education program that the PIs are running at UNLV. In this program, students will learn state-of-the-art analytical methods with hands-on experience on ICP-MS and the application of geochemical tracers in hydrology. We will include the students who attend this summer class in our proposed research. We plan to offer this class annually to both undergraduate and graduate students. As such, we will train a considerable number of students who will work in water resources fields. Finally, the proposed study will help two mid-career scientists to utilize hydrology study to foster interdisciplinary collaboration among NSHE institutions.

In summary, we will generate and compile the first complete suite of metal element compositions in a set of springs in the Moapa Valley and its upgradient valleys in southern Nevada. This will allow us to use multiple geochemical tracers to test existing models about the sources and pathways of spring waters. The results will be presented at the Nevada Water Research Association Annual Conference as well as at international meetings, such as the American Geophysical Union Annual Meeting. Eventually, we expect a publication in a peer-reviewed journal. Over the course of the proposed research, several students (including graduate, undergraduate, and high school students) will be trained in hydrologic science.

Abstract

Coronavirus Disease 2019 (COVID-19) is caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). First emerging in China in December of 2019, this virus has unleashed the worst pandemic since the Spanish Flu of 1918. To date, there have been over 23 million cases and 389,000 fatalities in the United States. As the pandemic has progressed, surveillance of wastewater has emerged as a powerful tool for detecting and tracking viral outbreaks across time and across populations. In late 2020, both DRI and UNLV received Coronavirus Aid, Relief, and Economic Security (CARES) Act funding to develop scientific infrastructure for tracking of the COVID pandemic. In DRI’s pilot study, several rural and Tribal wastewater systems were sampled and used to develop concentration, RNA purification, and RT-qPCR tools to quantify SARS-CoV-2 in environmental samples. Concurrently, UNLV used over 200 clinical viral genomes from nasopharyngeal swabs to analyze viral genomes from wastewater samples in Reno and Las Vegas, Nevada, and Tucson, Arizona, identifying several unique strains of the virus in the process. Using RT-qPCR and genomic sequencing, the work proposed here combines the capabilities of both groups with the aim of filling in geographic blank spots on the US map of SARS-CoV-2 strain distribution from rural locations. Other project objectives include: (1) identifying the most effective steps in wastewater treatment for removal of this virus, (2) tracking viral abundance over an extended period of time from the Furnace Creek wastewater system in Death Valley National Park to determine which of the major regional strains are present in this very remote location, (3) aiding the National Park Service in managing public health policy, and (4) documenting the predicted eventual decline of the pandemic at a single location. This project has an extensive educational component, which involves undergraduates from Nevada State College, graduate students from UNLV/DRI, and a UNLV/DRI postdoc. The work also establishes new professional relationships between DRI and the Nevada Institute of Personalized Medicine and various water management authorities across rural and Tribal entities of the rural Southwest.