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Physical Sciences and Mathematics Commons™
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University of Nevada, Las Vegas
Civil and Environmental Engineering and Construction Faculty Research
- Keyword
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- Climate change (3)
- Computer simulation (3)
- North America – Colorado River Watershed (3)
- Ocean-atmosphere interaction (3)
- Rayleigh waves (3)
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- Streamflow (3)
- Carbon emissions (2)
- Energy consumption (2)
- HEC-RAS (2)
- Long-range weather forecasting (2)
- Model-integrated computing (2)
- PDO (2)
- Photovoltaics (2)
- Treatment plant design (2)
- Water reuse (2)
- 2D flow (1)
- AMO (1)
- Artificial neural network (ANN) (1)
- Atlantic Multidecadal Oscillation (AMO) (1)
- Atmospheric carbon dioxide (1)
- Beach erosion (1)
- Beach nourishment (1)
- California – Santa Barbara (1)
- Carbon footprint (1)
- Clear specimen (1)
- Climate variability (1)
- Climatic changes (1)
- Coastal processes (1)
- Coastal zone management (1)
- Coupled (1)
Articles 1 - 30 of 36
Full-Text Articles in Physical Sciences and Mathematics
Real-Time Pm10 Emission Rates From Paved Roads By Measurement Of Concentrations In The Vehicle's Wake Using On-Board Sensors Part 2. Comparison Of Scamper, Traker™, Flux Measurements, And Ap-42 Silt Sampling Under Controlled Conditions, Dennis R. Fitz, Kurt Bullimer, Vic Etyemezian, Hampden D. Kuhns, John A. Gillies, George Nikolich, David E. James, Rodney Langston, Russell S. Merle Jr.
Real-Time Pm10 Emission Rates From Paved Roads By Measurement Of Concentrations In The Vehicle's Wake Using On-Board Sensors Part 2. Comparison Of Scamper, Traker™, Flux Measurements, And Ap-42 Silt Sampling Under Controlled Conditions, Dennis R. Fitz, Kurt Bullimer, Vic Etyemezian, Hampden D. Kuhns, John A. Gillies, George Nikolich, David E. James, Rodney Langston, Russell S. Merle Jr.
Civil and Environmental Engineering and Construction Faculty Research
Representative soil was evenly applied to an 800-m section of road surface. The test area was of sufficient length to allow for measurement at constant speeds of up to 72 km hr−1. SCAMPER and TRAKER™ mobile measurement vehicles made repeated test runs while an instrumented tower measured upwind-downwind horizontal PM10 flux. AP-42 methods were used to collect silt samples and calculate PM10 emission factors. Both silt loadings and vehicle speeds were varied during the experiment. Street sweeping the as-found roadway showed an initial rise in PM10 emission rates. Both TRAKER and SCAMPER measured rapid decay of PM10 emission rates after …
Renewable Energy Generation And Ghg Emission Reduction Potential Of A Satellitewater Reuse Plant By Using Solar Photovoltaics And Anaerobic Digestion, Jonathan R. Bailey, Saria Bukhary, Jacimaria R. Batista, Sajjad Ahmad
Renewable Energy Generation And Ghg Emission Reduction Potential Of A Satellitewater Reuse Plant By Using Solar Photovoltaics And Anaerobic Digestion, Jonathan R. Bailey, Saria Bukhary, Jacimaria R. Batista, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
Wastewater treatment is a very energy-intensive process. The growing population, increased demands for energy and water, and rising pollution levels caused by fossil-fuel-based energy generation, warrants the transition from fossil fuels to renewable energy. This research explored the energy consumption offset of a satellite water reuse plant (WRP) by using solar photovoltaics (PVs) and anaerobic digestion. The analysis was performed for two types of WRPs: conventional (conventional activated sludge system (CAS) bioreactor with secondary clarifiers and dual media filtration) and advanced (bioreactor with membrane filtration (MBR)) treatment satellite WRPs. The associated greenhouse gas (GHG) emissions were also evaluated. For conventional …
Design Aspects, Energy Consumption Evaluation, And Offset For Drinking Water Treatment Operation, Saria Bukhary, Jacimaria Batista, Sajjad Ahmad
Design Aspects, Energy Consumption Evaluation, And Offset For Drinking Water Treatment Operation, Saria Bukhary, Jacimaria Batista, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
Drinking water treatment, wastewater treatment, and water distribution are energy-intensive processes. The goal of this study was to design the unit processes of an existing drinking water treatment plant (DWTP), evaluate the associated energy consumption, and then offset it using solar photovoltaics (PVs) to reduce carbon emissions. The selected DWTP, situated in the southwestern United States, utilizes coagulation, flocculation, sedimentation, filtration, and chlorination to treat 3.94 m3 of local river water per second. Based on the energy consumption determined for each unit process (validated using the plant’s data) and the plant’s available landholding, the DWTP was sized for solar PV …
Bringing Statistical Learning Machines Together For Hydro-Climatological Predictions - Case Study For Sacramento San Joaquin River Basin, California, Balbhadra Thakur, Ajay Kalra, Sajjad Ahmad, Kenneth W. Lamb, Venkat Lakshmi
Bringing Statistical Learning Machines Together For Hydro-Climatological Predictions - Case Study For Sacramento San Joaquin River Basin, California, Balbhadra Thakur, Ajay Kalra, Sajjad Ahmad, Kenneth W. Lamb, Venkat Lakshmi
Civil and Environmental Engineering and Construction Faculty Research
Study region: Sacramento San Joaquin River Basin, California Study focus: The study forecasts the streamflow at a regional scale within SSJ river basin with largescale climate variables. The proposed approach eliminates the bias resulting from predefined indices at regional scale. The study was performed for eight unimpaired streamflow stations from 1962–2016. First, the Singular Valued Decomposition (SVD) teleconnections of the streamflow corresponding to 500 mbar geopotential height, sea surface temperature, 500 mbar specific humidity (SHUM500), and 500 mbar U-wind (U500) were obtained. Second, the skillful SVD teleconnections were screened non-parametrically. Finally, the screened teleconnections were used as the streamflow predictors …
Changes In Snow Phenology From 1979 To 2016 Over The Tianshan Mountains, Central Asia, Tao Yang, Qian Li, Sajjad Ahmad, Hongfei Zhou, Lanhai Li
Changes In Snow Phenology From 1979 To 2016 Over The Tianshan Mountains, Central Asia, Tao Yang, Qian Li, Sajjad Ahmad, Hongfei Zhou, Lanhai Li
Civil and Environmental Engineering and Construction Faculty Research
Snowmelt from the Tianshan Mountains (TS) is a major contributor to the water resources of the Central Asian region. Thus, changes in snow phenology over the TS have significant implications for regional water supplies and ecosystem services. However, the characteristics of changes in snow phenology and their influences on the climate are poorly understood throughout the entire TS due to the lack of in situ observations, limitations of optical remote sensing due to clouds, and decentralized political landscapes. Using passive microwave remote sensing snow data from 1979 to 2016 across the TS, this study investigates the spatiotemporal variations of snow …
Management Of An Urban Stormwater System Using Projected Future Scenarios Of Climate Models: A Watershed-Based Modeling Approach, Ranjeet Thakali, Ajay Kalra, Sajjad Ahmad, Kamal Qaiser
Management Of An Urban Stormwater System Using Projected Future Scenarios Of Climate Models: A Watershed-Based Modeling Approach, Ranjeet Thakali, Ajay Kalra, Sajjad Ahmad, Kamal Qaiser
Civil and Environmental Engineering and Construction Faculty Research
Anticipating a proper management needs for urban stormwater due to climate change is becoming a critical concern to water resources managers. In an effort to identify best management practices and understand the probable future climate scenarios, this study used high-resolution climate model data in conjunction with advanced statistical methods and computer simulation. Climate model data from the North American Regional Climate Change Assessment Program (NARCCAP) were used to calculate the design storm depths for the Gowan Watershed of Las Vegas Valley, Nevada. The Storm Water Management Model (SWMM), developed by the Environmental Protection Agency (EPA), was used for hydrological modeling. …
Climate Change And Eutrophication: A Short Review, Mohammad Nazari-Sharabian, Sajjad Ahmad, Moses Karakouzian
Climate Change And Eutrophication: A Short Review, Mohammad Nazari-Sharabian, Sajjad Ahmad, Moses Karakouzian
Civil and Environmental Engineering and Construction Faculty Research
Water resources are vital not only for human beings but essentially all ecosystems. Human health is at risk if clean drinking water becomes contaminated. Water is also essential for agriculture, manufacturing, energy production and other diverse uses. Therefore, a changing climate and its potential effects put more pressure on water resources. Climate change may cause increased water demand as a result of rising temperatures and evaporation while decreasing water availability. On the other hand, extreme events as a result of climate change can increase surface runoff and flooding, deteriorating water quality as well. One effect is water eutrophication, which occurs …
Higher Education Capacity Building In Water Resources Engineering And Management To Support Achieving The Sustainable Development Goal For Water In Pakistan, Steven J. Burian, Mercedes Ward, Tariq Banuri, M. Aslam Chaudhry, Sajjad Ahmad, Bakhshal Lashari, Rasool Bux Mahar, Davey Stevenson, Jim Vanderslice, Kamran Ansari, Munir Babar, Abdul Latif Qureshi
Higher Education Capacity Building In Water Resources Engineering And Management To Support Achieving The Sustainable Development Goal For Water In Pakistan, Steven J. Burian, Mercedes Ward, Tariq Banuri, M. Aslam Chaudhry, Sajjad Ahmad, Bakhshal Lashari, Rasool Bux Mahar, Davey Stevenson, Jim Vanderslice, Kamran Ansari, Munir Babar, Abdul Latif Qureshi
Civil and Environmental Engineering and Construction Faculty Research
Achieving the Sustainable Development Goals requires a multi‐pronged approach, with a key element being the development of a trained Community of Practice to sustain the advances in the relevant sectors. The engagement of higher education as a catalyst in the development and capacity building of the next generation of professionals and citizens comprising the Community of Practice is essential to meet the challenges of poverty, climate change, and clean water and to sustain those advances past 2030. This paper describes a capacity building program funded by the United States Agency for International Development to partner the University of Utah, in …
Potential Of Rainwater Harvesting In Meeting The Domestic Outdoor Demand: A Study In Dry And Wet Regions Of The United States, Kazi Ali Tamaddun, Ajay Kalra, Sajjad Ahmad
Potential Of Rainwater Harvesting In Meeting The Domestic Outdoor Demand: A Study In Dry And Wet Regions Of The United States, Kazi Ali Tamaddun, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
Feasibility of meeting the outdoor water demand with rainwater harvesting (RWH) was evaluated for the states of Arizona and Florida as representatives of dry and wet regions, respectively, using a system dynamic model. The potential of RWH was found to be highly sensitive to the demand of water, desert landscaping potential, and the percentage of households with RWH systems. The percentage of demand met through RWH and the storage potential of a 50-gallon rainwater barrel was found to be significant even for arid regions. The model can be used to compare among various influencing parameters of RWH systems.
Study Of Potential Integrated Management Of Water Resources In Las Vegas Valley, Haroon Stephen, Yoohwan Kim, Sajjad Ahmad
Study Of Potential Integrated Management Of Water Resources In Las Vegas Valley, Haroon Stephen, Yoohwan Kim, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
Water resource management under short term system perturbations such as storms and longer-term systemic changes caused by climate change such as droughts is a challenge when multiple agencies are involved. To address this challenge this research focuses on water management under changing climate conditions and population growth through understanding the agency water jurisdictions, management strategies, and modes of operation in Las Vegas Valley. A framework for integrated management through sharing data and models is presented that combines drinking water supply, flood control, and waste water treatment. This framework can be adopted to improve coordination among different water management agencies.
Precipitation And Indian Ocean Climate Variability-Acase Study On Pakistan, Kazi Ali Tamaddun, Ajay Kalra, Waqas Ahmed, Ghulam Hussain Dars, Steve Burian, Sajjad Ahmad
Precipitation And Indian Ocean Climate Variability-Acase Study On Pakistan, Kazi Ali Tamaddun, Ajay Kalra, Waqas Ahmed, Ghulam Hussain Dars, Steve Burian, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
The study evaluated the relationship between two climate variability indicators – sea- surface temperature (SST) and 500-mbar geopotential height (HGT/Z500) – and the monsoonal precipitation pattern of Pakistan. Data from 30 precipitation gauges were obtained and were analyzed over a period of 35 years from 1980 to 2014. Singular-valued decomposition (SVD) technique was used to determine the association of previous year’s SST and HGT with the current year’s monsoonal precipitation. The results indicated that the association of SST and HGT with precipitation varied depending on the lead-times selected. Multiple regions of the North Indian Ocean were identified that showed significant …
2d Unsteady Routing And Flood Inundation Mapping For Lower Region Of Brazos River Watershed, Manahari Bhandari, Narayan Nyaupane, Shekhar Raj Mote, Ajay Kalra, Sajjad Ahmad
2d Unsteady Routing And Flood Inundation Mapping For Lower Region Of Brazos River Watershed, Manahari Bhandari, Narayan Nyaupane, Shekhar Raj Mote, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
Present study uses two dimensional flow routing capabilities of hydrologic engineering center's river analysis system (HEC-RAS) for flood inundation mapping in lower region of Brazo River watershed subjected to frequent flooding. For analysis, river reach length of 20 km located at Richmond, Texas, was considered. Detailed underlying terrain information available from digital elevation model of 1/9-arc second resolution was used to generate the two-dimensional (2D) flow area and flow geometrics. Streamflow data available from gauging station USGS08114000 was used for the full unsteady flow hydraulic modeling along the reach. Developed hydraulic model was then calibrated based on the manning's roughness …
A Conceptualized Groundwater Flow Model Development For Integration With Surface Hydrology Model, Chao Chen, Ajay Kalra, Sajjad Ahmad
A Conceptualized Groundwater Flow Model Development For Integration With Surface Hydrology Model, Chao Chen, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
A groundwater system model was developed and calibrated in the study area of Lehman Creek watershed, eastern Nevada. The model development aims for integrating the surface hydrologic model - precipitation runoff modeling system (PRMS) model - with the three-dimensional (3D) finite-difference model MODFLOW. A two-layer groundwater model was developed with spatial discretization of 100 x 100 m grid. The water balance was estimated with inflows of gravity drainage and initial streamflow estimated from a calibrated PRMS model, and with outflows of spring discharges, boundary fluxes, and stream base flow. A steady-state model calibration was performed to estimate the hydraulic properties. …
Ice-Cover And Jamming Effects On Inline Structures And Upstream Water Levels, Addison Jobe, Swastik Bhandari, Ajay Kalra, Sajjad Ahmad
Ice-Cover And Jamming Effects On Inline Structures And Upstream Water Levels, Addison Jobe, Swastik Bhandari, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
River ice cover is a reoccurring phenomenon in the Northern United States every year. Sheets and layers of ice result in a rise of water surface elevation and may lead to ice jams in a river. This research explains the modeling of a river reach through Northern Illinois containing a structural weir and how the water profile is effected during ice cover and ice jam events. The Hydraulic Engineering Center’s River Analysis System was used in conjunction with Esri ArcMap software to model a portion of the river for analysis. The study area of the Rock River flowing through Oregon, …
Multi-Scale Correlation Analyses Between California Streamflow And Enso/Pdo, Kazi Ali Tamaddun, Ajay Kalra, Sajjad Ahmad
Multi-Scale Correlation Analyses Between California Streamflow And Enso/Pdo, Kazi Ali Tamaddun, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) are two of the most important climate indices that influence the western U.S. hydrology significantly. This study evaluated how these two indices have influenced California streamflow over the years and determined their correlation at multiple time-scales. Data were obtained from 14 unimpaired streamflow stations of California for a study period of 63 years (i.e., 1951 to 2013). The concept of continuous wavelet transform was applied to observe the variance in each time-series at multiple time-scale bands over the years. The correlation was found to be higher in the latter half …
Response Of Climate Change On Urban Watersheds: A Case Study For Las Vegas, Nv, Narayan Nyaupane, Ranjeet Thakali, Ajay Kalra, Lorenzo Mastino, Marco Velotta, Sajjad Ahmad
Response Of Climate Change On Urban Watersheds: A Case Study For Las Vegas, Nv, Narayan Nyaupane, Ranjeet Thakali, Ajay Kalra, Lorenzo Mastino, Marco Velotta, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
The current research is a partnering effort between Southern Illinois University Carbondale and City of Las Vegas to assess the vulnerability to drought, extreme heat, and extreme precipitation. This study focuses on precipitation and usesdifferent climate scenarios from the high-resolution North American Regional Climate Change Assessment Program (NARCCAP) climate model data to evaluate the existing stormwater infrastructure of the Gowan watershed in the Las Vegas valley. Six NARCCAP modelsconsidered in the study have shown the Gamma distribution as the best fitted from Kolmogorov Smirnov best fit test. Delta change method is adopted to quantify the effect of climate change on …
Flood Risk Assessment Using The Updated Fema Floodplain Standard In The Ellicott City, Maryland, United States, Ranjeet Thakali, Ranjit Bhandari, Giles-Arnaud Arif-Deen Kandissounon, Ajay Kalra, Sajjad Ahmad
Flood Risk Assessment Using The Updated Fema Floodplain Standard In The Ellicott City, Maryland, United States, Ranjeet Thakali, Ranjit Bhandari, Giles-Arnaud Arif-Deen Kandissounon, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
Every Year, flooding causes a calamitous impact on the people, economy, and environment all over the world. In recent years, the flood-related damages have been increasing in the United States regardless of several investments in the flood control measures. Floodplain mapping is an important tool for management that aids in the planning of infrastructures within the floodplain zone. With the magnifying effects of climate change on the hydrological cycle the study of floodplain is becoming a key tool in the water management. Federal Emergency Management Agency has recently updated their floodplain standard as per the presidential executive order 2015 on …
Coupling Hec-Ras And Hec-Hms In Precipitation Runoff Modelling And Evaluating Flood Plain Inundation Map, Balbhadra Thakur, Ranjan Parajuli, Ajay Kalra, Sajjad Ahmad, Ritu Gupta
Coupling Hec-Ras And Hec-Hms In Precipitation Runoff Modelling And Evaluating Flood Plain Inundation Map, Balbhadra Thakur, Ranjan Parajuli, Ajay Kalra, Sajjad Ahmad, Ritu Gupta
Civil and Environmental Engineering and Construction Faculty Research
The climate change and land use change have raised the challenges associated with increased runoff and flood management. The risks associated with flooding have been increasing with development in flood plain and changing climate resulting in increase in inundation of flood plain. The current study will help to evaluate the extent of flood plain in the study area – copper slough watershed (CSW) in Champaign, Illinois; utilizing the known precipitation and land use. The study of CSW is taken into account, as this is the largest watershed of Champaign City and had undergone major land use change increasing the flooding …
Using Wavelet To Analyze Periodicities In Hydrologic Variables, Balbhadra Thakur, Pratik Pathak, Ajay Kalra, Sajjad Ahmad, Miguel Bernardez
Using Wavelet To Analyze Periodicities In Hydrologic Variables, Balbhadra Thakur, Pratik Pathak, Ajay Kalra, Sajjad Ahmad, Miguel Bernardez
Civil and Environmental Engineering and Construction Faculty Research
The trend and shift in the seasonal temperature, precipitation and streamflow time series across the Midwest have been analyzed, for the period 1960-2013, using the statistical analyses (Mann- Kendall test with and without considering short term persistence (MK2 and MK1, respectively) and Pettitt test). The paper also utilizes a relatively new approach, wavelet analysis, for testing the existence of trend and shift in the time series. The method has the ability to decompose a time series in to lower (trend) and higher frequency components (noise). Discrete wavelet transform (DWT) has been employed in the present study with an aim to …
Streamflow Pattern Variations Resulting From Future Climate Change In Middle Tianshan Mountains Region In China, Feiyun Zhang, Lanhai Li, Sajjad Ahmad
Streamflow Pattern Variations Resulting From Future Climate Change In Middle Tianshan Mountains Region In China, Feiyun Zhang, Lanhai Li, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
In arid and semi-arid regions of North West china, glacier-melt, seasonal snowmelt and rainfall are the primary sources of flow in the rivers that originate from alpine areas. Spring and summer peak flow resulting from snowmelt and rainfall, respectively, are the main characteristics of streamflow pattern. Because of the damages caused by the spring and summer peak flow, a better understanding of the streamflow pattern variation under future climate warming is crucial. To analyze the variation of streamflow pattern under climate warming, the Kaidu River and the Manasi River watersheds in northern and southern slopes of Middle Tianshan Mountains, located …
Estimation Of Performance Indices For The Planning Of Sustainable Transportation Systems, Alexander Paz, Pankaj Maheshwari, Pushkin Kachroo, Sajjad Ahmad
Estimation Of Performance Indices For The Planning Of Sustainable Transportation Systems, Alexander Paz, Pankaj Maheshwari, Pushkin Kachroo, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
In the context of sustainable transportation systems, previous studies have either focused only on the transportation system or have not used a methodology that enables the treatment of incomplete, vague, and qualitative information associated with the available data. This study proposes a system of systems (SOS) and a fuzzy logic modeling approach. The SOS includes the Transportation, Activity, and Environment systems. The fuzzy logic modeling approach enables the treatment of the vagueness associated with some of the relevant data. Performance Indices (PIs) are computed for each system using a number of performance measures. The PIs illustrate the aggregated performance of …
Estimating Annual Precipitation For The Colorado River Basin Using Oceanic-Atmospheric Oscillations, Ajay Kalra, Sajjad Ahmad
Estimating Annual Precipitation For The Colorado River Basin Using Oceanic-Atmospheric Oscillations, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
Estimating long-lead time precipitation under the stress of increased climatic variability is a challenging task in the field of hydrology. A modified Support Vector Machine (SVM) based framework is proposed to estimate annual precipitation using oceanic-atmospheric oscillations. Oceanic-atmospheric oscillations, consisting of Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation (AMO), and El Niño–Southern Oscillation (ENSO) for a period of 1900–2008, are used to generate annual precipitation estimates with a 1 year lead time. The SVM model is applied to 17 climate divisions encompassing the Colorado River Basin in the western United States. The overall results revealed that …
Losing The Lake: Development And Deployment Of An Educational Game, Joseph M. Vesco, Katie Gilgen, Anne Paine, Marissa Owens, Michael Nussbaum, Gale M. Sinatra, Sajjad Ahmad, Kent J. Crippen, Sergiu Dascalu, Frederick C. Harris
Losing The Lake: Development And Deployment Of An Educational Game, Joseph M. Vesco, Katie Gilgen, Anne Paine, Marissa Owens, Michael Nussbaum, Gale M. Sinatra, Sajjad Ahmad, Kent J. Crippen, Sergiu Dascalu, Frederick C. Harris
Civil and Environmental Engineering and Construction Faculty Research
When asked what the top three issues of the Las Vegas region were, the reply was “water, water, water!" This was the result of a survey done a few years ago of Las Vegas Valley TV anchors. The reason for this response is that sustainability of the urban environments requires sufficient water resources as does population growth. With the advent of global climate change, this resource is in danger. Water flow and mountainous ice packs are impacted by this change in climate there by impacting the amount of water the the region. This is compounded over time as the population …
Evaluating Changes And Estimating Seasonal Precipitation For Colorado River Basin Using Stochastic Non-Parametric Disaggregation Technique, Ajay Kalra, Sajjad Ahmad
Evaluating Changes And Estimating Seasonal Precipitation For Colorado River Basin Using Stochastic Non-Parametric Disaggregation Technique, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
Precipitation estimation is an important and challenging task in hydrology because of high variability and changing climate. This research involves (1) analyzing changes (trend and step) in seasonal precipitation and (2) estimating seasonal precipitation by disaggregating water year precipitation using a k-nearest neighbor (KNN) nonparametric technique for 29 climate divisions encompassing the Colorado River Basin. Water year precipitation data from 1900 to 2008 are subdivided into four seasons (i.e., autumn, winter, spring, and summer). Two statistical tests (Mann-Kendall and Spearman’s rho) are used to evaluate trend changes, and a rank sum test is used to identify the step change in …
The Carbon Footprint Associated With Water Management Policy Options In The Las Vegas Valley, Nevada, Eleeja Shrestha, Sajjad Ahmad, Walter Johnson, Jacimaria R. Batista
The Carbon Footprint Associated With Water Management Policy Options In The Las Vegas Valley, Nevada, Eleeja Shrestha, Sajjad Ahmad, Walter Johnson, Jacimaria R. Batista
Civil and Environmental Engineering and Construction Faculty Research
A system dynamics model was developed to estimate the carbon dioxide (CO2) emissions associated with conveyance of water from the water source to the distribution laterals of the Las Vegas Valley. In addition, the impact of several water management policies, including water conservation, reuse, and population growth rate change was evaluated. The results show that, at present, nearly 0.53 million metric tons of CO2 emissions per year are released due to energy use for water conveyance in distribution laterals of the Valley from Lake Mead, located 32.2 km (20 miles) southeast of the Las Vegas at an …
Using Oceanic-Atmospheric Oscillations For Long Lead Time Streamflow Forecasting, Ajay Kalra, Sajjad Ahmad
Using Oceanic-Atmospheric Oscillations For Long Lead Time Streamflow Forecasting, Ajay Kalra, Sajjad Ahmad
Civil and Environmental Engineering and Construction Faculty Research
We present a data-driven model, Support Vector Machine (SVM), for long lead time streamflow forecasting using oceanic-atmospheric oscillations. The SVM is based on statistical learning theory that uses a hypothesis space of linear functions based on Kernel approach and has been used to predict a quantity forward in time on the basis of training from past data. The strength of SVM lies in minimizing the empirical classification error and maximizing the geometric margin by solving inverse problem. The SVM model is applied to three gages, i.e., Cisco, Green River, and Lees Ferry in the Upper Colorado River Basin in the …
Role Of Forward Model In Surface-Wave Studies To Delineate A Buried High-Velocity Layer, Xiaohui Jin, Barbara Luke, Carlos Calderon-Macias
Role Of Forward Model In Surface-Wave Studies To Delineate A Buried High-Velocity Layer, Xiaohui Jin, Barbara Luke, Carlos Calderon-Macias
Civil and Environmental Engineering and Construction Faculty Research
Procedures are tested and compared for processing Rayleigh surface wave data to obtain one-dimensional shear wave velocity profiles for a hypothetical site that contains a buried high-velocity layer (HVL). The main purpose of such an investigation would be to discriminate and characterize the HVL. When target dispersion curves are derived from synthetic time histories, for the most part, the HVL is better identified when profiles are inverted using only the fundamental mode of Rayleigh wave propagation, rather than a more compatible but more complex forward model. The outcomes imply that in practice, a simple forward model might be more successful …
Interpreting Surface-Wave Data For A Site With Shallow Bedrock, Daniel W. Casto, Barbara Luke, Carlos Calderon-Macias, Ronald Kaufmann
Interpreting Surface-Wave Data For A Site With Shallow Bedrock, Daniel W. Casto, Barbara Luke, Carlos Calderon-Macias, Ronald Kaufmann
Civil and Environmental Engineering and Construction Faculty Research
The inversion of dispersive Rayleigh-wave data has been shown to be successful in providing reliable estimated shear-wave velocities within unconsolidated materials in the near surface. However, in a case where the multi-channel analysis of surface waves method was applied to a site consisting of clay residuum overlying basalt bedrock, inversion for the fundamental-mode Rayleigh wave resulted in shear-wave velocities within the rock that are less than half of expected values. Forward modeling reveals that the fundamental-mode dispersion curve is hardly sensitive to bedrock velocity perturbations over a practical range of wavelengths, leading to poorly constrained solutions. Standard surface-wave methods can …
Improved Parameterization To Invert Rayleigh-Wave Data For Shallow Profiles Containing Stiff Inclusions, Carlos Calderon-Macias, Barbara Luke
Improved Parameterization To Invert Rayleigh-Wave Data For Shallow Profiles Containing Stiff Inclusions, Carlos Calderon-Macias, Barbara Luke
Civil and Environmental Engineering and Construction Faculty Research
Inversion of shear-wave velocity profiles from phase-velocity measurements of Rayleigh-wave energy for sites containing stiff layers can be erroneous if such layers are not characterized in the starting or reference model. Incorporation of a priori knowledge then is key for converging upon a realistic or meaningful solution. Resolving soil profiles in desert regions where stiff layers cemented with calcium carbonate are intermixed with softer, uncemented media is an application for which locating shallow stiff inclusions has important implications. Identification of the stiff layers is critical for foundation design and cost estimating of excavations. A parameterization that seems adequate for this …
Relationships Between Pacific And Atlantic Ocean Sea Surface Temperatures And U.S. Streamflow Variability, Glenn A. Tootle, Thomas C. Piechota
Relationships Between Pacific And Atlantic Ocean Sea Surface Temperatures And U.S. Streamflow Variability, Glenn A. Tootle, Thomas C. Piechota
Civil and Environmental Engineering and Construction Faculty Research
An evaluation of Pacific and Atlantic Ocean sea surface temperatures (SSTs) and continental U.S. streamflow was performed to identify coupled regions of SST and continental U.S. streamflow variability. Both SSTs and streamflow displayed temporal variability when applying the singular value decomposition (SVD) statistical method. Initially, an extended temporal evaluation was performed using the entire period of record (i.e., all years from 1951 to 2002). This was followed by an interdecadal-temporal evaluation for the Pacific (Atlantic) Ocean based on the phase of the Pacific Decadal Oscillation (PDO) (Atlantic Multidecadal Oscillation (AMO)). Finally, an extended temporal evaluation was performed using detrended SST …