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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Glacial Meltwater Modeling To Simulate Lake Water Budget (1996-2013) In Taylor Valley, Antarctica, Julian Michael Cross
Glacial Meltwater Modeling To Simulate Lake Water Budget (1996-2013) In Taylor Valley, Antarctica, Julian Michael Cross
Dissertations and Theses
The McMurdo Dry Valleys (MDV), the largest ice-free region (4,500 km2) in Antarctica, are a polar desert with an average annual temperature of -18ºC. In Taylor Valley, one of the MDV, closed-basin, perennially ice-covered lakes occupy the valley floor. Their water balance is controlled by inflow from glacial meltwater runoff and loss due to sublimation, making them sensitive indicators of climate. In this study, a physically-based model of glacier meltwater and lake ice sublimation is adapted to explain modern (1996 to 2013) lake-level variations. Meltwater model results were improved by the inclusion of MODIS remotely-sensed albedo measurements (E …
Evaluating The Impact And Distribution Of Stormwater Green Infrastructure On Watershed Outflow, Benjamin Fahy
Evaluating The Impact And Distribution Of Stormwater Green Infrastructure On Watershed Outflow, Benjamin Fahy
Dissertations and Theses
Green Stormwater Infrastructure (GSI) has become a popular method for flood mitigation as it can prevent runoff from entering streams during heavy precipitation. In this study, a recently developed neighborhood in Gresham, Oregon hosts a comparison of various GSI projects on runoff dynamics. The study site includes dispersed GSI (rain gardens, retention chambers, green streets) and centralized GSI (bioswales, detention ponds, detention pipes). For the 2017-2018 water year, hourly rainfall and observed discharge data is used to calibrate the EPA's Stormwater Management Model to simulate rainfall-runoff dynamics, achieving a Nash-Sutcliffe efficiency of 0.75 and Probability Bias statistic of 3.3%. A …
From Probabilistic Socio-Economic Vulnerability To An Integrated Framework For Flash Flood Prediction, Sepideh Khajehei
From Probabilistic Socio-Economic Vulnerability To An Integrated Framework For Flash Flood Prediction, Sepideh Khajehei
Dissertations and Theses
Flash flood is among the most hazardous natural disasters, and it can cause severe damages to the environment and human life. Flash floods are mainly caused by intense rainfall and due to their rapid onset (within six hours of rainfall), very limited opportunity can be left for effective response. Understanding the socio-economic characteristics involving natural hazards potential, vulnerability, and resilience is necessary to address the damages to economy and casualties from extreme natural hazards. The vulnerability to flash floods is dependent on both biophysical and socio-economic factors. This study provides a comprehensive assessment of socio-economic vulnerability to flash flood alongside …
Ensemble Data Assimilation For Flood Forecasting In Operational Settings: From Noah-Mp To Wrf-Hydro And The National Water Model, Mahkameh Zarekarizi
Ensemble Data Assimilation For Flood Forecasting In Operational Settings: From Noah-Mp To Wrf-Hydro And The National Water Model, Mahkameh Zarekarizi
Dissertations and Theses
The National Water Center (NWC) started using the National Water Model (NWM) in 2016. The NWM delivers state-of-the-science hydrologic forecasts in the nation. The NWM aims at operationally forecasting streamflow in more than 2,000,000 river reaches while currently river forecasts are issued for 4,000. The NWM is a specific configuration of the community WRF-Hydro Land Surface Model (LSM) which has recently been introduced to the hydrologic community. The WRF-Hydro model, itself, uses another newly-developed LSM called Noah-MP as the core hydrologic model. In WRF-Hydro, Noah-MP results (such as soil moisture and runoff) are passed to routing modules. Riverine water level …
A Multivariate Modeling Approach For Generating Ensemble Climatology Forcing For Hydrologic Applications, Sepideh Khajehei
A Multivariate Modeling Approach For Generating Ensemble Climatology Forcing For Hydrologic Applications, Sepideh Khajehei
Dissertations and Theses
Reliability and accuracy of the forcing data plays a vital role in the Hydrological Streamflow Prediction. Reliability of the forcing data leads to accurate predictions and ultimately reduction of uncertainty. Currently, Numerical Weather Prediction (NWP) models are developing ensemble forecasts for various temporal and spatial scales. However, it is proven that the raw products of the NWP models may be biased at the basin scale; unlike model grid scale, depending on the size of the catchment. Due to the large space-time variability of precipitation, bias-correcting the ensemble forecasts has proven to be a challenging task. In recent years, Ensemble Pre-Processing …
Streamflow Modeling Of Johnson Creek Subwatersheds Using The Precipitation Runoff Modeling System, Theophilus Matthew Malone
Streamflow Modeling Of Johnson Creek Subwatersheds Using The Precipitation Runoff Modeling System, Theophilus Matthew Malone
Civil and Environmental Engineering Master's Project Reports
Johnson Creek, in the Portland, Oregon metropolitan region, has several pollutants on the U.S. Environmental Protection Agency's (EPA) 303(d) list including excess heat, low dissolved oxygen, and harmful bacteria. Understanding streamflow response to precipitation events is an important component to evaluating water quality trends and calculating the Total Maximum Daily Load (TMDL) for pollutants of concern. Investigating the streamflow-precipitation relationship on the subwatershed scale can give insight to the hydrologic response of a given watershed. However, developing rating curves for several subwatersheds can be cost and time prohibitive. The objective of this project was to develop a hydrologic model using …
Towards Improving Drought Forecasts Across Different Spatial And Temporal Scales, Shahrbanou Madadgar
Towards Improving Drought Forecasts Across Different Spatial And Temporal Scales, Shahrbanou Madadgar
Dissertations and Theses
Recent water scarcities across the southwestern U.S. with severe effects on the living environment inspire the development of new methodologies to achieve reliable drought forecasting in seasonal scale. Reliable forecast of hydrologic variables, in general, is a preliminary requirement for appropriate planning of water resources and developing effective allocation policies. This study aims at developing new techniques with specific probabilistic features to improve the reliability of hydrologic forecasts, particularly the drought forecasts. The drought status in the future is determined by certain hydrologic variables that are basically estimated by the hydrologic models with rather simple to complex structures. Since the …
A Hydrologic Analysis Of Government Island, Oregon, Scott Gregory Bittinger
A Hydrologic Analysis Of Government Island, Oregon, Scott Gregory Bittinger
Dissertations and Theses
Government Island, located in the Columbia River approximately 16 km (10 mi) upstream of the confluence with the Willamette River, is a wetland mitigation site prompted by expansion of the southwest quadrant of Portland International Airport. The purpose of the study is to predict water levels in two enclosed lowland areas, Jewit Lake and Southeast Pond, based on levels of the Columbia River, precipitation, and evapotranspiration. Mitigation is intended to convert 1.13 km2 (237 acres) of seasonally flooded wetland to 1.27 km2 (267 acres) of semi-permanently flooded wetland and seasonally flooded wetland. Flooding of the wetland is most likely to …