19 resultados para hydrologic sciences
em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States
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A newsletter for alumni and friends of the Iowa State University College of Human Sciences.
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This paper describes the application of the Soil and Water Assessment Tool (SWAT) model to the Maquoketa River watershed, located in northeast Iowa. The inputs to the model were obtained from the Environmental Protection Agency’s geographic information/database system called Better Assessment Science Integrating Point and Nonpoint Sources (BASINS). Climatic data from six weather stations located in and around the watershed, and measured streamflow data from a U.S. Geological Survey gage station at the watershed outlet were used in the sensitivity analysis of SWAT model parameters as well as its calibration and validation for watershed hydrology and streamflow. A sensitivity analysis was performed using an influence coefficient method to evaluate surface runoff and base flow variations in response to changes in model input hydrologic parameters. The curve number, evaporation compensation factor, and soil available water capacity were found to be the most sensitive parameters among eight selected parameters when applying SWAT to the Maquoketa River watershed. Model calibration, facilitated by the sensitivity analysis, was performed for the period 1988 through 1993, and validation was performed for 1982 through 1987. The model performance was evaluated by well-established statistical methods and was found to explain at least 86% and 69% of the variability in the measured stream flow data for the calibration and validation periods, respectively. This initial hydrologic modeling analysis will facilitate future applications of SWAT to the Maquoketa River watershed for various watershed analysis, including water quality.
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Nationwide, about five cents of each highway construction dollar is spent on culverts. In Iowa, average annual construction costs on the interstate, primary, and federal-aid secondary systems are about $120,000,000. Assuming the national figure applies to Iowa, about $6,000,000 are spent on culvert construction annually. For each one percent reduction in overall culvert costs, annual construction costs would be reduced by $60,000. One area of potential cost reduction lies in the sizing of the culvert. Determining the flow area and hydraulic capacity is accomplished in the initial design of the culvert. The normal design sequence is accomplished in two parts. The hydrologic portion consists of the determination of a design discharge in cubic feet per second using one of several available methods. This discharge is then used directly in the hydraulic portion of the design to determine the proper type, size, and shape of culvert to be used, based on various site and design restrictions. More refined hydrologic analyses, including rainfall-runoff analysis, flood hydrograph development, and streamflow routing techniques, are not pursued in the existing design procedure used by most county and state highway engineers.
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Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
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Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
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Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
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Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
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Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
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Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
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Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
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Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
Resumo:
Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
Resumo:
Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
Resumo:
Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
Resumo:
Stories we hope will inform and inspire you. Stories about how the college is constantly striving to make new discoveries, encourage and educate students and serve Iowans. Stories of the people who make this college one of the premier institutions of agriculture and life sciences in the world.
