38 resultados para landscape characteristics
em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States
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The present study is an integral part of a broader study focused on the design and implementation of self-cleaning culverts, i.e., configurations that prevent the formation of sediment deposits after culvert construction or cleaning. Sediment deposition at culverts is influenced by many factors, including the size and characteristics of material of which the channel is composed, the hydraulic characteristics generated under different hydrology events, the culvert geometry design, channel transition design, and the vegetation around the channel. The multitude of combinations produced by this set of variables makes the investigation of practical situations a complex undertaking. In addition to the considerations above, the field and analytical observations have revealed flow complexities affecting the flow and sediment transport through culverts that further increase the dimensions of the investigation. The flow complexities investigated in this study entail: flow non-uniformity in the areas of transition to and from the culvert, flow unsteadiness due to the flood wave propagation through the channel, and the asynchronous correlation between the flow and sediment hydrographs resulting from storm events. To date, the literature contains no systematic studies on sediment transport through multi-box culverts or investigations on the adverse effects of sediment deposition at culverts. Moreover, there is limited knowledge about the non-uniform, unsteady sediment transport in channels of variable geometry. Furthermore, there are few readily useable (inexpensive and practical) numerical models that can reliably simulate flow and sediment transport in such complex situations. Given the current state of knowledge, the main goal of the present study is to investigate the above flow complexities in order to provide the needed insights for a series of ongoing culvert studies. The research was phased so that field observations were conducted first to understand the culvert behavior in Iowa landscape. Modeling through complementary hydraulic model and numerical experiments was subsequently carried out to gain the practical knowledge for the development of the self-cleaning culvert designs.
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Other Audit Reports
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Other Audit Reports
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Other audit reports
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Other Audit Reports
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One of the most important issues in portland cement concrete pavement research today is surface characteristics. The issue is one of balancing surface texture construction with the need for durability, skid resistance, and noise reduction. The National Concrete Pavement Technology Center at Iowa State University, in conjunction with the Federal Highway Administration, American Concrete Pavement Association, International Grinding and Grooving Association, Iowa Highway Research Board, and other states, have entered into a three-part National Surface Characteristics Program to resolve the balancing problem. As a portion of Part 2, this report documents the construction of 18 separate pavement surfaces for use in the first level of testing for the national project. It identifies the testing to be done and the limitations observed in the construction process. The results of the actual tests will be included in the subsequent national study reports.
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Other Audit Reports - 28E Organizations
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Surface characteristics represent a critical issue facing pavement owners and the concrete paving industry. The traveling public has come to expect smoother, quieter, and better drained pavements, all without compromising safety. The overall surface characteristics issues is extremely complex since all pavement surface characteristics properties, including texture, noise, friction, splash/spray, rolling resistance, reflectivity/illuminance, and smoothness, are complexly related. The following needs and gaps related to achieving desired pavement surface characteristics need to be addressed: determined how changes in one surface characteristic affect, either beneficially or detrimentally, other characteristics of the pavement, determine the long-term surface and acoustic durability of different textures, and develop, evaluate, and standardize new data collection and analysis tools. It is clear that an overall strategic and coordinated research approach to the problem must be developed and pursued to address these needs and gaps.
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Audit report on America’s Agricultural Industrial Heritage Landscape, Inc., d/b/a Silos and Smokestacks National Heritage Area (Silos and Smokestacks), in Waterloo, Iowa for the years ended December 31, 2006 and 2005
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Landscape amenities can be scarce in places with large areas of open space. Intensely farmed areas with high levels of monocropping and livestock production are akin to developed open space areas and do not provide many services in terms of landscape amenities. Open space in the form of farmland is plentiful, but parks and their services are in short supply. This issue is of particular importance for public policy because it is closely linked to the impact of externalities caused by agricultural activities and to the indirect effects of land use dynamics. This study looks at the impact of landscape amenities on rural residential property values in five counties in North Central Iowa using a hedonic pricing model based on geographic information systems. The effect of cropland, pasture, forest, and developed land as land uses surrounding the property is considered, as well as the impact of proximity to recreational areas. The study also includes the effect of other disamenities, such as livestock facilities and quarries, which can be considered part of the developed open space and are a common feature of the Iowa landscape.
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Audit report on America’s Agricultural Industrial Heritage Landscape, Inc., d/b/a Silos and Smokestacks National Heritage Area, in Waterloo, Iowa for the years ended December 31, 2007 and 2006
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Audit report on America’s Agricultural Industrial Heritage Landscape, Inc., d/b/a Silos and Smokestacks National Heritage Area, in Waterloo, Iowa for the years ended December 31, 2008 and 2007
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A report to the Iowa State Conservation Commission and to the Iowa State Preserves Advisory Board
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Audit report on America’s Agricultural Industrial Heritage Landscape, Inc., d/b/a Silos and Smokestacks National Heritage Area (Silos and Smokestacks), in Waterloo, Iowa for the years ended December 31, 2009 and 2008
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Audit report on America’s Agricultural Industrial Heritage Landscape, Inc., d/b/a Silos and Smokestacks National Heritage Area, in Waterloo, Iowa for the years ended December 31, 2010 and 2009
