No description available.

No description available.

No abstract was provided. / Thesis / Master of Engineering (ME)

The Weeks Bay watershed in Baldwin County, Alabama has experienced rapid changes in landuse/ landcover (LULC) from 1990 to 2000. These changes have resulted in increased upland erosion and higher concentrations of suspended sediment within the watershed. For this research project a spatial model was developed to identify potential sources of sediment relevant to LULC and slope. Landsat satellite imagery was classified to assess LULC within the Weeks Bay watershed. The classification includes forested vegetation, herbaceous vegetation (seasonal and persistent), mixed/ transitional vegetation, urban/ built-up areas, sparse/ residual vegetation and water, with an overall accuracy of 78%. Change detections of the classified images yielded substantial increases in urban areas (92.5%). These data were coupled with slope data in a geographic information system and a raster analysis provided a qualitative evaluation of potential sediment sources within the Weeks Bay watershed based on the change in LULC and slopes of the landscape.

No description available.

No description available.

Thesis (Ph. D.)--University of Washington, 2002. / Includes bibliographical references (leaves 240-251).

published_or_final_version / Mechanical Engineering / Master / Master of Science in Engineering

A tilting bed flume study was made to examine the relationships between velocity, suspended sediment and infiltration rate in alluvial channels for velocities from 2 to 5 feet per second and suspended sediment up to 0.6 percent. Preliminary experiments using samples from Rhllito Creek near Tucson, Arizona to define limits for the flume study included mechanical analyses of bed sediments, permeability and infiltration tests, and analyses of suspended sediment in flood waters. Flume experiments using bed materials from Rillito Creek were made with constant velocity and variable suspended sediment content, then with constant suspended sediment and variable velocity. Considerable variability was found in the mechanical analyses, permeability and infiltration tests, and suspended sediment content for samples from different locations. The flume studies indicated a direct relationship between velocity and infiltration rate and an inverse relationship between the suspended sediment content and infiltration rate in the ranges tested. Very poor correlation was found between the preliminary permeability and infiltration tests and the flume infiltration rates, but good correlation was obtained for the flume results with the flow losses and natural recharge occurring in the river channels in the Tucson area.

Many determinations have been made of the dielectric constant of water, and of its variations caused by temperature and frequency. The dielectric constant of water has a relatively high value as compared with those of many other substances with which water is commonly associated. Consequently, measurements of the dielectric constant (or of the electrical capacitance) of materials such as soil, cereal and grain have been used as indications of their moisture contents. This study was undertaken to determine whether or not a capacitance method can be used to measure sediment concentrations in water. Laboratory measurements were made of varying concentrations of several individual artificial sediments, natural sediments, and pure salts in distilled water. A flow-through-type conductivity cell was used in which the capacitor plates are fixed in relation to each other. The equation for capacitance of the flow through cell can be written as C = kD where C capacitance in farads, k = a constant determined by the physical configuration of the cell, D = dielectric constant, and it is seen that C varies directly as D. Typical values of salt and sediment concentrations existing in natural streams in the United States were determined from the literature. Conclusions of the study are summarized as follows: 1. The capacitance method of measuring concentrations of sediment in natural streams is not practical for the following reasons. The presence of even small quantities of conducting and/or magnetic sediments in the measured samples invalidates the measurements. Concentrations of sediments in most streams in the United States are too low during most of the year to be sensed by the capacitance method. Concentrations of dissolved solids in many streams in the United States are high enough during at least part of the year to render capacitance measurements inaccurate. The surface chemistry of clay-size particles prevents their being reliably measured with the capacitance method. 2. The capacitance method of measurement may be applicable for particular or specialized uses, such as the determination in the laboratory of concentrations of mixtures of known nonconducting and nonmagnetic particulate matter. Such measurements are not noticeably affected by the salts used in this study until their concentrations exceed about 10 meq/l. It is recommended that further efforts to adapt the capacitance method to the measurement of stream sediments be discontinued.