Show simple item record

dc.contributor.advisorMathewson, Christopher C.
dc.creatorAllison, John Bryan
dc.date.accessioned2005-08-29T14:39:22Z
dc.date.available2005-08-29T14:39:22Z
dc.date.created2006-05
dc.date.issued2005-08-29
dc.identifier.urihttp://hdl.handle.net/1969.1/2347
dc.description.abstractThe coastal wetlands at Aransas National Wildlife Refuge near Austwell, Texas, support the last migrating population of whooping cranes during the winter months (October through April). With a population currently at 216 individuals, these are the rarest cranes in the world. The wetlands in which they winter are a part of the San Antonio Bay system, a bay that receives constant fresh water flow from the Guadalupe River. Currently there is a plan for using water diverted from the Guadalupe River just before it enters San Antonio Bay as a water supply for the greater San Antonio metropolitan area located 200 km to the northwest. The Guadalupe River delivers nutrients and sediment into the estuary along with fresh water. Because of the importance of sediment within a tidal wetland ecosystem, it is imperative to understand the sediment budget and underlying forces that drive it if one is to ultimately grasp how this ecosystem functions. To document natural and anthropogenic factors exerting control over sediment movement in this system, three sites on tidal creeks near the boundary between marsh and bay were chosen. The Gulf Intracoastal Waterwayparallels the marsh edge. Over six, non-consecutive weeks water level and velocity were automatically monitored in the tidal creeks. Automated water samplers extracted water samples that were analyzed for suspended sediment. In addition, bedload traps were deployed in one creek to monitor sediment movement along the channel bottom. Inflow exceeded outflow during the study. As a result there was a net influx of suspended sediments into the marsh. Bedload material also moves with current direction, and it appears to move in response to barge induced outflow currents. Barges passing on the Gulf Intracoastal Waterway exert influence on water level, flow direction, and velocity within tidal creeks. Natural factors such as winds, tides, and freshwater input from upland runoff or river discharge also impact suspended and bedload sediments.en
dc.format.extent1495131 bytesen
dc.format.mediumelectronicen
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherTexas A&M University
dc.subjectsedimenten
dc.subjectfluxen
dc.subjectAransasen
dc.subjectbedloaden
dc.subjecttidal creeken
dc.subjectmarshen
dc.titleCharacterization of sediment movement in tidal creeks adjacent to the gulf intracoastal waterway at Aransas National Wildlife Refuge, Austwell, TX: study of natural factors and effects of barge-induced drawdown currentsen
dc.typeThesisen
thesis.degree.departmentGeology and Geophysicsen
thesis.degree.disciplineGeologyen
thesis.degree.grantorTexas A&M Universityen
thesis.degree.nameMaster of Scienceen
thesis.degree.levelMastersen
dc.contributor.committeeMemberDavis, Stephen E.
dc.contributor.committeeMemberHallmark, Charles T.
dc.type.genreElectronic Thesisen
dc.type.materialtexten
dc.format.digitalOriginborn digitalen


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record