Eastern watershed analysis of alternate approaches to delineation in Austin, TX


Eastern watershed analysis of alternate approaches to delineation in Austin, TX

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dc.contributor.advisor Paterson, Robert G.
dc.creator Vermillion, Elizabeth Lauren, 1982-
dc.date.accessioned 2010-11-24T21:53:09Z
dc.date.accessioned 2010-11-24T21:53:18Z
dc.date.available 2010-11-24T21:53:09Z
dc.date.available 2010-11-24T21:53:18Z
dc.date.created 2010-05
dc.date.issued 2010-11-24
dc.date.submitted May 2010
dc.identifier.uri http://hdl.handle.net/2152/ETD-UT-2010-05-1296
dc.description.abstract Drainage area is a measure of the number of acres feeding into a creek. Drainage area threshold is the amount of acreage required for the creek to be included on a map. Watersheds mapped according to higher drainage area thresholds will show creek systems that are shorter and concentrated at the bottom of the watershed. Watersheds mapped according to lower drainage area thresholds show creek systems that are longer and extend further up the watershed. Since all watersheds are subject to different land uses, soil types, geology, etc., they should be mapped according to different drainage area thresholds. Headwaters are where creeks begin. There is empirical evidence that properly functioning headwaters significantly reduce erosion, improve water quality, slow stormwater flows, and provide habitat. If municipalities use lower drainage area thresholds to define their creeks, they can include more headwaters in their creek setback requirements. This professional report identifies the Harris Branch watershed as being under relatively more pressure to develop and exhibiting more environmental risk than other watersheds in Austin, Texas’ Desired Development Zone. Creeks in the watershed are redrawn according to reduced drainage area thresholds using a simple ArcGIS analysis. The analysis reveals a critical mass where creek setbacks appear to be too extensive. If creeks with a drainage area of 5 acres are protected by development code, the setbacks created have excessive branching that could be too restrictive for development. A critical mass ratio should be considered when determining which drainage area threshold is most appropriate for a watershed. The critical mass ratio is equal to the number of branches allowed per a specified distance of creek centerline. The process of identifying this critical mass ratio can help growing cities find a balance between the need to encourage development in designated areas and the need to protect natural creek systems everywhere. I recommend that municipalities review the effects of reducing drainage area threshold for each watershed, and then identify the drainage area threshold that, when protected by setback requirements, allows for extended and connected greenways as well as an increase in density.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subject Drainage area threshold
dc.subject Creek setbacks
dc.subject Watershed management
dc.subject Water quality
dc.subject Storm water management
dc.subject Austin, Texas
dc.title Eastern watershed analysis of alternate approaches to delineation in Austin, TX
dc.date.updated 2010-11-24T21:53:19Z
dc.contributor.committeeMember Schuster, Stefan
dc.description.department Community and Regional Planning
dc.type.genre thesis
dc.type.material text
thesis.degree.department Community and Regional Planning
thesis.degree.discipline Community and Regional Planning
thesis.degree.grantor University of Texas at Austin
thesis.degree.level Masters
thesis.degree.name Master of Science in Community and Regional Planning

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