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travertine deposits as records of urbanization impacts austin tx n.
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Travertine Deposits as Records of Urbanization Impacts, Austin, TX PowerPoint Presentation
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Travertine Deposits as Records of Urbanization Impacts, Austin, TX

Travertine Deposits as Records of Urbanization Impacts, Austin, TX

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Travertine Deposits as Records of Urbanization Impacts, Austin, TX

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  1. Travertine Deposits as Records of Urbanization Impacts, Austin, TX Laura M. DeMott December 1, 2005

  2. Outline • Background • Objectives • Work Accomplished • Problems Encountered! • Future work

  3. Background What is a Travertine? • Travertines are surface deposits of calcite (CaCO3) • They precipitate directly from supersaturated spring waters via degassing of CO2 • The calcite structure can record the water chemistry at the time of travertine precipitation.

  4. Background • Urbanization causes many changes to water chemistry, amount, etc. • Urbanization in Austin has increased dramatically over the past 40 years with no record of what the water was like beforehand • Can travertine geochemistry show these effects?

  5. Objectives • Create base map showing sample sites and urban land use • Delineate the drainage areas for each site as a proxy for recharge areas • Contour the water table?

  6. Data Sources • Satellite photos, Topo maps, TXDOT • TNRIS (http://www.tnris.state.tx.us/digital.htm) • Aquifers, Well data • TWDB (http://www.twdb.state.tx.us/mapping/gisdata.asp) • Counties • Texas General Land Office (http://www.glo.state.tx.us/gisdata/gisdata.html) • Flowlines • NHD (http://nhd.usgs.gov/data.html)

  7. Building the Base Map

  8. Why Plotting by Coordinates is Better Than Plotting by Hand

  9. Drainage Areas • DEM Problems! • Stupid geology computers won’t let me download USGS seamless DEMs • Other DEMs won’t work! • Only working DEM of poor quality

  10. Future Work • Find a DEM that works! • Delineate the watersheds for each of my sites • Figure out how to contour the potentiometric surface based on TWDB well data • Show the areas contributing groundwater to the springs

  11. QUESTIONS?