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Improving Water Resource Infrastructure in Texas: Geodatabase Project Status Update

Explore the progress of the National Hydrography Dataset High Resolution project in Texas, addressing data completeness, flowline connectivity issues, and future goals to enhance water resource management.

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Improving Water Resource Infrastructure in Texas: Geodatabase Project Status Update

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  1. A Geodatabase Infrastructure for Texas Project Status Presented by: Tyler Jantzen GIS in Water Resources CE394K.3 November 29, 2005

  2. Background Information • National Hydrography Dataset High Resolution (NHDH) is being compiled for U.S. • NHDH is listed as complete for the state of Texas • 24 Subregions lie within Texas • These 24 Subregions contain 1.8 million flowlines, and over 688,000 miles of streamlength. • Ultimate Goal: To trace a drop of water from source to sink

  3. Medium Resolution vs. High Resolution Medium Resolution: 1:100,000 1.38 GB High Resolution: 1: 24,000 20x number of lines 3x length of lines 7.33 GB 24 Subregions

  4. NHD Subregions in Texas

  5. Problem Definition • Some subregions are missing data

  6. Problem Definition • Flowlines are not physically connected These are duplicates, and should be connected

  7. Problem Definition • Some flowlines are not initialized properly • Uninitialized flow direction makes flow tracing impossible

  8. Problem Definition • Cannot “trace” from top to bottom of basin • How can the extent of the problem be quantified? Trace should reach entire subregion Trace Upstream Trace Downstream

  9. Data Requirements • 24 NHD Subregion Personal Geodatabases • Information at http://nhd.usgs.gov • Download at ftp://nhdftp.cr.usgs.gov/NHD_HUC and ftp://nhdftp.usgs.gov/SubRegions • Texas Natural Resource Information System (TNRIS)

  10. Methodology Developed • Place flag at subregion outlet • Trace upstream or Find disconnected • Place additional flags where trace ends Simulates “fixing” a disconnect • Continue until majority of subregion is traced

  11. Results • Measure data completeness: Drainage Density • DD<1 → Likely incomplete • DD>1 → Likely complete

  12. Results • Using Trace Upstream function

  13. Results • Using Find Disconnected function

  14. Conclusions • If 55 fixes were made, 91% of the network would be connected • 12 of the 24 regions are still missing data

  15. Future Work • Fill in missing data • Create single geodatabase for entire state • Measure connectivity for single large geodatabase

  16. Recommendations • With minimal fixes (55) over the entire state, a majority (91%) of the streams will be connected to the network • These fixes, if made, will significantly increase the utility of the NHD

  17. Questions?

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