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Enhancing High-Resolution NHD through Value-Added Attributes: Insights from the 2012 Stewardship Conference

Join Josh Lear from the Nebraska Department of Natural Resources in exploring value-added attributes (VAAs) that enhance high-resolution National Hydrography Dataset (NHD). This presentation highlights the derivation of VAAs, their applications, and solutions to navigate divergences in datasets. Key insights include the challenges posed by braids and canals, evaluation of VAAs, and preliminary results highlighting the effectiveness of VAAs in improving navigation determinism. Learn the significance of information in hydrological mapping and data interpretation.

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Enhancing High-Resolution NHD through Value-Added Attributes: Insights from the 2012 Stewardship Conference

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  1. Value-Added Attributes for High-Resolution NHD NHD Stewardship Conference March 30, 2012 New Orleans, Louisiana Josh Lear Nebraska Department of Natural Resources

  2. Goals: • Understand how Value-Added Attributes translate to high resolution NHD • Understand Value added attributes • How they are derived • How to use them • Find a simple solution to navigating divergences

  3. Agenda • Context for discussion • Preparation and evaluation • Observations • Conclusions

  4. Subregion 1015 - Niobrara

  5. THE NAVIGATION ISSUE GNIS_ID FCode ReachCode Divergence Stream Gage Point of Diversion

  6. Value Added Attributes • FromNode/ToNode • StartFlag/TerminalFlag • VPUin/VPUout • StreamLevel • Divergence • DnDrainCount • Hydrosequence • DnLevel • UpHydroSeq/DnHydroSeq/DnMinorHydroSeq • StreamOrder/StreamCalc • LevelPathID • TerminalPathID • UplevelPathID/DnLevelPathID • PathLength • ArbolateSum • RtnDIV

  7. Navigation Determinants DNR • GNIS_ID • Fcodes • ReachCodes Value-Added Attributes • GNIS_ID • Ftype • LengthKM • + boundary information DNR relationships are local VAA relationships are system-wide

  8. Evaluation • Prepared 1015 using NHDPlus QAQC Tools • 4 Variations based on FlowDirection: • All features “WithDigitized” • Braids “Uninitialized” • Canals “Uninitialized” • Canals and braids “Uninitialized” • VAAs calculated • All Divergences evaluated for downstream navigation

  9. Preliminary Results – (AllFlow) 457 Divergences • 108 failed using the DNR approach (24%) • Not enough information • VAAs always navigated the divergence • Divergent flag • 82 Divergent flags assigned incorrectly

  10. Observations: • Errors still existed in the Flowline • Braids, Field drains • Removing braids improved VAAs • Canals -flow the wrong direction • Canals w/no returns – disconnected drains • Canal w/returns distort the VAAs significantly • Removing canals improved VAAs

  11. Canal – StreamLevel Error

  12. Observations: • Substantial agreement between methods • GNIS_ID • FCodes played a minor role • ReachCode

  13. ReachCode Miss

  14. Preliminary Conclusions: • VAAs are a superior solution • Information is the key • On the flowline • In the VAA program

  15. To Do: • Recalculate and Re-evaluate VAAs for 1015 • Configuration: • Braids, Field Drains, Canals off • Calculate VAAs • Canals on • Look at the other attributes • Catch my flight home

  16. Thanks: • Jeff Simley and USGS • Cindy McKay and Horizon Systems Inc. • NHD Community

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