Indiana National Hydrography Dataset (NHD) Improvement and Application Workshop

1. NHD Local-Resolution Development Indiana National Hydrography Dataset (NHD) Improvement and Application Workshop

2. Agenda • Background • Pilot Study • Approach • Project Tasks • Conversion • Conflation • Demo • Status / Next Steps

3. Background • Working closely with IGIC Waters Workgroup to develop Local-Resolution NHD for the State of Indiana • Product must meet USGS NHD capture standards • Loaded into USGS National Map and IndianaMap upon QC and approval • More detailed hydrography, more accurate spatial locations • All attributes that currently exist in the 1:24K NHD will be transferred (conflated)

4. Background Pilot study conducted in Summer 2009 • Small watershed in Hamilton County (Morse Reservoir and agricultural land) • Broad representation of the water features to be included in the statewide project • Designed to provide a basis for stream location accuracy and upstream drainage area limit assessments • No 1:24K NHD attributes conflated • Written report of findings

5. Background Statewide project completed by HUC-8 watershed sub-basin in phases: • Upper Eel will be first sub-basin completed • Linework QC and approval prior to conflation • Interim attribute QC before reach codes are allocated • Attribute conflation QC before work begins on additional sub-basins • 37 additional sub-basins in state • Local subcontractors will assist with hydrography

6. Approach • Creation of local-resolution hydrography • 5 feature classes created • NHDFlowline (Stream/River, Canal/Ditch, Artificial Path) • NHDWaterbody (Lake/Pond, Swamp/Marsh, Reservior) • NHDArea (Large Stream/River, Large Canal/Ditch) • NHDPoint (Gaging Station, Well) • NHDLine (Dams)

7. Approach • 6 acre upstream drainage limit • Features digitized from orthoimagery and elevation data • 1:24K NHD attribute conflation – NHD attribute population for new features

8. Approach • Base Data • Imagery • 2005 one foot and/or half foot pixel RGB orthophotography • Terrain (Contours, DEMs, Hillshades) • 2005 five foot cell size DEM (ISTAR) • Supplemented by newer and/or more accurate local data where available

9. Approach • Reference Files • Local Hydrography provided by the State • National Wetlands Inventory (NWI) • INDNR Dams • DOT Bridges • 1:24K NHD • Karst Dyelines

10. Project Tasks - Conversion • Hydro-correct elevation data • Generate 6 acre basins and streams for reference (guidance for upstream limits and stream location) • Generate contours, DEMs, hillshades for reference

11. Project Tasks - Conversion • Digitize NHD features • Create 1:2,400 or 1:1,200 scale hydrography layer (dependent upon imagery source) to the 6 acre upstream drainage limit • Imagery will be primary source for data conversion, terrain data used where features are not visible • 1:24K NHD used as reference to ensure all features from the 1:24K NHD have been incorporated • Hydrography edge-matched to 1:24K NHD along state borders

12. Project Tasks - Conversion • Business Rules • NHDFlowline • If 1:24K flowline extends further upstream than 6 acres, it will be maintained • If features from 1:24K flowline no longer visible, not included in local resolution dataset • If feature is less than 20 feet wide and less than 600 feet long it will be captured as a flowline

13. Project Tasks - Conversion • Business Rules • NHDArea • If feature is more than 20 feet wide and more than 600 feet long it will be captured as an area • All 1:24K NHDAreas will be retained if the feature is visible in the imagery

14. Project Tasks - Conversion • Business Rules • NHDWaterbodies • ¼ acre or larger will be collected; if less than that but included in 1:24K NHD and visible in imagery, it will be kept • Generated using ERDAS Objective (Ortho-recognition software)

15. Project Tasks - Conversion • Business Rules • NHDPoints – no new features added, copy over and adjust existing 1:24K NHD features as necessary • NHDLines – new features added if found in reference files (dams), will also copy over and adjust existing 1:24K NHD features as necessary

16. Project Tasks - Conversion • Prep data for conflation • The NHDinGeo version 2.0 database schema will be used • Combination of USGS scripts, and ArcGIS 9.3 tools to check: • Topology • Flow direction • FCode population • Artificial paths • Connectors

17. Project Tasks - Conflation • Conflation of1:24K NHD attributes and data population for new features • USGS NHD GeoConflation Toolset • Reach codes, GNIS info conflated from 1:24K NHD, and generated for new features using the USGS NHD tools • Intermittent/Perennial designations conflated for1:24K attributes only

18. Project Tasks - Conflation • Quality Control of conflated attributes: • Most performed through NHD GeoConflation queues at various stages • After permanent reach codes assigned, checks for gapped or branched reach codes • Checks for gapped or branched GNIS names • Subsequent processing steps cannot proceed until potential problems have been resolved * Close coordination with and approval by USGS

19. Project Tasks - Conflation • Waters Workgroup will check out 1:24K NHD sub-basins as conflation occurs to avoid any other edits being made to the sub-basin • Feature level, FGDC compliant metadata generated for each sub-basin

20. Demo

21. Status / Next Steps • Status • Completed conflation training with USGS • Base data received for Upper Eel pilot area • Next Steps • Complete conversion and conflation tasks for Upper Eel pilot area • 3 iterations of QC performed by Indiana’s QC team • Prioritize work, outline schedule for remaining sub-basins • Train and engage subcontractors

22. Questions and Answers