Local Resolution NHD Photo-Based Revision for West Virginia Jackie Strager Kurt Donaldson Kevin Kuhn April 24, 2007 Denver, CO West Virginia GIS Technical Center Natural Resource Analysis Center West Virginia University WV State GIS Coordinator’s Office

Introduction Status of NHD in West Virginia –33 sub-basins –Medium, high resolution NHD complete –Pilot projects underway for Local Resolution (LR) NHD creation

Local Resolution Pilot Project Objectives –Meet with potential data users –Develop methods and standards –Assemble 1:4800 source data statewide –Assemble final LR-NHD for two pilot watersheds –Show benefits of LR-NHD for water resource applications

LR NHD Process Steps 1. Capture local hydro features 2. Data prep and revision 3. Pre-conflation steps 4. Conflation/QAQC steps 5. Ensure data stewardship

1. Capture local hydro features Statewide aerial photography, 2003 Contractor digitized hydro features from stereo pairs Local scale hydro features from SAMB photos Sutton Lake, WV 1:4800 streams 1:4800 polygons Features with visible water only Single-lined up to 50ft wide Double-lined over 50ft wide Lakes/ponds (min. 100ft wide) Swamps/marshes No name or code attributes Correct flow direction Edge-matched

2. Data prep/revision Systematically examine contractor’s hydro data for incomplete and missing features Close double-lined streams Add DLG codes Approximately 15-20% of streams were not adequately captured in source local datasets. 1:4800 streams in source Additional 24K streams added

3-4. Pre-conflation, conflation For pilot watersheds: USGS routines and NHD Geo-Conflation Toolkit (NHDGCT) –Pre-conflation –Conflation –QAQC Load into national dataset

5. Long term maintenance Involve interested cooperators Encourage NHD stewardship process Project communications Show benefits of LR-NHD data Website:

Benefits of LR NHD Common data framework among NHD scales 1:100,000 scale NHD Medium resolution 1:24,000 scale NHD High resolution 1:4800 scale streams Local resolution (approximated from SAMB stream data) Sutton Lake

Benefits Provides more highly detailed cartographic base 24K NHD streams LR NHD streams Flatwoods WV

Benefits More accurate source data Source for 24K NHD: Big Chimney quad Last revised: 1976 Source for LR NHD: 2003 Aerial photo Revised LR NHD streams shown in yellow

Benefits Quantifies recent changes in stream drainage 24K NHD streams LR NHD streams Active mine permit, Lockwood quad Valley fill area EPA: Up to 1,200 miles of streams lost in multi-state mountaintop-removal mining region

Benefits Supports modeling of flow and hydrology at detailed local scale More accurate stream mileage for stream mitigation projects, riparian buffers Aids in floodplain mapping and emergency planning More detailed dataset for resource management and planning, permitting, cumulative impact analysis

Benefits Supports WV legislative requirement –WV Water Resources Protection Act –Quantify nature and extent of water resources

Future Considerations Completion of LR NHD Cartographic issues Edge-matching Encouraging partnerships Data stewardship –Updates, maintenance

Thank you!