national elevation dataset - hydrologic derivatives (ned-h)
DESCRIPTION
National Elevation Dataset - Hydrologic Derivatives (NED-H). Kris Verdin. EROS Data Center. [email protected]. NED-H Description. The N ational E levation D ataset- H ydrologic Derivatives Multi-layer dataset of topographically-derived data layers of hydrologic significance - PowerPoint PPT PresentationTRANSCRIPT
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Kris VerdinEROS Data [email protected]
National Elevation Dataset - Hydrologic Derivatives (NED-H)
NED-H Description
• The National Elevation Dataset-Hydrologic Derivatives
• Multi-layer dataset of topographically-derived data layers of hydrologic significance
• Derived from NED in U.S. Albers projection, 30 m cell size
National Elevation Dataset - Hydrologic Derivatives (NED-H)
NED-H Core Data Layers• Raster Layers• Hydrologically
Conditioned DEM• Flow directions• Flow accumulations• Slope• Aspect• Compound Topographic
Index
• Vector Layers• Synthetic Streamlines• Reach Catchments• Metadata
National Elevation Dataset - Hydrologic Derivatives (NED-H)
NED-H Rationale
• Responsive to the need for better watershed boundaries for the country
• Serves to integrate two of USGS’ key National Datasets - NED and NHD
• Will provide nation-wide, reliable flow direction dataset
National Elevation Dataset - Hydrologic Derivatives (NED-H)
NED-H Cooperators
• USGS Mapping & Water Divisions– EROS team providing core team– Cooperative development of the WBD – NAWQA funded development of Stage 2 tools
• National Weather Service– Bulk processing of Stage 1 data– Using Stage 1 product in AMBER modeling effort
• EPA Office of Research & Development– funding Stage 3 tool development
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Development Stages• 3 Stage Plan for development
– Stage 1: Blind Pass Processing • Cataloging Unit used as processing unit• National Weather Service’s National Severe
Storms Lab in Norman, OK• California being done by WRD in Sacramento
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Development Stages
• Stage 1 Post-processing
– Stage 1a: Clean-up of sink processing• Digital Dam-break algorithm
– Stage 1b: Attribution of Pfafstetter ID to reach catchments
• Will immediately be useful as input to AMBER modeling
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Stage 1a:Digital Dam-break algorithm
• Post-processing of large spurious sink features filled in Stage 1
• Typically, these features are “filled” to allow uninterrupted flow
• Iterative algorithm identifies controlling pour point and breaks the digital dam
• Results in preservation of detail of DEM and improved streamline generation
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Cataloging Unit #05020003
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Detail of Output from Stage 1
National Elevation Dataset - Hydrologic Derivatives (NED-H)
NHD 1:100,000 scale streamlines
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Sinks identified in Stage 1
National Elevation Dataset - Hydrologic Derivatives (NED-H)
NED-H Streamlines generated after filling large sink
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Post-processing of large sink features
National Elevation Dataset - Hydrologic Derivatives (NED-H)
New sink mask and derived streamlines
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Stage 1b:Pfafstetter Attribution
• Provides unique ID number for every reach catchment – ~1000 per C.U.
• Pfafstetter number carries topological information – no linkage table required
• Numbers developed on catchment basis and transferred onto streamlines
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Pfafstetter Demonstration
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Development Stages
• Stage 2: Vector Editing– In-depth QA/QC of Stage 1 products by local or
regional stakeholders– ArcView based procedures for Stage 2
cooperators– Output is watershed and subwatershed
delineations for WBD along with areas identified for correction in Stage 3
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Stage 2 cooperators
• USGS – Utah, New York, Cheaspeake Bay area
• EPA
• USFS - Alaska
• State agencies
• Stage 2 training – Thursday afternoon
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Development Stages
• Stage 3: Raster Editing – Feedback from Stage 2 is incorporated into NED-
H DEM via raster edits where required– Revised DEM and derivatives reflect correct
drainage pattern– Derived streamlines are conflated with NHD for
final transfer of attributes• Reach Code is common attribute
National Elevation Dataset - Hydrologic Derivatives (NED-H)
Stage 3 Tools
• Highway overpass/blockage tool
• Improved flow direction algorithm through flat area
• Sink clearing tool
http://edcnts12.cr.usgs.gov/ned-h