New Documents for the National Hydrography Dataset

National Hydrography Dataset Feature Catalog Based on 1:24,000-scale USGS Topographic Map Content U.S. Department of the Interior U.S. Geological Survey

AREA OF COMPLEX CHANNELS – Glacial outwash in Alaska

AREA TO BE SUBMERGED Dam under construction will create Lake Nighthorse in CO

Artificial Path – no real world image

BAY/INLET

BRIDGE – C&O Canal Carried over the Monocacy River

Los Angeles Aqueduct CANAL/DITCH – C/D Type = Aqueduct PIPELINE – Pipeline Type = Aqueduct; Aboveground Both of these features function as an aqueduct – “A structure designed to transport domestic or industrial water from a supply source to a distribution point, often by gravity” However, they have different forms. One is an “artificial open waterway…” and the other is a “closed conduit…”

Coastline

Connector

GATE

PIPELINE – Penstock above ground

PIPELINE - Elevated

PLAYA

ROCK

WATER INTAKE/OUTFLOW – Hoover Dam

San Francisco/San Pablo/Suisun Bay ESTUARY Looking south west towards the Pacific Ocean

San Francisco/San Pablo/Suisun Bay Estuary – currently coded as SEA/OCEAN (grey-blue) in the NHD. New guidance for delineation of ESTUARY would separate the ESTUARY from SEA/OCEAN as shown by the solid green line (approximately the Golden Gate Bridge). Pink straight line indicates line of sight from the photo. The red line in the Pacific Ocean is the three-mile limit. This is the preferred limit for SEA/OCEAN – current limit of SEA/OCEAN is the edge of the USGS quadrangle maps – hence the straight lines.

Hassayampa River - WASH

In the NHD, WASHES are delineated only as areas. If there is no perennial channel within the wash, ARTIFICIAL PATHS are added to allow flow through the network. Hassayampa River

National Hydro Dataset Data Dictionary Data Model version 1.06 U.S. Department of the Interior U.S. Geological Survey

Remember to show the document to the Stewards

Hydrography Feature Classes Field NameDefinitionApplies toComments ComID10-digit integer that uniquely identifies the occurrence of each feature. All feature classes National Database key. All maintenance activities depend on this ID. FDateDate of last feature modification.All feature classes ResolutionSource resolution. Currently NHD is available as separate resolutions. Plans are to develop a single- resolution database holding the highest resolution data with tools to allow for generalization All feature classes Domain of values: Local >1:12,000 High 1:24,000/12,000 Medium 1:100,000 GNIS_IDUnique identifier assigned by GNIS, length 10. All feature classes GNIS_ID = “null” if no name associated with the feature GNIS_NameProper name, specific term, or expression by which a particular geographic entity is known, length 65. All feature classes GNIS_Name = “null” if no name associated with the feature LengthKMLength of linear feature based on Albers Equal Area, length 8. NHDFlowline NHDLine Computed AreaSqKmArea of areal feature based on Albers Equal Area, length 8. NHDArea NHDWaterbody Computed ElevationThe vertical distance from a given datum. NHDArea NHDWaterbody Stage of the water elevation is encoded in the FCode. ReachCodeUnique identifier composed of two parts. The first eight digits is the subbasin code as defined by FIPS 103. The next six digits are randomly assigned, sequential numbers that are unique within a subbasin, length 14. NHDFlowline NHDWaterbody NHDPoint Required for all NHDFlowlines. NHDWaterbody and NHDPoint feature classes allow reach codes, but does not require them. FlowDirDirection of flow relative to coordinate order, length 4. NHDFlowlineDomain of values: With digitized Uninitialized WBAreaComI D The ComID of the waterbody through which the Flowline flows. NHDFlowlineOnly applies to Artificial Path FTypeThree-digit integer value; unique identifier of a feature type. All feature classes Click here for the feature catalog FCodeFive-digit integer value; composed of the feature type and combinations of characteristics and values. All feature classes Click here for the feature catalog

National Hydro Database Stewardship Handbook Review Draft Please send comments to: Keven Roth U.S. Department of the Interior U.S. Geological Survey

Things to come Metadata

Data in Previous Slide shows edits (in pink) in Metadata record for the updates shown in previous slide is: “Update high-resolution NHD for Benton and Washington Counties, AR from 25ft LIDAR derived DEM and 6in and 12in ortho-imagery, dated 2004 and This process started with current high resolution USGS NHD geodatabase files. These data were downloaded, extracted and reprojected to NAD 83 State Plane Arkansas N. Next, the NRCS 10-digit Hydrologic Unit Code (HUC) boundary was obtained from GeoStor, Arkansas official geodata clearinghouse. The HUC boundary was projected to the State Plane projection and used, in part, to determine the true spatial extent of 8-digit HUC (Sub-basin) boundaries with Benton and Washington Counties. Next, hydrological analyses were performed on a 25ft LIDAR derived DEM using ArcInfo 9.1 hydrologic tools. The 25ft DEM was generated by the Center for Advanced Spatial Technologies (CAST) at the University of Arkansas using a bare earth point cloud obtained from Landair Mapping, Inc as part of the August 2004 LIDAR acquisition (Washington & Benton Counties, AR) coordinated by John McLarty, Elizabeth Bowen, Brian Culpepper, and Dr. Jack Cothren of the Northwest Arkansas Imagery Task Force. The purpose of hydrological analysis was to determine flow accumulation and direction throughout Benton and Washington Counties, thus providing an indicator as to the location of undocumented streams. Finally high resolution 2004 and 2006 true-color orthoimages, distributed by the Northwest Arkansas Regional Planning Commission and co-operative partners, were added to ArcMap 9.1 project file along with NHD, HUC high resolution boundaries and DEM flowpaths. Navigating between all 4 datasets, the 1D and 2D NHD features were updated to reflect temporal changes. Presence of 2D features were determined if the feature could be clearly seen to have area in either the 2004 or 2006 orthoimages when the screen was set to a scale of 1:4,800. Once identified, a polygon boundary was drawn, or updated, to show the feature at its high water mark (its greatest area in either of the available orthoimages). 1D features were identified using a combination of flow accumulation values (determined by DEM hydrological analyses) and supporting visual data in the orthoimagery (i.e. location of vegetative stream buffers), and drawn or updated accordingly. Consultation with the USGS concluded that undocumented streams would most likely occur in areas where the flow accumulation value was >2000 (greater than 2000 upslope pixels); therefore, areas having a value of <2000 were rarely considered for possible streams. All new 1D and 2D features were assigned feature codes (fcodes) in accordance to USGS NHD definitions, along with new reach codes.”

This metadata record was automatically generated by the disconnected edit check- in program because no metadata was supplied. NHD Update Update Lines based on 2002 Photography