A new line-based feature class, U024.StreamsNHDHighRes, representing streams, creeks, canals, and other water courses is now available on the SGID 9.2 ArcSDE Database Server in the U024.Hydrology feature dataset. This feature class was derived from the National Hydrology Dataset (NHD) flow lines layer and offers the GNIS stream name (where available), reach code, and feature type/code among other attributes (see description of added cartographic attributes below). The NHD line work has been photo revised to the latest edition of the black and white DOQ aerial photography. Shapefiles and File-Based Geodatabase files for this layer are available on AGRC’s ftp site at: ftp://ftp.agrc.utah.gov/SGID_Vector/Hydrology/SGID_U024_StreamsNHDHighRes
The state of Utah contains many hydrologic units and the relevant units have been aggregated into this new composite layer that includes some features that cross the state boundary (these have been split at the boundary into 2 features) and, also some features outside the state boundary. In order to allow for cartographic projects that are bounded by the state boundaries, an attribute field called InUtah has been added and can be used to query just those features within Utah (InUtah = 1).
In addition, an attribute field called IsMajor has been added to facilitate the display of major streams. This attribute was coded by AGRC staff to represent perennial and other important stream features in the state (IsMajor = 1). Streams shown on the state highway map were used as a starting point for assigning this attribute value.
Other notes:
AGRC plans to host the full NHD hydrologic modelling datasets in the future, at present this data is available by NHD subregion from the USGS website: http://nhd.usgs.gov/data.html
A feature class called SGID.UtahMajorRivers was recently added to the SGID Database Server. This feature class will be removed soon as its purpose has been incorporated into the U024.StreamsNHDHighRes feature class in the IsMajor field.
