The SGID'sU024.StreamsNHDHighRes feature class represents streams, creeks, canals, and other water courses and was derived from the National Hydrology Dataset (NHD) flow lines layer. This layer has just been updated to improve the feature geometry and name attributes for the Jordan sub basin, which is basically Salt Lake County.
TVC’s are an interim product of the USGS DEM production system. In providing these TVCs, the USGS nor the AGRC expresses no warranty or guarantee that they meet any standard for accuracy or completeness. Overall consistency may vary across the entire set of TVCs. A general rule is that a TVC will contain about 98%+ of the data found in a Standard DLG hypsography file. For fiscal year 2006, the USGS and the AGRC has not identified any resources to repair or improve any of the TVCs found deficient.
A portion of the 2nd Congressional District was omitted from the U024.AdjustedUSHouseDistricts2002 feature class. This missing area in NE Utah County has been added to this district and the new data is now available from the SGID Database Server and the SGID ftp site.
As of 12/20/07, this problem is now fixed in the U024.AdjustedUniqueHouseSenate feature class as well.
A new polyline-based feature class, U024.LakesNHDHighRes, representing lakes, ponds, reservoirs, evaporation ponds, swamps, tailings ponds, and other water bodies 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 name (where available), reach code, and feature type/code among other attributes (see description of added cartographic attributes below). The NHD polygon 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_LakesNHDHighRes
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 water bodies. This attribute was coded by AGRC staff (IsMajor = 1). Water bodies greater than 0.9 sq kilometers in area were used as a starting point for assigning this attribute value.
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
