The North Carolina Center for Geographic Information and Analysis, and the North Carolina Department of Environment and Natural Resources, Division of Water Quality, developed this digital Hydrography 1:100,000 data with Use Support attributes to enhance planning, siting and impact analysis in areas directly affecting surface waters consisting of streams and rivers, lakes, ponds, reservoirs, and shorelines. These files enable users to identify areas which have special restrictions for building and development based on the locations of these surface waters and their water quality classifications. This file also enables users to determine whether a particular surface water is meeting its designated uses and to what extent. Although based on the USGS 1:100,000-scale Digital Line Graphs, the linework was supplemented with USGS 1:24,000-scale data where the NC DENR-DWQ had classified streams which did not appear on the 1:100,000-scale bases. This statewide coverage is stored by river basin. The river basin coverages contain annotation for major streams and major highways.
Post DLG and data refinements include: a) Translation of DLG to ARC/INFO data format b) Review and correction for incompleteness and/or incorrect DLG attributes c) Internal and external (in-progress) coordinate edgematching of features along map edges d) Addition of hydrographic features as required by DWQ for stream classifications e)Addition of hydrographic attributes as identified in attribute table specifications f) Deletion of all swamp apparent limits and area label points system filename : /library/librb/tiles/<tilename>/hy100 files range in size from 502 KB to 28.2 MB Use support for each basin will be updated on a 5 year schedule concurrent with the Division of Water Quality basinwide planning schedule. Stream classification information will be updated as changes occur. The following table shows the most current stream classification update and use support update, if any has occured.
Data creation and revision dates
Internal feature number.(Source:
ESRI)
Feature geometry.(Source:
ESRI)
Feature geometry.(Source:
ESRI)
This data was created to assist governmental agencies and others in making resource management decisions through use of a Geographic Information System (GIS).
1:100,000-scale Digital Line Graph Files were taken from the USGS and refined. Post DLG and data refinements include: a) Translation of DLG to ARC/INFO data format b) Review and correction for incompleteness and/or incorrect DLG attributes c) Internal and external (in-progress) coordinate edgematching of features along map edges d) Addition of hydrographic features as required by DWQ for stream classifications e) Addition of hydrographic attributes as identified in attribute table specifications f) Deletion of all swamp apparent limits and area label points DWQ Stream classification index numbers were marked onto 1:24,000-scale vellum plots of the 1:100,000-scale hydrography. The index numbers were added to the digital files on screen. Where streams were coded by DWQ but not present in the digital file, 1:24,000-scale hydrographic features were digitized off of USGS base maps. Index numbers, stream classes, and stream locations were checked by DWQ using plots generated by CGIA. The linework is tiled to 1:100,000-scale map extents and stored in a digital library. These files are updated as needed. Water quality for specific stream reaches was evaluated by DWQ and a use support rating assigned. This rating identifies how well a stream reach meets its designated uses. Ratings and additional attributes are maintained in an ACCESS database or EXCEL spreedsheet and updated by river basin on a 5 year rotation. DWQ provided this spreadheet to RTI for joining to the 100k hydrography data layer. DWQ provides CGIA with updates as they occur. Dataset copied. All of the western North Carolina datasets were merged together and reprojected to geographic wgs 84.
Dataset copied.
All attribute codes have been extensively edited for accuracy by the associated agency. Stream codes, classifications and use support - NCDENR, DWQ; Linework, DLG code - NCCGIA. Attribute accuracy is considered high.
Hydrography 1:100,000-scale features were taken from the USGS 1:100,000-scale DLGs. Supplemented hydrographic features were digitized from 1:24,000-scale bases and the linework checked against the bases to within a linewidth.
These data represent the locations and identities of surface waters consisting of streams and rivers, lakes, ponds, and shorelines, as depicted on USGS 1:100,000-scale digital line graphs and supplemented to reflect hydrographic features classified by the state but not represented on the original DLG linework. Each stream reach is labeled with stream classification and use support information. All stream segments are approved by DWQ whether they are the original DWQ boundaries or changes to original boundaries.
Using ESRI's ARC/INFO GIS software, the dataset was built for arc and polygon topology using the "build" command. The data set was then cleaned with a fuzzy tolerance of 1 meter. Topology has not been edited since the last build or clean.
Acknowledgement of products derived from this data set should cite the following: The source of the Hydrography (1:100,000) with use support attributes is the North Carolina Corporate Geographic Database. Earlier versions of this dataset may exist. The user must be sure to use the appropriate data set for the time period and river basin of interest. While efforts have been made to ensure that these data are accurate and reliable within the state of the art, CGIA cannot assume liability for any damages or misrepresentation caused by any inaccuracies in the data or as a result of changes to the data caused by system transfers.
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