Surface water (hydrography) data
Historically, the Wisconsin DNR Hydrography geospatial data layer has been stored and managed in ArcInfo coverage format with annual, updated releases provided to the user community as shapefiles. However, in recent years the DNR has adopted a more robust spatial data storage format called geodatabase for managing the hydrography GIS layer. In 2011, the DNR completed converting the Hydrography coverage to the advanced geodatabase model.
Conversion from coverage to geodatabase
The main objective of this data conversion project was to take the existing Hydrography data model and implement it in a geodatabase. It was also important to keep the federal Hydrography data model (National Hydrography Database - NHD) in mind during this transition. The NHD is now at 1:24,000-scale nationwide and is already being managed in a geodatabase. The US Environmental Protection Agency, US Geological Survey (USGS) and US Forest Service as well as all of our neighboring state environmental agencies are adopting NHD as their framework surface water layer. Based on our business relationships with these agencies, it was determined that we should strive to be as consistent as possible with the federal model in order to facilitate a future consolidation of the DNR Hydrography and federal NHD database. The DNR is currently identifying strategies for consolidating these two models.
What's new in the hydrography geodatabase?
With the geodatabase, edits are available in real time because the quality assurance processing occurs at the time of each edit instead of in one large programming process at the end of each fiscal year. The geodatabase is versioned which allows edits to be made on a production copy of the geodatabase which then gets reconciled with the database the user sees. Typical edits include name changes, Waterbody Identification Code (WBIC) changes, added flow path connectors, lake extent modifications etc. To date, the Hydrography geodatabase remains a reflection of the blue water represented on 7.5-minute USGS topographic maps.
Some of the new features in the DNR hydrography geodatabase include:
- The addition of Lake Superior and Lake Michigan with flow connections from all of their tributaries. (Note: The source of this information is the 1:24,000-scale NHD - USGS National Hydrography Database)
- A hydrography junction feature class - junctions allow two or more lines to connect, and facilitate the transfer of flow between them. Hydrography junction subtypes indicate intersections at headwaters, stream confluences, shoreline intersections, etc.
- The hydrography bank feature class holds all of the shorelines separately from the water features. Water Body Identification Codes (WBICs) for shorelines are available by linking the bank feature class to the water area feature class via the "WATERBODYHYDROID" field.
- The "HYDROID" field replaces both "SW_NO" and "SHAID_NO" as the unique identifier for each feature, and is now unique across the entire database.
- A new point feature class has been created for future support of features such as springs, gauge stations, dams etc. However, this feature class is currently empty.
- Cartographic features such as original water course, channel in water area and wall features (e.g. fish hatchery walls, earthen walls, etc.) are now stored in a separate feature class called "W23324.WD_HYDRO_LINE_LN_24K".
- A new hydrography category of "UNSPECIFIED OPEN WATER" has been added to identify areas of open water which have not been classified.
Coordinate system (map projection)
The Hydrography data layer is managed in the DNR's standard coordinate referencing system: Wisconsin Transverse Mercator (WTM) based on the 1991 adjustment to the North American Datum of 1983 - WTM83, NAD83(1991). Linear measures are in meters. Area measurements are in square meters.
The Hydrography geodatabase is stored using a high precision spatial reference.
The Hydrography geodatabase is approximately 225 Megabytes in size.
- Getting Started with WDNR Hydrography Geodatabase [PDF 474KB]
- DNR 24K hydrography Decision Rules
- hydrography Geodatabase Metadata
The DNR Hydrography database was developed statewide using several 1:24,000-scale sources. This data layer includes information about surface water features represented on the USGS 1:24,000-scale topographic map series such as perennial and intermittent streams, lakes, etc. Because the sources of the Hydrography data span many years and originate from several sources, the data may reflect areas of transition from one source to another. As a result, the water features as represented in the Hydrography data may not always match what you see on a particular USGS quad or Digital Raster Graphic (DRG). General source information is presented on this map: Wisconsin Hydrography Source Information.
A large portion of the Agency's Water Body Identification Codes (WBICs) have been incorporated into the Hydrography layer, along with surface water names from the USGS Geographic Names Information System (GNIS) database.
Note: Wetlands delineations are not included in the DNR Hydrography data layer. For information about DNR Wetlands data, see the Wisconsin Wetland Inventory web page.
How to access the hydrography geodatabase
DNR staff can access the Hydrography geodatabase in the agency's Central GIS data repository. The Hydrography feature classes are stored in the feature data set "W23324.WD_HYDRO_DATA_24K". DNR Region staff may find it best to export the geodatabase to their local server for performance reasons. Instructions on how to access, export and use the geodatabase are provided in the Getting Started with WDNR 24K hydrography Geodatabase guide.
Users external to the DNR can access the geodatabase from the DNR Public GIS FTP site at ftp://dnrftp01.wi.gov/geodata/hydro_24k/. The "Getting Started..." guide is also available at that location.
Reporting hydrography errors
If you find any issues with the Hydrography data, please report them via email to Ann Schachte (email@example.com ) with the following information:
- HYDROID of the feature in question; OR if the feature is missing, a location coordinate or description (i.e.,latitude/longitude or WTM coordinate, or Public Land Survey System Township, Range and Section identifier) that identifies the area in question.
- A brief description of the issue and requested modification.
- Optional (but very useful)
- A screen capture of the area containing the feature(s) involved in the request
- The Water Body Identification Code (WBIC) of the feature in question