Surface Water (Hydrography) Data

To date, the Hydro GIS layer has been stored and managed in ArcInfo coverage format with annual, updated releases provided to the user community as shapefiles. However, ESRI has developed a more robust spatial data storage and management environment called geodatabase which has become the new standard framework for ArcGIS. DNR has recently completed converting the hydro coverage to the advanced geodatabase model.

Conversion from Coverage to Geodatabase

The main objective of the project was to take the existing hydro data model and implement it in 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 nation-wide and is already being managed in a geodatabase. USEPA, USGS, USFS 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 WDNR hydro and federal NHD database. Work will begin in FY10 to identify strategies for consolidating these two models.

What's New in the Hydro Geodatabase?

With the geodatabase, edits are available in real time because the QA/QC 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, WBIC changes, added flow path connectors, lake extent modifications etc. To date, the hydro geodatabase remains a reflection of the blue water represented on 7.5 minute USGS topographic maps.

Some of the new features in the DNR hydro geodatabase include:

The addition of Lake Superior and Lake Michigan with flow connections from all their tributaries. (Note: Source of the lake data: Hiigh resolution NHD - 24K National Hydrography Database)
A hydro junction feature class - junctions allow two or more lines to connect and facilitate the transfer of flow between them. Hydro junction subtypes indicate intersections at headwaters, stream confluences, shoreline intersections etc.
The hydro bank feature class holds all of the shorelines separately from the water features. Water Body ID Codes (WBICs) for shorelines are available by linking the bank feature class to the water area feature class via the waterbodyhydroid field
The HYDROID replaces both SW_NO and SHAID_NO as the unique id 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 presently 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 hydrotype of UNSPECIFIED OPEN WATER has been added to identify areas of open water which have not been classified

Geodatabase Specs

Coordinate System (projection)

Wisconsin Transverse Mercator (WTM), North American Datum 1983/1991 adjustment (NAD91). This will be specified in ArcGIS version 9.3 as NAD 1983 Wisconsin TM. You may be familiar with the previous naming convention of NAD_1983_HARN_Transverse_Mercator - same coordinate system, different name. Linear measures are in meters. Area measurements are in square meters.

Precision

The 24K Hydro geodatabase is stored in ArcSDE using a high precision spatial reference

Size

The hydro geodatabase is approximately 225 MB in size.

Geodatabase Documentation

Getting Started with WDNR Hydro Geodatabase [PDF 474KB]
DNR 24K Hydro Decision Rules
Hydro Geodatabase Metadata

24K Data Sources

The DNR 24K Hydrography database was developed statewide using several 1:24,000-scale sources. This 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 24K 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 24K Hydro data may not always match what you see on a particular USGS quad or Digital Raster Graphic (DRG). General source information can be obtained in the map Wisconsin 24K Hydrography Source Information.

A large portion of the Agency's Water Body Identification Codes (WBICs) have been incorporated into the hydro layer, along with surface water names from the U.S. Geological Survey's Geographic Names Information System (GNIS) database.

Note: Wetlands delineations are not included in the DNR 1:24,000-scale Hydrography data layer. See the Wisconsin Wetland Inventory web page.

How to Access the 24K Hydrography Geodatabase

DNR staff can access the 24K Hydrography geodatabase in the Central ArcSDE/Oracle GIS data repository. It is stored in the feature data set "W23324.WD_HYDRO_DATA_24K". Regional 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 Hydro Geodatabase guide.

Users external to WDNR can access the geodatabase from the public WDNR ftp site at ftp://dnrftp01.wi.gov/geodata/hydro_24k/. The Getting Started guide is also available at that location.

Reporting 24K Hydro Errors

If you find any issues with the 24K hydro data, please report them via email to Ann Schachte (ann.schachte@wisconsin.gov ) with the following information

Required
- HYDROID of the feature in question OR if the feature is missing, a location coordinate or description (e.g. lat/long, wtm,TRS) that gets the editor to the right area
- 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
- Water Body ID Code (WBIC) of the feature in question

Last Revised: Tuesday January 19 2010