This file is a statewide digital watershed file. It was created primarily for state and federal agency use. The watersheds define Strahler (Strahler 1952 p. 1120) third order stream drainage by contours on U.S. Geological Survey (USGS) 7.5 minute quadrangle map sheets. Some watersheds drainage areas were defined for streams less than third order and some large area watershed were split to maintain a maximum size of 15,000 acres. The watershed boundaries in this file were developed in a joint state and federal effort to create a consistent watershed file for use by all government agencies with an interest in Maryland's watersheds. The U.S. Natural Resources Conservation Service (NRCS) redefined the third order watersheds creating the HUA14 file. This file contains all of the HUA14 watersheds and some added watersheds to maintain water quality sampling sites. It was also used to create the Maryland Sub-Watershed file.
This file was created to identify and define third order watershed from contours on the U.S. Geological Survey (USGS) 7.5 minute quadrangle map sheets. In addition to identifying Strahler third order streams it was necessary to separate certain streams to ensure their association with a proper receiving body of water. Some watersheds were split to maintain the size of watershed areas for state planning purposes. It was intended to maintain a unique watershed number in both this file and HUA14 so that state and federal agencies would have a consistent code for reference. This file has both the federal codes and the state codes for cross referencing. Most of the watersheds in this file are the same as the watershed boundaries in the federal file HUA14. There is one difference in the watershed files. This file has a buffered shoreline added to separate the Chesapeake Bay from land. The parent federal file HUA14 identifies watersheds by the federal Hydrologic Unit Code (HUA or HUC code) while the state file uses the Maryland Department of the Environment (MDE) watershed codes.
See Maryland's Sub-Watershed which is an 8-digit watershed file and its metadata. The State political boundary in this file is used for all Statewide files created by the Geographic Information Services Division of MD DNR. HUA14 Watershed codes are in the file. MDE collects data to the MDE8DIGT code. MD DNR maintains data for the 10 Tributary Strategy Watersheds in the STRACODE and STRANAME field. This file is derived from SHED1998.
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|Category||Science & Environment|
|Regions||District of Columbia, District of Columbia, Maryland, Washington|
|Data type||Vector polygon||Feature count||1136|
|Attributes||SWSH987F, SWSH987F_I, MAJOR1, MINOR1, ACRE, X_COORD, Y_COORD, MDE6DIGT, MDE6NAME, MDE8DIGT, MDE8NAME, SHEDNUM, DNR12DIG, WHOLE, MARYLAND, LAND, DC, STRACODE, STRANAME, HUA14, HUA11, HUA8, STFIPS, CNTYFIPS, CO|
|Services||Vector Query API|