Description: This polygon file represents the Phase 5 Chesapeake Bay model segments in Maryland. This is the scale iat which nurient and sediment loads are calculated in the Phase 5 model. The file represents an intection of the model watershed segments (also known as river segments) and county boundaires (land segments). The unique modeling segments are oftehn referred to as land-river segments.
Definition Expression: N/A
Copyright Text: Maryland Department of the Environment - Science Services Administration, TMDL Development Program & US EPA Chesapeake Bay Program
Description: This file (SWSUB8) is a statewide digital watershed file. It depicts the State with 138 separate watersheds each with an 8-digit numeric code. The file was created primarily for State and Federal agency use. The creation of this file goes back many years and involved several State and Federal agencies. This file was derived from a more detailed watershed file (Maryland's Third-Order Watershed). The process used to create this file is consistent with the elevation contour information found on the US Geological Survey's 7.5 minute topographic quadrangle maps and the Maryland Department of the Environment's watershed location and naming conventions. This file is similar, but not identical, to the US Natural Resources Conservation Service's (NRCS) Hydrologic Unit Code (HUC11) watershed file. 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 watershed drainage areas were defined for streams less than third order and some large area Watersheds were split to maintain a maximum size of 15,000 acres.
Description: This file (SWSHED12) 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.
Description: Statewide County Political Boundaries prepared by the Maryland State Highway way Administration with attributes for types of BMP's falling within each County.