This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. 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. Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Watersheds/FeatureServer/2 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. The Maryland coastal zone is comprised of the land - water and subaqueous land between the territorial limits of Maryland in the Chesapeake Bay - Atlantic Coastal Bays and the Atlantic Ocean - as well as the towns - cities and counties that contain and help govern the thousands of miles of Maryland shoreline. The Maryland coastal zone extends from three miles out in the Atlantic Ocean to the inland boundaries of the 16 counties and Baltimore City that border the Atlantic Ocean - Chesapeake Bay and the Potomac River up to the District of Columbia. This area encompasses two-thirds of the State s land area and is home to almost 70% of Maryland's residents. Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Watersheds/FeatureServer/4 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. Hydrologic unit boundaries define the aerial extent of surface water drainage to a point. Hydrologic units through four levels were created in the 1970's and have been used extensively throughout the United States. During that time the U.S. Geological Survey (USGS) developed a hierarchical hydrologic unit code (HUC) for Hydrologic unit boundaries define the aerial extent of surface water drainage to a point. Hydrologic units through four levels were created in the 1970's and have been used extensively throughout the United States. During that time the U.S. Geological Survey (USGS) developed a hierarchical hydrologic unit code (HUC) for the United States. This system divides the country into 21 Regions - 222 Subregions - 352 Accounting Units - and 2 - 149 Cataloging Units based on surface hydrologic features. The smallest USGS unit (8-digit HU) is approximately 448 - 000 acres. During the late 1970's the Natural Resources Conservation Service (NRCS) - formerly the Soil Conservation Service - initiated a national program to further subdivide HU's into smaller watersheds for water resources planning. A 3-digit extension was added to the 8-digit identification. By the early 1980's this 11-digit HU mapping was completed for most of the U.S. These data demonstrate Maryland's watersheds as represented by the federal Hydrologic Unit Code denoted by an 11-digit numerical code. The watersheds were defined using contours on U.S. Geological Survey (USGS) 7.5 minute quadrangle map sheets. The state has been divided into 138 watersheds that are identified by Maryland - using an 8-digit numerical code. These watersheds are equivalent to the HUC 11-digit codes. The watershed file is generally considered to be map accurate at a scale of 1:24 - 000. A new 12-digit watershed file is available from DNR which provides more detailed line work for over 1 - 100 watersheds which is approximately equivalent to the HUC 14-digit code. Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Watersheds/FeatureServer/0 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. Maryland Tributary Teams-comprised of local citizens - farmers - business leaders and government officials appointed by the Governor-are working to keep local waterways clean and healthy. TheTributary Team jurisdictions were determined from the watershed boundaries that 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. Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Watersheds/FeatureServer/5 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. Chesapeake Bay Watershed Outline. Defines extent of the Chesapeake Bay watershed within the state of Maryland. Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Watersheds/FeatureServer/3 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. The digital segmented network based on watershed boundaries - ERF1-2 - includes enhancements to the U.S. Environmental Protection Agency's River Reach File 1 (RF1) (USEPA - 1996; DeWald and others - 1985) to support national and regional-scale surface water-quality modeling. Alexander and others (1999) developed ERF1 - which assessed the hydrologic integrity of the digital reach traces and calculated the mean water time-of-travel in river reaches and reservoirs. ERF1-2 serves as the foundation for SPARROW (Spatially Referenced Regressions (of nutrient transport) On Watershed) modeling. Within the context of a Geographic Information System - SPARROW estimates the proportion of watersheds in the conterminous U.S. with outflow concentrations of several nutrients - including total nitrogen and total phosphorus - (Smith - R.A. - Schwarz - G.E. - and Alexander - R.B. - 1997). This version of the network expands on ERF1 (version 1.2; Alexander et al. 1999) - and includes the incremental and total drainage area derived from 1-kilometer (km) elevation data for North America. Previous estimates of the water time-of-travel were recomputed for reaches with water- quality monitoring sites that included two reaches. The mean flow and velocity estimates for these split reaches are based on previous estimation methods (Alexander et al. - 1999) and are unchanged in ERF1-2. Drainage area calculations provide data used to estimate the contribution of a given nutrient to the outflow. Data estimates depend on the accuracy of node connectivity. Reaches split at water- quality or pesticide-monitoring sites indicate the source point for estimating the contribution and transport of nutrients and their loads throughout the watersheds. The ERF1-2 coverage extends the earlier ERF1 coverage by providing digital-elevation-model (DEM-based estimates of reach drainage area founded on the 1-kilometer data for North America (Verdin - 1996; Verdin and Jenson - 1996). A 1-kilometer raster grid of ERF1-2 projected to Lambert Azimuthal Equal Area - NAD 27 Datum (Snyder - 1987) - was merged with the HYDRO1K flow direction data set (Verdin and Jenson - 1996) to generate a DEM-based watershed grid - ERF1_2WS. The watershed boundaries are maintained in a raster (grid cell) format as well as a vector (polygon) format for subsequent model analysis. Both the coverage - ERF1-2 - and the grid - ERF1-2WS are available at: http://water.usgs.gov/lookup/gisgetlist. The version of RF1 used to compile ERF1-2 was an early edition of a USGS RF1 translation and was updated by USEPA (USEPA - 1996). The capabilities of the enhanced version of RF1 (ERF1-2) and the current USEPA version have not been evaluated. The user is referred to the USEPA version [http://www.epa.gov/owow/monitoring/rf/rfindex] for discussions of streamflow accuracy and general background on the origin of RF1. Last Updated: Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Waterbodies/MapServer/0 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in th

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. Line features of rivers and streams (detailed shape) in Maryland. Last Updated: Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Waterbodies/MapServer/2 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. Although the State of Maryland has no natural lakes - it has an abundance of created lakes and ponds that are used for wildlife habitat - recreation - water supply - and other reasons. This digital file shows the locations of the largest and most significant lakes - as well as some of the smaller lakes and ponds in the state. Most of the digitized lakes and ponds are greater than 2 acres. Last Updated: Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Waterbodies/MapServer/3 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. Polygon boundaries of lakes (generalized shape) in Maryland. Last Updated: Feature Service Layer Link: http://geodata.md.gov/imap/rest/services/Hydrology/MD_Waterbodies/MapServer/1 ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

This is a MD iMAP hosted service. Find more information on http://imap.maryland.gov. The MD_Surface_Waters Feature Dataset includes 7 feature classes that geospatially depict the surface water bodies of Maryland. These feature classes are being provided so that data from the 2012 Integrated Report of Surface Water Quality can be displayed in geographic form for users of all levels. These different feature classes represent the different assessment unit scales utilized on the 2012 IR - some of which overlap in space. In addition - provided in the attribute tables for the Impoundments - Rivers_Streams - and Tidal_Waters feature classes is the use class designation as specified in COMAR Section 26.08.02.08. More information about these feature classes is contained in the metadata for each feature class. Map Service Link: http://mdewin64.mde.state.md.us/arcgis/rest/services/ MDE_Water_Quality/MD_IntegratedReportSurfaceWaterQuality_2013/MapServer ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively "the Data") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.