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Maryland State Government Maryland Department of the Environment

Integrated Report (IR) Water Quality Assessment Maps

picture of water quality mapThe map links below provide the user with surface water quality assessment information found in the Integrated Report of Surface Water Quality.  These pages each have an embedded map (similar to Google Maps) capable of showing stream-segment level assessment information.  No special software is needed although the map will perform better with the latest version browsers (e.g. Internet Explorer 9 or later, Mozilla Firefox version 40.0.1, Google Chrome).  Maps were split into major pollution-type groupings to avoid having an abundance of overlapping assessment information. The data shown via the links below is the most current information, displaying IR assessment information from Maryland's EPA-Approved 2014 Integrated Report of Surface Water Quality.

Please note: All of the maps below are symbolized according to the Integrated Reporting category. Click here to view descriptions of the Integrated Reporting categories. Click here to view an on-line video tutorial on how to use the maps.

Also included, at the bottom of the page, is a link allowing users can download the latest Integrated Report geodatabase (ESRI ArcGIS format).

Click here to return to the Water Quality Mapping Center.

Click here to return to the Integrated Report main page.


Water Quality Map Links


  • BACTERIA - This map displays all bacteria assessment information including assessments for both tidal and non-tidal waters, designated bathing beaches, and shellfish harvesting waters.


  • BIOLOGICAL - This map displays all biological assessment information including assessments for both tidal and non-tidal waters.


  • IONS - This map displays all ion (e.g. chlorides, sulfates) assessment information. Only non-tidal flowing waters have been assessed. Note: Some of the ion assessments overlap spatially.


  • METALS - This map displays all metals (e.g. chromium, mercury, etc) assessment information including assessments for both tidal and non-tidal waters as well as impoundments. Note: Many of the specific metal assessments overlap spatially. 


  • NUTRIENTS - This map displays all nutrient-related assessments for rivers, impoundments and estuarine waters. Parameters assessed include nitrogen, phosphorus, and various types of biochemical oxygen demand (BOD). Note: Many of the nutrient assessments overlap spatially.


  • PCBs - This map displays all polychlorinated biphenyl assessments (PCB) for rivers, impoundments, and estuarine waters.


  • PESTICIDES - This map displays all pesticide assessments for rivers, impoundments, and estuarine waters. Note: A few of the pesticide assessments overlap spatially.


  • PH - This map displays all pH assessments.  pH assessments are largely limited to non-tidal flowing waters.


  • STREAM MODIFICATIONS - This map displays all stream modification (e.g. stream channelization, inadequate riparian buffer) assessment information. Only non-tidal flowing waters have been assessed. Note: Some of the stream modification assessments overlap spatially. 


  • SEDIMENTS - This map displays all sediment-related assessments for rivers, impoundments, and estuarine waters.


  • TEMPERATURE - This map displays all temperature assessments completed for Use Class III and III-P streams.


  • TOXICS - This map displays all toxics assessments for rivers, impoundments, and estuarine waters.


  • TRASH - This map displays the trash assessments for the Anacostia River and portions of the Patapsco River. 


GIS Downloads

Download MD's 2014 Integrated Report Relational Geodatabase

This geodatabase contains water quality assessment information from the 2014 Integrated Report organized in a relational geodatabase. Click the "Download..." link above for a zip file which includes the following water bodies/assessment scales:

  • Tidal Waters - Covers the Chesapeake Bay, the Coastal Bays, and the Atlantic Ocean nutrient, biological and sediment assessments.
  • Impoundments - Covers all assessment information for impoundments.
  • Rivers Streams - Covers all assessment information for flowing waters in Maryland.
  • Tidal Waters 8-digit Watersheds - Covers fish tissue and metals assessment information for tidal waters assessed at the 8-digit watershed scale.
  • Tidal Waters Contact Recreation - Covers bacteria assessments conducted for determining if the water contact recreation use (swimming) is being supported.
  • Tidal Waters Shellfish Harvest - Covers bacteria assessments conducted in shellfish harvesting waters in order to protect public health against foodborne pathogens.
  • Tidal Waters Category Points - Covers point-based assessments for toxics coming from NPDES dischargers and from a historical oil spill (Chalk Point).  These assessments originated from historical Category 4b assessments.  However, some have been reassessed and are now meeting water quality standards. 


Download MD's 2014 Integrated Report Individual Water body-Pollutant Layers


This geodatabase has all of the same water quality assessment information that the geodatabase above contains, however; instead of being a relational geodatabase, it contains pre-made layers each depicting a single water body-pollutant combination (e.g. impoundments assessed for sediments). Click the "Download..." link above for a zip file which includes this information.


Contact Information


For questions or comments concerning this page please contact Matthew Stover at or 410-537-3611.