MS4 Water Quality Monitoring
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Maryland’s municipal separate storm sewer system (MS4) permits require counties and municipalities to report data on local water quality as well as various stormwater management efforts. These data are available to the public through the StormwaterPrint interactive portal. In StormwaterPrint, users can explore data in a geographical interface as well as download and analyze data for their own interests.
MDE's Integrated Water Planning Program (IWPP), in conjunction with the Interstate Commission on the Potomac River Basin (ICPRB), and the Center for Watershed Protection (CWP) have conducted pilot trend analyses of historic MS4 permit required chemical monitoring data for three targeted sub-watersheds, which had the longest periods or record, fewest data quality issues, and ideal monitoring designs to relate any changes in ambient water quality to watershed restoration. The report summarizing the pilot trend analyses of the chemical data and additional analyses are available for download below.
The Department updated the monitoring requirements outlined in the Assessment of Controls section of the latest MS4 permits issued to Phase I jurisdictions. The overall goal is to evaluate the effects of best management practice (BMP) implementation and other management strategies on local water quality. The requirements include BMP Effectiveness monitoring and Watershed Assessment monitoring. The Monitoring Guidelines document provides technical guidelines and criteria for performing the required monitoring in accordance with the Assessment of Controls section of the MS4 permit.
