ArcGIS Online for MarylandEsri ArcGIS Online Map Image Layer which provides access to the MDOT SHA OHD NPDES data products MDOT SHA OHD NPDES data are organized into a series of drainage systems with stormwater management facilities that are interconnected, allowing for flow-tracing function through distinct systems. A drainage system is defined as a series of storm drain structures or point features (i.e., manholes, inlets, endwalls) that connect hydraulically through conveyance (linear) features such as pipes and / or ditches. Closed and open storm drain structures are connected by pipe and ditch conveyance to create the drainage system. Stormwater management facilities (SWMFAC), also known as stormwater best management practices (BMP) are inventoried with the storm drain system. A system can include both open and closed storm drain features. MDOT SHA NPDES data are owned & mantained by the MDOT SHA Office of Highway Development (OHD). For more information, contact MDOT SHA OIT Enterprise Information Services: Email: GIS@mdot.maryland.govArcGIS DynamicMapLayerhttps://hub.arcgis.com/datasets/2b22407f3c524223bb58950ea9a657b8_7engMaryland iMapPublicDAMS [Maryland]Web servicesMarylandLast Modified: 2026-03-05