Background
As a government agency that owns and maintains separate storm sewer systems, the Maryland State Highway Administration (SHA) is mandated to file a National Pollutant Discharge Elimination System (NPDES) permit with the Maryland Department of the Environment (MDE). The permit requires the inventory, inspection, and maintenance of SHA stormwater infrastructure. SHA is responsible for maintaining storm drain infrastructure on more than 5,000 miles of roadway statewide (Figure 1.1). SHA has developed a program consisting of SHA personnel, data managers, and subject matter experts to support the permit requirements and maintain these roadways. The tasks involved in the SHA NPDES data collection program are often completed by engineering consultants for SHA.
 
The 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 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 (SWMF), 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.

SWMFAC
Stormwater Management Facilities
Stormwater management facilities (SWMFAC) are structural best management practices that temporarily store or treat stormwater runoff to reduce flooding, remove pollutants, and provide other amenities. Stormwater BMPs are impoundment areas that treat stormwater runoff to reduce flooding, remove pollutants, and provide other benefits such as wildlife attraction. Pollutant removal can be accomplished through retaining permanent pools of water, detaining water temporarily and then releasing it slowly, infiltrating runoff into the ground, filtering the water through a medium into the ground, or combining multiple treatments. Stormwater management facilities are represented as polygons in the database.
 
SHA supplies a list of BMPs to be inventoried and inspected for the county prior to work commencing. If a stormwater BMP is receiving SHA runoff, the feature is inventoried, regardless of the owner. Attributes recorded for each stormwater BMP feature include type, location, status, and owner. Refer to the Maryland Stormwater Management Guidelines for State & Federal Projects - Volume I & II for stormwater BMP types and common features related to stormwater BMPs.
 
Stormwater BMPs that receive SHA runoff are inventoried. SHA will supply the team with a list of stormwater BMPs for a county, and it is the team’s responsibility to identify additional stormwater BMPs along SHA ROW. Stormwater BMP design plan sheets will be supplied to the team and should be used as the source for the stormwater BMP inventory. 
 
Stormwater BMPs that are inventoried include, but are not limited to, ponds, wetlands, infiltration practices, filtration practices, and ESD BMPs. Stormwater BMPs are inventoried and recorded in the SWMFAC feature class. Due to the large number of different types, sizes, and shapes of these facilities, the SWMFAC table entries are not as standardized as the storm drain structure elements.

 Published 9/6/2019 by Elliott Plack

For more information, contact MDOT SHA OIT Enterprise Information Services: 
Email: GIS@mdot.maryland.gov 

Last Published: 11/06/2019 

Publisher: J.Lloyd (jlloyd@mdot.maryland.gov)
Background
As a government agency that owns and maintains separate storm sewer systems, the Maryland State Highway Administration (SHA) is mandated to file a National Pollutant Discharge Elimination System (NPDES) permit with the Maryland Department of the Environment (MDE). The permit requires the inventory, inspection, and maintenance of SHA stormwater infrastructure. SHA is responsible for maintaining storm drain infrastructure on more than 5,000 miles of roadway statewide (Figure 1.1). SHA has developed a program consisting of SHA personnel, data managers, and subject matter experts to support the permit requirements and maintain these roadways. The tasks involved in the SHA NPDES data collection program are often completed by engineering consultants for SHA.
 
The 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 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 (SWMF), 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.

SWMFAC
Stormwater Management Facilities
Stormwater management facilities (SWMFAC) are structural best management practices that temporarily store or treat stormwater runoff to reduce flooding, remove pollutants, and provide other amenities. Stormwater BMPs are impoundment areas that treat stormwater runoff to reduce flooding, remove pollutants, and provide other benefits such as wildlife attraction. Pollutant removal can be accomplished through retaining permanent pools of water, detaining water temporarily and then releasing it slowly, infiltrating runoff into the ground, filtering the water through a medium into the ground, or combining multiple treatments. Stormwater management facilities are represented as polygons in the database.
 
SHA supplies a list of BMPs to be inventoried and inspected for the county prior to work commencing. If a stormwater BMP is receiving SHA runoff, the feature is inventoried, regardless of the owner. Attributes recorded for each stormwater BMP feature include type, location, status, and owner. Refer to the Maryland Stormwater Management Guidelines for State & Federal Projects - Volume I & II for stormwater BMP types and common features related to stormwater BMPs.
 
Stormwater BMPs that receive SHA runoff are inventoried. SHA will supply the team with a list of stormwater BMPs for a county, and it is the team’s responsibility to identify additional stormwater BMPs along SHA ROW. Stormwater BMP design plan sheets will be supplied to the team and should be used as the source for the stormwater BMP inventory. 
 
Stormwater BMPs that are inventoried include, but are not limited to, ponds, wetlands, infiltration practices, filtration practices, and ESD BMPs. Stormwater BMPs are inventoried and recorded in the SWMFAC feature class. Due to the large number of different types, sizes, and shapes of these facilities, the SWMFAC table entries are not as standardized as the storm drain structure elements.

Published 9/6/2019 by Elliott Plack

For more information, contact MDOT SHA Geospatial Technologies: 

Email: GIS@mdot.maryland.gov 



Last Published: 11/06/2019 

Publisher: J.Lloyd (jlloyd@mdot.maryland.gov)
[]
{'Title': 'MDOT SHA NPDES Simple SWMFAC', 'Author': '', 'Comments': 'Background\nAs a government agency that owns and maintains separate storm sewer systems, the Maryland State Highway Administration (SHA) is mandated to file a National Pollutant Discharge Elimination System (NPDES) permit with the Maryland Department of the Environment (MDE). The permit requires the inventory, inspection, and maintenance of SHA stormwater infrastructure. SHA is responsible for maintaining storm drain infrastructure on more than 5,000 miles of roadway statewide (Figure 1.1). SHA has developed a program consisting of SHA personnel, data managers, and subject matter experts to support the permit requirements and maintain these roadways. The tasks involved in the SHA NPDES data collection program are often completed by engineering consultants for SHA.\n\xa0\nThe 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 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 (SWMF), 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.\n\nSWMFAC\nStormwater Management Facilities\nStormwater management facilities (SWMFAC) are structural best management practices that temporarily store or treat stormwater runoff to reduce flooding, remove pollutants, and provide other amenities. Stormwater BMPs are impoundment areas that treat stormwater runoff to reduce flooding, remove pollutants, and provide other benefits such as wildlife attraction. Pollutant removal can be accomplished through retaining permanent pools of water, detaining water temporarily and then releasing it slowly, infiltrating runoff into the ground, filtering the water through a medium into the ground, or combining multiple treatments. Stormwater management facilities are represented as polygons in the database.\n\xa0\nSHA supplies a list of BMPs to be inventoried and inspected for the county prior to work commencing. If a stormwater BMP is receiving SHA runoff, the feature is inventoried, regardless of the owner. Attributes recorded for each stormwater BMP feature include type, location, status, and owner. Refer to the Maryland Stormwater Management Guidelines for State & Federal Projects - Volume I & II for stormwater BMP types and common features related to stormwater BMPs.\n\xa0\nStormwater BMPs that receive SHA runoff are inventoried. SHA will supply the team with a list of stormwater BMPs for a county, and it is the team’s responsibility to identify additional stormwater BMPs along SHA ROW. Stormwater BMP design plan sheets will be supplied to the team and should be used as the source for the stormwater BMP inventory. \n\xa0\nStormwater BMPs that are inventoried include, but are not limited to, ponds, wetlands, infiltration practices, filtration practices, and ESD BMPs. Stormwater BMPs are inventoried and recorded in the SWMFAC feature class. Due to the large number of different types, sizes, and shapes of these facilities, the SWMFAC table entries are not as standardized as the storm drain structure elements.\n\nPublished 9/6/2019 by Elliott Plack\n\nFor more information, contact MDOT SHA Geospatial Technologies: \n\nEmail: GIS@mdot.maryland.gov \n\n\n\nLast Published: 11/06/2019 \n\nPublisher: J.Lloyd (jlloyd@mdot.maryland.gov)', 'Subject': 'A simplified NPDES SWMFAC dataset, which represents physical stormwater facilities that accept drainage from SHA facilities. Stormwater BMPs that are inventoried include, but are not limited to, ponds, wetlands, infiltration practices, filtration pra', 'Category': '', 'AntialiasingMode': 'None', 'TextAntialiasingMode': 'Force', 'Version': '2.9.0', 'Keywords': 'NPDES,SWMFAC,BMP,stormwater,stormwater facility,pond,infiltration,grass swale'}
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