USGS highway monitoring station on the Open-Graded Friction Course pavement site, Interstate 95 near Needham, Massachusetts.
Effectiveness of Open-Graded Friction Course Pavement in Reducing Suspended-Sediment Loads Discharged from Massachusetts Highways
Completed
By New England Water Science Center
December 29, 2022
The U.S. Geological Survey New England Water Science Center, in cooperation with Massachusetts Department of Transportation (MassDOT), is evaluating how a type of porous pavement affects the discharge of suspended sediment in comparison to the asphalt surface commonly used on Massachusetts highways. The project will expand the understanding of highway runoff concentrations of suspended sediment, how it moves through and across different pavement, and whether the porous pavement is effective in retaining highway sediments and associated constituents conveyed in stormwater runoff.
Sources/Usage: Public Domain. View Media Details
Stormwater discharges from Massachusetts roadways can adversely affect the quality of receiving water and may result in the failure of a water body to meet Massachusetts surface water-quality standards. Many studies have shown that stormwater runoff can be a source of suspended sediment/solids, nutrients, and metals. MassDOT is responsible for implementing structural and nonstructural source control methods to reduce the loading of various constituents from roadway surfaces to receiving water bodies. However, land adjacent to highways is often unavailable for construction of structural source controls, such as wet ponds or gravel wetlands, that treat highway runoff. Additionally, routinely using nonstructural source controls, such as street sweeping, is generally not practical on major highways.
Open-graded friction course pavement (OGFC), commonly referred to as porous pavement, is a layer of porous asphalt overlaying the surface of impervious hot-mix or dense-graded asphalt (HMA). HMA is the wearing surface commonly used on Massachusetts highways. Different formulations of OGFC have been used in the United States since 1950. The application of OGFC to highway surfaces reduces highway noise and allows water to drain into the porous layer, reducing spray and hydroplaning while increasing wet-pavement friction and surface glare. Water that infiltrates into the OGFC layer moves in the direction of the highway slope and discharges from the pavement edge. Recent studies indicate that OGFC can reduce concentrations of sediment and associated constituents discharged from highways by retaining sediment in the porous layer of asphalt. Some of these studies suggest that OGFC can improve water quality during the asphalt’s structural lifespan of 8-to-10 years.
Sources/Usage: Public Domain. View Media Details
MassDOT has adopted the use of OGFC as the standard wearing surface for limited access highways in parts of Massachusetts based on its original design benefits. Existing data collected regarding water-quality benefits of OGFC are limited, with many of the studies performed in the southern part of the country where the climate and highway maintenance practices are substantially different than in Massachusetts. Furthermore, the gradation of the OGFC used in these areas differ from the standard OGFC gradation specifications used by MassDOT. Because OGFC is becoming more widely implemented, it is important to gain a better understanding of the water-quality benefits that this pavement can provide in Massachusetts and other New England states. Accurate and defensible data are needed by MassDOT to help identify OGFC as a linear structural source control to protect the quality of receiving waters and aquatic life.
Environmental mitigation based on inadequate evaluations of stormwater impacts can be costly, ineffective, and counterproductive. The project is anticipated to expand the current knowledge base of highway-runoff concentrations of selected constituents, better understand the mobilization and transport processes for selected constituents on different pavement surfaces, evaluate the relative effectiveness of OGFC pavement as a linear structural-source control, and provide new data that can be used to identify possible environmental effects of highway runoff on receiving waters in the Northeast and possibly other regions of the United States. The project also will provide information and data necessary to guide runoff-quality modeling efforts and to help balance the costs of monitoring with the degree of precision necessary for estimating potential effects of runoff on receiving waters.
Sources/Usage: Public Domain. View Media Details
The primary objective of this investigation is to characterize concentrations and loads of suspended sediment discharged from a section of traditional dense-graded HMA and from a section of OGFC on Interstate 95 near Needham, Massachusetts over a 3-year period. At the study site, Interstate 95 is a 10-lane highway separated by a concrete median barrier and runs north to south through a residential and commercial area. The average daily traffic volume for the highway is about 150,000 vehicles per day at the study site. Prior to the start of this study in 2018, Interstate 95 was resurfaced with OGFC, except for a segment of southbound highway, that was resurfaced with traditional HMA to serve as a control section for comparison to the OGFC. Additionally, 72-foot-long fiberglass trenches with slotted grates meeting highway semitrailer 20-ton loading specifications were embedded in concrete flush with the surface course beneath the OGFC and flush with the HMA on outer southbound lane. Each trench collects runoff from the respective pavement type and conveys the water to a metering manhole buried adjacent to the highway.
Automated monitoring methods are used to characterize the quantity and quality of runoff at each site. Each monitoring station is equipped to continuously measure discharge and automatically collect samples of highway runoff. Highway runoff is sampled at each station for every runoff event year-round and analyzed for concentrations of suspended sediment including particle size breaks at 0.063- and 0.250-mm in diameter. Flow-proportional samples of highway runoff are composited into bottles by automatic samplers. A flow proportional sample is one in which each sample volume represents a consistent volume of discharge. Additional samples of highway runoff, as well as samples of sediment retained in the collection system, are obtained, and analyzed for nutrients and total-recoverable metals. Each trench system is cleaned annually, and the dry mass of sediment is tabulated along with loads of suspended sediment discharged from each manhole.
The following USGS online publication was approved for release and has been made available to the public.
Scientific Investigations Report 2023–5127: Highway-Runoff Quality From Segments of Open-Graded Friction Course and Dense-Graded Hot-Mix Asphalt Pavement on Interstate 95, Massachusetts, 2018–21
Suggested citation:
Smith, K.P., Spaetzel, A.B., and Woodford, P.A., 2023, Highway-runoff quality from segments of open-graded friction course and dense-graded hot-mix asphalt pavement on Interstate 95, Massachusetts, 2018–21: U.S. Geological Survey Scientific Investigations Report 2023–5127, 59 p., https://doi.org/10.3133/sir20235127
USGS highway monitoring station on the Open-Graded Friction Course pavement site
USGS highway monitoring station on the Open-Graded Friction Course pavement site, Interstate 95 near Needham, Massachusetts.
Open-Graded Friction Course pavement
Example of new Open-Graded Friction Course (OGFC) pavement layer at the start of the project. OGFC, commonly referred to as porous pavement, is a layer of porous asphalt spread over the surface of impervious hot mix or dense-graded asphalt (HMA) that is traditionally used as the wearing surface in Massachusetts.
Example of new Open-Graded Friction Course (OGFC) pavement layer at the start of the project. OGFC, commonly referred to as porous pavement, is a layer of porous asphalt spread over the surface of impervious hot mix or dense-graded asphalt (HMA) that is traditionally used as the wearing surface in Massachusetts.
Initial construction of trench and metering manhole
Initial construction of trench and metering manhole. Trench collects runoff from the respective pavement type and conveys the water to a metering manhole buried adjacent to the highway.
Initial construction of trench and metering manhole. Trench collects runoff from the respective pavement type and conveys the water to a metering manhole buried adjacent to the highway.
The U.S. Geological Survey New England Water Science Center, in cooperation with Massachusetts Department of Transportation (MassDOT), is evaluating how a type of porous pavement affects the discharge of suspended sediment in comparison to the asphalt surface commonly used on Massachusetts highways. The project will expand the understanding of highway runoff concentrations of suspended sediment, how it moves through and across different pavement, and whether the porous pavement is effective in retaining highway sediments and associated constituents conveyed in stormwater runoff.
Sources/Usage: Public Domain. View Media Details
Stormwater discharges from Massachusetts roadways can adversely affect the quality of receiving water and may result in the failure of a water body to meet Massachusetts surface water-quality standards. Many studies have shown that stormwater runoff can be a source of suspended sediment/solids, nutrients, and metals. MassDOT is responsible for implementing structural and nonstructural source control methods to reduce the loading of various constituents from roadway surfaces to receiving water bodies. However, land adjacent to highways is often unavailable for construction of structural source controls, such as wet ponds or gravel wetlands, that treat highway runoff. Additionally, routinely using nonstructural source controls, such as street sweeping, is generally not practical on major highways.
Open-graded friction course pavement (OGFC), commonly referred to as porous pavement, is a layer of porous asphalt overlaying the surface of impervious hot-mix or dense-graded asphalt (HMA). HMA is the wearing surface commonly used on Massachusetts highways. Different formulations of OGFC have been used in the United States since 1950. The application of OGFC to highway surfaces reduces highway noise and allows water to drain into the porous layer, reducing spray and hydroplaning while increasing wet-pavement friction and surface glare. Water that infiltrates into the OGFC layer moves in the direction of the highway slope and discharges from the pavement edge. Recent studies indicate that OGFC can reduce concentrations of sediment and associated constituents discharged from highways by retaining sediment in the porous layer of asphalt. Some of these studies suggest that OGFC can improve water quality during the asphalt’s structural lifespan of 8-to-10 years.
Sources/Usage: Public Domain. View Media Details
MassDOT has adopted the use of OGFC as the standard wearing surface for limited access highways in parts of Massachusetts based on its original design benefits. Existing data collected regarding water-quality benefits of OGFC are limited, with many of the studies performed in the southern part of the country where the climate and highway maintenance practices are substantially different than in Massachusetts. Furthermore, the gradation of the OGFC used in these areas differ from the standard OGFC gradation specifications used by MassDOT. Because OGFC is becoming more widely implemented, it is important to gain a better understanding of the water-quality benefits that this pavement can provide in Massachusetts and other New England states. Accurate and defensible data are needed by MassDOT to help identify OGFC as a linear structural source control to protect the quality of receiving waters and aquatic life.
Environmental mitigation based on inadequate evaluations of stormwater impacts can be costly, ineffective, and counterproductive. The project is anticipated to expand the current knowledge base of highway-runoff concentrations of selected constituents, better understand the mobilization and transport processes for selected constituents on different pavement surfaces, evaluate the relative effectiveness of OGFC pavement as a linear structural-source control, and provide new data that can be used to identify possible environmental effects of highway runoff on receiving waters in the Northeast and possibly other regions of the United States. The project also will provide information and data necessary to guide runoff-quality modeling efforts and to help balance the costs of monitoring with the degree of precision necessary for estimating potential effects of runoff on receiving waters.
Sources/Usage: Public Domain. View Media Details
The primary objective of this investigation is to characterize concentrations and loads of suspended sediment discharged from a section of traditional dense-graded HMA and from a section of OGFC on Interstate 95 near Needham, Massachusetts over a 3-year period. At the study site, Interstate 95 is a 10-lane highway separated by a concrete median barrier and runs north to south through a residential and commercial area. The average daily traffic volume for the highway is about 150,000 vehicles per day at the study site. Prior to the start of this study in 2018, Interstate 95 was resurfaced with OGFC, except for a segment of southbound highway, that was resurfaced with traditional HMA to serve as a control section for comparison to the OGFC. Additionally, 72-foot-long fiberglass trenches with slotted grates meeting highway semitrailer 20-ton loading specifications were embedded in concrete flush with the surface course beneath the OGFC and flush with the HMA on outer southbound lane. Each trench collects runoff from the respective pavement type and conveys the water to a metering manhole buried adjacent to the highway.
Automated monitoring methods are used to characterize the quantity and quality of runoff at each site. Each monitoring station is equipped to continuously measure discharge and automatically collect samples of highway runoff. Highway runoff is sampled at each station for every runoff event year-round and analyzed for concentrations of suspended sediment including particle size breaks at 0.063- and 0.250-mm in diameter. Flow-proportional samples of highway runoff are composited into bottles by automatic samplers. A flow proportional sample is one in which each sample volume represents a consistent volume of discharge. Additional samples of highway runoff, as well as samples of sediment retained in the collection system, are obtained, and analyzed for nutrients and total-recoverable metals. Each trench system is cleaned annually, and the dry mass of sediment is tabulated along with loads of suspended sediment discharged from each manhole.
The following USGS online publication was approved for release and has been made available to the public.
Scientific Investigations Report 2023–5127: Highway-Runoff Quality From Segments of Open-Graded Friction Course and Dense-Graded Hot-Mix Asphalt Pavement on Interstate 95, Massachusetts, 2018–21
Suggested citation:
Smith, K.P., Spaetzel, A.B., and Woodford, P.A., 2023, Highway-runoff quality from segments of open-graded friction course and dense-graded hot-mix asphalt pavement on Interstate 95, Massachusetts, 2018–21: U.S. Geological Survey Scientific Investigations Report 2023–5127, 59 p., https://doi.org/10.3133/sir20235127
USGS highway monitoring station on the Open-Graded Friction Course pavement site
USGS highway monitoring station on the Open-Graded Friction Course pavement site, Interstate 95 near Needham, Massachusetts.
USGS highway monitoring station on the Open-Graded Friction Course pavement site, Interstate 95 near Needham, Massachusetts.
Open-Graded Friction Course pavement
Example of new Open-Graded Friction Course (OGFC) pavement layer at the start of the project. OGFC, commonly referred to as porous pavement, is a layer of porous asphalt spread over the surface of impervious hot mix or dense-graded asphalt (HMA) that is traditionally used as the wearing surface in Massachusetts.
Example of new Open-Graded Friction Course (OGFC) pavement layer at the start of the project. OGFC, commonly referred to as porous pavement, is a layer of porous asphalt spread over the surface of impervious hot mix or dense-graded asphalt (HMA) that is traditionally used as the wearing surface in Massachusetts.
Initial construction of trench and metering manhole
Initial construction of trench and metering manhole. Trench collects runoff from the respective pavement type and conveys the water to a metering manhole buried adjacent to the highway.
Initial construction of trench and metering manhole. Trench collects runoff from the respective pavement type and conveys the water to a metering manhole buried adjacent to the highway.