Regulating Stormwater Underground
Watershed managers and best management practice designers seeking to "treat stormwater where it hits the ground" should be aware of a relatively new EPA regulation that might affect existing or planned structures. Under EPA's Underground Injection Control (UIC) Program, which is part of the Safe Drinking Water Act, some stormwater structures are classified as Class V injection wells and require permits.
The regulation has been around since 1999, but many stormwater programs still are unaware of it. In part, this is because the agencies dealing with surface water and groundwater are often separate; in addition, many Phase II stormwater programs are relatively new and still coming to grips with the National Pollutant Discharge Elimination System requirements and others that more directly affect them. EPA is making a renewed effort to publicize the UIC Program, however, with new materials available on-line and representatives reaching across the surface-water/groundwater barrier to address stormwater structures.
It's usually considered good practice to deal with stormwater runoff on-site, infiltrating stormwater back into the soil rather than routing it long distances through a storm drain system. There are many techniques for doing this, including preventing certain types of drainage—from roof downspouts, parking lots, driveways, and sidewalks, for example—from reaching the storm sewers and then treating it on-site with vegetated swales or rain gardens. Making this a widespread practice across many small locations can add up to a tremendous savings on the burden the storm sewer has to carry (see the "Footing Drain Disconnection" article in our July/August 2003 issue.) In other cases, larger infiltration basins, subsurface recharge beds, or drywells are used to collect runoff and slowly feed it back into the soil. Some fee-based stormwater programs even offer incentives in the form of reduced impervious-surface fees for property owners who install drywells.
Designers generally understand that in some places—particularly those with a high groundwater table or extremely permeable soils—pretreating stormwater before it's infiltrated is a good idea. Many are unaware, however, that the UIC Program regulates BMPs that could pose a potential threat to the drinking-water supply. More than 90% of public water systems in the United States use groundwater for at least part of their water supply, primarily from shallow aquifers that also recharge lakes, streams, and rivers. EPA anticipates that—specifically because of NPDES Phase II requirements for dealing with stormwater—Class V wells will become more numerous and might affect drinking-water supplies.
gricultural and industrial pollutants in stormwater runoff are of particular concern.
The UIC Program defines and regulates five different classes of injection wells, ranging from Class I—usually located at industrial sites and sometimes involving hazardous wastes, which inject material far below the surface and below any potential drinking-water source—to the shallow Class V, which is somewhat of a catch-all category.
What exactly is covered under the UIC Program? EPA defines a Class V injection well as "any bored, drilled, or driven shaft, or dug hole that is deeper than its widest surface dimension, or an improved sinkhole, or a subsurface fluid distribution system." It also characterizes Class V wells as structures that "inject nonhazardous fluids into or above a [underground source of drinking water] and are typically shallow, on-site disposal systems, such as floor and sink drains which discharge directly or indirectly to ground water, dry wells, leach fields, and similar types of drainage wells."
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Although most detention basins and underground stormwater storage systems don't fall into this category, depending on the design—and on exactly what constitutes a "fluid distribution system" under EPA's definition—some underground pipes and chambers, as well as infiltration beds under porous pavement installations, will qualify.
It's important for those planning and designing stormwater BMPs to understand what's covered; EPA requires surveys and prior notification before construction of certain types of wells. The agency also offers suggestions to keep stormwater drainage systems from threatening subsurface drinking-water sources, including not only siting and design but also public education to prevent people from misusing the systems. Information is available at www.epa.gov/safewater/uic.html.
Author's Bio: Janice Kaspersen is the editor of Stormwater magazine.
March-April 2004
Regulating Stormwater Underground
Watershed managers and best management practice designers seeking to "treat stormwater where it hits the ground" should be aware of a relatively new EPA regulation that might affect existing or planned structures. Under EPA's Underground Injection Control (UIC) Program, which is part of the Safe Drinking Water Act, some stormwater structures are classified as Class V injection wells and require permits. The regulation has been around since 1999, but many stormwater programs still are unaware of it. In part, this is because the agencies dealing with surface water and groundwater are often separate; in addition, many Phase II stormwater programs are relatively new and still coming to grips with the National Pollutant Discharge Elimination System requirements and others that more directly affect them. EPA is making a renewed effort to publicize the UIC Program, however, with new materials available on-line and representatives reaching across the surface-water/groundwater barrier to address stormwater structures.
It's usually considered good practice to deal with stormwater runoff on-site, infiltrating stormwater back into the soil rather than routing it long distances through a storm drain system. There are many techniques for doing this, including preventing certain types of drainage—from roof downspouts, parking lots, driveways, and sidewalks, for example—from reaching the storm sewers and then treating it on-site with vegetated swales or rain gardens. Making this a widespread practice across many small locations can add up to a tremendous savings on the burden the storm sewer has to carry (see the "Footing Drain Disconnection" article in our July/August 2003 issue.) In other cases, larger infiltration basins, subsurface recharge beds, or drywells are used to collect runoff and slowly feed it back into the soil. Some fee-based stormwater programs even offer incentives in the form of reduced impervious-surface fees for property owners who install drywells.
Designers generally understand that in some places—particularly those with a high groundwater table or extremely permeable soils—pretreating stormwater before it's infiltrated is a good idea. Many are unaware, however, that the UIC Program regulates BMPs that could pose a potential threat to the drinking-water supply. More than 90% of public water systems in the United States use groundwater for at least part of their water supply, primarily from shallow aquifers that also recharge lakes, streams, and rivers. EPA anticipates that—specifically because of NPDES Phase II requirements for dealing with stormwater—Class V wells will become more numerous and might affect drinking-water supplies.
gricultural and industrial pollutants in stormwater runoff are of particular concern.
The UIC Program defines and regulates five different classes of injection wells, ranging from Class I—usually located at industrial sites and sometimes involving hazardous wastes, which inject material far below the surface and below any potential drinking-water source—to the shallow Class V, which is somewhat of a catch-all category.
What exactly is covered under the UIC Program? EPA defines a Class V injection well as "any bored, drilled, or driven shaft, or dug hole that is deeper than its widest surface dimension, or an improved sinkhole, or a subsurface fluid distribution system." It also characterizes Class V wells as structures that "inject nonhazardous fluids into or above a [underground source of drinking water] and are typically shallow, on-site disposal systems, such as floor and sink drains which discharge directly or indirectly to ground water, dry wells, leach fields, and similar types of drainage wells."
Although most detention basins and underground stormwater storage systems don't fall into this category, depending on the design—and on exactly what constitutes a "fluid distribution system" under EPA's definition—some underground pipes and chambers, as well as infiltration beds under porous pavement installations, will qualify.
It's important for those planning and designing stormwater BMPs to understand what's covered; EPA requires surveys and prior notification before construction of certain types of wells. The agency also offers suggestions to keep stormwater drainage systems from threatening subsurface drinking-water sources, including not only siting and design but also public education to prevent people from misusing the systems. Information is available at www.epa.gov/safewater/uic.html.