SS-1 Definitions

Remediation

is the process of cleaning up a contaiminated site by physical, chemical or biological means.  Remediation processes are typically applied to contaiminated soil and grounwater.

Site Assessment
is an evaluation of above-ground (including facilities) and subsurface characteristics, including the geology and hydrology of the site to determine if a release has occurred, as well as the extent and concentration of release.  Information genereated during a site assesment is used to support remedial action decisions. 
Constructed Wetland
is an enigineered system designed to stimulate natural wetland functions for water purification.  Constructed wetlands are essentially treatement systems that remove contaminants from wastewater.
Impervious Surfaces
promote runoff of precipitation volumes instead of infiltration into the subsurface.  The imperviousness or degree of runoff potential can be estimated for differenct surface materials.
Stormwater Runoff
consists of water volumes that are created during precipitation events and flow over surfaces into sewer systems or receiving waters.  All precipitation waters that leave project site boundaries on the surface are considered to be stormwater runoff volumes.
Total Phosphorus (TP)
consists of organically bound phosphates, poly-phosphates and orthophosphates in stormwater, the majority of which originates from fertilizer apllication.  Chemical precipitation is the typical removal mechanism for phosphorus.
Total Suspended Solids (TSS)
are particles or flocs that are too small or light to be removed from stormwater via gravity settling.  Suspended solid concentrations are typically removed via filtration.
Infiltration Basins and Trenches
are devices used to encourage subsurface infiltration of runoff volumes through temporary surface storage.  Basins are ponds that can store large volumes of stormwater.  They need to drain within 72 hours to maintain aerobic conditions and to be avilable for the next storm event.  Trenches are similar to infiltration basins except that they are shallower and function as a  subsurface resevoir for stormwater volumes.  Pretreatment to remove sediment and oil may be necessary to avoid cloggin of infiltration basins are not possible.
Porous Pavement and Permeable Surfaces
are used to reate permeable surfaces that allow runoff to infiltrate into the subsurface.  These surfaces are typically maintained with a vacuuming regime to avoid potential cloggin and failure problems.
Vegetated Filter Strips and Grassed Swales
utilize vegetation to filter sediment and pollutants from stormwater.  Strips are appropriate for treating low-velocity surface sheet flows in areas where runoff is not concentrated.  They are often used as pretreatment for other stormwater measures such as infiltration basins and trenches.  Swales consist of a trench or ditch with vegetation and require occasional mowing.  They also encourage subsurface infiltration, similar to infiltration basins and trenches.
Filtration Basins
remove sediment and polluntants from stormwater runoff using a filter media such as sand or gravel.  A sediment trap is usually included to remove sediment from stormwater before filtering to avoid clogging.
Dentention Ponds
capture stormwater runoff and allow polluntatns to drop out before release to a stormwater or water body.  A variety of dention pond designs are available, wich some utilizing only gravity while others use mechanical equipment such as pipes and pumps to facilitate transport.  Some ponds are dry except during storm events; others permanently store water volumes.