As used in this chapter, the following terms shall have the meanings
indicated:
CRITICAL ENVIRONMENTAL AREA
A specific geographic area designated by state or local agency
having exceptional or unique characteristics that make the area environmentally
important.
DEVELOPMENT
To make a site, lot, area of land or any portion thereof
available for use by physical alteration. Development includes but
is not limited to providing access to a site, clearing or removal
of vegetation, grading, excavation, earth moving, providing utilities
and other services, such as parking facilities, stormwater management
and erosion control systems and sewage disposal systems, altering
landforms, creating impervious surfaces or construction of a structure
on the land.
DRY WELL
Similar to an infiltration trench, but smaller with inflow
from a pipe; commonly covered with soil and used for drainage areas
of less than one acre, such as roadside inlets and rooftop runoff.
EROSION
The removal of soil particles by the action of water, wind,
ice or other geological agents.
EXFILTRATION
The downward movement of runoff through the bottom of an
infiltration system into the soil.
EXTENDED DETENTION
A practice to store stormwater runoff by collection as a
temporary pool of water and provide for its gradual (attenuated) release
over 24 hours or more; a practice which is used to control peak discharge
rates and which provides gravity-settling of pollutants.
FIRST FLUSH
The delivery of a disproportionately large load of pollutants
during the early part of storms due to the rapid runoff of accumulated
pollutants. The first flush in these guidelines is defined as the
runoff generated from a one-year twenty-four-hour storm event from
land which has been made more impervious from predevelopment conditions
through land grading and construction/development activities.
FLOODPLAIN
For a given flood event, that area of land temporarily covered
by water which adjoins a watercourse.
FOREBAY
An extra storage area or treatment area, such as a sediment
pond or created wetland, near an inlet of a stormwater management
facility to trap incoming sediments or take up nutrients before they
reach a retention or extended detention pond.
IMPERVIOUS AREA
Impermeable surfaces, such as pavement or rooftops, which
prevent the percolation of water into the soil.
INFILTRATION
A practice designed to promote the recharge of groundwater
by containment and concentration of stormwater in porous soils.
INFILTRATION BASIN
An impoundment made by excavation or embankment construction
to contain and exfiltrate runoff into the soil layer.
OUTFALL
The terminus of a storm drain where the contents are released.
PEAK FLOW
The maximum rate of flow of water at a given point and time
resulting from a storm event.
PEAK FLOW ATTENUATION
The reduction of the peak discharge of storm runoff by storage
and gradual release of that storage.
RETENTION
A practice designed to store stormwater runoff by collection
as a permanent pool of water without release except by means of evaporation,
infiltration or attenuated release when runoff volume exceeds the
permanent storage capacity of the permanent pool.
RIPRAP
A combination of large stone, cobbles and boulders used to
line channels, stabilize stream banks and reduce runoff velocities.
RISER
A vertical pipe that is used to control the discharge rate
from a pond for a specified design storm.
STREAM
A watercourse or body of water, either man-made or natural,
whether perennial, ephemeral/intermittent or continual.
STREAM CORRIDOR
The landscape features on both sides of a stream, including
soils, slope and vegetation, whose alteration can directly impact
the stream's physical characteristics and biological properties.
SWALE
A natural depression or wide shallow ditch used to temporarily
route and/or filter runoff.