Unless otherwise stated, the following words shall, for the purpose
of this chapter, have the meaning herein indicated. Words in the present
tense include the future tense. Words in singular include the plural,
and words in the plural the singular.
ADMINISTRATION
The Maryland Department of the Environment (MDE) Water Management
Administration (WMA).
ADVERSE IMPACT
Any deleterious effect on waters or wetlands, including their
quality, quantity, surface area, species composition, aesthetics or
usefulness for human or natural uses, which are or may potentially
be harmful or injurious to human health, welfare, safety or property,
to biological productivity, diversity, or stability or which unreasonably
interfere with the enjoyment of life or property, including outdoor
recreation.
AGRICULTURAL LAND MANAGEMENT PRACTICES
Those methods and procedures used exclusively in the cultivation
of land to further crop and livestock production, including tillage,
plowing, discing, harrowing, pasturing and installation of conservation
measures. Construction of new buildings or impervious area is not
considered an agricultural activity.
APPLICANT
Any person who executes the necessary forms to procure official
approval of a project or a permit to carry out construction of a project,
including his heirs, successors and assigns.
AQUIFER
A porous water-bearing geologic formation generally restricted
to materials capable of yielding an appreciable supply of water.
BEST MANAGEMENT PRACTICE (BMP)
A structural device or nonstructural practice designed to
temporarily store or treat stormwater runoff in order to mitigate
flooding, reduce pollution, and provide other amenities.
BUILDING
Any structure, either temporary or permanent, having walls
and a roof, designed or used for the shelter of any person, animal
or property.
CHANNEL PROTECTION STORAGE VOLUME (Cpv)
The volume used to design structural management practices
to control stream channel erosion. Methods for calculating the channel
protection storage volume are specified in the 2000 Maryland Stormwater
Design Manual.
CLEARING
The removal of trees and brush from the land but shall not
include the ordinary mowing of grass.
CONVEYANCE
The ability of a pipe, culvert, swale or similar facility
to carry the peak flow from the design storm.
DESIGN MANUAL
The 2000 Maryland Stormwater Design Manual, and all subsequent
revisions, that serves as the official guide for stormwater management
principles, methods, and practices.
DETENTION STRUCTURE
A permanent structure for the temporary storage of runoff
which is designed so as not to create a permanent pool of water.
DEVELOPMENT
To change the runoff characteristics of a parcel of land
in conjunction with residential, commercial, industrial, or institutional
construction or alteration.
DIRECT DISCHARGE
The concentrated release of stormwater to tidal waters or
vegetated tidal wetlands from new development or redevelopment projects
in the critical area.
DRAINAGE AREA
That area contributing runoff to a single point measured
in a horizontal plane, which is enclosed by a ridgeline.
DRAINAGE CONVEYANCE FACILITY
A stormwater management facility designed and constructed
to transmit stormwater runoff and shall include roadside ditches,
swales, drainage ditches, channels, pipes, conduits, culverts, streams,
storm sewers, etc.
EASEMENT
A grant or reservation by the owner of land for the use of
such land by others for a specific purpose or purposes and which must
be included in the conveyance of land affected by such easement.
ENERGY DISSIPATOR
A device used to slow the velocity of stormwater particularly
at points of concentrated discharge such as pipe outlets.
ENVIRONMENTAL SITE DESIGN (ESD)
Using small-scale stormwater management practices, nonstructural
techniques, and better site planning to mimic natural hydrologic runoff
characteristics and minimize the impact of land development on water
resources. Methods for designing environmental site design practices
are specified in the Design Manual.
EXEMPTION
Those land development activities that are not subject to
the stormwater management requirements contained in this chapter.
EXTENDED DETENTION
A stormwater design feature that provides gradual release
of a volume of water in order to increase settling of pollutants and
protect downstream channels from frequent storm events. Methods for
designing extended detention best management practices are specified
in the Design Manual.
EXTREME FLOOD VOLUME (QF)
The storage volume required to control those infrequent but
large storm events in which overbank flows reach or exceed the boundaries
of the one-hundred-year floodplain.
FINAL LAND DEVELOPMENT PLAN
The last of three required plan approvals that includes the
information necessary to allow all approvals and permits to be issued
by the approving agency.
FLOW ATTENUATION
Prolonging the flow time of runoff to reduce the peak discharge.
GRADING
Any act by which soil is cleared, stripped, stockpiled, excavated,
scarified, filled, or any combination thereof.
IMPERVIOUS AREA
Any surface that does not allow stormwater to infiltrate
into the ground. For the purposes of stormwater design, stoned areas
used for vehicles shall be considered impervious area.
INFILTRATION
The passage or movement of water into the soil surface.
MAXIMUM EXTENT PRACTICABLE (MEP)
Designing stormwater management systems so that all reasonable
opportunities for using environmental site design planning techniques
and treatment practices are exhausted and, only where absolutely necessary,
a structural best management practice is implemented.
MINOR RESIDENTIAL SUBDIVISION
The division of a single lot, tract or parcel of land existing
as of April 1, 1995, into four of fewer single-family residential
lots, tracts or parcels of land, either all at one time, or lot by
lot, provided that the proposed lots, tracts or parcels of land thereby
created have frontage on an existing improved community street or
streets, and provided further that there is not created by the subdivision
any new street or streets.
OVERBANK FLOOD PROTECTION VOLUME (QP)
The volume controlled by structural practices to prevent
an increase in the frequency of out-of-bank flooding generated by
development. Methods for calculating the overbank flood protection
volume are specified in the Design Manual.
PERSON
The federal government, the state, any county, municipal
corporation, or other political subdivision of the state, or any of
their units, or an individual receiver, trustee, guardian, executor,
administrator, fiduciary, or representative of any kind, or any partnership,
firm, association, public or private corporation, or any other entity.
PLANNING TECHNIQUES
A combination of strategies employed early in project design
to reduce the impact from development and to incorporate natural features
into a stormwater management plan.
PRELIMINARY LAND DEVELOPMENT PLAN
The second of three required plan approvals that includes
the information necessary to allow a detailed evaluation of a proposed
project.
RECHARGE VOLUME (ReV)
That portion of the water quality volume used to maintain
groundwater recharge rates at development sites. Methods for calculating
the recharge volume are specified in the Design Manual.
RECORD DRAWINGS
A set of prints of the original facilities showing those
changes made during the construction process.
REDEVELOPMENT
Any construction, alteration, or improvement performed on
sites where existing land use is commercial, industrial, institutional,
or multifamily residential and existing site impervious area exceeds
40%.
RETENTION STRUCTURE
A permanent structure that provides for the storage of runoff
by means of a permanent pool of water.
RETROFITTING
The implementation of environmental site design practices,
the construction of structural best management practices, or the modification
of an existing structural best management practice in a previously
developed area to improve water quality over current conditions.
SEDIMENT
Soils or other surficial materials transported or deposited
by the action of wind, water, ice, or gravity as a product of erosion.
SHEET FLOW
Runoff which flows over the ground surface as a thin, even
layer, not concentrated in a channel.
SITE
Any tract, lot, or parcel of land, or combination of tracts,
lots, parcels of land, that is in one ownership, or is contiguous
and in diverse ownership, where development is to be performed as
part of a unit, subdivision, or project.
SKETCH PLAN
The first of three required plan approvals that includes
the information necessary to allow an initial evaluation of a proposed
project.
STABILIZATION
The prevention of soil movement by any of various vegetative
and/or structural means.
STORMWATER
Water that originates from a precipitation event.
STORMWATER MANAGEMENT SYSTEM
Natural areas, environmental site design practices, stormwater
management measures, drainage conveyance facilities and any other
structure through which stormwater flows, infiltrates, or discharges
from a site.
STRIPPING
Any activity that removes the vegetative surface cover, including
tree removal, clearing, grubbing, and storage or removal of topsoil.
VARIANCE
The modification of the minimum stormwater management requirements
for specific circumstances such that strict adherence to the requirements
would result in unnecessary hardship and not fulfill the intent of
this chapter.
WAIVER
The reduction of stormwater management requirements by the
Dorchester County Department of Public Works for a specific development
on a case-by-case review basis.
WATERCOURSE
Any natural or artificial stream, river, creek, ditch, swale,
channel, canal, conduit, culvert, drain, waterway, gully, ravine or
wash, in and including any adjacent area that is subject to inundation
from overflow or floodwater.
WATER QUALITY VOLUME (WQV)
The volume needed to capture and treat 90% of the average
annual rainfall events at a development site. Methods for calculating
the water quality volume are specified in the Design Manual.
WATERSHED
The total drainage area contributing runoff to a single point.