The following definitions are provided for the terms used in this
article:
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 is or may potentially
be harmful or injurious to human health, welfare, safety or property
or 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 in the cultivation of land
in order to further crop and livestock production and conservation
of related soil and water resources.
APPLICANT
Any person, firm, or governmental agency who or which executes
the necessary forms to procure official approval of a project or a
permit to carry out construction of a project.
APPROVING AGENCY
The entity responsible for the review and approval of stormwater
management plans.
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.
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.
CONCEPT PLAN
The first of three required plan approvals that includes
the information necessary to allow an initial evaluation of a proposed
project.
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.
DEVELOP LAND
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 AREA PLAN
A plan developed to treat stormwater runoff at the natural
low point of an area including one or more individual lots.
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.
ENVIRONMENTAL SITE DESIGN (ESD)
Using small-scale stormwater management practices, nonstructural
techniques, and better site planning to mimic natural hydrologic runoff
characteristics and to minimize the impact of land development on
water resources. Methods for designing ESD practices are specified
in the Design Manual.
EXEMPTION
Those land development activities that are not subject to
the stormwater management requirements contained in this article.
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 BMPs 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.
FEE IN LIEU
A fee paid to a stormwater utility capital improvement fund
managed by the Town of Leonardtown in place of stormwater management
to be used to retrofit existing stormwater management features. This
fee may be allowed when the property will not support enough ESD features
to meet the requirements for a particular site without reducing the
density below the maximum allowable in the applicable zone.
FINAL STORMWATER MANAGEMENT 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.
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 ESD planning techniques and treatment practices
are exhausted, and only where absolutely necessary a structural BMP
is implemented.
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.
PERMEABLE PAVING
Paving material that will provide a firm surface but allow
stormwater to infiltrate into the ground.
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.
PERVIOUS AREA
Any surface that allows stormwater to infiltrate into the
ground.
PLANNED UNIT DEVELOPMENT (PUD)
A mixed-use zone intended to implement smart growth by using
clustering and high-density development to attain an overall density
of five feet dwelling units per acre. This zoning district is characterized
by a mix of residential housing types and commercial sites amid substantial
acreage of preserved communal open green space and sensitive natural
areas.
PLANNING TECHNIQUES
A combination of strategies employed early in the project
design to reduce the impact from development and to incorporate natural
features into a stormwater management plan.
RECHARGE VOLUME (Rev)
That portion of the water quality volume use to maintain
groundwater recharge rates at development sites. Methods for calculating
the recharge volume are specified in the Design Manual.
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% or the proposed development is located in a PIRD Zone.
RETENTION STRUCTURE
A permanent structure that provides for the storage of runoff
by means of a permanent pool of water.
RETROFITTING
The implementation of ESD practices, the construction of
a structural BMP, or the modification of an existing structural BMP
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.
SITE
Any tract, lot, or parcel of land, or combination of tracts,
lots or parcels of land that are in one ownership, or are contiguous
and in diverse ownership, where development is to be performed as
part of a unit, subdivision, or project.
SITE DEVELOPMENT PLAN
The second of three required plan approvals that includes
the information necessary to allow a detailed 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 CAPITAL IMPROVEMENTS FUND
A fund established to pay for retrofitting existing stormwater
facilities, building new facilities and replacing deteriorating portions
of the Town's stormwater management system.
STORMWATER MANAGEMENT PLAN
A set of drawings or other documents submitted as a prerequisite
to obtaining a stormwater management approval, which contains all
of the information and specifications pertaining to stormwater management.
STORMWATER MANAGEMENT SYSTEM
Natural areas, ESD practices, stormwater management measures,
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 article.
WAIVER
The reduction of stormwater management requirements by the
Commissioners of Leonardtown for a specific development on a case-by-case
review basis.
WATERCOURSE
Any natural or artificial stream, river, creek, ditch, 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.