The following definitions are provided for the terms used in
this chapter:
The Maryland Department of the Environment (MDE) Water Management
Administration (WMA).
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.
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.
Any person, firm, or governmental agency who executes the
necessary forms to procure official approval of a project or a permit
to carry out construction of a project.
The entity responsible for the review and approval of stormwater
management plans.
A porous water bearing geologic formation generally restricted
to materials capable of yielding an appreciable supply of water.
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.
The professional engineer, surveyor, or landscape architect
who will be responsible for the signing and sealing of the engineer's
stormwater management certification that is required on all stormwater
management plans, and for performing the required inspections during
construction.
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.
The City of Hagerstown, a Maryland Municipal Corporation.
The City's duly appointed City Engineer or his or her duly
authorized representative.
The removal of trees and brush from the land but shall not
include the ordinary mowing of grass.
The first of three required plan approvals that include the
information necessary to allow an initial evaluation of a proposed
project.
The 2000 Maryland Stormwater Design Manual, and all subsequent
revisions, that serves as the official guide for stormwater management
principles, methods, and practices.
A permanent structure for the temporary storage of runoff
which is designed so as not to create a permanent pool of water.
To change the runoff characteristics of a parcel of land
in conjunction with residential, commercial, industrial, or institutional
construction or alteration.
The concentrated release of stormwater to tidal waters or
vegetated tidal wetlands from new development or redevelopment projects
in the critical area.
The physical change of grades or cover of the ground surface
in either a permanent or temporary manner.
That area contributing runoff to a single point measured
in a horizontal plane, which is enclosed by a ridge line.
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.
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 ESD practices are specified in the
Design Manual.
Those land development activities that are not subject to
the stormwater management requirements contained in this chapter.
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.
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.
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.
Prolonging the flow time of runoff to reduce the peak discharge.
Any act by which soil is cleared, stripped, stockpiled, excavated,
scarified, filled, or any combination thereof. This includes the removal
of roots, stumps, and similar material to a nominal depth below the
surface of the ground.
Any surface that prevents or significantly impedes the infiltration
of water into the underlying soil, including any structure, building,
patio, sidewalk, compacted gravel, pavement, asphalt, concrete, stone,
brick, tile, or artificial turf. Impervious area also includes any
area used by or for motor vehicles, heavy equipment, regardless of
the surface type or material, including any road, driveway or parking
lot.
[Amended 4-28-2020 by Ord. No. O-20-16]
New development that occurs on vacant, bypassed and underutilized
lands within existing developed areas. The site on which the in-fill
development is occurring shall not be part of an overall development
plan such as that found in industrial/business parks. In-fill development
shall typically be limited to site areas less than three acres in
size.
The passage or movement of water into the soil surface.
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. The City Engineer shall be responsible for determining
whether or not the MEP standard has been met.
The design and construction of a facility necessary to control
stormwater from more than one development.
The design and construction of systems necessary to control
stormwater within an immediate development.
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.
Any individual, firm, association, syndicate, co-partnership,
corporation, trust, or any other legal entity of agent thereof commencing
proceedings under this chapter to effect development or redevelopment
for himself or others.
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.
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.
Those items that are commonly found in urban runoff, including
sediment, nutrients, trace metals, pesticides, herbicides, bacteria,
and hydrocarbons.
The conditions of the site that exist prior to the development
that is subject to the requirements of this chapter. The City's 1982
aerial photography will be used as a guide in establishing predevelopment
conditions.
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.
Any construction, alteration, or improvement that is performed
on sites where existing land use is commercial, industrial, institutional,
or multifamily residential and existing site impervious area exceeds
40%.
A permanent structure that provides for the storage of runoff
by means of a permanent pool of water.
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.
Soils or other surficial materials transported or deposited
by the action of wind, water, ice, or gravity as a product of erosion.
Any tract, lot, or parcel of land, or combination of tracts,
lots, 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.
The second of three required plan approvals that includes
the information necessary to allow a detailed evaluation of a proposed
project.
The Washington County Conservation District, or its duly
authorized representative.
The prevention of soil movement by any of various vegetative
and/or structural means.
Water that originates from a precipitation event.
Natural areas, ESD practices, stormwater management measures,
and any other structure through which stormwater flows, infiltrates,
or discharges from a site.
A constructed facility which provides quantitative and/or
qualitative treatment of stormwater that flows into it, including
but not limited to wet and dry detention basins, wetlands, wet and
dry swales, bioretention filters, sand filters, infiltration trenches
and basins, rain gardens, and rainwater-harvesting devices.
[Added 4-28-2020 by Ord. No. O-20-16]
Any activity that removes the vegetative surface cover including
tree removal, clearing, grubbing, and storage or removal of topsoil.
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.
The reduction of stormwater management requirements by the
City for a specific development on a case-by-case review basis.
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.
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.
The total drainage area contributing runoff to a single point.
