Md. Code Regs. 26.17.02.02 - Definitions
A. The following
definitions describe the meaning of terms used in this chapter and the 2000
Maryland Stormwater Design Manual , Volumes I & II. The definitions will be
valid unless the context in which they are used clearly requires a different
meaning. Terms not defined below shall have the meanings given to them in the
relevant statutes or, if not defined in statutes, the meanings attributed by
common use. The definitions for these terms are provided below as a
convenience, but persons affected by the Department 's regulations should be
aware that these definitions are subject to amendment by the General
Assembly.
B. In this chapter, the
following terms have the meanings indicated.
(1) "Administration " means the Water
Management Administration.
(2)
"Agricultural land management practices" means 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.
(3) "Approving agency " means the entity
responsible for review and approval of stormwater management plans.
(4) "Aquifer " means a porous water-bearing
geologic formation generally restricted to materials capable of yielding an
appreciable supply of water.
(5)
"Best management practice (BMP)" means 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.
(6) "Channel protection storage volume" means
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, Volumes I &
II.
(7) "Concept plan " means the
first of three required plan approvals that includes the information necessary
to allow an initial evaluation of a proposed project.
(8) "Department " means the Department of the
Environment.
(9) "Design Manual "
means the 2000 Maryland Stormwater Design Manual , Volumes I & II, that
serves as the official guide for stormwater management principles, methods, and
practices.
(10) "Detention
structure " means a permanent structure for the temporary storage of runoff
which is designed so as not to create a permanent pool of water.
(11) "Develop land " means to change the
runoff characteristics of a parcel of land in conjunction with residential,
commercial, industrial, or institutional construction or alteration.
(12) "Direct discharge " means the
concentrated release of stormwater to tidal waters or vegetated tidal wetlands
from new development or redevelopment projects in the Critical Area.
(13) "Direct runoff " means the flow of
rainwater, snowmelt, or spring flow over the land surface toward stream
channels.
(14) "Drainage area "
means that area contributing runoff to a single point measured in a horizontal
plane, which is enclosed by a ridge line.
(15) Environmental Site Design.
(a) "Environmental site design (ESD) " means
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.
(b) "Environmental site design (ESD) " design
methods are specified in the Design Manual .
(16) "Extended detention " means 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 .
(17) "Extreme
flood volume " means the storage volume required to control those infrequent but
large storm events in which overbank flows reach or exceed the boundaries of
the 100-year floodplain.
(18)
"Final stormwater management plan" means the last of three required plan
approvals that includes the information necessary to allow all approvals and
permits to be issued by the appropriate authority.
(19) "Flow attenuation " means prolonging the
flow time of runoff to reduce the peak discharge .
(20) "Impervious area " means any surface that
does not allow stormwater to infiltrate into the ground.
(21) "Infiltration " means the passage or
movement of water into the soil surface.
(22) "Maximum extent practicable (MEP) " means
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.
(23) "Off-site stormwater management " means
the design and construction of a facility necessary to control stormwater from
more than one development.
(24)
"On-site stormwater management " means the design and construction of systems
necessary to control stormwater within an immediate development.
(25) "Overbank flood protection volume " means
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 .
(26) "Person " means 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.
(27) "Planning techniques " means a
combination of strategies employed early in project design to reduce impact
from development and to incorporate natural features into a stormwater
management plan.
(28) "Recharge
volume " means that portion of the water quality volume used to maintain ground
water recharge rates at development sites. Methods for calculating the recharge
volume are specified in the Design Manual.
(29) "Redevelopment " means any construction,
alteration, or improvement performed on sites where existing land use is
commercial, industrial, institutional, or multifamily residential and the
existing site impervious area exceeds 40 percent.
(30) "Retention structure " means a permanent
structure that provides for the storage of runoff by means of a permanent pool
of water.
(31) "Retrofitting " means
the construction of a structural BMP in a previously developed area, the
modification of an existing structural BMP, or the implementation of a
nonstructural practice to improve water quality over current
conditions.
(32) "Sediment " means
soils or other surficial materials transported or deposited by the action of
wind, water, ice, or gravity as a product of erosion.
(33) "Site " means any tract, lot, 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.
(34) "Site development plan" means the second
of three required plan approvals that includes the information necessary to
allow a detailed evaluation of a proposed project.
(35) "Stormwater " means water that originates
from a precipitation event .
(36)
"Stormwater management " means, for:
(a)
Quantitative control, a system of vegetative and structural measures that
control the increased volume and rate of surface runoff caused by man-made
changes to the land; and
(b)
Qualitative control, a system of vegetative, structural, and other measures
that reduce or eliminate pollutants that might otherwise be carried by surface
runoff.
(37) "Stormwater
Management Subtitle" means Environment Article, Title 4, Subtitle 2, Annotated
Code of Maryland and cumulative supplement.
(38) "Stormwater management system" means
natural areas, ESD practices, stormwater management measures, and any other
structure through which stormwater flows, infiltrates, or discharges from a
site.
(39) "Water quality volume "
means the volume needed to capture and treat 90 percent of the average annual
runoff volume at a development site . Methods for calculating the water quality
volume are specified in the Design Manual .
(40) "Watershed " means the total drainage
area contributing runoff to a single point.
Notes
State regulations are updated quarterly; we currently have two versions available. Below is a comparison between our most recent version and the prior quarterly release. More comparison features will be added as we have more versions to compare.
No prior version found.