The following definitions are provided for the terms used in this article:
ADMINISTRATIONThe Maryland Department of the Environment (MDE) Water Management Administration (WMA).
ADVERSE IMPACTAny 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 PRACTICESThose 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.
APPLICANTAny 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 AGENCYThe entity responsible for the review and approval of stormwater management plans.
AQUIFERA 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.
CLEARINGThe removal of trees and brush from the land, but shall not include the ordinary mowing of grass.
CONCEPT PLANThe first of three required plan approvals that includes the information necessary to allow an initial evaluation of a proposed project.
DESIGN MANUALThe 2000 Maryland Stormwater Design Manual, and all subsequent revisions, that serves as the official guide for stormwater management principles, methods, and practices.
DETENTION STRUCTUREA permanent structure for the temporary storage of runoff, which is designed so as not to create a permanent pool of water.
DEVELOP LANDTo change the runoff characteristics of a parcel of land in conjunction with residential, commercial, industrial, or institutional construction or alteration.
DIRECT DISCHARGEThe concentrated release of stormwater to tidal waters or, vegetated tidal wetlands from new development or redevelopment projects in the Critical Area.
DRAINAGE AREAThat area contributing runoff to a single point, measured in a horizontal plane, which is enclosed by a ridgeline.
DRAINAGE AREA PLANA plan developed to treat stormwater runoff at the natural low point of an area including one or more individual lots.
EASEMENTA 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.
EXEMPTIONThose land development activities that are not subject to the stormwater management requirements contained in this article.
EXTENDED DETENTIONA 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 LIEUA 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 PLANThe 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 ATTENUATIONProlonging the flow time of runoff to reduce the peak discharge.
GRADINGAny act by which soil is cleared, stripped, stockpiled, excavated, scarified, filled, or any combination thereof.
IMPERVIOUS AREAAny surface that does not allow stormwater to infiltrate into the ground.
INFILTRATIONThe 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 PAVINGPaving material that will provide a firm surface but allow stormwater to infiltrate into the ground.
PERSONThe 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 AREAAny 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 TECHNIQUESA 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.
REDEVELOPMENTAny 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 STRUCTUREA permanent structure that provides for the storage of runoff by means of a permanent pool of water.
RETROFITTINGThe 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.
SEDIMENTSoils or other surficial materials transported or deposited by the action of wind, water, ice, or gravity as a product of erosion.
SITEAny 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 PLANThe second of three required plan approvals that includes the information necessary to allow a detailed evaluation of a proposed project.
STABILIZATIONThe prevention of soil movement by any of various vegetative and/or structural means.
STORMWATERWater that originates from a precipitation event.
STORMWATER CAPITAL IMPROVEMENTS FUNDA 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 PLANA 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 SYSTEMNatural areas, ESD practices, stormwater management measures, and any other structure through which stormwater flows, infiltrates, or discharges from a site.
STRIPPINGAny activity that removes the vegetative surface cover, including tree removal, clearing, grubbing, and storage or removal of topsoil.
VARIANCEThe 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.
WAIVERThe reduction of stormwater management requirements by the Commissioners of Leonardtown for a specific development on a case-by-case review basis.
WATERCOURSEAny 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.
WATERSHEDThe total drainage area contributing runoff to a single point.