For the purpose of this chapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
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 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 executes the necessary forms to procure official approval of a project or a permit to carry out construction of a project.
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, Volumes I & II.
CLEARING. The removal of trees and brush from the land but shall not include the ordinary mowing of grass.
COMMERCIAL PLAN. A plan for any institutional, industrial, or commercial structure or its related appurtenances including both public and private which is not included in the definition of residential plan. For purposes of this chapter, roadways, parks, parking lots, fire stations, fire halls, businesses, manufacturing complexes, distribution centers, churches, and other such facilities shall be considered commercial.
CONCEPT PLAN. The first of 3 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.
DRAINAGE AREA. That area contributing runoff to a single point measured in a horizontal plane, which is enclosed by a ridge line.
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 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 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 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 100-year floodplain.
FINAL STORMWATER MANAGEMENT PLAN. The last of 3 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.
OFF-SITE STORMWATER MANAGEMENT. The design and construction of a facility necessary to control stormwater from more than 1 development.
ON-SITE STORMWATER MANAGEMENT. The design and construction of systems necessary to control stormwater within an immediate development.
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.
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.
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.
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%.
RESIDENTIAL ESD. An environmental site design selected for use in a residential application as approved by Garrett County. The compositions of residential ESD's are subject to the Design Manual.
RESIDENTIAL PLAN. A plan for a single structure occupied by only 1 or 2 families (as in a duplex) or its related structures located on the same lot as a single-family residential structure. Related structures include detached garages not used for commercial use, pools, decks and storage sheds. By definition, a RESIDENTIAL PLAN will use ESD to the MEP for stormwater management. Any plan meeting the criteria for single-family, but using alternative form of stormwater management will be considered a commercial plan.
RESIDENTIAL STRUCTURE. A single structure occupied by only 1 or 2 families or its related structures located on the same lot as a single-family residential structure. Related structures include detached garages not used for commercial use, pools, decks, and storage sheds.
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, which are in 1 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 3 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 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, which 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 the chapter.
WAIVER. The reduction of stormwater management requirements by the Stormwater Management Office 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 flood water.
WATERSHED. The total drainage area contributing runoff to a single point.
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.
(Res. 2010-8, passed 6-15-2010)