Skip to code content (skip section selection)
In this Article, the following words and phrases have the following meanings unless the context indicates otherwise:
Administration: The Water Management Administration of the Maryland Department of the Environment.
Administrative waiver: A decision by the Department to allow the construction of a development to be governed by the County stormwater management law in effect as of May 4, 2009. An administrative waiver is distinct from a waiver granted under Section 19-24.
Agricultural land management practice: Any method or procedure used in the cultivation of land in order to further crop and livestock production and conservation of related soil and water resources.
Applicant: A landowner, contract purchaser or other person that assumes the legal responsibility for developing land subject to this Article.
Approval: A documented action by the Department after a review to determine and acknowledge the sufficiency of submitted material to meet the requirements of a specified stage in the County’s development review process. Approval does not mean an acknowledgment by the Department that submitted material has been received for review.
Best management practice: A structural device or nonstructural practice designed to temporarily store or treat stormwater runoff to mitigate flooding, reduce pollution, recharge groundwater, and provide other amenities related to the management of stormwater runoff.
Board: The County Planning Board.
Channel protection storage volume: The volume used to design structural best management practices to control stream channel erosion.
Commission: The Maryland-National Capital Park and Planning Commission.
Concept plan: The first of 3 required plan approvals that includes the information necessary to allow an initial evaluation of a proposed project.
Department: The Department of Permitting Services.
Design Manual: The 2000 Maryland Stormwater Design Manual, as revised from time to time, which serves as the official guide for stormwater management principles, methods, and practices in Maryland.
Development: A project that consists of subdividing land or adding buildings and other improvements to individual parcels of land.
Director: The Director of the Department of Permitting Services or the Director’s designee.
Director of Environmental Protection: The Director of the Department of Environmental Protection, or the designee of the Director of Environmental Protection.
Director of Finance: The Director of the Department of Finance or the Director’s designee.
District: The Montgomery Soil Conservation District.
Drainage area: That area that contributes runoff to a single point, measured in a horizontal plane.
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 development on water resources. Methods to design ESD practices are specified in the Design Manual.
Erosion: The process by which the ground surface is worn away by the action of wind, water, ice, or gravity.
Executive: The County Executive or the County Executive’s designee.
Extreme flood volume: The storage volume required to control the infrequent but large storm events during which overbank flows reach or exceed the boundaries of the 100-year floodplain.
Final project approval: Approval of the final stormwater management plan and erosion and sediment control plan required to construct a project’s stormwater management facilities. Final project approval also includes securing bonding or financing for final development plans if either is required as a prerequisite for approval.
Final stormwater management design plan. The last of 3 required plan approvals that includes the information necessary to allow all approvals and permits to be issued by the appropriate authority.
Functional master plan: A master plan for conserving and managing a watershed.
Impervious area or impervious surface: 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, swimming pool, or artificial turf. Impervious surface also includes any area used by or for motor vehicles or heavy commercial equipment, regardless of surface type or material, including any road, driveway, or parking area.
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 environmental site design planning techniques and treatment practices are exhausted and, only where absolutely necessary, a structural best management practice is implemented.
Nonprofit organization: A corporation, foundation, or other legal entity that is exempt from income taxation under Section 501(c)(3) of the Internal Revenue Code.
Nonstructural maintenance: Grass cutting; removal of litter and debris, tree limbs, algae and aquatic plants; tree and shrub trimming and removal; maintenance of fences; aesthetic improvements such as graffiti removal, and any other enhancement in and around a stormwater management facility that is not essential to ensure that the facility continues to function properly.
Off-site stormwater management: The design and construction of a facility to control stormwater runoff from more than one development. An off-site stormwater management facility may be located in a development and would be on-site with respect to that development, but the facility is off-site with respect to all other developments that the facility serves.
On-site stormwater management: The design and construction of stormwater practices to control stormwater runoff in a development.
Overbank flood protection volume: The volume controlled by structural practices to prevent an increase in the frequency of out of bank flooding generated by development.
Person: An individual; a legal entity; or a department, agency, or instrument of the County or to the extent allowed by law, federal, state, or local government.
Planning Director: The Director of the County Planning Department, or the Director’s designee.
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.
Preliminary plan: A preliminary plan of subdivision, approved under Chapter 50.
Preliminary project approval: An approval as part of the Department’s preliminary development or planning review process that includes at least:
(a) the number of planned dwelling units or lots;
(b) the proposed project density;
(c) the proposed size and location of all land uses for the project;
(d) a plan that identifies:
(1) the proposed drainage patterns;
(2) the location of each point of discharge from the site; and
(3) the type, location, and size of each stormwater management measure based on site-specific stormwater management requirement computations; and
(e) any other information required by the Department, including:
(1) the proposed alignment, location, and construction type and standard for any road, access way, and area of vehicular traffic;
(2) a demonstration that the methods by which the development will be supplied with water and wastewater service are adequate; and
(3) the size, type, and general location of all proposed wastewater and water system infrastructure.
Recharge volume: The portion of the water quality volume used to maintain groundwater recharge rates at a development site.
Redevelopment: Any construction, alteration, or improvement that:
(a) exceeds or equals 5,000 square feet of land disturbance; and
(b) is performed on a site where the existing land use is commercial, industrial, institutional, or multifamily residential and existing imperviousness is greater than 40 percent.
Residential property: A property that contains a detached dwelling unit, one or more townhouses, duplexes or other attached dwelling units, or a multi-family dwelling.
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 under one ownership, or are contiguous and under diverse ownership, where development is performed as part of a unit, subdivision, or project.
Site development stormwater management plan: The second of 3 required plan approvals which includes information necessary to allow detailed evaluation of a proposed project.
Stabilization: the prevention of soil movement by any of various vegetative or structural means.
Stormwater: Water that originates from precipitation.
Stormwater management: The collection, conveyance, storage, treatment, and control of stormwater as needed to reduce accelerated stream channel erosion, increased flood damages, or water pollution.
Stormwater management facility: An infiltration device, filtering device, stormwater pond, stormwater wetland, hydrodynamic structure, or other practice designed and constructed to control stormwater to reduce accelerated stream channel erosion and pollution of surface waters. A stormwater management facility does not include environmental site design practices or any nonstructural stormwater management system.
Stormwater management participation project: A capital improvement project in which both the County and the property owner jointly fund the construction of a regional stormwater management facility intended to benefit properties in addition to those belonging to the property owner.
Stormwater management plan: A set of representations, drawings or other documents, including development phasing statements, which contains all of the information and specifications that the Department requires an applicant to submit in order to obtain a stormwater management approval.
Stormwater management system: Natural areas, environmental site design practices, stormwater management measures, and any structure through which stormwater flows, infiltrates, or discharges from a site.
Structural maintenance: The inspection, construction, reconstruction, modification, repair, and cleaning of any part of a stormwater management facility undertaken to assure that the facility remains in the proper working condition to serve its intended purpose and prevent failure. Structural maintenance does not include landscaping, grass cutting, or trash removal.
Watershed: The total drainage area contributing runoff to a single point.
Watershed management plan: A plan to satisfy the regulatory requirements of the County’s National Pollutant Discharge Elimination System permit issued by the Maryland Department of the Environment under the federal Clean Water Act.
Water Quality Protection Charge: An excise tax charged to a property owner for the privilege of maintaining impervious surfaces on the owner’s property.
Water quality volume: The volume needed to capture and treat 90 percent of the average annual runoff volume at a development site. (1980 L.M.C., ch. 60, § 3; 1985 L.M.C., ch. 27, § 1; 1996 L.M.C., ch. 20, § 1; 1998 L.M.C., ch. 12, § 1; 2001 L.M.C., ch. 14 , § 1; 2001 L.M.C., ch. 27 , § 1; 2002 L.M.C., ch. 3 , § 1; 2002 L.M.C., ch. 16, § 2; 2010 L.M.C., ch. 34 , § 1; 2013 L.M.C., ch. 4 , § 1; 2013 L.M.C., ch. 11, § 1; 2015 L.M.C., ch. 54, § 1; 2016 L.M.C., ch. 20, § 1; 2018 L.M.C., ch. 6, §1.)
Editor’s note—See County Attorney Opinion dated 5/20/91 indicating that the Washington Suburban Sanitary Commission is exempt from listed local permits, including Chapters 8, 19, 22, 50, and 59, but must comply with State law regarding sediment control and fire safety.