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Editor’s noteSection 19-19, Penalties and other forms of relief, derived from 1976 L.M.C., ch. 14, § 1; 1983 L.M.C., ch. 22, § 22; and 1986 L.M.C., ch. 45, § 1, was repealed by 2001 L.M.C., ch. 27, § 1.
Notes
| [Note] | *Editor’s noteSee County Attorney Opinion dated 12/13/99 explaining that the County has the authority to inspect stormwater management facilities constructed before 1985, but maintenance responsibility lies with the owner. 2002 L.M.C., ch. 3, § 2, which amended all sections of Article II, states: Until supersedes, a Regulation issued before this Act took effect [June 20, 2002] remains in effect to the extent the regulation is consistent with Chapter 19, as amended by this Act. This Act does not apply to a violation of Chapter 19 that initially accrued before this Act took effect [June 20, 2002]. 2001 L.M.C., ch. 27, § 2, states: Transition. Until superseded, a Regulation issued before this Act took effect [February 27, 2002] remains in effect to the extent the regulation is consistent with Chapter 19, as amended by this Act. This Act does not apply to a violation of Chapter 19 that initially accrued before this Act took effect [February 27, 2002]. |
The purpose of this Article is to protect, maintain and enhance the public health, safety, and general welfare by establishing minimum requirements and procedures to control the adverse impacts associated with increased stormwater runoff from developed and developing lands. The primary goal of the County is to maintain after development, as nearly as possible, the pre-development runoff characteristics, and to reduce stream channel erosion, pollution, siltation and sedimentation, and local flooding by implementing environmental site design to the maximum extent practicable and using appropriate structural best management practices only when necessary. The 2000 Maryland Stormwater Design Manual and any later revisions are incorporated by reference as if fully contained in this Article. (1980 L.M.C., ch. 60, § 3; 1985 L.M.C., ch. 27, § 1; 2001 L.M.C., ch. 27, § 1; 2002 L.M.C., ch. 3, § 1; 2010 L.M.C., ch. 34, § 1.)
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 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.
(a) The Director may, for good cause shown, grant an administrative waiver to a development that received a preliminary project approval before May 4, 2010. Administrative waivers expire as provided under subsection (b) and may be extended as provided under subsection (c).
(b) Expiration of an administrative waiver.
(1) Except as provided in subsection (c), an administrative waiver must expire on:
(A) May 4, 2013, if the development does not receive final project approval before that date; or
(B) May 4, 2017, if the development receives final project approval before May 4, 2013.
(2) All construction authorized under an administrative waiver must be completed by:
(A) May 4, 2017; or
(B) if the waiver is extended under subsection (c), the date the waiver expires.
(c) Extension of an administrative waiver.
(1) Except as provided in paragraph (2), an administrative waiver must not be extended.
(2) An administrative waiver may only be extended if, by May 4, 2010 the development:
(A) received a preliminary project approval; and
(B) was subject to a development rights and responsibilities agreement or a tax increment financing approval.
(3) An administrative waiver extended under paragraph (2) expires when the development rights and responsibilities agreement or the tax increment financing approval expires. (2010 L.M.C., ch. 34, § 1.
(a) The Department of Environmental Protection, in cooperation with the Department, the Board, and other appropriate agencies, may develop watershed management plans to implement stormwater management policies that apply individually to specific watersheds in the County. Each watershed management plan should:
(1) include detailed hydrologic and hydraulic analyses to determine hydrograph timing;
(2) evaluate stormwater quantity and quality, and base flow and groundwater management needs;
(3) include a cumulative impact assessment of watershed development;
(4) identify existing flooding, receiving stream channel, water quality, biological resources, and habitat conditions;
(5) specify the types of stormwater management, stream restoration and wetlands protection practices to be implemented;
(6) identify specific opportunities for stormwater retrofit, stream and wetlands restoration, and groundwater recharge;
(7) specify where the Director may grant waivers of on-site stormwater management controls;
(8) be consistent with the Design Manual’s General Performance Standards for Stormwater Management in Maryland; and
(9) be approved by the Administration.
(b) The Board should prepare functional master plans under Division II of the Land Use Article of the Maryland Code to preserve, conserve, and manage natural resources in each of the County’s watersheds for the County Council’s review and approval. Each functional master plan should address land use, impervious impact on streams and waterways, stream buffers, wildlife and stream habitat, forest preservation, and other issues related to the permitting of stormwater management facilities and the development of watershed management plans. (1980 L.M.C., ch. 60, § 3; 1985 L.M.C., ch. 27, § 1; 2001 L.M.C., ch. 27, § 1; 2002 L.M.C., ch. 3, § 1; 2010 L.M.C., ch. 34, § 1; 2013 L.M.C., ch. 4, § 1.)
(a) An applicant must use the ESD planning techniques and practices and structural stormwater management measures established in this Article and the Design Manual, either alone or in combination, in a stormwater management plan. An applicant must demonstrate that environmental site design has been implemented to the maximum extent practicable before a structural best management practice is included in a stormwater management plan.
(b) ESD planning techniques and practices.
(1) An applicant must apply the following planning techniques according to the Design Manual to satisfy the on-site stormwater management requirements of Section 19-24:
(A) preserve and protect natural resources;
(B) conserve natural drainage patterns;
(C) minimize impervious area;
(D) reduce runoff volume;
(E) use ESD practices to maintain 100% of the average annual pre- development groundwater recharge volume for the site;
(F) use green roofs, permeable pavement, reinforced turf, and other alternative surfaces;
(G) limit soil disturbance, mass grading, and compaction;
(H) cluster development; and
(I) any practice approved by the Administration.
(2) An applicant must design the following ESD treatment practices according to the Design Manual to satisfy the on-site stormwater management requirements of Section 19-24:
(A) disconnection of rooftop runoff;
(B) disconnection of nonrooftop runoff;
(C) sheetflow to conservation areas;
(D) rainwater harvesting;
(E) submerged gravel wetlands;
(F) landscape infiltration;
(G) infiltration berms;
(H) dry wells;
(I) micro-bioretention;
(J) rain gardens;
(K) swales;
(L) enhanced filters; and
(M) any practice approved by the Administration.
(3) The use of ESD planning techniques and treatment practices specified in this Section must not conflict with existing State or County laws.
(c) Structural stormwater management practices.
(1) An applicant must design the following structural stormwater management practices according to the Design Manual to satisfy the on-site stormwater management requriements of Section 19-24:
(A) stormwater management ponds;
(B) stormwater management wetlands;
(C) stormwater management infiltration;
(D) stormwater management filtering systems; and
(E) stormwater management open channel systems.
(2) An applicant must consider the performance criteria specified in the Design Manual with regard to general feasibility, conveyance, pretreatment, treatment and geometry, environment and landscaping, and maintenance when selecting structural stormwater management practices.
(3) An applicant must select structural stormwater management practices to accommodate the unique hydrologic or geologic region of the County where the property to be developed is located.
(d) An applicant may use an alternative ESD planning technique or treatment practice or structural stormwater management measure for new development runoff control if it meets the performance criteria established in the Design Manual and is approved by the Administration. Any practice used for a redevelopment project must be approved by the Department.
(e) Before modifying the on-site stormwater control requirements or design criteria, the applicant must submit to the Department an analysis of the impacts of stormwater flows downstream in the watershed. The analysis must include hydrologic and hydraulic calculations necessary to determine the impact of hydrograph timing modifications of the proposed development on a dam, highway, structure, or natural point of restricted streamflow, established with the Department’s concurrence, downstream from the first downstream tributary whose drainage area equals or exceeds the contributing area to the project or stormwater management facility. (2010 L.M.C., ch. 34, § 1.)
(a) Concept plan. Before the Board may approve a preliminary plan of subdivision, an applicant must submit a stormwater management and sediment control concept plan to the Department for review and approval. Each plan submitted for concept approval must provide sufficient information for the Department to make an initial assessment of the proposed project and determine whether stormwater can be managed according to this Article and the Design Manual. Each concept plan is subject to the following conditions and requirements:
(1) A natural resources inventory must be reviewed and approved by the Department or the Planning Director before the applicant submits a concept plan under this Section.
(2) The plan must indicate how the stormwater management and sediment control criteria will be applied to each proposed development or redevelopment project. The Department may require a plan to analyze the downstream effects of any proposed development or redevelopment project. The basic design criteria, methodologies, and construction specifications used in developing the plan must be specified in the Design Manual and any other criteria established by regulation.
(3) The plan must describe how environmental site design practices will be implemented to the maximum extent practicable and allow use of any structural best management practice only where the applicant shows that environmental site design or another nonstructural best management practice is not a viable option.
(4) The plan must include:
(A) a map, at a scale specified by the Department, showing site location, existing natural features, water and other sensitive resources, topography, and natural drainage patterns;
(B) the anticipated location of each proposed impervious area, building, roadway, parking, sidewalk, utility, and other site improvement;
(C) the location of the proposed limit of disturbance, erodible soils, steep slopes, and any area to be protected during construction;
(D) preliminary estimates of stormwater management requirements, the location of each ESD practice to be used, and the location of each point of discharge from the site; and
(E) any other information the Director requires.
(5) Any stormwater management plan must be consistent with any watershed management plan that the Department of Environmental Protection has approved or any flood management plan that the Administration has approved involving the site of the proposed development or redevelopment project.
(6) The Department must refer the concept plan to the Department of Environmental Protection, the Department of Transportation, and the Board for comment before approving the plan.
(b) Site development stormwater management plan. Before the Board may approve a site plan, the applicant must submit a site development stormwater management plan to the Department for review and approval. The applicant may combine the site development stormwater management plans with the concept plan required under subsection (a) if the Director approves. Any site development stormwater management plan submitted for review and approval must include:
(1) all information provided during the concept plan review;
(2) final site layout, exact impervious area locations and acreages, proposed topography, a delineated drainage area at each point of discharge from the site, and stormwater volume computations for ESD practices and structural measures;
(3) a proposed erosion and sediment control plan that contains the construction sequence, any phasing necessary to limit earth disturbances and impacts to natural resources, and an overlay plan showing the type and location of each ESD and erosion and sediment control practice to be used;
(4) a narrative that supports the site development design, describes how ESD will be used to meet the minimum control requirements, and justifies any proposed structural stormwater management measure; and
(5) any other information the Director requires.
(c) Final stormwater management design plan
(1) Any person required under this Chapter to obtain a sediment control permit must include a final stormwater management design plan as part of the permit application. The final stormwater management design plan must conform to both the concept plan and site development stormwater management plan and serve as the basis for all later construction. The applicant must submit a final stormwater management design plan for approval in the form of construction drawings accompanied by a report that includes sufficient information to evaluate the effectiveness of the proposed runoff control design. The applicant must also submit a final erosion and sediment control plan under applicable State Regulations. Any plan submitted under this paragraph must meet all requirements of the Design Manual.
(2) Any report submitted for final stormwater management design plan approval must include:
(A) geotechnical investigations, including soil maps, borings, site-specific recommendations, and any additional information necessary for the final stormwater management design;
(B) a drainage area map depicting pre-development and post-development runoff flow path segmentation and land use;
(C) hydrologic computations of the applicable ESD and unified sizing criteria according to the Design Manual for each point of discharge from the site;
(D) hydraulic and structural computations for each ESD practice and structural stormwater management measure to be used; and
(E) a narrative that supports the final stormwater management design.
(3) Construction drawings submitted for final stormwater management design plan approval must include:
(A) a vicinity map;
(B) existing and proposed topography and any proposed drainage area, including any area necessary to determine downstream analysis for each proposed stormwater management facility;
(C) any proposed improvement, including the location of any building or other structure, impervious surface, storm drainage facility, and all grading;
(D) the location of any existing and proposed structure;
(E) any easement and right-of-way;
(F) the delineation, if applicable, of the 100-year floodplain and any on-site wetland;
(G) structural and construction details, including representative cross sections for each component of the proposed drainage system or systems and stormwater management facilities;
(H) all necessary construction specifications;
(I) a sequence of construction;
(J) data for total site area, disturbed area, new impervious area, and total impervious area;
(K) a table showing the ESD and unified sizing criteria volumes required in the Design Manual;
(L) a table of materials to be used for stormwater management facility planting;
(M) each soil boring log and location;
(N) an inspection and maintenance schedule;
(O) certification by the applicant that all stormwater management construction will be completed according to this plan; and
(P) an as-built certification signature block, to be executed after project completion.
(4) The maintenance schedule required under this Section must cover the life of any structural stormwater management facility or system of ESD practices and must specify the maintenance to be completed, the time period for completion, and the responsible party that will perform the maintenance. The maintenance schedule must be printed on the approved final stormwater management plan.
(d) Plan preparation. The Director may require the stormwater management concept, site development stormwater management, and final stormwater management and design plans to be prepared by a professional engineer, professional land surveyor, registered architect or landscape architect licensed in Maryland, or any other individual whose qualifications are acceptable to the Department. If a stormwater best management practice requires either a dam safety permit from the Administration or a small pond approval from the District, the Director must require the design plan to be prepared by a professional engineer licensed by the State of Maryland.
(e) Runoff. If a stormwater management plan involves direction of some or all runoff off site, the developer must obtain from any adjacent property owner any easement or other necessary property interest concerning water flow. Approval of a stormwater management plan does not create or imply any right to direct runoff onto any adjacent property without that property owners’s permission. (1980 L.M.C., ch. 60, § 3; 1985 L.M.C., ch. 27, § 1; 2001 L.M.C., ch. 27, § 1; 2002 L.M.C., ch. 3, § 1; 2006 L.M.C., ch. 37, § 1; 2010 L.M.C., ch. 34, § 1.)
Editor’s note — Former §§ 19-23, “Storm water management chapter,” and 19-25, “Storm water Management required for a development,” were repealed, re-enacted with amendments, renumbered § 19-23, and retitled pursuant to 2002 L.M.C., ch. 3, § 1.
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