Town of Indian Head, MD Stormwater Management Plans

Prior to any subdivision or development activity, the developer shall submit SWM plans for review and approval. Plan review shall be a three-step process, including:

(1)

A SWM concept plan;

(2)

A SWM development plan; and

(3)

A final SWM plan, including a final erosion and sediment control plan.

Combined plan applications.

(1)

The Town may allow certain project types with minor impacts, including but not limited to those listed below in Subsection B(2), to submit combined plan applications, provided that:

(a)

Compliance with ESD to the MEP standard is demonstrated;

(b)

All of the information required for each plan review phase is included.

(2)

Project types that may be considered for combined plan applications include, but are not limited to, the following:

(a)

Plat applications proposing no more than five lots, a common driveway, road layback, frontage improvements, utility work, or entrance/road widening improvements;

(b)

Bridge repair and rehabilitation projects;

(c)

Road widening and repair projects;

(d)

Minor building additions disturbing less than one acre of total area;

(e)

Utility projects which do not propose any additional impervious area;

(f)

Certain redevelopment projects where the SWM concept plan requirement to identify natural resources could be combined with the SWM development plan requirements;

(g)

Residential projects consisting of one lot and disturbing less than one acre of total area; and

(h)

Projects designated as fast-track projects, based on criteria approved by the Town.

Approval of a SWM concept plan, a SWM development plan, or a final SWM plan under this chapter shall not relieve the developer from the obligation to comply with all other applicable requirements for development.

Plans and designs for stormwater management shall be prepared, signed and sealed by a registered professional.

If a stormwater BMP requires either a dam safety permit from MDE or small pond approval from the local SCD, the Town shall require that the design be prepared by a professional engineer licensed in the state.

SWM concept plan. The SWM concept plan shall be prepared prior to the submittal of a subdivision plan, zoning site plan, MXD Phase II plan, or PUD Phase II plan. The SWM concept plan may be submitted prior to or concurrently with a subdivision, zoning site plan, MXD Phase II plan, or PUD Phase II plan. The SWM concept plan shall contain sufficient information for an initial assessment of the proposed development and whether stormwater management can be provided in accordance with this chapter and the Design Manual. Plans submitted for SWM concept plan approval shall include:

(1)

A map at a scale not smaller than one inch equals 100 feet showing site location, existing natural features, water and other sensitive resources, topography, and natural drainage patterns;

(2)

The anticipated location of all proposed impervious areas, buildings, roadways, parking, sidewalks, utilities, and other site improvements;

(3)

The location of the proposed limit of disturbance, erodible soils, steep slopes, and areas to be protected during construction;

(4)

Preliminary estimates of stormwater management requirements, the selection and location of ESD practices to be used, and the location of all points of discharge from the site;

(5)

A narrative that supports the concept design and describes how ESD will be implemented to the MEP; and

(6)

Any other information requested by the Town.

SWM development plan. After the SWM concept plan has been approved, the developer shall submit a SWM development plan consistent with the approved SWM concept plan and all conditions of approval, and any written waiver or variance request. The SWM development plan may be submitted concurrently with or after the submission of a zoning site plan or preliminary subdivision plan application, or MXD Phase II plan or PUD Phase II plan. SWM development plans shall include:

(1)

All details developed during the SWM concept plan review phase;

(2)

Final site layout, impervious area locations and acreages, proposed topography, delineated drainage areas at all points of discharge from the site, proposed hydrologic analysis for runoff rates, storage volumes, and discharge velocities, individual ESD locations and sizing computations for ESD practices, locations, and sizing computations for structural BMPs, and discharge calculations demonstrating safe conveyance off-site;

(3)

Adequate information to determine the level of control required for the ten-year and 100-year frequency storm events;

(4)

For waiver or variance requests under this chapter, the developer shall submit an analysis of the cumulative impacts of stormwater flows downstream in the watershed. The analysis shall include hydrologic and hydraulic calculations necessary to determine the impact of hydrograph timing modifications of the proposed development upon a dam, highway, structure, or natural point of restricted streamflow. The point of investigation is to be established with the concurrence of the Town, downstream of the first downstream tributary whose drainage area equals or exceeds the contributing area to the development or stormwater management facility.

(5)

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 types and locations of ESD and erosion and sediment control practices to be used;

(6)

A narrative that supports the SWM development design, describes how ESD will be used to meet the minimum control requirements, and justifies any proposed structural BMP; and

(7)

Any other information required by the Town.

Final SWM plans. After the SWM development plan has been approved, the developer shall submit final erosion and sediment control plans (in accordance with COMAR 26.17.01.05.) and final SWM plans that are consistent with the approved SWM development plan and all conditions of approval. Final SWM plans shall be submitted as a part of the improvement plans for the subdivision or development.

(1)

Final SWM plans shall include:

(a)

A vicinity map, at a scale not to exceed one inch equals 2,000 feet;

(b)

Existing and proposed topography (including source and date) and proposed drainage areas, including areas necessary to determine downstream analysis for safe conveyance and proposed stormwater management facilities;

(c)

Any proposed improvements, including location of buildings or other structures, impervious surfaces, storm drainage facilities, and all grading;

(d)

The location of existing and proposed structures and utilities;

(e)

All existing and proposed easements and rights-of-way, including recording references where applicable;

(f)

The delineation, if applicable, of the 100-year floodplain and any on-site wetlands;

(g)

Structural and construction details including representative cross sections for all components 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 construction;

(m)

All soil boring logs and locations;

(n)

An inspection and maintenance schedule;

(o)

Certification by the developer that all stormwater management construction will be done according to this plan;

(p)

An as-built certification signature block to be executed after development completion; and

(q)

Any other information requested by the Town.

(2)

The final SWM plan shall also include a report that includes:

(a)

Geotechnical investigations including soil maps, borings, site specific recommendations, other testing, and any additional information necessary for the final stormwater management design;

(b)

Drainage area maps depicting predevelopment 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 all points of discharge from the site;

(d)

Hydraulic and structural computations for all ESD practices and structural BMP measures to be used;

(e)

A narrative that supports the final stormwater management design; and

(f)

Any other information requested by the Town.

If a stormwater management plan involves direction of some or all runoff off of the site, it is the responsibility of the developer, in accordance with state law, to obtain from adjacent property owners any easements or other necessary property interests concerning flowage of water. Approval of a stormwater management plan does not create or affect any right to direct runoff onto adjacent property without that property owner's permission.

The Town shall perform a comprehensive review of the stormwater management plans for each phase of site design. Coordinated comments will be provided for each plan phase that reflect input from all appropriate agencies, including but not limited to Charles County, MDE, and the Town Planning and Zoning Administrator and Department of Public Works. All comments from the Town and other appropriate agencies shall be addressed and approval received at each phase of project design before subsequent submissions.

[Amended at time of adoption of Code (see Ch. 1, General Provisions, Art. III)]