§ 33-4-107. STORMWATER MANAGEMENT PLANS.

(a)

In general. Unless an exemption, waiver, or variance has been granted and except as provided in subsection (f) of this section, before any grading or building permit is issued or any grading or building is conducted, the applicant shall comply with the requirements for the concept, development, and final stormwater management plans.

(b)

Concept stormwater management plan.

(1)

An applicant shall submit a concept stormwater management plan that provides sufficient information for an initial assessment of the proposed project and determination as to whether stormwater management can be provided in accordance with § 33-4-106.1 of this title.

(2)

The concept stormwater management plan shall include:

(i)

A plan at 1 inch = 100 feet or smaller showing site location, existing man-made and natural features, water and other sensitive resources, topography and existing drainage patterns;

(ii)

All proposed impervious areas, buildings, roadways, parking, sidewalks, utilities, and other site improvements;

(iii)

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

(iv)

Preliminary determination of stormwater management requirements, including type, size and location of proposed ESD practices, supporting computations, and all points of discharge from the site;

(v)

A narrative supporting the concept stormwater management design and demonstrating that ESD will be implemented to the MEP; and

(vi)

Any other information required by the Department.

(c)

Development stormwater management plan.

(1)

Following concept stormwater management plan approval by the Department, the applicant shall submit a development stormwater management plan that addresses comments received during the concept stormwater management plan review phase.

(2)

The development stormwater management plan shall include:

(i)

All information submitted during the concept stormwater management plan review phase;

(ii)

Final site layout, exact impervious area locations and acreages, existing and proposed topography, delineated drainage areas at all points of discharge from the site, and stormwater volume computations for ESD and other stormwater management practices and structures;

(iii)

An erosion and sediment control plan that includes the sequence of construction, any phasing necessary to minimize earth disturbances and impacts to the natural resources, and an overlay plan showing the types and locations of ESD and erosion and sediment control practices to be used;

(iv)

A narrative supporting the development stormwater management plan demonstrating that ESD will be implemented to the MEP and justifying any proposed structural stormwater management measures; and

(v)

Any other information required by the Department.

(d)

Submission of final plans for approval.

(1)

Following development stormwater management plan approval by the Department, the applicant shall submit for approval a final erosion and sediment control plan and a final stormwater management plan to both the Department and the Soil Conservation District (SCD) that addresses comments received during the development stormwater management phase.

(2)

The final stormwater management plan shall serve as the basis for all subsequent construction.

(3)

The applicant shall submit a final stormwater management plan that:

(i)

Meets the design requirements of this title;

(ii)

Includes sufficient information to evaluate the effectiveness and acceptability of measures proposed for protecting water resources; and

(iii)

Contains supporting computations, drawings, and sufficient information describing the manner, location, and type of measures in which stormwater runoff will be managed from the entire site, including ESD.

(e)

Same — Minimum.

(1)

The minimum information to be submitted in support of a stormwater management plan shall be as provided in paragraphs (2) through (8) of this subsection.

(2)

Site characteristics:

(i)

Topography showing existing and proposed contours, including area downstream from the site necessary to analyze the adverse impact to property and resources, resulting from development of the site;

(ii)

Geotechnical investigation, including borings for construction and borings or test pits for infiltration practices;

(iii)

Location of all watercourses, impoundments, nontidal wetlands, tidal wetlands, and forest buffers on or adjacent to the site or into which stormwater flows; and

(iv)

Delineation of riverine floodplains, if applicable;

(3)

Computations:

(i)

Hydrology;

(ii)

Hydraulic;

(iii)

Structural; and

(iv)

Dam breach analysis, if required;

(4)

A narrative supporting the final stormwater management plan design;

(5)

Other information:

(i)

Vicinity map;

(ii)

Drainage area map showing:

1.

The watershed boundaries;

2.

Drainage area;

3.

Stormwater flow paths;

4.

Existing and proposed land use; and

5.

Hydrologic soil groups;

(iii)

Proposed improvements, including:

1.

Locations of buildings or other structures;

2.

Impervious surfaces; and

3.

Storm drainage facilities;

(iv)

Location of all utilities pertinent to the design;

(v)

Structural details for all components of the proposed stormwater management devices and practices;

(vi)

Sequence of construction;

(vii)

Maintenance responsibility;

(viii)

Material specifications;

(ix)

Construction specifications;

(x)

Location of easements;

(xi)

Certifications;

(xii)

Required landscaping and planting material;

(xiii)

Table of required and proposed storage volumes;

(xiv)

Table showing total site area, disturbed area, new impervious area, and total impervious area;

(xv)

Structure classification;

(xvi)

Maintenance inspection schedule;

(xvii)

Certification by the applicant that all stormwater management construction shall be in accordance with the final stormwater management plan; and

(xviii)

Certification by a Maryland registered professional engineer, a Maryland registered land surveyor, or a Maryland registered landscape architect that the final stormwater management plan meets the minimum design standards set forth in the Code, subject to the following:

1.

Pond designs requiring Soil Conservation District or Administration Dam Safety Division approval shall be certified by a professional engineer;

2.

A land surveyor may not certify geotechnical or structural components of a structural stormwater BMP; and

3.

A landscape architect may not certify a structural stormwater BMP that requires hydraulic or structural design of system components;

(6)

Estimate of stormwater management construction costs;

(7)

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

(8)

Other information as required by the Director or the Design Manual.

(f)

Alternate procedure. A project may proceed directly from the concept stormwater management plan phase to the final stormwater management plan phase when the applicant demonstrates to the satisfaction of the Department that ESD to the MEP has been used to address stormwater management, including:

(1)

A narrative that supports the concept stormwater management plan and final design plan and which demonstrates that ESD will be achieved to the MEP and that land use and runoff discharges are minimized; and

(2)

CPV is addressed by treating runoff from the 1-year, 24-hour design storm with ESD.

(1988 Code, § 14-156) (Bill No. 53-01, § 1, 7-2-2001; Bill No. 94-02, § 2, 7-1-2004; Bill No. 25-10, § 1, 6-1-2010)

Editor's note:
  Section 3 of Bill No. 25-10 provides that the legislation is retroactive to May 4, 2010.