Sec. 26.17.02.09. Stormwater Management Plans

A. The design of stormwater management plans shall be prepared by any individual whose qualifications are acceptable to the approving agency. The approving agency may require that the design be prepared by either a professional engineer, professional land surveyor, or landscape architect licensed in the State, as necessary to protect the public or the environment. If a stormwater BMP requires either a dam safety permit from the Department or small pond approval by the appropriate soil conservation district, the approving agency shall require that the design be prepared by a professional engineer licensed in the State.

B. Stormwater management and development plans shall be consistent with adopted and approved watershed management plans or flood management plans as approved by the Department in accordance with the Flood Hazard Management Act of 1976 (Environment Article, Title 5, Subtitle 8, Annotated Code of Maryland).

C. An operation and maintenance plan shall be required as a condition of stormwater management plan approval.

D. If a stormwater management plan involves direction of some or all runoff off of the site, it is the responsibility of the developer 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.

E. Contents and Submission of Stormwater Management Plans.

(1) The owner/developer is responsible for submitting phased stormwater management plans for development projects according to the comprehensive review and approval process specified in Regulation .04 of this chapter, the Design Manual, and county and municipal stormwater management ordinances. Plans shall be submitted for the concept, site development, and final stormwater management construction phases of project design. Comments from the appropriate approval authority shall be addressed and approval received at each phase of project design before subsequent submissions.

(2) The owner/developer shall submit a concept plan that provides sufficient information for an initial assessment of the proposed project and whether stormwater management can be provided according to this chapter and the Design Manual. Plans submitted for concept approval shall include, but are not limited to:

(a) A map at a scale specified by the appropriate approval authority showing site location, existing natural features, water and other sensitive resources, topography, and natural drainage patterns;

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

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

(d) 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;

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

(f) Any other information required by the approving Agency.

(3) Following concept plan approval by the appropriate authority, the owner or developer shall submit site development plans that reflect comments received during the previous review phase. Plans submitted for site development approval shall be of sufficient detail to allow site development to be reviewed and include but not be limited to:

(a) All information provided during the concept plan review phase;

(b) Final site layout, exact impervious area locations and acreages, proposed topography, delineated drainage areas at all points of discharge from the site, and stormwater volume computations for ESD practices and quantity control structures;

(c) 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;

(d) 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

(e) Any other information required by the approving Agency.

(4) Following site development approval by the appropriate authority, the owner/developer shall submit final erosion and sediment control and stormwater management plans that reflect the comments received during the previous review phase. Plans submitted for final approval shall be of sufficient detail to allow all approvals and permits to be issued according to the following:

(a) Final erosion and sediment control plans shall be submitted according to COMAR 26.17.01.05; and

(b) Final stormwater management plans shall be submitted for approval in the form of construction drawings and be accompanied by a report that includes sufficient information to evaluate the effectiveness of the proposed runoff control design.

(5) Reports submitted for final stormwater management plan approval shall include, but are not limited to:

(a) Geotechnical investigations including soil maps, borings, site-specific recommendations, and any additional information necessary for the final stormwater management design;

(b) Drainage area maps depicting predevelopment and postdevelopment 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 stormwater management measures to be used;

(e) A narrative that supports the final stormwater management design; and

(f) Any other information required by the approving agency.

(6) Construction drawings submitted for final stormwater management plan approval shall include, but are not limited to:

(a) A vicinity map;

(b) Existing and proposed topography and proposed drainage areas, including areas necessary to determine downstream analysis for the proposed stormwater management facilities;

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

(d) The location of existing and proposed structures;

(e) Any easements and rights-of-way;

(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 planting;

(m) All soil boring logs and locations;

(n) An inspection and maintenance schedule;

(o) Certification by the owner/developer that all stormwater management construction will be done according to this plan;

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

(q) Any other information required by the approving agency.

F. Standard plans specified in Regulation .08D of this chapter are considered an acceptable stormwater management plan for satisfying the requirements of §E of this regulation.