D.C. Mun. Regs. tit. 21, r. 21-519

Current through Register Vol. 71, No. 52, December 27, 2024

Rule 21-519 - STORMWATER MANAGEMENT: PLAN

519.1

A Department-approved stormwater management plan (SWMP) shall:

(a) Govern all construction for which stormwater management is required;

(b) Govern all applicable maintenance activities; and

(c) Demonstrate compliance with this chapter.

519.2

A submitted SWMP and supporting documentation shall contain information sufficient for the Department to determine whether the SWMP complies with this chapter including:

(a) Existing site conditions, including the identification and location of each existing Best Management Practice (BMP) and whether it will remain on the site and in use or will be removed;

(b) Proposed site design;

(c) Each land use proposed for the site;

(d) Identification and location of each proposed BMP, including geographic coordinates;

(e) Design and performance of each BMP for stormwater retention, detention, and treatment;

(f) Conveyance capacity of stormwater infrastructure;

(g) Environmental characteristics of the site;

(h) Pre- and post-development hydrologic computations, including:

(1) Calculation of required stormwater management volume for:

(A) The entire site; and

(B) Each individual drainage area; and

(2) On-site and off-site retention volumes;

(i) Maintenance plan and schedule for each proposed BMP;

(j) Monitoring plan for each BMP that captures stormwater for use;

(k) For each proposed BMP not included in the Department's Stormwater Management Guidebook (SWMG):

(1) Separate identification and description; and

(2) Documentation of performance and effectiveness;

(l) Construction sequence for:

(1) Each BMP; and

(2) The related development or improvement project, if any.

(m) A list of the construction and waste material to be stored on site and a description of the material and each pollution control measure that will be implemented to minimize exposure to stormwater discharge, including:

(1) Each storage practice;

(2) A spill prevention response;

(3) The United States Environmental Protection Agency (EPA) identification number, or copy of application to EPA for identification number, for each hazardous waste that will be stored on site; and

(4) Proof of payment of each applicable fee.

519.3

The retention capacity of each BMP in a SWMP shall be calculated using the applicable equations for calculating retention value in Chapter three (3) of the Department's Stormwater Management Guidebook.

519.4

The pollutant removal efficiency of each BMP in a SWMP shall be calculated using the applicable equation in Chapter three (3) of the Department's SWMG.

519.5

The Department may require for each area that a project proposes for use to meet the requirements of this chapter, including a contiguous area or an area with a shared BMP:

(a) Information listed in this section; or

(b) A SWMP.

519.6

A submitted SWMP shall use:

(a) A standard drawing size of twenty-four inches by thirty-six inches (24 in. x 36 in);

(b) One (1) of the following horizontal scales of profile, unless otherwise approved:

(1) One inch equals ten feet (1 in. = 10 ft.);

(2) One inch equals twenty feet (1 in. = 20 ft.);

(3) One inch equals thirty feet (1 in. = 30 ft.);

(4) One inch equals forty feet (1 in. = 40 ft.);

(5) One inch equals fifty feet (1 in. = 50 ft.); or

(6) One inch equals eighty feet (1 in. = 80 ft.);

(c) One (1) of the following vertical scales of profile, unless otherwise approved:

(1) One inch equals two feet (1 in. = 2 ft.);

(2) One inch equals four feet (1 in. = 4 ft.);

(3) One inch equals five feet (1 in. = 5 ft.); or

(4) One inch equals ten feet (1 in = 10 ft.); and

(d) Drafting media that yield first or second generation reproducible drawings with a minimum letter size of No. 4 (1/8 inch).

519.7

A SWMP shall not be approved without the signature and seal of the Director or the Director's designee on the plan.

519.8

For each as-built SWMP that an applicant submits to the Department, an applicant shall provide that a professional engineer licensed in the District of Columbia, certifies with seal and signature that:

(a) The design, and installation for an as-built plan:

(1) Conforms to engineering principles applicable to stormwater management; and

(2) Complies with the requirements of this chapter; and

(b) A set of instructions for operation and maintenance of each BMP has been provided to the applicant.

519.9

AS WMP for a project shall be consistent with all other permitting submittals to the District.

519.10

The approved SWMP for a major regulated project shall be available on site for Department review for the entire period of construction during ordinary business hours.

D.C. Mun. Regs. tit. 21, r. 21-519

Final Rulemaking published at 60 DCR 10640 (July 19, 2013); amended by Final Rulemaking published at 67 DCR 844 (1/31/2020)

Authority: Department of Consumer and Regulatory Affairs Civil Infractions Act of 1985, effective October 5, 1985, as amended (D.C. Law 6-42; D.C. Official Code §§ 2-1801.01 et seq. (2007 Repl. & 2012 Supp.)); District Department of the Environment Establishment Act of 2005, §§ 101 et seq., effective February 15, 2006, as amended (D.C. Law 16-51; D.C. Official Code §§ 8-151.01 et seq. (2008 Repl. & 2012 Supp.)); National Capital Revitalization Corporation and Anacostia Waterfront Corporation Reorganization Act of 2008, effective March 26, 2008 (D.C. Law 17-138; 55 DCR 1689), as amended by the Anacostia Waterfront Environmental Standards Amendment Act of 2012, effective October 23, 2012 (D.C. Law 19-192; D.C. Official Code §§ 2-1226.31 et seq.) (2012 Supp.)); The Soil Erosion and Sedimentation Control Act of 1977, effective September 28, 1977 (D.C. Law 2-23; 24 DCR 792), as amended by the Soil Erosion and Sedimentation Control Amendment Act of 1994, effective August 26, 1994, (D.C. Law 10-166; 41 DCR 4892; 21 DCMR §§ 500 -15); Uniform Environmental Covenants Act of 2005, effective May 12, 2006, as amended (D.C. Law 16-95; D.C. Official Code §§ 8-671.01 et seq. (2008 Repl.)); Water Pollution Control Act of 1984, effective March 16, 1985, as amended (D.C. Law 5-188; D.C. Official Code §§ 8-103.01 et seq. (2008 Repl. & 2012 Supp.)); and Mayor's Order 2006-61, dated June 14, 2006, and its delegations of authority.