No person shall develop any land for residential, commercial, industrial, or institutional uses without providing stormwater management measures that control or manage runoff from such developments, except as provided within this section. Stormwater management measures must be designed consistent with the Design Manual and constructed according to an approved plan for new development or the policies stated in § 213-9 of this chapter for redevelopment.
A. 
The following development activities are exempt from the provisions of this chapter and the requirements of providing stormwater management:
(1) 
Agricultural land management practices;
(2) 
Additions or modifications to existing single-family detached residential structures if they comply with Subsection A(3) of this section;
(3) 
Any developments that do not disturb over 5,000 square feet of land area; and
(4) 
Land development activities that the Administration determines will be regulated under specific state laws, which provide for managing stormwater runoff.
B. 
Nothing in this section shall prohibit the City Engineer from requiring stormwater management controls upon the evaluation of the cumulative effects of previous exemptions. Conditions evidenced in the City's 1982 aerial photographs shall be used to evaluate these effects.
A. 
Except as provided in Subsections B and D of this section, the City Engineer shall grant stormwater management quantitative control waivers only to those projects within areas where watershed management plans have been developed consistent with Subsection G of this section. Written requests for quantitative stormwater management waivers shall be submitted that contain sufficient descriptions, drawings, and any other information that is necessary to demonstrate that ESD has been implemented to the MEP. A separate written waiver request shall be required in accordance with the provisions of this section if there are subsequent additions, extensions, or modifications to a development receiving a waiver.
B. 
Except as provided in Subsection D of this section, if watershed management plans consistent with Subsection G of this section have not been developed, stormwater management quantitative control waivers may be granted to the following projects, provided that it has been demonstrated that ESD has been implemented to the MEP:
(1) 
Projects that are in-fill development located in a priority funding area where the economic feasibility of the project is tied to the planned density, and where implementation of the 2009 regulatory requirements would result in a loss of the planned development density, provided that:
(a) 
Public water and sewer and stormwater conveyance exist;
(b) 
The quantitative waiver is applied to the project for the impervious cover that previously existed on the site only;
(c) 
ESD to the MEP is used to meet the full water quality treatment requirements for the entire development; and
(d) 
ESD to the MEP is used to provide full quantity control for all new impervious surfaces; or
(2) 
Projects where the City Engineer determines that unusual circumstances exist that prevent the reasonable implementation of quantity control practices.
C. 
Except as provided in Subsection D of this section, stormwater management qualitative control waivers apply only to:
(1) 
In-fill development projects where ESD has been implemented to the MEP and it has been demonstrated that other BMPs are not feasible;
(2) 
Redevelopment projects if the requirements of § 213-9 of this chapter are satisfied; or
(3) 
Sites where the City Engineer determines that circumstances exist that prevent the reasonable implementation of ESD to the MEP.
D. 
Stormwater management quantitative and qualitative control waivers may be granted for phased development projects if the stormwater management facilities were designed to meet the 2000 regulatory requirements (and the City's stormwater management ordinance). All reasonable efforts to incorporate ESD in future phases must be demonstrated.
E. 
Waivers shall only be granted when it has been demonstrated that ESD has been implemented to the MEP and must:
(1) 
Be on a case-by-case basis;
(2) 
Consider the cumulative effects of the City's waiver policy;
(3) 
Reasonably ensure the development will not adversely impact stream quality;
(4) 
Demonstrate that the waiver will not increase known undesirable flooding; and
(5) 
Address in a reasonable manner known downstream drainage deficiencies.
F. 
If the City establishes an overall watershed management plan for a specific watershed, then the City may develop quantitative waiver and redevelopment provisions that differ from §§ 213-8 and 213-9 of this chapter.
G. 
A watershed management plan developed for the purpose of implementing different stormwater management policies for waivers and redevelopment shall:
(1) 
Include detailed hydrologic and hydraulic analyses to determine hydrograph timing;
(2) 
Evaluate both quantity and quality management and opportunities for ESD implementation;
(3) 
Include a cumulative impact assessment of current and proposed watershed development;
(4) 
Identify existing flooding and receiving stream channel conditions;
(5) 
Be conducted at a reasonable scale;
(6) 
Specify where on-site or off-site quantitative and qualitative stormwater management practices are to be implemented;
(7) 
Be consistent with the General Performance Standards for Stormwater Management in Maryland found in the Design Manual; and
(8) 
Be approved by the Administration.
A. 
Stormwater management plans are required by the City for all redevelopment, unless otherwise specified by watershed management plans developed according to § 213-8G of this chapter. Stormwater management measures must be consistent with the Design Manual.
B. 
All redevelopment designs shall:
(1) 
Reduce impervious area within the limit of disturbance (LOD) by at least 50% according to the Design Manual;
(2) 
Implement ESD to the MEP to provide water quality treatment for at least 50% of the existing impervious area within the LOD; or
(3) 
Use a combination of Subsection B(1) and (2) of this section for at least 50% of the existing site impervious area.
C. 
Alternative stormwater management measures may be used to meet the requirements in Subsection B of this section if the owner/developer satisfactorily demonstrates to the City Engineer that impervious area reduction has been maximized and ESD has been implemented to the MEP. Alternative stormwater management measures include, but are not limited to:
(1) 
An on-site structural BMP;
(2) 
An off-site structural BMP to provide water quality treatment for an area equal to or greater than 50% of the existing impervious area; or
(3) 
A combination of impervious area reduction, ESD implementation, and an on-site or off-site structural BMP for an area equal to or greater than 50% of the existing site impervious area within the LOD.
D. 
The City may develop separate policies for providing water quality treatment for redevelopment projects if the requirements of Subsections A and B of this section cannot be met. These policies may include, but not be limited to:
(1) 
A combination of ESD and an on-site or off-site structural BMP;
(2) 
Retrofitting including existing BMP upgrades, filtering practices, and off-site ESD implementation;
(3) 
Participation in projects providing stormwater quality enhancement at sites designated and approved by the City Engineer; the scope and specific practices used in these projects must be reviewed and approved by the City Engineer, and must comply with all applicable local, state, and federal permit requirements, regulations, etc.;
(4) 
Pollution trading with another entity, if a City-specific pollution trading program is approved by the Administration and adopted by the City Council;
(5) 
Payment of a fee-in-lieu into a Stormwater Management Fund, if such a fund is created by the City Council, that would be dedicated to providing stormwater management/storm drainage improvements at locations designated by the City Engineer; the operation of the fund would be governed by policies approved by the Administration and adopted by the City Council; or
(6) 
A partial waiver of the treatment requirements if ESD is not practicable.
E. 
The determination of what alternatives will be available may be made by the City Engineer at the appropriate point in the development review process. The City Engineer shall consider the prioritization of alternatives in Subsection C of this section after it has been determined that it is not practicable to meet the 2009 regulatory requirements using ESD. In deciding what alternatives may be required, the City Engineer may consider factors including, but not limited to:
(1) 
Whether the project is in an area targeted for development incentives such as a priority funding area, a designated enterprise or incentive zone;
(2) 
Whether the project is necessary to accommodate growth consistent with comprehensive plans; or
(3) 
Whether bonding and financing have already been secured based on an approved development plan.
F. 
Stormwater management shall be addressed according to the new development requirements in the Design Manual for any net increase in impervious area.
The City Engineer may grant a written variance from any requirement of Article IV, Stormwater Management Criteria, if there are exceptional circumstances applicable to the site such that strict adherence will result in unnecessary hardship and not fulfill the intent of this chapter. A written request for variance shall be provided to the City Engineer and shall state the specific variances sought and reasons for their granting. The City Engineer shall not grant a variance unless and until sufficient justification is provided by the person developing land that the implementation of ESD to the MEP has been investigated thoroughly.