No person shall develop any land for residential, commercial, industrial, or institutional uses without having provided stormwater management measures that control or manage runoff from such developments, except as provided within this chapter. The 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 § 123-8 for redevelopment.
The following development activities are exempt from the provisions of this chapter and the requirements of providing stormwater management:
A.
Agricultural land management activities;
B.
Additions or modifications to existing single-family detached residential structures if they comply with Subsection C of this section;
C.
Developments that do not disturb over 5,000 square feet of land area, including new and redevelopment.
D.
Land development activities that the Administration determines will be regulated under specific state laws, which provide for managing stormwater runoff.
A.
Except where provided in § 123-7B and 123-7D of this chapter, the Department shall grant stormwater management quantitative control waivers only to those projects within areas where watershed management plans have been developed consistent with § 123-7G of this chapter. 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 where provided in § 123-7D of this chapter, if watershed management plans consistent with § 123-7G of this chapter have not been developed, then 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)
That have direct discharges to tidally influenced receiving waters;
(2)
That are infill 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 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
(3)
When the approving agency determines that circumstances exist that prevent the reasonable implementation of quantity control practices.
C.
Except where provided in § 123-7D of this chapter, stormwater management qualitative control waivers apply only to:
D.
Stormwater management quantitative and qualitative control waivers may be granted for phased development projects if a system is designed to meet the 2000 regulatory requirements and the Department's ordinance for multiple phases has been constructed by May 4, 2010. If the 2009 regulatory requirements cannot be met for the future phases constructed after May 4, 2010, all reasonable efforts to incorporate ESD must be demonstrated.
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 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 Department for all redevelopment unless otherwise specified by watershed management plans developed according to § 123-7F of this chapter. Stormwater management measures must be consistent with the Design Manual.
B.
C.
Alternative stormwater management measures may be used to meet the requirements in § 123-8B of this chapter if the owner/developer satisfactorily demonstrates to the Department 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 BMP to provide water quality treatment for an area equal to or greater than 50% of the existing impervious area;
(3)
A combination of impervious area reduction, ESD implementation, and 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.
If the owner/developer satisfactorily demonstrates to the Department that the requirements of § 123-8A and 123-8B cannot be fully met through the alternatives proposed in § 123-8C, then the following measures will be accepted to satisfy the remaining treatment requirement:
(1)
Retrofitting of existing structural stormwater management facilities that were designed and constructed before the adoption of the Design Manual to meet current qualitative requirements of the Design Manual. The original facility that is proposed to be retrofitted must treat an area of imperviousness at least as large as 100% of the impervious area within the redevelopment site;
(2)
Retrofitting of an existing commercial, residential or industrial lot that was designed and constructed before the adoption of the Design Manual to provide ESD to the MEP. The lot proposed for retrofitting must contain an area of imperviousness at least as large as 100% of the impervious area within the redevelopment site;
(3)
Stream restoration at a ratio of at least 2:1;
E.
The determination of what alternatives will be available may be made by the Department at the appropriate point in the development review process. The Department shall consider the prioritization of alternatives in § 123-8D of this chapter after it has determined that it is not practicable to meet the 2009 regulatory requirements using ESD. In deciding what alternatives may be required, the Department 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 transit-oriented development area, or a designated base realignment and closure revitalization and 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 Department may grant a written variance from any requirement of Article IV (Stormwater Management Criteria) of this chapter if there are exceptional circumstances applicable to the site such that strict adherence will result in unnecessary hardship and not fulfill the intent of the chapter. A written request for variance shall be provided to the Department and shall state the specific variances sought and reasons for their granting. The Department 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.
A.
All recorded lots or parcels shall institute ESD practices to the MEP (unless already addressed at time of subdivision or provisions of SWM stated on the recorded final plat). If ESD volumes can be met fully on site, an R&I form shall be submitted to this Department for approval and associated fee paid. (See § 123-17.) If ESD volumes cannot be managed fully on site, a variance form shall be submitted for approval and a fee in lieu shall be paid per the schedule below.
B.
Fees in lieu of stormwater management practices shall be required at the discretion of the Engineer when a written variance is issued in accordance with the provisions of this chapter. The Board has established a fee schedule for fees in lieu of stormwater management practices based on the following (which may be amended from time to time):
Type of Development | Fee |
|---|---|
Single-family residential | $600 per dwelling unit |
Commercial development | $8,000 per impervious acre |