§ 23-7. Redevelopment.

(a) In general.

(1) Stormwater management plans are required for all redevelopment, unless otherwise specified by watershed management plans developed under § 23-6(b) of this subtitle.

(2) Stormwater management measures must be consistent with the State's Design Manual.

(b) Waived requirements.

Unless otherwise specified by the Department, a redevelopment project need not comply with requirements of the State's Design Manual for:

(1) recharge volume;

(2) channel protection storage volume;

(3) overbank flood protection volume; and

(4) extreme flood protection volume.

(c) Applicable requirements – In general.

(1) All redevelopment projects must, in accordance with the State's Design Manual, reduce existing site impervious areas within the limits of disturbance by at least 50%.

(2) If site conditions prevent the reduction of impervious area, then environmental site design practices must be implemented to the maximum extent practicable for at least 50% of the site's existing impervious area within the limits of disturbance.

(3) If a combination of impervious area reduction and stormwater practice implementation is used, the combined area must equal or exceed 50% of the site's existing impervious area within the limits of disturbance.

(d) Applicable requirements – Alternatives.

(1) Alternative stormwater management measures may be used to meet the requirements of subsection (c) of this section if the applicant satisfactorily demonstrates to the Department that:

(i) impervious area reduction has been maximized; and

(ii) environmental site design has been implemented to the maximum extent practicable.

(2) Alternative stormwater management measures include:

(i) an on-site structural best management practice;

(ii) off-site implementation of structural best management practices to provide water quality treatment for an area equal to at least 50% of the existing impervious area within the limits of disturbance; and

(iii) a combination of impervious area reduction, environmental site design implementation, and an on-site or off-site structural best management practice for an area equal to at least 50% of the existing site impervious area within the limits of disturbance.

(e) Separate policies.

(1) The Department may develop separate policies for providing water quality treatment for redevelopment projects if the Department determines that the provisions of subsections (c) and (d) of this section have been implemented to the maximum extent practicable.

(2) The Department's criteria for separate policies are outlined in the City's Design Guidelines.

(3) Any separate redevelopment policy must be reviewed and approved by the State Water Management Administration.

(4) These separate policies may include:

(i) a combination of impervious area reduction, environmental site design, and on-site and off-site structural best management practices;

(ii) retrofitting to improve water quality over current conditions by:

A. construction of structural best management practices in a previously developed area; or

B. modification of existing structural best management practices;

(iii) watershed or stream restoration;

(iv) pollution trading;

(v) design criteria based on watershed management plans developed under § 23-6(b) of this subtitle;

(vi) payment of offset fees that are dedicated exclusively for stormwater management within the same watershed as the proposed development;

(vii) a partial waiver of the treatment requirements if environmental site design is not practicable; or

(viii) other practices approved by the Department.

(5) The Department will determine during the concept design phase which alternative measures may be made available. Prioritization of the alternative measures listed in paragraph (4) of this subsection must be considered after a determination by the Department that it is not practical to meet the 2009 regulatory requirements using environmental site design.

(6) When determining which alternative measures may be authorized under paragraph (4) of this subsection for a project, the Department may consider whether:

(i) the redevelopment project is located in an area designated as:

A. a priority funding area under State Finance and Procurement Article Title 5, Subtitle 7B;

B. a transit oriented development area under State Transportation Article Title 7, Subtitle 1; or

C. a base realignment and closure revitalization and incentive zone under State Economic Development Article Title 5, Subtitle 13;

(ii) the redevelopment project is necessary to accommodate growth consistent with the City's comprehensive plan for the area in which the project will be located; or

(iii) bonding and financing have been secured based on an approval of a redevelopment plan approved by the Department.

(f) Applicable requirements – Increased impervious area.

For any net increase in impervious area resulting from the project, stormwater management must be addressed according to the new development requirements of the State's Design Manual.