(a) The Department of the Environment shall implement the provisions of this subtitle and shall consult the Department of Natural Resources from time to time, including during the adoption of regulations, concerning the impact of stormwater on waters of the State.
(b) (1) The Department shall adopt rules and regulations which establish criteria and procedures for stormwater management in Maryland.
(2) The rules and regulations shall:
(i) Indicate that the primary goal of the State and local programs will be to maintain after development, as nearly as possible, the predevelopment runoff characteristics;
(ii) Make allowance for the difference in hydrologic characteristics and stormwater management needs of different parts of the State;
(iii) Specify that watershed–wide analyses may be necessary to prevent undesirable downstream effects of increased stormwater runoff;
(iv) Specify the exemptions a county or municipality may grant from the requirements of submitting a stormwater management plan;
(v) 1. Specify the minimum content of the local ordinances or the rules and regulations of the affected county governing body to be adopted which may be done by inclusion of a model ordinance or model rules and regulations; and
2. Establish regulations and a model ordinance that require:
A. The implementation of environmental site design to the maximum extent practicable;
B. The review and modification, if necessary, of planning and zoning or public works ordinances to remove impediments to environmental site design implementation; and
C. A developer to demonstrate that environmental site design has been implemented to the maximum extent practicable and standard best management practices have been used only where absolutely necessary;
(vi) Indicate that water quality practices may be required for any redevelopment, even when predevelopment runoff characteristics are maintained;
(vii) Specify the minimum requirements for inspection and maintenance of stormwater practices;
(viii) Specify that all stormwater management plans shall be designed to:
1. Prevent soil erosion from any development project;
2. Prevent, to the maximum extent practicable, an increase in nonpoint pollution;
3. Maintain the integrity of stream channels for their biological function, as well as for drainage;
4. Minimize pollutants in stormwater runoff from new development and redevelopment in order to:
A. Restore, enhance, and maintain the chemical, physical, and biological integrity of the waters of the State;
B. Protect public health;
C. Safeguard fish and aquatic life and scenic and ecological values; and
D. Enhance the domestic, municipal, recreational, industrial, and other uses of water as specified by the Department;
5. Protect public safety through the proper design and operation of stormwater management facilities;
6. Maintain 100% of average annual predevelopment groundwater recharge volume for the site;
7. Capture and treat stormwater runoff to remove pollutants and enhance water quality;
8. Implement a channel protection strategy to reduce downstream erosion in receiving streams; and
9. Implement quantity control strategies to prevent increases in the frequency and magnitude of out–of–bank flooding from large, less frequent storm events;
(ix) 1. Establish a comprehensive process for approving grading and sediment control plans and stormwater management plans; and
2. Specify that the comprehensive process established under item (i) of this item takes into account the cumulative impacts of both plans; and
(x) Incorporate the most recent precipitation data available.
(3) (i) The Department shall review and update the regulations adopted under this section at least once every 5 years.
(ii) In reviewing and updating the regulations adopted under this section, the Department shall:
1. At a minimum, revise water quality and water quantity control standards using the most recent precipitation data available; and
2. As necessary, update and revise the regulations to meet the requirements of this subtitle.
(4) (i) On or before November 1, 2021, the Department shall report to the General Assembly, in accordance with § 2–1257 of the State Government Article, on:
1. The most recent precipitation data available;
2. The Department’s plans for immediately updating water quantity control standards for watersheds where flooding events occurred on or after January 1, 2000; and
3. The Department’s plans for updating all other regulations adopted under this section.
(ii) After November 1, 2021, the Department shall report to the General Assembly, in accordance with § 2–1257 of the State Government Article, on any revisions the Department intends to make to the regulations adopted under this section before publishing the regulations.
(c) (1) At least 6 months before the proposal of regulations under this section, the Department shall:
(i) Post the regulatory process that the Department follows on the Department’s website; and
(ii) Consult with the following groups and stakeholders on the impact of the proposed regulations:
1. The Commission on Environmental Justice and Sustainable Communities; and
2. Stakeholders with expertise on stormwater design standards and climate science, including stakeholders from:
A. An academic institution;
B. The Chesapeake Bay Program;
C. The Chesapeake Bay Commission;
D. The Maryland Emergency Management Agency;
E. The Maryland Association of Soil Conservation Districts;
F. Local government;
G. A private sector entity with design and construction experience; and
H. An association that has expertise in stormwater restoration projects.
(2) Before any regulations required under this section are adopted, the Department shall hold at least one public hearing in the affected immediate geographic areas of the State and shall consult with the affected counties and municipalities.
(d) The Department may not delay the implementation of any new requirements or standards established under regulations adopted under this section.
(e) The Department shall provide technical assistance, training, research, and coordination in stormwater management technology to the local governments consistent with the purposes of this subtitle.