Sec. 26.17.02.06. Minimum Control Requirements

A. County and Municipal Requirements.

(1) The minimum control requirements established in this section and the Design Manual shall be contained in each county and municipal ordinance as they apply to the applicable parts of the State. The minimum control requirements for each county and municipality are provided in §A(2) and (3) of this regulation.

(2) All counties and their incorporated municipalities shall require that the planning techniques, nonstructural and structural practices, and design methods specified in the Design Manual be used to implement ESD to the MEP. Stormwater management plans for development projects subject to this chapter shall be designed using the ESD sizing criteria, recharge volume, water quality volume, and channel protection storage volume criteria according to the Design Manual. The MEP standard is met when channel stability and 100 percent of the average annual predevelopment groundwater recharge are maintained, nonpoint source pollution is minimized, and structural stormwater management practices are used only if determined to be absolutely necessary.

(3) Control of the 2-year frequency storm event, 10-year frequency storm event, or both is required according to the Design Manual if any county or municipality determines that additional stormwater management is necessary because historical flooding problems exist and downstream floodplain development and conveyance system design cannot be controlled.

(4) An approving agency may require more than the minimum control requirements specified in this regulation if hydrologic or topographic conditions warrant or if flooding, stream channel erosion, or water quality problems exist downstream from a proposed project.

B. Alternate minimum control requirements may be adopted subject to Administration approval. The Administration shall require a demonstration that alternative requirements will implement ESD to the MEP and control flood damages, accelerated stream erosion, water quality, and sedimentation, including, if necessary, address comprehensive watershed studies.

C. Development in watersheds designated as interjurisdictional flood hazard watersheds within this chapter may not increase the downstream peak discharge for the 100-year frequency storm event and shall comply with flood management plans as approved by the Department in accordance with the Flood Hazard Management Act of 1976 (Environment Article, Title 5, Subtitle 8, Annotated Code of Maryland).