In order to reduce stormwater runoff volumes from developed
areas, and in order to encourage groundwater recharge, underground
basin drains, infiltration trenches, and cisterns are permitted to
which roof leaders may be connected. These drains may consist of stone-filled
basins which temporarily store and release water below ground surface.
Plans for such facilities shall be submitted to the municipality for
approval, and the basins shall be used only in those areas where soils,
geologic, and water table conditions permit. Performance criteria
which govern the location, design, construction, and maintenance of
these infiltration facilities are contained in Appendix A, Section
IV, of this chapter. Suggested guidelines are contained in
Standards and Specifications for Infiltration Practices (MD DNR).
At a minimum, these infiltration facilities shall be designed to temporarily
store a volume of runoff from a two-year, twenty-four-hour design
storm.