C3.5: Design Functional Stormwater Features as Amenities – Above Green

(4-5 points)

INTENT

Provide a connection to the local climate and hydrology by integrating aesthetically pleasing stormwater features that are visually and physically accessible and manage on-site stormwater.

REQUIREMENTS

The requirements apply to stormwater features that use precipitation as their sole source of water and that function as stormwater management elements (e.g., bioswales, raingardens, vegetated roofs). These features must be designed to be visually and physically accessible to site users from proposed high-use portions of the site.

Ensure site precipitation is treated as an amenity in the way it is received, conveyed, and managed on site for at least:
- 50 percent of stormwater features 4 points
- 100 percent of stormwater features 5 points
  - Percentages are based on total square footage (square meters) of the stormwater features, including conveyance features.
  - Cisterns and vaults that are used for retention purposes and considered amenities should be included in the percentage calculations. However, exclude those used only for rainwater collection and reuse.
Ensure the section of the site maintenance plan (see O+M P8.1: Plan for sustainable site maintenance) is complete. The plan must describe appropriate maintenance activities that do not use chemicals likely to harm aquatic life, such as chlorine and bromine (except where required by local health code), and that ensure habitat for mosquitoes will not be created.

RECOMMENDED STRATEGIES

Design and maintain water features as natural ecosystems with water sources, native plants and native plant communities, and other aquatic organisms appropriate for local conditions.
Natural swimming pools or other water features intended for human contact may require additional treatment such as ozonation or thermal treatment.
Employ artists and craftspeople to collaborate with the design team to create rainwater systems that combine function and aesthetic appeal.
Employ low impact development strategies that emphasize site design and planning techniques to mimic the natural infiltration-based, groundwater-driven hydrology of historic landscapes.