1. Under the Behind the Intent section, in the first sentence, remove "to make this credit more achievable."
2. Under the Behind the Intent, revise the second paragraph to read "Thresholds" rather than "Requirements" for zero lot line projects. The following sentence should also be added to the end of the paragraph: "New exemplary performance thresholds for all projects have been added, including exemplary performance under Option 2. Natural landcover conditions which rewards projects for fostering resilience by designing for future precipitation conditions."
3. Remove the first bullet under Step-by-Step Guidance and the following bullets:
Option 1, Step 2. Obtain Rainfall Data for Project Location: Use daily rainfall data and the methodology in the U.S. Environmental Protection Agency (EPA) Technical Guidance on Implementing the Stormwater Runoff Requirements for Federal Projects under Section 438 of the Energy Independence and Security Act to determine the percentile amount to be retained.
Option 1, Step 2. Obtain Rainfall Data for Project Location: Once you've gathered the rainfall events data, any rainfall events less than or equal to 0.1 inches should be omitted.
Option 1, Step 7. Conventional grey infrastructure devices and hard runoff conveyance systems, such as detention or retention ponds, pipes, culverts and vaults, can be compliant if used as a component of LID
/GI systems to meet the requirements of this credit.
4. The following bullets should be included following the "Further Explanation" header:
Examples of acceptable LID
techniques include the following:
• planting rain gardens with native or adapted plant material (e.g. trees or shrubs);
• installing a vegetated roof;
• using permeable paving, consisting of porous above-ground materials (e.g., open pavers, engineered products), a base layer designed to drain water away from the building, and (often) a 6-inch-deep (150 millimeters) subbase; and
• installing permanent infiltration
or collection features (e.g., vegetated swale, rain garden, rainwater cistern) that can retain the runoff from the associated percentile of regional or local rainfall events.
Treatment of Runoff:
Projects teams should consider prioritizing infiltration
of runoff from impervious surfaces considered to be a significant source of pollutants in rainwater runoff. Such surfaces include those which are subject to: vehicular use; industrial activities; or storage of erodible or leachable materials, wastes, or chemicals and which receive direct rainfall or the run-on of rainfall.
5. The following sentence should be included following Further Explanation>Green Infrastructure and Low-impact Development Strategies: "Employ LID
and GI strategies that mimic the natural infiltration
-based, groundwater-driven hydrology of the site."
6. The sentence under Further Explanation>Project Type Variations, zero lot line projects should be removed and replaced with the following: "Any setback area resulting from a planned below-grade space, such as an underground parking garage, does not void a project’s zero lot line status so long as the setback area is designed as pedestrian-oriented amenity space, such as outdoor seating."
7. An "Exemplary Performance" section should be included under "Referenced Standards". For Option 1, a table should be included indicating that EP for All Projects is 98th percentile and EP for zero lot line projects is 95th percentile. A second bullet should be included for Option 2. Natural landcover conditions, and the following EP language should be included underneath: "Retain on site an additional 20% in runoff volume to address future precipitation rates (1.2 * [difference in annual runoff volume from the natural landcover to the post-developed condition]) using LID
and GI practices."
8. The v4.1 Definitions section should be revised to only include the following definition: " retain (rainwater) on site to capture and reserve a specified volume of rainfall to mimic natural hydrologic function. Retention is a function of rainwater management that includes strategies involving evapotranspiration
, and capture and reuse