This credit is based upon LEED BD+C 2009 SS Credits 6.1 and 6.2, and is intended to incentivize the use of natural best practices instead of structural practices.
Definitions:
The baseline condition is the site condition prior to LEED registration.
Green infrastructure is a soil and vegetation-based approach to wet weather manage-ment that is cost-effective, sustainable, and environmentally friendly. Green infrastructure management approaches and technologies infiltrate, evapotranspire, capture and reuse stormwater to maintain or restore natural hydrologies (US EPA).
Low Impact Development (LID) is defined as an approach to managing stormwater runoff that emphasizes on-site natural features to protect water quality by replicating the natural land cover hydrologic regime of watersheds and addressing runoff close to its source. Examples include better site design principles such as minimizing land disturbance, pre-serving vegetation, minimizing impervious cover, and design practices like rain gardens, vegetated swales and buffers, permeable pavement, rainwater harvesting, and soil amendments. These are engineered practices that may require specialized design assis-tance.
“Manage Onsite” refers to capturing and retaining the specified volume of rainfall to mimic natural hydrologic function. This includes, but is not limited to, strategies that manage volume through evapotranspiration, infiltration, or capture and reuse.
A multi-tenant complex is defined as a site that that was master-planned for the devel-opment of stores, restaurants and other businesses. Retailers may share one or more services and/or common areas.
Natural Site Hydrology is defined as the natural land cover function of water occurrence, distribution, movement, and balance.
Credit Submittals
General
- Register a username at LEEDuser.com, and participate in online forum
- Submit the feedback survey using the link on the USGBC.org credit page; supply PDF of your survey/confirmation of completion with credit documentation
Credit Specific
NC, CS, SCHOOLS, RETAIL, HEALTHCARE
Option 1
- Provide a narrative describing the proposed practices to be implemented on the project site and what qualifies these strategies as LID or green infrastructure techniques that best replicate natural site hydrology processes.
- Provide any applicable specifications, drawings, and storage and infiltration cal-culations of the LID practices utilized on site.
- Provide calculations showing the 95th percentile regional or local rainfall event amount and how the runoff is managed onsite by these practices.
Option 2 – Path 1
- In addition to the submittals listed in Option 1, provide any applicable specifica-tions, drawings, and water balance calculations describing natural site hydrology and post-development partitioning of annual rainfall volumes. Natural site hydrol-ogy conditions can be determined using a combination of pre-settlement vegeta-tion maps and soil maps. Where detailed pre-settlement vegetation maps do not exist, typical land cover for the project’s EPA Level IV Ecoregion can be used.
Option 2 – Path 2
- Provide all submittals listed in Option 1 for the 98th percentile regional or local rainfall event.
Zero Lot Line Projects:
- Provide all submittals listed under “NC, CS, Schools, Retail, Healthcare” above, but for the 85th percentile threshold.
Provide density calculations or density information from the municipality in which the project is located.
Retail NC Projects:
- Provide all submittals listed under “NC, CS, Schools, Retail, Healthcare” above.
- Provide a narrative describing the distributed techniques and watershed ap-proach, if used.
EBOM
Establishment:
- Provide any applicable specifications, drawings and calculations demonstrating that the implemented strategies result in the reduction of impervious surfaces and/or capture and treat water from the impervious surfaces.
- Provide a narrative describing the inspection program, including details about timing/schedule, scope, and procedure for identifying and performing any neces-sary repairs or stabilization.
Performance:
- Provide documentation and dates of all inspections, maintenance, and repairs performed.
Additional Questions
- The goal is to replicate the natural hydrology and water balance of the site. What obstacles make this difficult? Obstacles may or may not be specific to the proposed credit requirements.
- What climate data source is most applicable for your area?