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Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
Pilot Credit Closed
This pilot credit is closed to new registrations
To reduce runoff volume and improve water quality by replicating the natural hydrology and water balance of the site, based on historical conditions and undeveloped ecosystems in the region.
Requirements
* This credit language is drawn from the LEED v4 draft. Where other point totals are noted, this pilot credit is worth 1 point in total. *
Option 1. Percentile of rainfall events
Path 1. 95th percentile (2 points except Healthcare, 1 point Healthcare)
In a manner best replicating natural site hydrology processes, manage on site the runoff from the developed site for the 95th percentile of regional or local rainfall events using low-impact development (LID) and green infrastructure.
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 95th percentile amount.
OR
Path 2. 98th percentile (3 points except Healthcare, 2 points Healthcare)
Achieve Path 1 but for the 98th percentile of regional or local rainfall events, using LID and green infrastructure.
OR
Path 3. Zero lot line projects only – 85th Percentile (3 points except Healthcare, 2 points Healthcare))
The following requirement applies to zero lot line projects in urban areas with a minimum density of 1.5 FAR. In a manner best replicating natural site hydrology processes, manage on site the runoff from the developed site for the 85th percentile of regional or local rainfall events, using LID and green infrastructure.
OR
Option 2. Natural land cover conditions (3 points except Healthcare, 2 points Healthcare)
Manage on site the annual increase in runoff volume from the natural land cover condition to the postdeveloped condition.
Path 1.
Achieve Option 1 and manage on site the annual increase in runoff volume from the natural land cover condition to the postdeveloped condition.OR
Path 2.
Achieve Option 1 but for the 98th percentile of regional or local rainfall events, using LID and green infrastructure.- Zero lot line projects only (3 points)
The credit requirements may be met using a coordinated approach affecting the defined project site that is within the master plan boundary. Distributed techniques based on a watershed approach are then required.
General Pilot Documentation Requirements
Register for the pilot credit- Participate in the LEEDuser pilot credit forum
- Complete the feedback survey:
Credit specific
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 calculations 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.
- Provide all submittals listed above, but for the 85th percentile threshold.
- Provide density calculations or density information from the municipality in which the project is located.
- Provide all submittals listed above.
- Provide a narrative describing the distributed techniques and watershed approach, if used.
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?
Changes:
- 1/15/2013: update with SSc4 from LEED v4 draft
What does it cost?
Cost estimates for this credit
On each BD+C v4 credit, LEEDuser offers the wisdom of a team of architects, engineers, cost estimators, and LEED experts with hundreds of LEED projects between then. They analyzed the sustainable design strategies associated with each LEED credit, but also to assign actual costs to those strategies.
Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.
This information is also available in a full PDF download in The Cost of LEED v4 report.
Learn more about The Cost of LEED v4 »Frequently asked questions
See all forum discussions about this credit »Documentation toolkit
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
Pilot Credit Closed
This pilot credit is closed to new registrations
To reduce runoff volume and improve water quality by replicating the natural hydrology and water balance of the site, based on historical conditions and undeveloped ecosystems in the region.
Requirements
* This credit language is drawn from the LEED v4 draft. Where other point totals are noted, this pilot credit is worth 1 point in total. *
Option 1. Percentile of rainfall events
Path 1. 95th percentile (2 points except Healthcare, 1 point Healthcare)
In a manner best replicating natural site hydrology processes, manage on site the runoff from the developed site for the 95th percentile of regional or local rainfall events using low-impact development (LID) and green infrastructure.
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 95th percentile amount.
OR
Path 2. 98th percentile (3 points except Healthcare, 2 points Healthcare)
Achieve Path 1 but for the 98th percentile of regional or local rainfall events, using LID and green infrastructure.
OR
Path 3. Zero lot line projects only – 85th Percentile (3 points except Healthcare, 2 points Healthcare))
The following requirement applies to zero lot line projects in urban areas with a minimum density of 1.5 FAR. In a manner best replicating natural site hydrology processes, manage on site the runoff from the developed site for the 85th percentile of regional or local rainfall events, using LID and green infrastructure.
OR
Option 2. Natural land cover conditions (3 points except Healthcare, 2 points Healthcare)
Manage on site the annual increase in runoff volume from the natural land cover condition to the postdeveloped condition.
Path 1.
Achieve Option 1 and manage on site the annual increase in runoff volume from the natural land cover condition to the postdeveloped condition.OR
Path 2.
Achieve Option 1 but for the 98th percentile of regional or local rainfall events, using LID and green infrastructure.- Zero lot line projects only (3 points)
The credit requirements may be met using a coordinated approach affecting the defined project site that is within the master plan boundary. Distributed techniques based on a watershed approach are then required.
General Pilot Documentation Requirements
Register for the pilot credit- Participate in the LEEDuser pilot credit forum
- Complete the feedback survey:
Credit specific
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 calculations 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.
- Provide all submittals listed above, but for the 85th percentile threshold.
- Provide density calculations or density information from the municipality in which the project is located.
- Provide all submittals listed above.
- Provide a narrative describing the distributed techniques and watershed approach, if used.
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?
Changes:
- 1/15/2013: update with SSc4 from LEED v4 draft
In the end, LEED is all about documentation. LEEDuser’s Documentation Toolkit, for premium members only, saves you time and helps you avoid mistakes with:
- Calculators to help assess credit compliance.
- Tracking spreadsheets for materials purchases.
- Spreadsheets and forms to give to subs and other team members.
- Guidance documents on arcane LEED issues.
- Sample templates to help guide your narratives and LEED Online submissions.
- Examples of actual submissions from certified LEED projects.
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