Warehouses-NC-v4 WEp1: Outdoor water use reduction

  • Get familiar with the WaterSense tool

    This prerequisite requires teams to design water-efficient landscapes, and encourages a multi-faceted and integrated approach. Outdoor water use is impacted by vegetation type, vegetation density, overall planted area, and irrigation efficiency, so consider all of these variables in approaching prerequisite compliance. 

    Minimizing turf grass, installing native and drought-tolerant plants, and using efficient irrigation systems will typically align with meeting the prerequisite requirements. 

    A landscape design that does not require permanent irrigation is the most straightforward way to earn this prerequisite, as long as programming and operations and maintenance practices align with a non-irrigated landscape.

    What’s New in LEED v4

    • This is now a prerequisite, rather than just a credit.
    • The U.S. EPA WaterSense Water Budget Tool is now the required calculation tool.

    FAQs

    The EPA WaterSense methodology and calculator allows only certain types of irrigation to be assigned to certain vegetation types. Why is this and won’t it skew results?

    The type of irrigation that can be assigned to certain vegetation types is pre-determined in the calculator, limiting user ability to make adjustments that might better reflect the design conditions. This is likely based on EPA’s assumptions about potential changes to the irrigation system and future use. GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). has not provided a work-around for this yet, so if you are concerned about the methodology not accurately reflecting project conditions to a degree that impacts your ability to meet the prerequisite, consider submitting a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide and proposing an alternative compliance path.    

    What if we just have a little green area on our rooftop? Is there a minimum amount of landscaped area to earn the prerequisite and credit?

    There is no minimum landscape areaThe landscape area is the total site area less the building footprint, paved surfaces, water bodies, and patios. to earn the prerequisite or the credit.

    One could argue that this discourages landscaping, but according to USGBC, hardscapes are addressed and, one could argue, discouraged by other credits, so this is considered a fair approach. 

  • WE Prerequisite 1: Outdoor water use reduction

    Intent

    To reduce outdoor water consumption.

    Requirements

    Reduce outdoor water use through one of the following options. Nonvegetated surfaces, such as permeable or impermeable pavement, should be excluded from landscape areaThe landscape area is the total site area less the building footprint, paved surfaces, water bodies, and patios. calculations. Athletic fields and playgrounds (if vegetated) and food gardens may be included or excluded at the project team’s discretion.

    Option 1. No irrigation required

    Show that the landscape does not require a permanent irrigation system beyond a maximum two-year establishment period.

    OR

    Option 2. Reduced irrigation

    Reduce the project’s landscape water requirement by at least 30% from the calculated baseline for the site’s peak watering month. Reductions must be achieved through plant species selection and irrigation system efficiency, as calculated by the Environmental Protection Agency (EPA) WaterSense Water Budget Tool.

    SITES-LEED Equivalency

    This LEED credit (or a component of this credit) has been established as equivalent to a SITES v2 credit or component. For more information on using the equivalency as a substitution in your LEED or SITES project, see this article and guidance document.

WaterSense Water Budget Tool

Project teams can use the EPA WaterSense Water Budget Tool to ensure a measure of efficiency and regional suitability for the amount of water applied to a landscape based on local climate data.

LEED v4 Outdoor Water Use Reduction Calculator

Project teams can use the USGBC Outdoor Water Use Reduction Calculator, recommended for use by projects outside of the U.S.

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Jun 24 2017
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