LEED v4 BD+C NC WE Outdoor Water Use Reduction implies the use of a calculator (Oudoor Water Use Reduction Calculator) that must be used to calculate savings against LEED beseline.
This calculator allows the definition of the following plant types:
- Trees;
- Shrubs;
- Groundcover;
- Turf grass.
Area occupied by each of the above plant types must be introduced in the LEED calculator.
When we ask design teams (landscape architects) to provide us the above referred information, they always ask us which criteria they shall use to calculate trees area. Most of the times trees are not alone (below trees there is also turf grass and/or groundcover), so it is not clear how to spit the area of these mix landscapes (trees plus grass and/or groundcover) into the different plant types required by the LEED calculator.
Can you please provide us some guidance?
Regards,
Denise Pinho
emily reese moody
Sustainability Director, Certifications & ComplianceJacobs
LEEDuser Expert
476 thumbs up
May 24, 2023 - 11:58 am
Hello,
We've been advised in the past to count the tree canopy SF anticipated at the 10-yr growth stage for the Open Space and Protect/Restore Habitat credits. I would think it would be the same for this Prereq/Credit.
I'm not sure about splitting the areas when there's also vegetation under the trees. For the other credits, you are not allowed to double-count the SF, but that makes sense for those takeoffs, whereas here, LEED wants you to account for the water use if they are separate. I'd encourage some other users to chime in for sure, and if there's not clear guidance, to send LEED Coach an inquiry for clarity.
Emily Purcell
Sustainable Design LeadCannonDesign
LEEDuser Expert
370 thumbs up
May 24, 2023 - 12:08 pm
This is a recurring question where I've never seen a definite answer either from USGBC or a landscape architect on a project team. I've also never gotten a comment back on a LEED review questioning the areas of trees/shrubs/grass when they occupy the same space, so it seems that USGBC understands the person completing this calculator will be making their best judgement of where to draw the line between different planting zones.
I think the approach Emily mentioned here, to count the same way as you do in the Open Space/Habitat credits, makes a lot of sense just to keep consistency between credits.