In a project that has both greenfield (dense tree coverage) and previously disturbed (small scale farming) areas, I am trying to determine whether there will be sufficient area to restore 30% of the previously disturbed portion of the site. The building is sited on both areas (but preserving 40%+ of the greenfield portion). A rainwater pond is required, which will take up area on the previously disturbed portion of the site.
The balance of the previously developed portion of the site (what's not building, parking, or rainwater management pond) is less than 30% of the total previously disturbed area. So I am curious as to whether a rainwater management pond, if landscaped with native/adapted vegetation, could contribute to that 30% restored area calculation. Has anyone ever successfully done this? Any tips or lessons learned?
Bryna Dunn
Vice PresidentMoseley Architects
8 thumbs up
March 4, 2024 - 1:44 pm
I received a response from LEED Coach on this topic and since the answer was so thorough I thought I would post here as a follow up:
Yes, a rainwater management pond landscaped with native/adapted vegetation could possibly contribute to the restored area. The key factor is how the pond is designed to provide aquatic vegetation. Not knowing more about your situation, there are a few scenarios to consider:
1. A pond or constructed wetland that is part of a rainwater management system can contribute to the credit if it provides sufficient variety of vegetation to create habitat. The credit does not have specific criteria for aquatic habitat, but if the bottom of the pond was an impervious surface used to detain rainwater, rather than a pervious, earthen bottom that supports plants, that might raise a red flag during the review and be questioned for whether it provides sufficient habitat.
2. Alternatively, the v4 credit states: "Project teams may exclude vegetated landscape areas that are constructed to accommodate rainwater infiltration from the vegetation and soils requirements, provided all such rainwater infiltration areas are treated consistently with SS Credit Rainwater Management." As you may have seen, the v4.1 requirements do not include this language. If the v4 Protect or Restore Habitat credit thresholds are achievable, the project could register under version 4 to use these requirements (and use the v4.1 substitutions for any other credits the team chooses). If the pond area can be excluded for providing infiltration, then the balance of the site that is previously disturbed, and needs to have 30% of it restored, would then be a much smaller area. Again, this approach assumes the bottom of the pond is contributing to infiltration, but wouldn't need to be providing habitat.
3. If the pond must have an impervious bottom, the review team would probably want to see documentation that verifies a sufficient variety and quantity of plants can be established. Otherwise, we might need input from the review department or possibly a CIR to determine whether a lined pond that is not used for infiltration could be considered restored habitat per #1 above, or considered part of a rainwater management system per #2. There are a few factors that might help make the case for either interpretation. For #1, whether the pond will have an earthen layer that can support aquatic plants above the impervious lining, and the quantity and diversity of plants that will be present would probably be important to address. For scenario #2, the Rainwater Management credit does allow the use of lined detention ponds to be considered LID/ GI measures if they are part of an overall system that provides sufficient infiltration, transpiration, or reuse to meet that credit. By extension, the question then would be whether such a pond could also be excluded from the area to be restored if it is part of the larger system providing infiltration. Let us know if you are dealing with one of these latter scenarios and we can see if GBCI will weigh in on that question or require a CIR for full consideration.