We are pursuing option 1 of the Rainwater management credit on our LEED v4 new construction project. I find that the credit requirement is not super clear on whether controlled rainwater discharge is allowed or not. See below for the two sources of language from the LEED v4 BD+C reference guide.
In the step-by-step guidance, it says that "Option 1 is for projects that elect to manage rainfall on their project site such that there is no immediate discharge after development for all rainfall event of a given depth." It sounds like BMPs used to slow down the discharge rate would be acceptable.
However, in the further explanation section, under "green infrastructure and low-impact development strategies", it says that "All run off from the chosen percentile of precipitation events must be managed such that there is no discharge from the site."
Has anybody had experience with this issue? What's your interpretation of the discharge requirement?
Thanks a lot for the help!