Can we obtain this credit for a site that already has natural drainage systems surrounding it, i.e. outside the site boundary?
The water that falls on the site is taken care of in a natural way. There are currently ditches around the site that lead runoff water to nearby ponds. The stormwater runs down to the pond and is infiltrated there. The site area is de-watered via ditches and culverts to a stream as well as a lake.
Rainwater that falls on e.g. car parks and sources of pollution (in this case diesel aggregates and tanks) will be 'cleaned' on site, i.e. only cleaned water will run off to the ponds, streams etc. It is then let out into the stormwater system. The stormwater flow will be delayed to ensure that the current rate will not increase in a 10 year storm event
The offsite pond is dimensioned for a 10 year storm. The site area is included [in the area that the system can take care of] and the amount of runoff will be accounted for, by including detention depositories in the design.
Will this be acceptable for obtaining this credit?
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
187 thumbs up
November 4, 2013 - 8:56 am
So are you implementing swm controls on site or not? I'm sorry, but your statement above is not very clear.
Be advised, 6.1 deals with only runoff rate and volume, not WQ.
Alicia Freire
Associatehurleypalmerflatt
38 thumbs up
December 3, 2013 - 7:31 am
The flow rate will be dealt with onsite, but the volume will be dealt with offsite.
Michael DeVuono
Regional Stormwater LeaderArcadis North America
LEEDuser Expert
187 thumbs up
December 3, 2013 - 10:51 am
If you are using an offsite location to control volume, but the increased volume is being carried to this offsite location via an existing drainage swale, you do not comply with this credit. You will be exceeding the pre-development flow through the channel.