The rain gardens are fed from the water running off of the driveway in the front (it’s designed to slope that direction). All the water from the roof is designed to run off to the rain garden located off the side of the deck (see photo taken from above of Fred working). I don’t know the exact absorption rate but we worked with our Architect Michael Huber and Kurt Luthold from Barr Engineering (both of whom worked on the design of our country watershed) to size the gardens appropriately. If you also notice we’ve placed circle cut outs filled with grass in the driveway to take in some of the water that will run down the drive as well.

Jason