Residential Washington DC
When the peal of thunder and flash of lightening signals another deluge from the heavens a sustainably designed patio and walkway allows the rain to infiltrate rather than run off. A flagstone patio and fire pit becomes more sustainable with Delaware River Rock edges which allow water from the slope above to slow and soak into the ground and not run off into the street.  Pea Gravel paths do the same thing… give the rain time to infiltrate.  Flagstone laid in stone dust rather than concrete is a more sustainable design. A streambed path does what nature would do – provide space and time for the water to soak into the earth. A day later it is a dry streambed pathway yet again.