Residential Washington DC
When the peal of thunder and flash of lightening signals another deluge from the heavens, a sustainably designed patio or path allows the rain to infiltrate rather than run off. A flagstone patio and fire pit becomes more sustainable with Delaware River Rock edges which allows water  to slowly soak into the ground rather than running off into the street.  Pea Gravel streamed paths do the same thing… give the rain time to infiltrate.  Flagstone laid in stone dust rather than concrete is a more sustainable design. Seat walls place edges around all these hardscaped areas.