Changes

For advice on decorative surface aggregates see [[Stone]]

For advice on decorative surface aggregates see [[Stone]]

 

Gravel used for [[underdrains]] in [[bioretention]], [[infiltration trenches]] and [[infiltration chambers|chambers]], and [[exfiltration trenches]] should be 20 OR 50 mm, uniformly-graded, clean (maximum wash loss of 0.5%), crushed angular stone that has a void ratio of 0.4<ref>Porosity of Structural Backfill, Tech Sheet #1, Stormtech, Nov 2012, http://www.stormtech.com/download_files/pdf/techsheet1.pdf accessed 16 October 2017 </ref>.

Gravel used for [[underdrains]] in [[bioretention]], [[infiltration trenches]] and [[infiltration chambers|chambers]], and [[exfiltration trenches]] should be 20 OR 50 mm, uniformly-graded, clean (maximum wash loss of 0.5%), crushed angular stone that has a void ratio of 0.4<ref>Porosity of Structural Backfill, Tech Sheet #1, Stormtech, Nov 2012, http://www.stormtech.com/download_files/pdf/techsheet1.pdf accessed 16 October 2017 </ref>.