Changes

Additional components include an [[underdrain]] to remove excess water and soil additives to enhance [[Nutrients|pollutant removal]]. <br>

Additional components include an [[underdrain]] to remove excess water and soil additives to enhance [[Nutrients|pollutant removal]]. <br>

Design assumptions are based on tool default values and STEP recommendations:

Design assumptions used to generate cost estimates are based on a 2,000 m2 asphalt drainage area, tool default values and the following STEP recommendations:

* Maximum impervious drainage area to permeable surface area (I:P area) ratio of 20:1.

* Maximum impervious drainage area to permeable surface area (I:P area) ratio of 20:1.

* Length to width ratio of bioretention area is 10:1.

* Length to width ratio of bioretention area is 10:1.