Parameter

Design criteria

FWS CWs

SSF CWs

Bed size (m²)

Larger if available

<2500

Length to width ratio

3:1 - 5:1

<3:1

Water depth (m)

0.3 - 0.5

0.4 - 1.6

Hydraulic slope (%)

<0.5

0.5 - 1

Hydraulic loading rate (m/day)

<0.1

<0.5

Hydraulic retention time (day)

5 - 30

2 - 5

Media

Natural media and industrial by-product preferred, porosity 0.3 - 0.5, particle size < 20 mm (50 - 200 mm for the inflow and outflow)

Vegetation

Native species preferred, plant density 80% coverage