Research indicates that runoff reduction from vegetated filter strips is a function of soil type, slope, vegetative cover and flow path length across the pervious surface.
+
A conservative runoff reduction rate for vegetated filter strips is 25% for HSG C and D soils and 50% for HSG A and B soils. These values apply to filter strips that meet the design criteria outlined in this section.
+
{| class="wikitable"
+
|+ Volumetric runoff reduction achieved by vegetated filter strips
+
|-
+
! Rowspan=2|Location
+
! Colspan=2|Runoff reduction
+
|-
+
!2 - 5 m
+
!8 - 15 m
+
|-
+
|Guelph, ON<ref>Abu-Zreig, M. Rudra, M. Lalonde. H. Whitely and N. Kaushik. 2004. Experimental investigation of runoff reduction and sediment removal by vegetated filter strips. Hydrologic Processes. 18: 2029-2037.</ref>
+
|20 %
+
|62 %
+
|-
+
|California, USA<ref>Barrett, M. 2003. Roadside Vegetated Treatment Sites (RVTS) Study Final Report, Report # CTSW-RT-03-028. California Department of Transportation. Sacramento, CA.</ref>