Changes

* Underdrain is elevated above the native soil and/or a flow restrictor is installed on the underdrain.

* Underdrain is elevated above the native soil and/or a flow restrictor is installed on the underdrain.

All permeable pavements have very high surface infiltration rates when appropriately maintained.  Therefore, the surface course type (i.e. PICP, pervious concrete) is not a key factor in determining volumetric runoff reduction performance.   

All permeable pavements have very high surface infiltration rates when appropriately maintained.  Therefore, the surface course type (e.g. permeable interlocking concrete pavers, pervious concrete, porous asphalt, etc.) is not a key factor in determining volumetric runoff reduction performance.

 

In Canadian and Swedish field studies, vacuum cleaning could only partially restore the surface infiltration capacity of permeable interlocking concrete pavers (PICP) with large spatial variability in the observed infiltration rates post cleaning.<ref> Drake, J., Bradford, A. 2013. Assessing the Potential for Restoration of Surface Permeability for Permeable Pavements Through Maintenance. Water Science and Technology. 2013, 68, 1950-1958. https://pubmed.ncbi.nlm.nih.gov/24225094/ </ref> Al-Rubaei, A.M., Stenglein, A.L., Viklander, M., Blecken, G.T. 2013. Long-Term Hydraulic Performance of Porous Asphalt Pavements in Northern Sweden. Journal of Irrigation and Drainage Engineering. 39 (6) June 2013. https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29IR.1943-4774.0000569 </ref>  Potential options for rehabilitating clogged permeable pavements identified to date include combining pressure washing with pure vacuum sweeping to help dislodge sediment accumulated within joints of PICP and porous asphalt <ref> Seghal, K.S., Drake, J., Van Seters, T., Vander Linden, W.K. 2018. Improving Restorative Maintenance Practices for Mature Permeable Interlocking Concrete Pavements. Water. 10 (11), 1588. https://www.mdpi.com/2073-4441/10/11/1588 </ref> <ref> Winston, R.J., Al-Rubaei, A.M., Blecken, G.T., Viklander, M., Hunt, W.F. 2016. Maintenance measures for preservation and recovery of permeable pavement surface infiltration rate – The effects of street sweeping, vacuum cleaning, high pressure washing and milling.  Journal of Environmental Management.  169(2016):132-144. https://www.sciencedirect.com/science/article/pii/S0301479715304412c </ref> <ref> Al-Rubaei, A.M., et al., 2013. Long-term hydraulic performance of porous asphalt pavements in Northern Sweden. Journal of Irrigation and Drainage Engineering, 139 (6), 499–505. https://ascelibrary.org/doi/abs/10.1061/%28ASCE%29IR.1943-4774.0000569 </ref>, and in pores of pervious concrete<ref> Chopra, M., et al., 2010. Effect of Rejuvenation Methods on the Infiltration Rates of Pervious Concrete Pavements. Journal of Hydrologic Engineering, 15 (6), 426–433. https://pennstate.pure.elsevier.com/en/publications/effect-of-rejuvenation-methods-on-the-infiltration-rates-of-pervi </ref>. Drainage performance evaluations of aged pervious concrete have shown its permeability does not decline as rapidly with age as PICP, but that vacuum cleaning techniques tested to date provide variable or insignificant restorative effect<ref> Drake, J., Bradford, A. 2013. Assessing the Potential for Restoration of Surface Permeability for Permeable Pavements Through Maintenance. Water Science and Technology. 2013, 68, 1950-1958. https://pubmed.ncbi.nlm.nih.gov/24225094/ </ref> Sustainable Technologies Evaluation Program (STEP). 2019. Permeable Pavements Maintenance. Technical Brief. October 2019. https://sustainabletechnologies.ca/app/uploads/2019/10/PDF-PP-maintenance-tech-brief_Oct2019.pdf </ref>

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