Pervious Concrete vs. Detention
Pervious Concrete vs. Detention
(OP)
Have any of you been running into the acceptance of pervious concrete being accepted as an alternative means for storm water runoff? Or a better way to ask this, are any of you seeing this as an enhancement to a storm detention area when you do not have space available that might be required due to the hydrology results?





RE: Pervious Concrete vs. Detention
RE: Pervious Concrete vs. Detention
RE: Pervious Concrete vs. Detention
To get detention during all design storms with pervious pavement, you need to provide underground storage under it.
Often, however, a reviewing agency will relax the requirement for a detention volume in exchange to the water quality benefits of increased retention/decreased impervious. Make sure that is what the reviewer is offering, because if the reviewer wants you to provide pervious pavement AND still prove detention of larger storms, you will not save anything.
Engineering is the practice of the art of science - Steve
RE: Pervious Concrete vs. Detention
RE: Pervious Concrete vs. Detention
So, what is the evidence about longevity and maintenance? Has anyone seen any studies/reports/documentation regarding the design life? Is the clogging potential an urban myth?
As with infiltration facilities, there are probably some historic instances of clogging that can be attributed to the construction practices or letting silt-laden runoff onto the permeable surface before the site is stabilized. The potential of clogging would be different on drive aisles than in parking stalls, and would likely vary depending on the frequency of use; consider the differences in overflow parking versus the most frequently used stalls.
RE: Pervious Concrete vs. Detention
The problem I have seen and heard with clogging is that rehab is pretty much impossible after you clog it. We assumed a 25% of optimum infiltration rate with full pore space for volume.
I had trouble talking developers into it though because I didn't know if resurfacing is as easy as asphalt.
RE: Pervious Concrete vs. Detention
Note, the city I am dealing with does accept pervious an alternative means for first flush applications and detention. I guess they view as an improvement to water quality and solids removal. I do worry about the maintenance but I have stated very strongly the manufacturer's recommended cleaning and who is responsible.