Enviro-Crete, Inc.

The West Coast Pervious Concrete Contractor

Making Gray Concrete Environmentally Green

Why Pervious Concrete? What is Pervious? About Us Maintenance CNCA CPCNC

Training Assistance More Information Projects Contact Us Values NRMCA

Hydrology

Many things need to be concidered when designing your project site. The first thing is to review your soils report.

How well did it "perk"?

Determine the average amount of rain to fall during a single event. How many events happen each year?

What is the volume of the 100 year flood?

Understand that 6” thick pervious concrete section holds up to 20% in the void structure, (about 1.94 gallons per square foot)

Quantify the remaining gallons of storage needed and calculate with the sub structure retaining about 40% in the voids, (about 7.74 gallons per square foot at 12” thick)

The best practice is to NOT include the value held in the concrete section!

Do you intend to retain and capture 100% of the storm water?

Does your site slope, or is it flat? Water still flows downhill ... the lower end may need additional retention area!

EXAMPLE:

If it rains 1.5” per day for three days, that is equal to 2.29 Gallons of water hitting a square foot of measure

If your site perks 1” per day, the soil in one square foot will absorb 1.86 Gallons in that three day period.

Mathematical Note: 1” of rain over one acre = 27,154 Gallons, or about .62 gallons per square foot according to USGS

Placing a 6" thick pervious concrete section over a 12" section of 3/4" crushed aggregate over an 8oz filter fabric works extremely well in most cases. Some soils won't require that much sub base material. Your engineer will need to perform the calculations. Be sure not to allow overcompaction of the native soils during construction, it slows down the perk you tested and designed for!

We are very proud to have met the new NRMCA standards for the "Installer" classification, and we are the highest certified Installer in California.

We want to be your West Coast pervious concrete contractor ...

making gray concrete environmentally green!

[Home][Company][Projects][Contact Us][Maintenance][Values][Why Pervious][What is Pervious][More Info]