San Francisco Data is in, Pervious Concrete Reigns Supreme

We have some great news to share backed by data-driven research!

Some of you may recall our work along Holloway Street back in 2017. If not, can you read about it here. The San Francisco Public Utilities Commission (SFPUC) hired us to install parking lanes along eight blocks of Holloway Street as part of a city-wide effort showcasing the effectiveness of green infrastructure and stormwater management in the Ingleside neighborhood.

Holloway Green Streets Project - north side

After completion, the area was carefully monitored between 2017-2019. Analyzing two years’ worth of data, the pervious concrete along with the rain gardens show an impressive overall reduction in stormwater volume of 77%! With results like this, it is no surprise the adaption of pervious concrete stormwater pavement systems into new green infrastructure design continues to grow at a rapid pace.

As SFPUC’s Green Infrastructure Planning Specialist, Mike Adamow said, “After four years of service, the pervious concrete installed on the SFPUC’s Holloway Green Street project has met or exceeded our expectations and is providing valuable lessons learned that we will use to inform the design of future projects. The combination of a well-trained and experienced contractor, a proven mix design, close contractor coordination with the concrete supplier during batching and delivery, along with proper protection after installation has resulted in an asset that should serve the SFPUC ratepayers well for years to come. As this and other types of permeable pavement installations age, it is becoming clear that the advantages of pervious concrete position this material to be the preferred permeable pavement type for future SFPUC projects.”

Detective Liguori is Back!

The Bay Area just had it’s first big storm of the year - foretelling of a very rainy winter season ahead! While most people took shelter, David Liguori hit the road in search of the latest scoop when it comes to pervious concrete outperforming conventional concrete and asphalt surfaces.

Where did his stormwater sleuthing lead him to this time? To a very water-bogged Daly City. Luckily for him, he found dry land thanks to a pervious parking lot that BAPC installed a few months ago. How did it fair in such torrential rain? Perfectly! Just take a look for yourself.

Pervious Concrete Dynamic System Modeling

We have been working with architects, engineers, homeowners and municipalities to really explain how pervious concrete is a comprehensive storm water mitigation device. It has proven difficult to help people to wrap their heads around how allowing water to soak in to where it falls, using pervious concrete, is a viable storm water management strategy - so we have started to use Dynamic System Modeling as a tool to help explain what is happening in a pervious concrete slab, and how much water it can infiltrate over time. 

When we use the concept of infiltration over time, pervious concrete systems provide huge capacity, far exceeding most climate’s most intense storm events. That is most easily demonstrated using a software modeling system. This allows insight as to a system’s capacity, and informs design, to ensure that the pavement and drain rock base will meet or exceed the required storm water infiltration amounts.

Contact us for a consultation on your project or to schedule an office presentation to learn more!

Stormwater Sleuthing - Episode 2 - Palo Alto

David Liguori is back in the field, this time comparing a long sloped asphalt driveway with a neighboring long and sloped pervious concrete driveway during a rainstorm last year.

Here Dave compares 2 sloped driveways in a rainstorm - one asphalt, and one pervious concrete. It is the great runoff comparison!

What did you think? Do you have a Stormwater Sleuthing location (in the Bay Area) that you would like David to investigate the next time it rains? Let us know in the comments below or contact us here. Thanks!

USGBC Greener Builder - a fantastic conference!

This was originally posted June 19, 2013.

Lauren Wray, our Director of Marketing, attended the USGBC’s Greener Builder Conference last week. Apparently the Greener Builder Conference is even GREENER then the Green Builder Conference that occurred in November! This conference did not disappoint. From the opening panel, pictured below, featuring Jeffrey A. Birdwell, Michael Deane, Kevin Hydes, Kirsten Ritchie and moderated by Cliff Brewis, the focus was on leading edge sustainability, and strategies to get regenerative planning and innovation into the building industry.

There were good options for every panel, but as pervious concrete sub-contractors, we went to the subcontractor panel, hosted by John Home and Jeff Swinyer of Rudolph and Sletten, pictured below.

Lauren, pictured below, was interested in the drive toward clear performance specs to allow for differentiation at the sub-contractor level. As a pervious concrete subcontractor, we differentiate ourselves with our embrace of leading edge technologies for mix design and installation. Unfortunately, many current specs don’t reflect the progress in the installation, mix designs, equipment and curing materials that has developed in the last few years. 

The next panel we attended discussed Environmental Product Disclosures (EPDs), a labeling system that discloses the resource footprint of the many materials that go into the built environment. The panel also included the next iteration, the Health Product Disclosures, which discloses the materials and chemicals that have been proven or correlated in causing health problems for humans.
Central Concrete, a sponsor of the event, has been heavily involved in the EPD project for disclosing the materials for the concrete industry. Below is a photo of the panelists from this panel.

The last panel of the day went over Net Zero Energy buildings with John Andary and Scott Shell, pictured below. It was a fascinating look at what is currently possible with technologies now: buildings that use as much energy as they make. The building case studies discussed also illustrated how livable and workable these spaces were, with thought for passive heating and cooling. Many of the designs features windows that bounced daylight far into the building envelope, as well as fresh air ventilation. It was a wonderful talk, even though their topics stayed primarily inside the building envelope.

The final speaker, Jason McLennan, pictured below, gave a wonderful talk on self limits. His talk really stood out for his candor and optimism. For a young guy, has accomplished quite a bit in the green building spaces. Currently he is pioneering the Living Building movement.

After his talk, Jason McLennan was joined by George Salah, of Google, and David Gottfried of the USGBC. They discussed everything from George’s living-building home construction project to Jason’s motivation to do the work that he does: “I give a shit.” That was wonderful.

FInally, after it was all over, we found that there was a fantastic array of beers, wine and snacks to round out the day’s networking. It was a great event, and one we will look forward to attending next year!

A BIG thank you to Charlie Nucci, who took these photos at the event. You can find more about Charlie and his work at his website here.

Pervious Concrete has an industry magazine!

Check out the most recent thinking about pervious concrete across the United States with great photos, articles and advertisements from local pervious experts in your area. PerviousPro is the brainchild of Dale Fisher and the people over at the NPCPA - the National Pervious Concrete Pavement Association. We even have an article written by Bay Area Pervious Concrete.

Check out this issue here:

http://viewer.epaperflip.com/Viewer.aspx?docid=85d951d5-33b1-47c8-b174-a05200d37fc9

Let us know what you think!

4 Layers for Stormwater Management

We at Bay Area Pervious Concrete have come  a long way towards developing the Pervious Concrete as a viable Stormwater Management System. Going through this diagram, you can see where the water goes -- one of our most frequently asked questions.

Starting at the bottom-SOIL
We do soil infiltration tests before our jobs so we can understand how fast the water will soak in, underneath the pervious concrete. Once we understand the infiltration rates and soil composition, we can engineer the appropriate depths to excavate for the next layer, the drain rock.

Before we lay the drain rock we sometimes will lay a layer of GEOTECH Fabric, which adds a helpful barrier against some less porous soil types. We determine the need for this during the soil composition and infiltration tests.

Now for the DRAIN ROCK!
Drain rock is laid several to many inches thick, depending on the rain event to be captured, the soil type below, and how much impervious surface is draining into this slab. It is a very specific type of drain rock, not the typical base used under concrete which is impervious - we want to maintain about  40% air space to both allow water to pass through and give it place to "hang out" if the soil has a slow infiltration rate.

Finally the PERVIOUS CONCRETE
The pervious concrete is then laid on top of the drain rock, screeded and rolled into place and covered in plastic, where it will cure for at least a week.

Redwood Avenue - Residential Installation

The Situation:
The client had flooding in the back and front of the house due to an uneven grade of the lot and excessive roof runoff.

Driveway before- 'pervious pavers' that had settled and were not performing the way the homeowner had hoped.

Sideyard before- muddy, and not very useful.

Why Pervious Concrete?
He initially wanted a pervious concrete driveway because of impervious ground cover limitations in his city.

The Solution:
We designed a pervious concrete driveway and side yard that is also the retention pond for all of the roof and yard runoff.The pervious concrete water retention system captures 100% of their runoff from the roof AND the lot. They now have a dry front yard, back yard and they can grill just off the kitchen without puddles!

Sideyard after- Now this space can be used for laundry and garbage bin storage.