1. APWA Complete Streets and Technology Conference
Use of Porous/Permeable Pavements as a Green Street Treatment
April 10, 2019
Presented by:
James Cramsie, P.E., QSD/P

2. Green Streets
Green Streets achieve multiple benefits, such as improved water quality and more livable communities, through the integration of stormwater treatment techniques which use natural processes and landscaping.
(Source: EPA)
So what is the definition of Green Streets? This is a definition from the Managing Wet Weather with Green Infrastructure Municipal Handbook (2008 Edition). Read Slide then move to next slide

3. What are Typical Elements of a Green Street?
Protection of the environment (Stormwater Management)
Minimize stormwater impacts on the surrounding area through a natural system approach that incorporates a variety of water quality, energy-efficiency, and other environmental best practices
Integrate green stormwater management features to increase infiltration and/or filtration of runoff, reduce flows, and enhance watershed health
Reduce the amount of water that is piped and discharged directly to streams and rivers
Make the best use of the street tree canopy for stormwater interception, as well as temperature mitigation and air quality improvement
Mitigate or prevent localized flooding
Now that we have a working definition of ‘Green Streets’, so based on that definition what are the typical elements that further define Green Street? I feel it can be divided into 2, Read the first one along with the bullet points, then the 2nd element with bullet points. This presentation will focus more on the Stormwater Management element. So, what are some specific elements of the Stormwater Management. Move to next slide.
Health and Prosperity (Improve Community)
Encourage pedestrian and/or bicycle access
Improve the aesthetics of a community
Increases a community’s livability

4. Elements of Stormwater Management
Street Trees/Landscaping
The first element is Street Trees and Landscape. Here are some images that reflect this element. Move to next slide.

5. Elements of Stormwater Management
Bioretention/Biofiltration Areas
The next element that take the street trees/landscape further is Bioretention/Biofiltration. Here are some images that shows street trees and landscape, but also incorporating stormwater capture. Move to next slide.

6. Elements of Stormwater Management
Porous/Permeable Pavements 
The 3rd element, and the one I will be focusing on is Porous/Permeable pavement. The images on the left and right show applications of these types of pavement. While the top middle image shows how these types of pavements work. Move to next slide.

7. What is Porous or Permeable Pavement?
Have connected spaces that allow water to percolate through the surface.
Porous:
Have spaces to allow water in, but are not necessarily connected and therefore do not always allow for percolation through the surface.
So what is Porous or Permeable pavement? I think it is important to understand the difference between these 2 terms, which are typically used interchangeably. Read each of the definitions. You may have also heard the term ‘Pervious’. This term is defined as ‘allowing water to pass through; permeable’. Now that we have basic understanding of the differences between these two terms, lets look at what type of permeable pavements are available for use. Move to next slide.

8. Types of Permeable Pavements
Pervious Asphalt Pavement (PAP)
(OPEN GRADE FRICTION COURSE)
(ASPHALT TREATED PERMEABLE BASE)
The first type is Pervious Asphalt Pavement (PAP). This slide shows a typical cross section that consists of reservoir layer (typically aggregate of some sort), with Asphalt Treated Permeable Base (ATPB) with an Open Grade Friction Course (OGFC). This figure was take from the Caltrans Porous Pavement Design Guidance, August 2014 Edition. I do want to point out that the thicknesses of each of these layers will vary from location to location, soil conditions, traffic index and will need to determined by a geotechnical engineer. Move to next slide.

9. Types of Permeable Pavements
Pervious Concrete Pavement (PCP)
The next type is Pervious Concrete Pavement (PCP). This slide shows a typical cross section that consists of reservoir layer (typically aggregate of some sort), with a pervious concrete layer. Move to next slide.

10. Types of Permeable Pavements
Permeable Interlocking Concrete Pavement (PICP)
The final type is Permeable Interlocking Concrete Pavement (PICP). This slide shows a typical cross section that consists of reservoir layer, with a chock course, with a bedding layer (typically sand) with the concrete pavers laid on top. Now that we have seen 3 types of permeable pavement types, what type of roadways might be suitable for one of these permeable pavement types? Move to next slide.

11. Classifications of Roadways
Major Arterials
Secondary Arterials
Collector Streets (Ex. Industrial areas)
Local Streets (Ex. Residential areas)
This slide list the typical roadway classifications. You have your Major and Secondary Arterials, which a main roadways through cities. Collector Streets are typically offshoots from the arterials, an example are streets within an industrial area and finally are Local Streets, with these being your residential areas. Move to next slide.

12. Challenges of using Permeable Pavement
Not recommended for high speed roadways (such as arterials) or heavy loaded roadway (such as industrial areas)
Subgrade consisting of impermeable soils (such as clayey soils)
Ongoing maintenance to avoid clogging
Initial costs are higher then conventional, but may be offset by reduced stormwater infrastructure costs
Sloped pavements require extra design considerations
So, use of permeable pavement is an option, what are the challenges to and benefits of using permeable pavements. This slide shows some of the challenges associated with using permeable pavements. Read first line and point out the Caltrans Chart, then finish reading the rest of the bullet items. Move to next slide.

13. Benefits of using Permeable Pavement
Reduction in contamination of water runoff and sediment loading
Recharging of groundwater supplies
Improves wet-weather visibility, tire spray and hydroplaning
Absorption of noise from tires and engines
Reduces stormwater runoff volume
There are several benefits to using permeable pavements, here is a short list of some of them. Read list of the bullet items. Move to next slide.

14. Opportunities to use Permeable Pavement
Parking lanes, Street Parking areas or Bike Lanes
Here are some example of potential applications. The images on the left and middle show use of Concrete Pavers in a parking lane while the image on the right shows the bike lane being constructed on Pervious Asphalt. Move to next slide.

15. Opportunities to use Permeable Pavement
Within intersections controlled by 4-way stops
These images show use of pavers within stop controlled intersections where speeds through the intersections are low. Even though these pictures show the use of concrete pavers, pervious asphalt or concrete could be used. Move to next slide.

16. Opportunities to use Permeable Pavement
Alley Ways
City of Los Angeles
Avalon Green Alley
The images shown in the previous slides were from other part of the country, but I wanted to highlight some project that have used here in Southern California. Some of you may already be aware of these or might have been involved with them. The images on the left are from the City of Santa Monica project for an alley project in the 1500 block of 17th Court. They used Pervious Concrete for the v-gutter running down the middle of the alley. Similarly the City of Los Angeles had the Avalon Green Alley project. Move to next slide.
City of Santa Monica
th Court

17. Opportunities to use Permeable Pavement
Curb and Gutters
These are a series of images from a project the City of Glendora did back in 2015 as a pilot project. It involved the removal and replace of a log stretch of existing deteriorated curb and gutter with a pervious concrete gutter. The picture on the left shows water flowing down the gutter during a rains storm, the middle picture shows the trickle of water stopping as it was percolating into the concrete and the picture on the right is from the downstream catch basin. As you can see the flow never reached the catch basin. Move to next slide.
City of Glendora
Pervious Concrete Gutter Pilot Project
(2015)

18. Available Guidance Documents
Caltrans: Porous Pavement Design Guidance, August 2014
CASQA: Technical Memo #2-Permeable Pavement Details and Standard Review, May 2017
FHWA: Tech Brief-Porous Asphalt Pavement with Stone Reservoirs, April 2015
City of Los Angeles: Series 480 Standard Plans (Green Streets Standard Plans)
Here is a brief list of some available guidance documents. In addition to these, there are various organizations that can provide guidance, such as the California Asphalt Pavement Association or the California Nevada Cement Association. Move to next slide.

19. Thank You!
Q & A