Parking Forest Materials

The Parking Forest:

Linear Tree Well Design Using Structural Soil

Sustainability for all the places between the buildings

503.334.8634www.greengirlpdx.com

[email protected] certified women business enterprise

The Parking Forest

An Assembly of Common Materials

The Parking Forest

A Close Up

THPRD in Plan

Structural Soil

Our “Secret Weapon”

Source: Cornell University – CU Structural Soil - http://www.hort.cornell.edu

How do we know it works?

Olympia Results 8 Years Later

Control Trees Planted in Compacted Native Soil

Trees Planted in Structural Soil

Assembly Procedure

Sunset Swim Center Parking Lot Construction Expenses

Item Cost

Porous Concrete $200,000

Drain Rock $62,000

Excavation $35,000

Mobilization $30,000

Curbs/Sidewalk $26,000

Landscaping $23,500

Soil/Structural Soil/Installation $18,000

Demolition/Removal $11,000

Striping/Wheel Stops/Signs $10,000

French Drain / Drain Pipe $3,000

12 Trees for Linear Well $1,600

Other Stuff $8,500

TOTAL CONSTRUCTION $427,600

Why these materials?

• Structural soil

• Amended Native Soil

• Trees

• Wheel stops

• Crush rock (in landscape area)


Structural Soil

• Structural soil versus structural supports


Proprietary mix versus mixed by contractor

Mixing Structural Soil

Photo Source: www.greelysand.com/cu-soil.html

Olympia Soil Recipe

4 cubic yards Crushed Rock ¾”-1¼”

+ 1 cubic yard Loam/organic topsoil

+ 1 pound Soil Binder “Stabilizer”

+ 46 gallons water__________

Makes 4.6 cubic yards Structural Soil

Structural Soil Costs - Olympia

“The price to supply, deliver and install the structural soil material per

cubic yard ranged from $19 to $85 with an average bid of $42, the median

price was $39.50.

The city paid $24 per cubic yard for the structural soil material to the low

bidder.

This compare to a price quote we received for the supply of CU structural

soil at $65 per cubic yard plus delivery. The source was over an hour’s drive

away and delivery charges were $85 per hr with a truck and trailer hauling 22

cubic yard. The expected cost delivered was $72 per cubic yard.”

Excerpted from “Structural Soil Demonstration Project”

http://olympiawa.gov/~/media/Files/CPD/Urban%20Forestry/Forms/StructuralSoil.as

hx

Source: City of Olympia -Structural Soil Demonstration Project


Amended native soil

Amended native soil versus faster draining “3-way” mix


Trees

Trees versus only shrubs &/or groundcover:

• Interception & evaporation

• Evapotranspiration

• Heat island effect


Wheel stops

Wheel stops versus curbs


Crushed rock

¼”x 10 crushed rock versus rounded rock or pavers

Siting Criteria

• Site is suitable for infiltration

• Non-expansive soils

• Soils should infiltrate at least 0.2 inches/hour*. Clay soils are OK!

*Based on 2ft of structural soil, 25% void ratio, facility empty in 30 hours to be ready for the next Type IA storm

The Other Project

PCC Sylvania Lot 10

• THPRD Sunset Swim Center = Redevelopment that manages rainfall

• PCC Sylvania Lot 10 = Retrofit that manages runoff

The Parking Forest Retrofit

at PCC Sylvania Lot 10

Ignore the piles of dirt. They’re

gone.

Design Differences at PCC Sylvania Lot 10

Left most of the parking lot unmodified/ impervious

Installed an impervious liner adjacent to impervious

asphalt

Installed an impervious liner adjacent to impervious

asphalt

Stakeholders chose a native

conifer

Water quality and quantity monitoring

Design Differences at PCC Sylvania Lot 10

Straight head-in parking

Donated “old school” solid bottom wheel

stops = not ideal

Just trees

Erosive forces

are an issue at PCC

Non-attentive forces

are an issue at PCC

Thank You!

Siting Criteria at PCC

• Site is suitable for infiltration

• Non-expansive soils

• Soils should infiltrate at least 0.2 inches/hour*. Clay soils are OK!

*Based on 2ft of structural soil, 25% void ratio, facility empty in 30 hours to be ready for the next Type IA storm

www.parkingforest.org

Parking Forest Materials

Design

Transcript of Parking Forest Materials