Innovative Use of Porous Pavement for Treatment of Roadway Runoff

Everett Gupton, PERon Horres, PE

ASCE-EWRG & APWASustainable Stormwater Symposium

September 15, 2010

Innovative Use of Porous Pavement for Treatment of Roadway Runoff

• WSDOT “Ecology Mix” Background• Pioneer Parkway – The Next Step• U.S. Highway 199 – Dowell Road to RCC– Project Description– Multi-Use Pathway Design for Stormwater Treatment– Future – Sampling and Testing

• Acknowledgements and More Information

Innovative use of Porous Pavement

OR

Innovative use of Ecology Mix Treatment System

OR

Utilize Both to Meet Project goals

WSDOT Ecology Embankment

• Goal to provide Stormwater BMP for use in areas with limited ROW availability

• Provide highway runoff with– Basic Treatment - Suspended Solids– Phosphorus Treatment– Enhanced Treatment – Dissolved Metals– Oils Treatment

• Treatment provide via filtration, chemical precipitation, sorption and biological uptake

WSDOT Ecology Embankment

• Crushed Rock• Dolomite• Gypsum• Perlite

WSDOT Ecology Embankment – Typical Section

WSDOT Ecology Embankment – Effectiveness

• Suspended Solids – Goal of > of 80% removal or 20 mg/l met

• Phosphorus – averaged > 80% removal• Zinc – median removal of 78.7 %• Copper – median removal of 39.2 %• Oil – not tested, removal meet goals based on

inferred removal mechanisms

Pioneer Parkway BRT Project

• Bus Rapid Transit system for Lane County Transit in the City of Springfield, OR

• 1.8 miles of new busway and associated stations

• Limited space availability for stormwater treatment

• Confined impervious surface at dedicated busway

Pioneer Parkway – Busway Ecology Embankment Filter Strip

Pioneer Parkway - ConstructionBusway construction showing:

•Polyethylene Sheeting

•Perforated Drain Pipe

•Water Quality Filter Material

Pioneer Parkway - Construction•Completed busway with Ecology Embankment Filter Strip

•Seeding of strip beginning to emerge

US Highway 199 WideningProject Summary• Widening of US Highway 199 (US

199) in Grants Pass• Construction of new and

extended bike/pedestrian path

Project Constraints• Limited ROW/Property

Acquisition Expenses• DEQ and SLOPES IV Stormwater

Regulations• Low Infiltrative Soils

Governing Stormwater Regulations

• From ODOT Bulletin GE09-02(B)– Stormwater runoff from a project shall not cause violations of water

quality standards in the receiving water– Provide water quality treatment for the total Contributing Impervious

Area using the most effect techniques practicable for the site– Avoid an increase in pre vs. post-construction flows from 42% of 2-year

event to 10-year event.• Oregon DEQ

– Treat pollutants of concern in roadway runoff (Petroleum, PAHs, Sediment, & Metals)

• SLOPES IV– All CIA runoff must be treated prior to commingling with offsite water.

Selection of Treatment BMPsAreas with No Pathway – Biofiltration Swale

Areas with Pathway – Pervious Pavement with Infiltrative Trench

Plan View of Pervious Pavement Trench System

1

1. Porous Asphalt Pavement Walking/Bike Path2. Perforated Underdrain Collection Pipe3. Existing Stormwater Crossing Culvert4. New Manhole Connection to Existing Stormwater

Culvert5. New Pipe Connection to Existing Ditch/Stream at

Grading Limits6. Cleanouts for Maintenance

2

3

4

4

5

5 6

R/W

R/W

Profile View of Pervious Pavement Trench System

3

1. Existing Ground Surface Profile2. Proposed Ground Surface Profile3. 8” Perforated HDPE or PVC Underdrain Collection Pipe4. Cleanout for Maintenance of Perforated Pipe5. New Manhole Connection to Existing Stormwater

Culvert

3

4

5

1 2

Pervious Pavement with Infiltrative Trench

183

51. Pervious HMAC wearing course – 3” thickness2. Porous choke aggregate – 1” thickness3. Porous graded aggregate base – 10” thickness under pathway 4. Drainage geotextile (pervious)5. Ecology Mix – 18” thickness6. Granular drain backfill material – 1’ – 2’ thickness7. Perforated HDPE or PVC drainpipe8. 1’ wide mountable curb9. Subgrade geotextile (impervious)

2

69

99

4

7

11’ 5’

4

Pervious Pavement with Infiltrative Trench

2

1. Aggregate shoulder collects first flush preventing sediment transport onto pervious pavement, minimizing clogging and the amount of maintenance needed.

2. Porous Aggregate provides volume for detention storage (sized for 25-Year).

3. Ecology Mix provides environment for treatment and slows runoff for detention.

4. Perforated drainpipe allows from connection to existing storm system after treatment occurs.

5. Outlet for events larger than the 25-Year storm. Water will exit to the backside ditch and eventually to the cross culvert.

3

1

4

5

Trench System Hydraulics• Maximum flow rate through the trench system is

dependent on the surface area of the Ecology Mix (L*W) along with the infiltration rate (q)

• Q = L * W * q

• Using SCS Type 1A storm, a volume balance was developed to track flow into and out of the system.

• (Qin – Qout) * ∆t = Volume of Storage

• Storage Volume detained in the aggregate base is slowly discharged at the tail end of the storm.

• The maximum volume at any time step was compared to the volume of the void spaces in the aggregate base to ensure containment of 25-Year Storm.

Water Quality Storm Hydrograph

Storage In Aggregate

& Ecology Mix

Treatment Time

Stored Volume

Discharge

Per SLOPES IV: WQ Storm is defined as 50% of the cumulative rainfall from the 2-Year, 24-hour Storm. Attributes

• Delayed Peak

• Small Reduction in Peak Flows

• Treatment Time is clearly visible

10-Year Storm Hydrograph

Storage In Aggregate & Ecology Mix

Stored Volume

Discharge

Attributes

• Delayed Peak

• Flattened and Reduced Peak Discharge

• Greater Volume of Storage

Flat Discharge Peak Flow

Hwy 199 – Future Plans

• Develop Sampling/Testing Plan to confirm treatment effectiveness

• Obtain funding source for Testing Project• Phase 1 testing to obtain pre-development

condition• Phase 2 of testing to measure effectiveness of

installed system

Acknowledgements

• ODOT Region 3 – Hwy 199, Dowell to RCC Project Staff

• Lane County Transit / City of Springfield / Pioneer Parkway Project Staff

• WSDOT Ecology Embankment – Technology Evaluation and Engineering Report, Herrera Environmental Consultants, Inc. July 14, 2006

Further Information

Contact Everett Gupton or Ron Horres

503-274-8772or

Gupton@pbworld.comHorres@pbworld.com

Questions ?