2016 stormwater management manual -...

2016 Stormwater Management Manual

Environmental Services l 2016 SWMM 2

Presentation Overview • Background and Context • Goals of the 2016 SWMM Revision • What’s new or clarified • Public Comment Process • 2016 SWMM Schedule


1991 Legal Order to control CSOs

1994 Amended CSO Order

1998 Steelhead and Coho Salmon listed as Threatened Species

1995 Portland’s first MS4 permit (Clean Water Act)

1970’s Clean Water Act Endangered Species Act Safe Drinking Water Act

1998 Columbia Slough listed for Water Quality

1991 Columbia River listed for Water Quality

1988 Fanno Creek listed for Water Quality

2000 Portland Harbor listed as a

Superfund Site (CERCLA)

1999 First Stormwater Management Manual

1993 Downspout Disconnection

Regulatory Context timeline not to scale


Regulatory Context

2008 SWMM (Green Streets)

2004 SWMM (Hierarchy)

2005 Underground Injection Control Permit (Safe Drinking Water Act)

2014 SWMM

timeline not to scale

2011 CSO Program Complete


Goals of the 2016 SWMM revision • Re-focus stormwater management requirements to be system specific

• Reinforce stormwater management hierarchy

• Consolidate policy into Chapter 1 • Move drainage reserves from Appendix A.3 into SWMM

• Update user interface for Presumptive Approach Calculator • Retire Excel spreadsheet

• Separate Chapter 4 Source Controls into separate Administrative Rule (Source Control Manual, or SCM)

• No substantial changes to content at this time


What does that mean? • Major restructuring of Chapter 1 and Chapter 3 • Complete reorganization of the Appendices • Revised Administrative Review and Appeals requirements that conform to

new citywide standards • Minor changes to Portland City Code 17.38 to authorizing implementation

of both the SWMM and the SCM and to provide for the revised Administrative Review and Appeals requirements


Chapter 1 – Requirements and Policies • Shift from citywide flow

control and pollution reduction requirements to system-specific requirements

• Reinforces the stormwater discharge and infiltration hierarchy

• What does each type of system need?

MS4

Combined UIC


System-specific requirements


More flexibility using UIC’s • Roof runoff AND pedestrian-only

plaza areas can drain directly to UICs • Expand “Discharge to UIC” criteria to

now include: • Residential streets • Driveways • Small parking lots (<50 spaces) • Spill control and additional pollution

reduction- private systems will need lynch-style catch basin; public systems will need sedimentation manhole


More clarity around protecting drainageways • Portland City Code 17.38 requires drainageway protection

• Appendix A.3 of 2014 SWMM; now throughout Chapters 1, 2, and 3

• BES implements protection through drainage reserves • Requires review of any proposed encroachments into reserve area


• Updates to Green Street Details and private typical details

• New Simplified and Tree Credit Worksheet Forms

Chapter 2 – Stormwater Facility and Conveyance Design


Updated language throughout • Clarify stormwater facility configurations and discharge configurations

• Eliminate use of the term “flow-through”


Online Presumptive Approach Calculator • Portland Online account required

• Save projects, export/import

• Incorporate hierarchy workflow into calculator (pre/post peak matching) • No need to run the PAC twice • Helps reinforce infiltration and discharge hierarchy

• Real time calculations (no buttons) • Required vs. recommended ranges

• Cannot run calculator with illogical numbers • Can run calculator with numbers outside of the recommended ranges

• Will provide warning and PAC report will print with • May need to submit under Performance Approach


Chapter 3 – Operations and Maintenance • Separate requirements for private and public facilities • Shift Presumptive O&M requirements and submittals to match Simplified • Incorporate conveyance features into private O&M requirements

• Shift drainage reserve protection from deed notice to O&M Plan on deed

Maintain drainageway conveyance, any improvements or enhancements, AND approved encroachments with O&M Plan


Clarify Public Works Permit O&M Requirements • New form for Public Works Projects • Developed Standard O&M Plan language for Green Streets

This Not this


Public Comment Process • Public Comment Period April 4 – May 6 • All documents and instructions posted online

www.portlandoregon.gov/bes/70389 • Includes 2014 SWMM and 2016 SWMM and SCM crosswalk

• Submit comments to:

[email protected]

http://www.portlandoregon.gov/bes/70389

mailto:[email protected]

mailto:[email protected]


2016 SWMM Schedule • Public Comment Period: April 4th - May 6th • City Council (minor code changes only): May (tbd) • Adoption: July 1st 2016 • Three month phase-in (use 2014 SWMM or 2016 SWMM/SCM) • 2016 SWMM and 2016 SCM required starting October 1st 2016


Thank you! • Questions?

Amber Clayton, SWMM Angela Henderson, SCM

2016 stormwater management manual -...

Documents