Highway Runoff Manual

Publication Number
M 31-16
Publication Version
M 31-16.05
Publication Date
Manual Manager
Alex Nguyen
Originator
WSDOT HQ Design Office, Highway Runoff Unit
Subject
Planning and design of stormwater management.

The Highway Runoff Manual (HRM) provides guidance to direct the planning and design of stormwater management facilities for existing and new Washington State highways, rest areas, park-and-ride lots, ferry terminals, and highway maintenance facilities throughout the state. The HRM establishes minimum requirements and provides uniform technical guidance.

Revision History

M 31-16.05 April 2019

Supplement February 2016

M 31-16.04 April 2014

M 31-16.03 November 2011

M 31-16.02 May 2010

June 2008

M 31-16.01 March 2007

2006 October

2006 May

2004 March

1995 February

8,683 animals crossed the Snoqualmie Pass East Project area

as recorded by WSDOT and partners in 2020 and 2021.

46% increase in Amtrak Cascades ridership to 251,000 passengers

in 2021 compared to 172,000 in 2020.

Nine wetland and stream mitigation sites across 32.7 acres added

to our monitoring program in 2021 to help offset climate change impacts.