180th St SE Drainage Improvements


The proposed project will reduce driveway and roadway flooding from occurring due to high flows in the ditch on the south side of 180th St SE.
  • The project will upsize the conveyance system including road and driveway culverts.
  • The cross culvert at 83rd Ave SE will be replaced.
  • Steep sections of the ditch will be armored with a flexible rock liner and rock check dams.
  • Driveways will be brought up to current design requirements, where applicable..


Work is anticipated to take place during late spring/summer 2021 using contract construction.

Traffic Impact

No full road closures are anticipated for this project. Single lane closures with flaggers and appropriate traffic control signage will be provided to route traffic around the construction site.


The project is funded by Surface Water Management revenues.

Land Disturbing Activity (LDA) Permit

This project will be reviewed for compliance with Chapter 30.63A (Drainage) and Chapter 30.63B (Land Disturbing Activity) SCC, as well as other applicable regulations in Title 30 SCC. Public Works will exercise its authority under Rule 5001 (Revised 10/2020).

A notice of Land Disturbing Activity (LDA) was published on December 31, 2020. This project is covered under the SEPA Programmatic Checklist entitled “Maintenance Work Program 2018-2023” with a DNS issue date of 10/17/2017 (see Checklist and DNS links below).

Public comments regarding this project were due on January 21, 2021.