Drainage Design & Erosion Control Manual

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Drainage Design and Erosion Control Manual 

The Drainage Design and Erosion Control Manual (DDECM) sets standards for reducing and managing stormwater runoff for all new development and redevelopment projects within the City of Tumwater.

Printer-friendly versions (PDFs) of the current DDECM are available below.

This manual is effective as of January 1, 2018 and meets the requirements set forth by the WA State Department of Ecology.  Revisions and updates to this plan will be integrated to the files below, with Errata files maintained separately.  A list of those changes can be found here: (no current revisions).

To review major changes from the City's 2011 Stormwater Design Manual and this current version, please click HEREpdf-icon-sm


Stormwater Maintenance Guide:  Use for developed sites to better understand ongoing maintenance needs of your stormwater system.

Questions?  Call (360) 754-4140 and request to speak to one of the following staff:

Matt Webb, Engineer III - for questions related to site development.

Amy Georgeson, Water Resources Specialist - for questions related to post-construction maintenance and inspection.

Dan Smith, Water Resources Program Manager - for questions related to manual variances, exceptions or revisions.