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The Official Website of the City of Kent

Surface Water Design Manual

The 2002 Kent Surface Water Design Manual (KSWDM) adopts the 1998 King County Surface Water design manual (KCSWDM) and applies to development proposals within the City of Kent. It includes all changes and deletions to the KCSWDM adopted by the City of Kent and is to be used for guidance in drainage review and design of stormwater facilities within the City.


In addition to the 2002 KSWDM, the City has adopted blanket adjustments to address specific elements within the KSWDM and changing regulations at the state level.


Chapter 5 of the 2009 City of Kent Design and Construction Standards (KDCS) references the 2002 KSWDM for the design of stormwater facilities.  Chapter 5 of the KDCS also includes requirements for easements and construction standards of stormwater systems in the City of Kent, including standard details for storm structures, appurtenances and erosion control.


Designers of storm water facilities located in the City of Kent should reference all of the above documents. 

Introduction and Table of Contents (PDF, 300KB) 

Chapter 1: Drainage Review and Requirements (PDF, 4.3MB) 

Chapter 2: Drainage Plan Submittal (PDF, 1.8MB) 

Chapter 3: Hydrologic Analysis and Design (PDF, 60KB) 

Chapter 4: Conveyance System Analysis and Design (PDF, 480KB) 

Chapter 5: Flow Control Design (PDF, 200KB) 

Chapter 6: Water Quality Design (PDF, 80KB) 

Appendix (PDF, 620KB) 

Reference (PDF, 2.2MB) 

Maps (PDF, 4MB)  

Blanket Adjustment 2013-1 

Blanket Adjustment 2011-1   

Blanket Adjustment 2010-1 

Blanket Adjustment 2009-1 

Blanket Adjustment 2008-1 

Blanket Adjustment 2008-2 

Blanket Adjustment 2005-1 

Blanket Adjustment 2004-1 & 2004-2