2009 Thurston County Drainage Design and Erosion Control Manual
The Thurston County Drainage Design and Erosion Control Manual sets standards for reducing and managing stormwater runoff on new development and redevelopment projects in the unincorporated areas of Thurston County. The manual also applies to projects within incorporated and urban growth areas that adopt the Thurston County manual.
The drainage manual you see on this page was approved by Thurston County commissioners on August 17, 2009 and took effect November 16, 2009. To view the adopting ordinance, click here. To see the previous, 1994 version, click here.
The new manual is consistent with the 2005 Department of Ecology Stormwater Manual for Western Washington. The updates were required under Thurston County's NPDES Phase II permit.
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2016 Drainage Design and Erosion Control Manual Revision for Thurston County
The FINAL DRAFT of the Thurston County Drainage Design and Erosion Control Manual (DDECM) was adopted by the Thurston County Board of Commissioners on October 18, 2016. The 2016 DDECM will be effective on December 31, 2016. Projects submitted for permitting after December 31, 2016 will be subject to the 2016 DDECM. The Final Draft of the 2016 DDECM is available for download below. The Stormwater Utility staff is in the process of completing final formatting and editorial changes prior to publication. The final document will be posted prior to the effective date.
DRAFT DRAINAGE AND CONTROL MANUAL JULY 2016
2009 Drainage Design and Erosion Control Manual for Thurston County
Design Guides for 2009 Drainage Manual Best Management Practices
Staff contact: Pat Allen (360) 867-2078. E-mail: AllenP@co.thurston.wa.us
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