Supporting Documents for 2009 Stormwater Drainage Manual
The 2009 Drainage Design and Erosion Control Manual for Thurston County requires the use of the Western Washington Hydrologic Model, Version 3 (WWHM3) with Thurston County enhancements for BMP design. The Thurston County enhancements include the use of additional rain gage stations and 15-minute time steps and also include a recharge calculator to demonstrate minimum infiltration requirements for projects.
Recharge Calculation Guide with Thurston Co. Enhancements
Department of Ecology approval of WWHM3 with Thurston Co. Enhancements
What You Need to Know About Abbreviated Drainage Plans
How to Determine Whether You Can Submit An Abbreviated Drainage Plan
Sample Abbreviated Drainage Plan
What is in the 2009 Drainage Manual?
Differences Between the 1994 and 2009 Drainage Manuals?
Stormwater Problems and Impacts: Why the Fuss?
Twelve Minimum Requirements & When They Apply
Project Documents/Templates
Complete and submit these documents as part of your stormwater maintenance agreement with Thurston County.
Agreement to Maintain Commercial Fillable Word Form | PDF
Agreement to Maintain Subdivision-Residential Fillable Word Form | PDF
Bond Quantities Worksheet Fillable Excel Worksheet
Checklist - Final Acceptance Requirements (Due prior to release of Financial Guarantees)
Low Pressure Air Test Report Form
Operation & Maintenance Cost Estimate Worksheet
Agreement to Maintain Fillable Word Form | PDF
Source Control Manual, Residential Stormwater Pollution Prevention