Personalize your online experienceSign Into My Dashboard
Home
RSSPrintEmailFacebookTwitterYouTube

Go To Search
Click to Home
Your GovernmentOur ResidentsFor VisitorsDoing BusinessHow Do I
Stormwater

Stormwater Manual
All new development and redevelopment must follow stormwater standards from the 2017 City of Issaquah Addendum to the Washington State Department of Ecology's most recent Stormwater Management Manual for Western Washington. Note: Use the 2014 amended Department of Ecology document.

The new standards include revised flow control, water quality, temporary erosion and sediment control (TESC), and stormwater Low Impact Development (LID) requirements.

Stormwater Flow Control
The default standard is the Level 2 flow control standard, assuming a historic (forested) pre-development condition. However, exemptions are available.

Refer to the the 2017 City of Issaquah Addendum to the Washington State Department of Ecology's most recent Stormwater Management Manual for Western Washington for more specific information.

Water Quality
Refer to the 2017 City of Issaquah Addendum to the Washington State Department of Ecology's most recent Stormwater Management Manual for Western Washington for more specific information.

TESC
Temporary Erosion and Sediment Control (TESC) permit coverage is required for all land disturbing activities (with some exceptions). TESC requirements are addressed in the Public Works permit for the project, typically a clearing and grading permit. For smaller projects that don't trigger a clearing and grading permit, a separate Public Works permit for TESC will be required.

Plan submittal requirements are revised to follow the
2017 City of Issaquah Addendum. Designated TESC supervisors during land disturbing activities shall be a Certified Erosion and Sediment Control Lead (CESCL).
 
Note: A separate Department of Ecology Construction Stormwater General Permit is required for sites having 1 acre or more of disturbed area.   

Stormwater Low Impact Development (LID)
To the maximum extent feasible, stormwater LID principles, facilities, and best management practices shall be incorporated into all new development and redevelopment.

Refer to
the 2017 City of Issaquah Addendum to the Washington State Department of Ecology's most recent Stormwater Management Manual for Western Washington for more specific information, including feasibility requirements, soil testing requirements, and design methods. 

For new development and redevelopment projects located within Central Issaquah, different LID requirements or exemptions may apply.