Drainage & Land Disturbing Activity
(Projects vested prior to September 30, 2010)
Standards
- Snohomish County Code Chapters:
- Engineering Design and Development Standards (EDDS)
- Snohomish County Drainage Manual
- 2005 Stormwater Management Manual for Western Washington
- Rule 3044: Standards for Construction Stormwater Pollution Prevention Plans (PDF)
- Rule 6225: Chapter 30.62A SCC Infiltration Standards (PDF)
Restrictions Related to Critical Areas
- Critical Areas: Channel Migration Zone Maps (SCC 30.62B.330)
- Southwest UGA: Little Bear Creek Watershed (SCC 30.63C.025)
- Serene Way: Frontage improvement standards
- Lake Stevens UGA: Tightline systems are required (SCC 30.63A.225)
- Lake Stevens UGA: Detention facility design requirements - Weiser Creek, Burri Creek, and Fox Creek basins (SCC 30.63A.226)
Outside Agency Requirements (Applicant's Responsibility)
- Snohomish Health District
- Washington Department of Fish and Wildlife - HPA permits
- Federal Army Corp of Engineers
- Washington State Department of Transportation
All Developments
All new development must use adequate temporary erosion control Best Management Practices (BMPs). If developing in a floodplain, please contact the flood hazard specialist at 425-388-3311. If your development will occur within 300 feet of a FWHCA fish bearing stream, demonstrate compliance with SCC 30.62A.320(1)(c) and Rule 6225: Chapter 30.62A SCC Infiltration Standards (PDF).
- Engineering Design and Development Standards (EDDS) (PDF)
- Drainage Regulations 30.63A (PDF)
- Grading Regulations 30.63B (PDF)
- Critical Area Regulations: 30.62A, 30.62B, and 30.62C
- Channel Migration Zones
Full Drainage Plan
Major development proposals (more than 5,000 square feet of new impervious surface area, or more than 5,000 cubic yards of gross cut or fill) generally require storm water detention and water quality treatment facilities designed by a professional engineer licensed in Washington.
- Construction / Full Drainage Plan Checklist (PDF)
- Drainage Facility Maintenance Covenant (DFMC) - subdivisions (PDF)
- Drainage Facility Maintenance Covenant (DFMC) - other (PDF)
- Drainage Facility Maintenance Covenant Submittal Checklist (PDF)
- Record Drawings (as-built) Checklist (PDF)
- Rule 3044 - Standards for Stormwater Pollution Prevention Plans (PDF)
- 2005 Department of Ecology Stormwater Management Manual, Volume II (PDF)
- Drainage Information Summary Form (PDF)
Targeted Drainage Plan
Other developments (more than 200 but less than 5,000 square feet of new impervious surface area) generally have no detention or water quality treatment requirements. A Targeted Drainage Plan can either be for construction, or can be a conceptual plan usually associated with a land use action going to hearing. View the Targeted Drainage Plan Checklist (PDF).
Grading Plan
A grading permit is required for all grading that does not meet the exemption requirements of 30.63B. When no impervious surfaces are proposed but a grading permit is still required, use the Grading Plan Submittal Checklist (PDF).
Grading Application
Low Impact Development
Low Impact Development (LID) is now available for projects meeting LID Ordinance 30.63C (PDF), and is offered as an alternative. Use the 2005 DOE Manual if claiming credits in your detention pond sizing for using LID techniques.
- Low Impact Development Manual (PDF)
- Request for Low Impact Development Pre-Application Meeting Notice (PDF)
- Stormwater Management Manual for Western Washington (revised 2005)
- Low Impact Development Stormwater Management Techniques, Bulletin #22 (PDF)
- Low Impact Development Supplemental
- Low Impact Development Modification from Snohomish County Code (PDF) (SCC)
- Low Impact Development Deviation from Engineering Design and Development Standards (EDDS)
- Stormwater Facility and Low Impact Development System Maintenance Covenant (PDF)
- Assignment of Funds in Lieu of LID Paving Bond (PDF)
- Low Impact Development Paving Bond (PDF)
Other Information Links
- Drainage Information for Home Builders (PDF)
- Drainage Needs Report and Maps
- Engineering and Design Standards Deviation Request (EDDS)
- Erosion Control for the Home Builder (PDF)
- Grading and Slope Information for Home Builders (PDF)
- Public Drainage Easement - Applicant's Submittal Checklist (PDF)
- Drainage Easement (PDF)
- Waiver and Modification Request (PDF)
- Washington State Department of Transportation Highway Runoff Manual
- Washington State Department of Transportation Hydraulics Manual