1.1 Purpose of This Manual

The Kitsap County Stormwater Code meets certain requirements that apply to the County from the 2019–2024 Phase II Western Washington National Pollutant Discharge Elimination System and State Waste Discharge General Permit for Discharges from Municipal Separate Storm Sewer Systems (referred to as the Phase II NPDES Municipal Stormwater Permit). Coverage under the general permit is issued by the Washington State Department of Ecology (Ecology) pursuant to the federal Clean Water Act and state law. One of the conditions of this permit requires the County to adopt and make effective a local program to prevent and control the impacts of stormwater runoff from new development, redevelopment and construction activities. This is accomplished largely through the Kitsap County (KC) Stormwater Code (Stormwater Code) and the associated Kitsap County Stormwater Design Manual (this manual).

The Stormwater Code is contained in Title 12 of the Kitsap County Code (KCC). The Stormwater Code contains regulatory requirements that provide for and promote the health, safety, and welfare of the general public. The provisions of the Stormwater Code are designed to accomplish the following:

1. Protect, to the greatest extent practicable, life, property and the environment from loss, injury, and damage by pollution, erosion, flooding, landslides, and other potential hazards, whether from natural causes or from human activity.

2. Support the water resource sustainability goals established in the Kitsap County 2009 “Water is a Resource NOT a Waste Stream Policy” (Resolution 109‑2009) and reaffirmed in 2016 (Resolution 134‑2016).

3. Protect the public interest in drainage and related functions of drainage basins, watercourses, and shoreline areas.

4. Protect receiving waters from pollution contributed by stormwater runoff.

5. Protect receiving waters from excessive flows or other forces that increase the rate of down-cutting, stream bank erosion, and/or the degree of turbidity and siltation, which will endanger aquatic and benthic life within these receiving waters.

6. Meet the requirements of state and federal law and the Phase II NPDES Municipal Stormwater Permit.

7. Protect the functions and values of environmentally critical areas as required under the State’s Growth Management Act and Shoreline Management Act.

8. Protect the public drainage system from loss, injury, and damage by pollution, erosion, flooding, landslides, strong ground motion, soil liquefaction, accelerated soil creep, settlement and subsidence, and other potential hazards, whether from natural causes or from human activity.

9. Fulfill the responsibilities of the County as trustee of the environment for future generations.