1. All activities covered by this chapter shall comply with the site planning and best management practice selection and design criteria in the stormwater manual, to implement the applicable minimum technical requirements listed in this chapter.

2. The city may allow alternative or regional approaches to stormwater treatment, flow control, or other minimum requirements per the basin/watershed provisions outlined in the Western Washington Phase II Municipal Stormwater Permit, Appendix 1, Section 7.

3. Low Impact Development. Consistent with the city of Lynnwood comprehensive plan (environmental resources element, and other sections) and surface water management comprehensive plan, low impact development principles and BMPs shall be employed to the maximum extent practicable. When low impact development principles and BMPs are employed, the design shall be consistent with the stormwater manual.

4. Perrinville Creek Basin flow control standard (applies to all discharges within the Perrinville Creek Basin) shall have an elevated level of flow control when Minimum Requirement No. 7 (Flow Control) is triggered for a new development or redevelopment project. Discharges to the Perrinville Creek Basin shall maintain flow durations at their predevelopment levels for all flows greater than one-half of the two-year flow up to the 50-year flow and hold the 100-year peak flow rate at its predevelopment level. The predevelopment peak flow rates for the two-year and 10-year runoff events are also intended to be maintained.

1. All drainage easements within the subject property shall be at least 20 feet in width for operation and maintenance of open channel or closed system installation, unless otherwise deemed necessary and approved by the director.

2. Open retention/detention ponds and infiltration facilities shall not be located in dedicated public road right-of-way areas unless specifically waived by the director.

1. Category 1 and Category 2 projects shall meet the minimum requirements outlined in the stormwater manual.

2. Additional requirements may be imposed by the director or designee on project sites to meet the purpose of this chapter based on site specific factors including, but not limited to, location, soil conditions, slope, and designated use. (Ord. 3443 § 1, 2023; Ord. 2833 § 2, 2010)