PART 400 - 600 Minimum Requirements.
30.63A.400 Minimum requirement 1: Preparation of a stormwater site plan.
When minimum requirement 1 applies pursuant to part 300 of this chapter, the applicant shall prepare a stormwater site plan.
(1) A stormwater site plan is a comprehensive report containing all of the technical information and analysis necessary for the evaluation of a proposed new development or redevelopment project for compliance with the requirements of this chapter.
(2) Prior to any land disturbing activity, the applicant shall submit a stormwater site plan that:
(a) Complies with this section and volume I, chapter 3 of the Drainage Manual;
(b) Uses site-appropriate development principles to retain native vegetation and minimize impervious surfaces to the extent feasible;
(c) Relies on volumes I through V of the Drainage Manual to select BMPs; and
(d) Includes a stormwater pollution prevention plan (SWPPP). The required procedures for preparing a SWPPP and the required content of the SWPPP are described in SCC 30.63A.445, 30.63A.450, and volume II, chapter 3 of the Drainage Manual.
(3) The following types of stormwater site planning work shall be performed by or under the direction of a professional engineer licensed in Washington State:
(a) Stormwater site plans that involve engineering calculations;
(b) Plans involving construction of treatment facilities or flow control facilities (detention ponds, bioretention or infiltration basins, etc.);
(c) Structural source control BMPs; and
(d) On-site drainage conveyance systems. (Added by Amended Ord. 10-026, June 9, 2010, Eff date Sept. 30, 2010; Amended by Ord. 15-102, Jan. 11, 2016, Eff date Jan. 22, 2016; Amended by Amended Ord. 21-025, June 16, 2021, Eff date July 1, 2021).