3101 CEDAR ST STORM DRAINAGE DESIGN 2025-07-25

MAGNUSSON KLEMENCIC ASSOCIATES ■ R.9 Discharge of Process Wastewaters Directly to Surface Waters N/A R.10 Dangerous (hazardous) Waster Generators N/A R.1 1 Minimum Functional Standards for Containers N/A R.12 Underground and Above-ground Storage Tank Requirements N/A R.13 Emergency Spill Prevention Control and Cleanup Requirements N/A R.14 Pesticide Regulations N/A R.15 Air Quality Regulations N/A R.16 Uniform Fire Code Requirements N/A SITE DEVELOPMENT PLAN The site plan is included as Figure 3. The project evaluated several concepts for detaining stormwater and concluded that the open pond concept served as the best management strategy available due to its potential for evaporation and treatment benefits (infiltration is not assumed due to the soil classifications). The site is proposed to be re-graded by raising the north/south mid-point in order to slope as much surface runoff to the north as possible through a rain garden and a conveyance swale. The south half of the project is too low in elevation to be able to slope to the north and still meet minimum pipe slopes and inverts,so the south half of the project collects runoff in a conventional pipe and drainage structure system that carries flow to the open ponds at the north end. MINIMUM TECHNICAL REQUIREMENTS The project is entirely contained within a single parcel. The minimum requirements for the project are summarized in Tables 1 and 2 below. Table 1. Minimum Stormwater Requirements for Parcel Portion of Joint Project Stormwater Minimum Management Manual Requirement# Description Vol. 1 Section Applicability 1 Stormwater Site Plan Preparation 2.2.1 Appl i es 2 Construction Stormwater Pollution 2.2.2 Appl i es Prevention 3 Source Control of Pollution 2.2.3 Appl i es 4 Preservation of Natural Systems 2.2.4 Appl i es 5 On-Site Stormwater Management 2.2.5 Appl i es 6 Runoff Treatment 2.2.6 Does not apply (combined system) Storm Drainage Design 4 Utility Plant Expanded Parking Facility, Everett,Washington