600 RIVERSIDE RD 2022-01-25 - Laserfiche WebLink

Permeable pavement in accordance with BMP T5.15 in Chapter 5 of Volume V. • Infeasible — The following infeasibility criteria preclude the use of permeable pavements: o The project is adjacent to a bulkhead for much of its length. Infiltrating water behind the bulkhead may compromise the structure. o A portion of the trail is constructed above contaminated soil capped with an engineered ' impermeable layer. Infiltrating runoff above this engineered cap could compromise its performance. o The trail is adjacent to the Snohomish River and will frequently see groundwater elevations within 1 foot of the bottom of the lowest gravel base course. ' Rain Gardens in accordance with BMP T5.14 in Chapter 5 of Volume V. ' • Infeasible — The following infeasibility criteria preclude the use of Rain Gardens: o The project is adjacent to a bulkhead for much of its length. Infiltrating water behind the bulkhead ' may compromise the structure. o A portion of the trail is constructed above contaminated soil capped with an engineered impermeable layer. Infiltrating runoff above this engineered cap could compromise its performance. o The trail is adjacent to the Snohomish River and will frequently see groundwater elevations within 1 foot of the bottom of the bioretention cell. Bioretention in accordance with Chapter 7 of Volume V. ' • Infeasible — See Rain Garden Infeasibility criteria. Sheet Flow Dispersion in accordance with BMP T5.12. • Infeasible — Existing slopes adjacent to the trail exceed 20 percent in some areas. ' Concentrated Flow Dispersion in accordance with BMP T5.11 in Chapter 5 of Volume V. • Infeasible — The following infeasibility criteria preclude the use of Concentrated Flow Dispersion: ' o Runoff is neither collected nor concentrated by the project. o Slopes adjacent to the trail exceed 20 percent in some areas. ' o Existing low points are maintained and fall within 50 feet of the Snohomish River. MINIMUM REQUIREMENT NO. 6: RUNOFF TREATMENT As discussed at the November 9, 2017, meeting between the Port of Everett team and the City of Everett ' Planning Department, Jane Zimmerman, prior to retirement, had confirmed that the project does not require any water quality improvements. Additionally, Minimum Requirement No. 6 is not applicable as there are no pollution -generating surfaces proposed with this project. ' Riverside Business Park — Port of Everett 3