3301 SEAWAY BLVD WHOLE SITE 2025-10-30

CITY OF EVERETT STORMWATER MANAGEMENT MANUAL 2.10 Projects with public maintenance of the stormwater facilities Storm facilities in rights-of-way,public easements,and those associated with residential subdivisions or any other development where the City will undertake maintenance of the facility,may have special restrictions regarding materials used and/or design criteria for open-air systems. Specific restrictions/criteria applying to this type of development include,but may not be limited to,the following: 1. Corrugated metal pipe may not be used in storm drainage systems,including detention pipes and wet tanks,unless otherwise approved by the City Engineer. 2. All stormwater detention and deep dead storage(deeper than 2.5 feet)shall be provided in underground,covered systems unless otherwise approved by the City Engineer. Only shallow vegetated storage,infiltration basins,and sand filter basins shall generally be allowed as open-air systems. Retaining walls associated with these open-air facilities shall not exceed three feet in height and side slopes shall not exceed 3:1(H:V). 3. Open-air stormwater facilities(such as wetponds,infiltration basins,and sand filter basins) providing runoff control for residential subdivisions or any other development where the City will undertake maintenance of the facilities shall be dedicated in a separate tract to the City of Everett. The tract dedicated shall include,at a minimum,all area within the high water mark,and may be required to include any required access roads or paths associated with the facilities. 4. The City may require an area 10 feet wide,as measured from the high water mark,to be provided around the perimeter of an open-air runoff control facility and included in a tract held in common ownership,with an easement granted to the City. The City strongly encourages landscaping of this area by the developer to provide screening for the pond and an aesthetically pleasing appearance. Maintenance and irrigation of the landscaping shall be provided as necessary to ensure successful plant establishment. 5. At a minimum,an area five feet wide must be available to the City for maintenance of any fencing associated with stonnwater management facilities. This area must be provided around the perimeter of the fence,on both sides. If this area is not contained within the dedicated drainage tract,then an easement must be granted to the City. 6. The developer shall establish appropriate vegetation in the entire dedicated right-of-way. 2.11 Setbacks I. All wet pool,detention and infiltrating facilities shall maintain minirmun setback distances as follows. All setbacks shall be horizontal unless otherwise specified: a. 1 foot positive vertical clearance fiom'any open water maximum surface elevation to structures within 25 feet. b. 10 feet from the open water maximum surface elevation or edge of the stormwater facility to property lines and on-site structures. • c. 50 feet flora top of slopes greater Percentthan 20, and greater than 10 feet high. A ' geotechnical analysis and report,must tie ptepated addressing the potential Impact of the facilityon the slope. neat ie ott laced setback but_in no cSb1U1l She set_, back lre`tes than vertical height:ofthe slo(�e. d. 10 feet from open water maximum surface elevation or edge of stormwater facility to a sanitaty sewer main or service. e. 50 feet from any septic tank,holding tank,containment vessel,pump chamber,and distribution box. Volume Ill—Flow Control and Treatment 2-15 f)//c