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PUBLIC WORKS PERMIT Date Applied: 10/21/2022 <br /> City of Everett Permit Services Public Works Permit#: PW2210-012 <br /> 3200 Cedar Street, 2"d Floor Associated Bldg Permit#: <br /> E V E R E T T <br /> Everett, WA 98201 Planning Reference#: <br /> WASHINGTON everettwa.gov/permits Public Works Fee: $65.00 <br /> PermitServices@everettwa.gov Schedule Inspections at:onIinePerm its.everettwa.gov <br /> 2022 DESIGN AND CONSTRUCTION STANDARDS AND SPECIFICATIONS <br /> (Mid 2022 update) STORM AND SURFACE WATER 4-13 <br /> 4-2.4 CULVERT DESIGN CRITERIA <br /> Culverts shall be designed in accordance with the following criteria: <br /> 1. Minimum culvert velocity shall be 2 feet per second, and a maximum culvert velocity shall be 15 <br /> feet per second at the design flow rate. Thirty feet per second may be used with an engineered <br /> outlet protection design. Velocity requirements will not be applied to culverts on natural systems <br /> designed to meet fish passage standards. <br /> 2. No maximum velocity for ductile iron or HDPE pipe shall be established, but outlet protection shall <br /> be provided. <br /> 3. All CPEP and PVC culverts and pipe systems shall have concrete or rock headwalls at exposed pipe <br /> ends. <br /> 4. Bends are not permitted in culvert pipes. <br /> 5. The following minimum cover shall be provided over culverts: <br /> a. 2 feet under roads. <br /> b. 1 foot under roadside applications and on private property, exclusive of roads. <br /> 6. If the minimum cover cannot be provided on a flat site, use ductile iron pipe and analyze for <br /> loadings. <br /> 7. Maximum culvert length shall be 250 feet. <br /> 8. Minimum separation from other pipes: <br /> a. 6 inches vertical (with bedding) and in accord with the City Sewer Utility Design criteria. <br /> b. 3 feet horizontal. <br /> Trench backfill shall be bank run gravel or suitable native material compacted to 95 percent Modified <br /> Proctor test to a depth of 2 feet; 90 percent below 2 feet compacted in 8-inch to 12-inch lifts. <br /> All driveway culverts shall be of sufficient length to provide a minimum 3:1 slope from the edge of the <br /> driveway to the bottom of the ditch. Culverts shall have beveled end sections to match the side slope. <br /> Page 2 of 2 <br /> _APPLICANT/JOB SITE COPY _ADDRESS FILE _TREASURER <br />