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. i <br /> • C <br /> Geotextile Property Test Method Geotextile Property Requirements' <br /> Seam Breaking Strength ASTM D4632 and 220 lbs min. • <br /> (if seams are present) ASTM 134884 <br /> (adapted for grab test) <br /> Puncture Resistance ASTM D4833 125 lbs min. <br /> Tear Strength,min.in ASTM D4533 90 lbs min. <br /> 1Y)\--- machine and x-machine <br /> direction <br /> Ultraviolet(UV)Radiation ASTM D4355 50 percent strength stability retained <br /> min.,after 500 hrs.In weatherometer <br /> AOS ASTM D4751 0.43 mm max. <br /> (#40 sieve) <br /> Water Permittivity _ ASTM D4491 0.5 sec-1 min. <br /> I All geotextile properties aremmhnurn average roll values(i.e,the test result for any sampled roll In a lot shall meet <br /> or exceed the values shown in the table). <br /> Concrete Liners <br /> I. Concrete liners may also be used for sedimentation chambers and for sedimentation and filtration <br /> • basins less than 1,000 square feet in area.Concrete shall be 5-inch thick Class 3000 or better and <br /> shall be reinforced by steel wire mesh.The steel wire mesh shall be six(6)gage wire or larger <br /> and 6 inch by 6 inch mesh or smaller.An"Ordinary Surface Finish"is required.When the <br /> underlying soil is clay or has an unconfined compressive strength of 0.25 ton per square foot or <br /> less,the concrete shall have a minimum 6 inch compacted aggregate base consisting of coarse <br /> • sand and river stone,crushed stone or equivalent with diameter of 0.75 to 1 inch.Where visible, <br /> the concrete shall be inspected annually and all cracks shall be sealed. <br /> 2. Portland cement liners are allowed irrespective of facility size,and shotcrete may be used on <br /> slopes. However,specifications must be developed by a professional engineer who certifies the <br /> liner against cracking or losing water retention ability under expected conditions of operation, <br /> including facility maintenance operations. Weight of maintenance equipment can be up to <br /> 80,000 pounds when Hilly loaded. <br /> 3. Asphalt concrete may not be used for liners due to its permeability to many organic pollutants. <br /> 4. If grass is to be grown over a concrete liner,slopes must be no steeper than 5H:1V to prevent the <br /> top dressing material from slipping. Textured liners may be used on slopes up to 3H:1 V upon <br /> recommendation by a geotechnical engineer that the top dressing will be stable for all site <br /> conditions,including maintenance. <br /> 2,8 Maintenance Requirements <br /> 1. Adequate provisions to facilitate maintenance operations must be included in the design of all <br /> stormwater facilities. Provisions must be made for regular and perpetual maintenance of the <br /> facility,including replacement and/or reconstruction of any media that are relied upon for <br /> treatment purposes. The maintenance checklists in Appendix F shall be used to identify required <br /> maintenance for specific BMPs. <br /> 2. Any standing water removed during maintenance operations must be disposed of to an approved <br /> discharge location. Discharge to a sanitaiy sewer at an approved discharge location may be an <br /> option. The City of Everett must be contacted prior to any discharge. Residuals must be <br /> Volume Ill—Flow Control and Treatment <br /> 2-12 <br />