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No.22-Maintenance Standards and Procedures for Permeable Pavement. <br /> Note that the inspection and routine maintenance frequencies listed below are recommended by Ecology.They do not supersede or replace the municipal stormwater permit requirements for inspection frequency required of <br /> municipal stormwater permittees for"stormwater treatment and flow control BMPs/facilities." <br /> Recommended Frequency <br /> Component Condition when Maintenance is Needed Action Needed <br /> Inspection Routine (Standards) (Procedures) <br /> Maintenance <br /> Surface/Wearing Course <br /> Permeable A,S Runoff from adjacent pervious areas deposits soil,mulch or •Clean deposited soil or other materials from permeable pavement or other adjacent surfacing <br /> Pavements,all sediment on paving •Check if surface elevation of planted area is too high,or slopes towards pavement,and can be regraded(prior to regrading, <br /> protect permeable pavement by covering with temporary plastic and secure covering in place) <br /> • Mulch and/or plant all exposed soils that may erode to pavement surface <br /> Porous asphalt or A or B None(routine maintenance) Clean surface debris from pavement surface using one or a combination of the following methods: <br /> pervious concrete • Remove sediment,debris,trash,vegetation,and other debris deposited onto pavement(rakes and leaf blowers can be used <br /> for removing leaves) <br /> •Vacuum/sweep permeable paving installation using: <br /> o Walk-behind vacuum(sidewalks) <br /> o High efficiency regenerative air or vacuum sweeper(roadways,parking lots) <br /> o ShopVac or brush brooms(small areas) <br /> • Hand held pressure washer or power washer with rotating brushes <br /> Follow equipment manufacturer guidelines for when equipment is most effective for cleaning permeable pavement.Dry <br /> weather Is more effective for some equipment. <br /> Ab Surface is clogged: •Review the overall performance of the facility(note that small dogged areas may not reduce overall performance of facility) <br /> Ponding on surface or water flows off the permeable •Test the surface infiltration rate using ASTM C1701 as a corrective maintenance indicator.Perform one test per installation, <br /> pavement surface during a rain event(does not infiltrate) up to 2,500 square feet.Perform an additional test for each additional 2,500 square feet up to 15,000 square feet total.Above <br /> 15,000 square feet,add one test for every 10,000 square feet. <br /> • If the results indicate an Infiltration rate of 10 inches per hour or less,then perform corrective maintenance to restore <br /> permeability.To clean clogged pavement surfaces,use one or combination of the following methods: <br /> •Combined pressure wash and vacuum system calibrated to not dislodge wearing course aggregate. <br /> •Hand held pressure washer or power washer with rotating brushes <br /> •Pure vacuum sweepers <br /> Note:If the annual/biannual routine maintenance standard to clean the pavement surface is conducted using equipment from <br /> the list above,corrective maintenance may not be needed. <br /> A Sediment present at the surface of the pavement •Assess the overall performance of the pavement system during a rain event.If water runs off the pavement and/or there is <br /> ponding then see above. <br /> • Determine source of sediment loading and evaluate whether or not the source can be reduced/eliminated.If the source <br /> cannot be addressed,consider increasing frequency of routine cleaning(e.g.,twice per year instead of once per year). <br /> Summer Moss growth inhibits Infiltration or poses slip safety hazard • Sidewalks:Use a stiff broom to remove moss in the summer when it Is dry <br /> •Parking lots and roadways:Pressure wash,vacuum sweep,or use a combination of the two for cleaning moss from <br /> pavement surface.May require stiff broom or power brush in areas of heavy moss. <br /> A Major cracks or trip hazards and concrete spelling and • Fill potholes or small cracks with patching mixes <br /> raveling • Large cracks and settlement may require cutting and replacing the pavement section.Replace in-kind where feasible. <br /> Replacing porous asphalt with conventional asphalt is acceptable if it is a small percentage of the total facility area and does <br /> not impact the overall facility function. <br /> •Take appropriate precautions during pavement repair and replacement efforts to prevent clogging of adjacent porous <br /> materials <br /> • Frequency:A=Annually;B=Biannually(twice per year);5=Perform inspections after major storm events(24-hour storm event with a 10-year or greater recurrence interval). <br /> b Inspection should occur during storm event. <br /> Volume V—Runoff Treatment BMPs—December 2014 <br /> 4-60 <br />