8525 EVERGREEN WAY BURGER KING 2021-05-10

• No.22-Maintenance Standards and Procedures for Permeable Pavement. 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 municipal stormwater permittees for"stormwater treatment and flow control BMPs/facilities." Recommended Frequency a Component Condition when Maintenance is Needed Action Needed Inspection Routine (Standards) (Procedures) Maintenance Surface/Wearing Course 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 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, protect permeable pavement by covering with temporary plastic and secure covering in place) • Mulch and/or plant all exposed soils that may erode to pavement surface Porous asphalt or A or B None(routine maintenance) Clean surface debris from pavement surface using one or a combination of the following methods: pervious concrete •Remove sediment,debris,trash,vegetation,and other debris deposited onto pavement(rakes and leaf blowers can be used for removing leaves) •Vacuum/sweep permeable paving Installation using: o Walk-behind vacuum(sidewalks) o High efficiency regenerative air or vacuum sweeper(roadways,parking lots) o ShopVac or brush brooms(small areas) •Hand held pressure washer or power washer with rotating brushes Follow equipment manufacturer guidelines for when equipment is most effective for cleaning permeable pavement.Dry weather is more effective for some equipment. As Surface is clogged: •Review the overall performance of the facility(note that small clogged areas may not reduce overall performance of facility) 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, 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 15,000 square feet,add one test for every 10,000 square feet. • If the results Indicate an infiltration rate of 10 inches per hour or less,then perform corrective maintenance to restore permeability.To clean clogged pavement surfaces,use one or combination of the following methods: •Combined pressure wash and vacuum system calibrated to not dislodge wearing course aggregate. • Hand held pressure washer or power washer with rotating brushes • Pure vacuum sweepers Note:If the annual/biannual routine maintenance standard to clean the pavement surface is conducted using equipment from the list above,corrective maintenance may not be needed. 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 ponding then see above. • Determine source of sediment loading and evaluate whether or not the source can be reduced/eliminated.If the source cannot be addressed,consider increasing frequency of routine cleaning(e.g.,twice per year instead of once per year). 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 •Parking lots and roadways:Pressure wash,vacuum sweep,or use a combination of the two for cleaning moss from pavement surface.May require stiff broom or power brush in areas of heavy moss. A Major cracks or trip hazards and concrete spatting and • Fill potholes or small cracks with patching mixes raveling •Large cracks and settlement may require cutting and replacing the pavement section.Replace in-kind where feasible. Replacing porous asphalt with conventional asphalt is acceptable if it is a small percentage of the total facility area and does not impact the overall facility function. •Take appropriate precautions during pavement repair and replacement efforts to prevent clogging of adjacent porous materials a Frequency:A=Annually;B=Biannually(twice per year);S=Perform inspections after major storm events(24-hour storm event with a 10-year or greater recurrence interval). b Inspection should occur during storm event. Volume V—Runoff Treatment BMPs—December 2014 4-60