Laserfiche WebLink
Table V-A.21: Maintenance Standards - Bioretention Facilities (continued) <br /> Recommended*Frequen <br /> Maintenance Com- Condition when Maintenance is Needed (Stand- <br /> ponent Inspection ards) Action Needed (Procedures) <br /> vegetation man- <br /> agement protocols) <br /> Note that the inspection and routine maintenance frequencies listed above are recommended by Ecology. They do not supersede or replace the municipal stormwater permit requirements for inspection frequency <br /> mittees for"stormwater treatment and flow control BMPs/facilities". quenc required y of municipal stormwater per- <br /> - a Frequency: A=Annually; B = Biannually(twice per year); M = Monthly; W=At least one visit should occur during the wet season(for debris/clog related maintenance, this inspection/maintenance visit should occur in <br /> trees have lost their leaves); S = Perform inspections after major storm events (24-hour storm event with a 10-year or greater recurrence interval). the early fall, after deciduous <br /> IPM-Integrated Pest Management <br /> ISA-International Society of Arboriculture <br /> Recommended Frequency a <br /> Table V-A.22: Maintenance Standards - Permeable Pavement <br /> Component Condition when Maintenance is Needed <br /> ::: Inspection �Routin�eMaintenance (Standards) Action Needed (Procedures) <br /> SurfacelWearing Course <br /> • Clean deposited soil or other materials from permeable pavement or other adjacent surfacing <br /> Permeable Pave- Runoff from adjacent pervious areas deposits <br /> ments, all A° S P Check if surface elevation of planted area is too high, or slopes towards pavement, and can be regraded (prior <br /> soil, mulch or sediment on paving to regrading, 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 /> Clean surface debris from pavement surface using one or a combination of the following methods: <br /> • Remove sediment, debris, trash, vegetation, and other debris deposited onto pavement(rakes and leaf <br /> blowers can be used for removing leaves) <br /> • Vacuum/sweep permeable paving installation using: <br /> A or B None(routine maintenance) Walk-behind vacuum (sidewalks) <br /> High efficiency regenerative air or vacuum sweeper(roadways, parking lots) <br /> Porous asphalt or per- o ShopVac or brush brooms (small areas) <br /> vious concrete Hand held pressure washer or power washer with rotating brushes Follow equipment manufacturer guidelines <br /> for when equipment is most effective for cleaning permeable pavement. Dry weather is more effective for <br /> some equipment. <br /> • Review the overall performance of the facility(note that small clogged areas may not reduce overall per- <br /> formance of facility) <br /> A Surface is clogged: Ponding on surface orvvater • Test the surface infiltration rate using ASTM C1701 as a corrective maintenance indicator. Perform one test <br /> — b flows off the permeable pavement surface dur- per installation, up to 2,500 square feet. Perform an additional test for each additional 2,500 square feet up to <br /> ing a rain event (does not infiltrate) 15,000 square feet total.Above 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 <br /> restore permeability. To clean clogged pavement surfaces, use one or combination of the following methods: <br /> 2019 Stormwater Management Manual for Western Washington <br /> Volume V-AppendixA -Page 1025 <br />