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Table V-4.5.2(21) Maintenance Standards - Bioretention Facilities <br /> (continued) <br /> Recommended Fre- Condition <br /> uenc <br /> Maintenance when Main- <br /> q Y a Action Needed (Pro- <br /> tenance cedures) <br /> is <br /> p Routine Main-Needed (Stand- ) <br /> Inspection tenance <br /> ards) <br /> cut or swale) <br /> Trash or other <br /> S debris present Remove/dispose <br /> Trash rack on trash rack <br /> A Bar screen dam-Repair/replace <br /> aged or missing <br /> Capacity Remove sediment or <br /> Overflow A, S reduced by sed- debris/dispose <br /> iment or debris <br /> • Plant <br /> roots, sed- . Jet clean or rotary <br /> iment or cut debris/roots from <br /> Clean orifice debris underdrain(s) <br /> at least bian- reducing <br /> nually (may capacity of • If underdrains are <br /> Underdrain Clean pipe need more fre- underdrain equipped with a flow <br /> pipe as needed restrictor(e.g., ori- <br /> quent clean- . Prolonged face)to attenuate <br /> ing during wet surface flows,the orifice <br /> season) <br /> ponding <br /> (see "Pon- must be cleaned reg- <br /> ded water ularly. <br /> Vegetation <br /> Vegetation sur- • Determine cause of <br /> vival rate falls poor vegetation <br /> below 75% growth and correct <br /> Facility bottom within first two condition <br /> area and Fall and years of estab- • Replant as neces- <br /> upland slope Spring lishment(unless sary to obtain 75% <br /> vegetation project O&M survival rate or <br /> manual or greater. Refer to ori- <br /> record drawing ginal planting plan, <br /> stipulates more or approved jur- <br /> 2014 Stormwater Management Manual for Western Washington <br /> Volume V- Chapter 4 -Page 870 <br />