4817 RUCKER AVE 2024-12-09 - Laserfiche WebLink

Table V-, .21 a Maintenance Standards - Bioretention Facilities (continued) Recommended Frequency a Maintenance Com- Condition when Maintenance is Needed (Stand- Action Needed (]Procedures) ponent Inspection Routine Main- ards) tenance Erosion control at inlet A Concentrated flows are causing erosion Maintain a cover of rock or cobbles or other erosion protection measure(e.g., matting)to protect the ground where con- centrated water enters the facility(e.g., a pipe,curb cut or swale) S Trash or other debris present on trash rack Remove/dispose A Bar screen damaged or missing Repair/replace Overflow A, S Capacity reduced by sediment or debris Remove sediment or debris/dispose Clean orifice at • Plant roots, sediment or debris reducing capa- least biannually cityof underdrain ® Jet clean or rota cut debris/roots from underdrain s Underdrain pipe Clean pipe as (may need more fre- rotary ( ) needed . Prolonged surface ponding(see"Ponded m If underdrains are equipped with a flow restrictor(e.g.,orifice)to attenuate flows,the orifice must be cleaned regularly. quent cleaning dur- ing wet season) water' Vegetation • Determine cause of poor vegetation growth and correct condition Vegetation survival rate falls below 75%within first o Replant as necessary to obtain 75%survival rate orgreater. Referto original planting plan, or approved jurisdictional Facility bottom area and upland slope veget- Fall and Spring two years of establishment(unless project O&M species list forappropriate plant replacements(See Appendix 3-Bioretention Plant List, in the LID Technical Guid- ante Manual forPuet Sound, ation manual or record drawing stipulates more or less than g (Hinman and Wulkan, 2012)). 75%survival rate). • Confirm that plant selection is appropriate for site growing conditions • Consultation with a landscape architect is recommended for removal,transplant,or substitution of plants Remove any diseased plants or plant parts and dispose of in an approved location(e.g., commercial landfill)to avoid risk of spreading the disease to other plants • Disinfect gardening tools afterpruning to prevent the spread of disease Vegetation(general) As needed Presence of diseased plants and plant material See the Pacific Northwest Plant Disease Management Handbook(Pscheidt and Ocamb, for information on dis- ease recognition and for additional resources ® Replant as necessary according to recommendations provided for"facility bottom area and upland slope vegetation". All pruning seasons • Prune trees and shrubs in a manner appropriate for each species. Pruning should be performed by landscape pro- (timing varies by Pruning as needed fessionals familiarwith proper pruning techniques species) . All pruning of mature trees should be performed by or underthe direct guidance of an ISA certified arborist A Large trees and shrubs interfere with operation of the • Prune trees and shrubs using most current ANSI A300 standards and ISA BMPs_ facility or access for maintenance . Remove trees and shrubs, if necessary. Trees and shrubs . Remove standing dead vegetation • Replace dead vegetation within 30 days of reported dead and dying plants (as practical depending on weather/planting Fall and Spring Standing dead vegetation is present season) • If vegetation replacement is not feasible within 30 days, and absence of vegetation may result in erosion problems, temporary erosion control measures should be put in place immediately. ® Determine cause of dead vegetation and address issue, if possible 2019 Stormwater Management Manual for Western Washington Volume V-Appendix A-Page 1021