9929 EVERGREEN WAY HORIZON BANK 2018-01-01 MF Import

A properly functioning system will remove solids from water by trapping particulates in the porous structure of the filter media. The flow through the system will naturally decrease as more and more solids are trapped. Eventually the flow through the system will be Icw enough to require replacement of the cartridges. It may be possible to extend the usable span of the cartridges by removing sediment from upstream trapping devices on an as-needed basis in order to prevent material from being re-suspended and discharged to tha system. Site conditions greatly influence maintenance requirements. StormFilter units located in areas with erosion or active censtruction shouid be inspected and maintained more often than those in fully stabilized areas. The mainlenance frequency may be adjusted as additional monitoring infonnation becomes available during the inspecticn program. Areas that develop known problems should be inspected more frequently than areas that demonstrate no problems, particularly after large storms. Ultimately, inspection and maintenance activities should be scheduled based on the historic records and characteristics of an individual StormFilter system. It is recommended that the maintenance agency develop a database to properly manage StormFilter maintenance programs. Prior to the development of the maintenance database, the following maintenance irequencies should be followed: Inspeclion/minor maintenance • One time per year • After Major Storms Ma�or maintenance • One time per year • In the event of a chemical spill Frequencies should be updated as required The recommended initial frequency f�r inspection/minor maintenance is two times per year fnr the precast uniL StormFilter units should be inspected after all major storms. Sediment removal and cartridc�e replacement on an annual basis is recomrnended until further knowledge is gained about a particular system. Once an understanding of site characteristics has been established, maintenance may not be needed for one to two years, but inspection is warranted. Maintenance Methods InspectionlMinor Maintenance The primary goal of a maintenance inspection is to assess the condilion of the cartridges relative to the level of sediment loading. It may be desirable to conduct this inspection during a storm to observe the relative flow through the fiitar cartridges. If the submerged caRridges are severely plugged, large amounts of sediments will he present and very little flnw wili be discharged from the drainage pipes. If this is the case, it is likely that the cartridges need to be replaced. Warning: In the case of a spill, the worker should abort maintenance activities until the proper guidance is obtained. Notify the local hazard control agency and Stormwater Management Inc. immediately. To conduct an inspection and/or minor maintenance: important: Maintenance must be performed by a utility worker familiar with StormFilter units. 1. if applicabie, set up safety equipment to protect pedestrians from fall hazards due to open vault doors or when work is being done near waikways or ro2dways. 2. Visually inspect the external condition of the unit and take notes concerr�ing defects/problems. Stormwater Management, Inc. C�2UO3 StonnFilter Operation and Maintenance Guidelines 4 of 9 I 351 �/