2600 FEDERAL AVE 2021 PORT OF EVERETT 2025-09-29

Maintenance Decision Tree The need for maintenance is typically based on results of the inspection. The following Maintenance Decision Tree should be used as a general guide.(Other factors,such as Regulatory Requirements, may fc need to be considered). Please note Stormwater Management StormFilter devices installed sy t - x downstream of,or integrated within,a stormwater storage facility 4 � typically have different operational parameters(i.e.draindown time). In these cases,the inspector must understand the relationship between the retention/detention facility and the treatment system by evaluating _A site specific civil engineering plans,or contacting the engineer of record, and make adjustments to the below guidance as necessary. Sediment a deposition depths and patterns within the StormFilter are likely to be quite different compared to systems without upstream storage and therefore shouldn't be used exclusively to evaluate a need for maintenance. Inspection Procedures 1. Sediment loading on the vault floor. a. If >4" of accumulated sediment, maintenance is The primary goal of an inspection is to assess the condition of the required. cartridges relative to the level of visual sediment loading as it relates to decreased treatment capacity. It may be desirable to conduct this 2. Sediment loading on top of the cartridge. inspection during a storm to observe the relative flow through the a. If >1/4"of accumulation, maintenance is required. filter cartridges. If the submerged cartridges are severely plugged, then typically large amounts of sediments will be present and very 3. Submerged cartridges. little flow will be discharged from the drainage pipes. If this is the a. If >4" of static water above cartridge bottom for more case,then maintenance is warranted and the cartridges need to be than 24 hours after end of rain event, maintenance replaced. is required. (Catch basins have standing water in the Warning: In the case of a spill,the worker should abort cartridge bay.) inspection activities until the proper guidance is obtained. 4. Plugged media. Notify the local hazard control agency and Contech Engineered a.While not required in all cases, inspection of the media Solutions immediately. within the cartridge may provide valuable additional To conduct an inspection: information. Important: Inspection should be performed by a person who is b. If pore space between media granules is absent, familiar with the operation and configuration of the StormFilter maintenance is required. treatment unit and the unit's role, relative to detention or 5. Bypass condition. retention facilities onsite. a. If inspection is conducted during an average rain fall 1. If applicable, set up safety equipment to protect and notify event and StormFilter remains in bypass condition surrounding vehicle and pedestrian traffic. (water over the internal outlet baffle wall or submerged 2. Visually inspect the external condition of the unit and take notes cartridges), maintenance is required. concerning defects/problems. 6. Hazardous material release. 3. Open the access portals to the vault and allow the system vent. a. If hazardous material release(automotive fluids or other) 4. Without entering the vault,visually inspect the inside of the is reported, maintenance is required. unit, and note accumulations of liquids and solids. 7. Pronounced scum line. 5. Be sure to record the level of sediment build-up on the floor of the vault, in the forebay, and on top of the cartridges. If flow a. If pronounced scum line(say > 1/4"thick) is present is occurring, note the flow of water per drainage pipe. Record above top cap, maintenance is required. all observations. Digital pictures are valuable for historical documentation. 6. Close and fasten the access portals. 7. Remove safety equipment. 8. If appropriate, make notes about the local drainage area relative to ongoing construction, erosion problems, or high loading of other materials to the system. 9. Discuss conditions that suggest maintenance and make decision as to whether or not maintenance is needed. 3