2000 TOWER ST INDEX HALL 2023-12-29

Table V-A.6: Maintenance Standards - Debris Barriers (e.g., Trash Racks) — Maintenance Components D Condition When Maintenance is Needed Results hen Maintenance is Performed General Trash and Debris Trash ordebns ing more than 20%of the openi mer. Bamercleared to design flow capacity. Bars are txml out of shape mom than Bars in place with no bends mom than 3/4 inch. Damai Missing Bars. Bars are missi mermissing. Bars in place according to design. Metal m are loose and and is causing 50% deterioration to any part of barrier. Barrier fired to design standards. Tim utlet Pipe Debts banner missing or not attached to pipe Banierfinnly attached to pipe — Table V-A.7: Maintenance Standards - Energy Dissipators Maintenance Com- Defect Conditions When Maintenance Is Needed Results Expected When Maintenance is ponents Performed External: Missing or Moved Rack Only one layerof rock exists above native soil in area five squarefeet or larger, "any exposure of native soil. Rack pad replaced to design standards. Rock Pad Erasion Soil erosion in oracl acerb to rock pad. Rack pad replaced to design standards. Pipe Plugged with Sediment Accumulated sediment that exceeds 20% of the design depth. Pipe cleaned/flushed so that it matches design. Not Discharging Water Properly Visual evidence of water discharging at concentrated points along March (normal condition is a'sheet low" of water along trench). Trench redesignetl or rebuilt to standards. Intent is to prevent erosion damage. Dispersion Trench Performers Plugged. Over 112 of perforations in pipe are plugged with debris and sediment. Perforated pipe cleaned or replaced. Water Flows Out Top of MistiibutoP Maintenance person observes or receives credible report of water lowing out during any stone less than the design slam or its causing Facility mouth or redesigned to standards. Catch Basin. or appears likely to cause damage. Receiving Area OverSaurafed Water in receiving area is causing or has potential of causing landslide problems. No danger of landslides. Internal: Wan a Damaged Post, Baffles, Side Structure dissipating flow deteriorates to l@ of original size or my concentrated wan spot exceeding one square foot which would Structure replaced to design standards. ManholdChamber of Chamber make structure unsound. Other Defects See Table V-A.5: Maintenance Standards - Catch Basins See Table V-A.5:Maintenance Standards - Catch Basins — Table V-A.8: Maintenance Standards -Typical BioRltration Swale — Maintenance Defect or Peals— Maintenance is Neetletl Recommended Malntenanceb Co Component lam SedimentAcou- wesediment deposits an grass free athe bio-swale. When finished, swale should be level from side to side and drain freely mutation on Sediment depth exceeds 2 inches. towardoutl areas of standing water once inflow has ceased. Grass General Standing Water When water stands in the swale between storms an Any of the following may apply: remove seiimenfor ,improve gradefmm head to feel of swale, remove clogged check dams, drain freely. add underdmins orconved to a wet biofillrah nswats. Flow spreader Flow never orclogged so that fiaws are not uniformly Ii the spreaderand clean so that flows are spread evenly overentire swale width. distributed through entireswalewidth. 2019 Sformwafer Management Manual for Western Washington Volume V-AppendixA-Page 1010