Changes

*For BMPs with [[underdrains|sub-drains/underdrains]] and flow restrictors, [[Pretreatment|pretreatment devices]] that prevent floating trash and debris from entering the practice should be used to prevent obstruction of the sub-drain pipe/flow restrictor.

*For BMPs with [[underdrains|sub-drains/underdrains]] and flow restrictors, [[Pretreatment|pretreatment devices]] that prevent floating trash and debris from entering the practice should be used to prevent obstruction of the sub-drain pipe/flow restrictor.

*For BMPs equipped with [[pretreatment]] that detains floating contaminants (e.g., oil and grease, trash and debris), such as [[oil and grit separators|hydrodynamic separators/oil and grit separators]] or [[forebays]] with baffle walls, remove trash and debris first using a bucket strainer. Floating oils and grease should then be removed off the top of the water using a vacuum truck.

*For BMPs equipped with [[pretreatment]] that detains floating contaminants (e.g., oil and grease, trash and debris), such as [[oil and grit separators|hydrodynamic separators/oil and grit separators]] or [[forebays]] with baffle walls, remove trash and debris first using a bucket strainer. Floating oils and grease should then be removed off the top of the water using a vacuum truck.

*Provide a means of draining [[infiltration chambers]] by gravity (e.g., pipe and valve through the control structure weir wall) to make [[inspection and maintenance]] work that requires drainage of the BMP (e.g., filter bed and control structure inspection and sediment removal, repairs to control structure) easier to perform.

*Provide a means of draining [[infiltration chambers]] by gravity (e.g., pipe and valve through the control structure weir wall) to make [[inspections and maintenance]] work that requires drainage of the BMP (e.g., filter bed and control structure inspection and sediment removal, repairs to control structure) easier to perform.

*To remove accumulated sediment from [[underdrain]] pipes and chamber system units, a hydrovac truck equipped with a JetVac nozzle should be employed that uses pressured jets of water to propel itself through the structure while scouring and directing suspending sediments to a collection point. As the nozzle is retrieved, the sediment is flushed into the manhole or catchbasin sump for removal by vacuuming. Selecting an appropriate JetVac nozzle will depend on the structure being cleaned. For chamber system units, fixed nozzles designed for culverts or large diameter pipe cleaning with rear-facing jets are preferable (consult product manufacturer for further guidance).

*To remove accumulated sediment from [[underdrain]] pipes and chamber system units, a hydrovac truck equipped with a JetVac nozzle should be employed that uses pressured jets of water to propel itself through the structure while scouring and directing suspending sediments to a collection point. As the nozzle is retrieved, the sediment is flushed into the manhole or catchbasin sump for removal by vacuuming. Selecting an appropriate JetVac nozzle will depend on the structure being cleaned. For chamber system units, fixed nozzles designed for culverts or large diameter pipe cleaning with rear-facing jets are preferable (consult product manufacturer for further guidance).