Overview and schedule of general maintenance activities for bioretention and infiltration practices Overview and schedule of general maintenance activities for bioretention and infiltration practices

Overview and schedule of general maintenance activities for bioretention and infiltration practices.
Link to this table

First Year of Operation
Activity	Frequency	Time period	Level of effort	O&M benefita
Check that there is no ponding in the pretreatment device and/or in the main treatment area.	At least twice after storm events > 0.5 inches	Within the first 6 months	< 1 hour	1
Check for evidence of clogging in the pretreatment device and/or in the main treatment area.	At least twice after storm events > 0.5 inches	Within the first 6 months	< 1 hour	1
Check for evidence of clogging or failing of the inlet, outlet, and bypass pipes.	At least twice after storm events > 0.5 inches	Within the first 6 months	< 1 hour	1
Remove any stormwater diversion or barriers once seedlings are established.	Once	When plants are sufficiently established	1-2 hours	1,2,3,4,5
Supplemental watering during drier periods, particularly if keeping stormwater offline until plant seedlings are established.	1/week initially	During first 2 months	1-2 hours	2,3,4,5,6
	As needed	First growing season	1-2 hours	2,3,4,5,6
Remove and replace dead plants	As needed	First growing season	2-4 hours	2,3,4,5,6
Spot reseeding of bare patches and eroding areas	As needed	First growing season	2-4 hours	1,2,3,4,5,6
After First Year of Operation
Activity	Frequency	Time period	Level of effort	O&M benefita
Check that there is no ponding in the pretreatment device and/or in the main treatment area	Semi-annually	48 hours after a rain event and when ground is not frozen. Note that deep sumps can have ponding	1-2	1
Check for evidence of clogging in the pretreatment device, the inlets/outlets/bypass pipes, and in the main treatment area. Look for evidence of short circuiting or low spots that cause flow path issues.	Semi-annually	n spring and fall	1-2	1
Supplemental watering	As needed during extended dry periods	During dry periods	1-2 hours	2,3,4,5,6
Remove trash and debris from the pretreatment device and/or in the main treatment area.	Monthly during rainy season	All year long. Cleaning may need to be done more frequently during the summer storm season and less during the drier winter season	1-2 hours	1,5
Inspect for and remove excess sediment in the pretreatment device and/or in the main treatment area.	Monthly	All year long	4 hours if removal is needed	1
Check and repair eroded areas	Annually	In fall or spring when vegetation has died down	4 hours if repair is needed	1,2,3,4,5
Mow grass filter strips and bioretention turf cover	Seasonally, but outside of the main pollinator or wildlife nesting season	During growing season	1-2 hours	2,3,4,5
Weed and remove invasive plants	Twice during growing season	During growing season	1-2 hours	2,3,4,5
Inspect plant composition and health and replace as needed	Annually	In fall or spring	4 hours if plant replacement is needed	2,3,4,5,6
Prune trees and shrubs	Annually	In fall or spring	2-4 hours	2,3,4,5
Inspect for and repair broken inlets or pipes	As needed	Any time	2 hours, more if repairs are needed	1
Renew mulchb	As needed	In fall or spring	1-2 hours	4,5
Spring cleanup (cut back and remove last year’s material)	Annually	In spring	2-4 hours	2,3,4,5
Fall cleanup (removed excessive leaf litter, particularly in areas with lots of trees)	Annually	In fall	2-4 hours	2,3,4,5
After 5+ Years of Operation (non-routine maintenance)
Activity	Frequency	Time period	Level of effort	O&M benefita
After long term operation of the practice, some occasional and infrequent maintenance activities might be required, such as bigger repairs, soil regeneration, or redesign of key elements of the practice.	As neede	As needed	Could be significant depending on the activity	1,2,3,4,5,6
aKey to Maintenance Benefits: Proper stormwater flow and infiltration Creation and maintenance of wildlife habitat Creation and maintenance of pollinator habitat Nutrient cycling and storage Aesthetics and public enjoyment Carbon sequestration bNote that many practitioners are minimizing the use of mulch or using alternatives to mulch to control weeds. Using mulch can cause clogging of inlet, outlet, and bypass pipes, and can introduce invasive species such as jump worms. Alternatives to mulch include ground vegetation such as clover or sedges, or arranging plantings in more dense configurations so as to minimize use of mulch.