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:

  1. Proper stormwater flow and infiltration
  2. Creation and maintenance of wildlife habitat
  3. Creation and maintenance of pollinator habitat
  4. Nutrient cycling and storage
  5. Aesthetics and public enjoyment
  6. 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.

This page was last edited on 2 August 2021, at 16:21.

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