Overview and schedule of general maintenance activities for swales
Link to this table

First Year of Operation
Activity Frequency Time Period Level of Effort O&M Benefit1
Check that there is no ponding 48 hours after event All year long 1 hour 1
Inspect entire BMP after rainfall After any event greater than 0.5” All year long (or during area’s rain season) 2-4 hours 1
Correct earthwork if inlet scouring or unwanted flow paths develop As needed All year long >4 hours 1
Spot reseed bare patches and eroding areas As needed First growing season 2-4 hours 3,4,5
Supplemental watering during drier periods, particularly if keeping stormwater offline until plant seedlings are established. As needed Dry periods 1-2 hours 3,4,5
Remove any stormwater diversion or barriers once seedlings are established. Once When plants are sufficiently established 1-2 hours 1,2,3,4,5
Inspect and remove invasive plants and weeds during plant community establishment Monthly First growing season 1-2 hours 5,6
Mowing (dry swales) side slopes and/or grass filter strip to maintain 4-12” of height Seasonally As needed (do not interrupt any vegetative establishment) 2-4 hours 1
After First Year of Operation
Activity Frequency Time Period Level of Effort O&M Benefit1
Check that there is no ponding 48 hours after event All year long 1 hour 1
Inspect inlet/outlet structures for structural damage and clogging. Annually All year long 1-2 hours 1
Correct earthwork if inlet scouring or unwanted flow paths develop As needed All year long >4 hours 1
Mowing (dry swales) side slopes and/or grass filter to maintain 4-12” of height Seasonally All year long 2-4 hours 1
Inspect for trash and debris Seasonally All year long 2-4 hours 1,5
Check for evidence of clogging in the pre-treatment device and/or in the main treatment area. Biannually In spring and fall 1-2 hours 1
Inspect and remove excess sediment in the pre-treatment device and/or in the main treatment area. Annually In spring (post- snowmelt) and fall 4 hours if removal is needed 1
Inspect plant composition and health and replace as needed (maintain >95% vegetative cover) Biannually In fall or spring 4 hours if plant replacement is needed 4,5
Prune and weed to maintain appearance and proper vegetative cover As needed Growing season 1-2 hours 4,5,6,
After 5+ Years of Operation (non-routine maintenance)
Activity Frequency Time Period Level of Effort per Visit O&M Benefit1
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 needed As needed Could be significant depending on the activity 1,2,3,4,5,6
1Key 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

This page was last edited on 3 August 2022, at 15:36.