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==Maintenance Training Documents and Videos== | ==Maintenance Training Documents and Videos== | ||
− | *[https://chesapeakestormwater.net/ | + | *[https://chesapeakestormwater.net/wp-content/uploads/2022/07/3768-7.pdf Chesapeake Stormwater Network TECHNICAL BULLETIN No. 10]. Bioretention Illustrated: A Visual Guide for Constructing, Inspecting, Maintaining and Verifying the Bioretention Practice |
− | *[https:// | + | *[https://stormwater.wef.org/event/trust-verify-getting-ready-new-era-urban-bmp-verification-chesapeake-bay/ Archived webcast from Chesapeake Stormwater Network] - TRUST BUT VERIFY: Urban BMP Verification in the Chesapeake Bay |
− | *[https://chesapeakestormwater.net/ | + | *[https://chesapeakestormwater.net/resource/bioretention-maintenance-in-the-trenches/ Archived webcast from Chesapeake Stormwater Network] - Bioretention Maintenance: In the Trenches |
*[https://www.youtube.com/watch?v=nK4x1rtyMds MSD Rain Garden and Planter Box Maintenance video] | *[https://www.youtube.com/watch?v=nK4x1rtyMds MSD Rain Garden and Planter Box Maintenance video] | ||
*[https://www.riversmarthomes.org/video-series DOEE RiverSmart Rain Garden Maintenance video] | *[https://www.riversmarthomes.org/video-series DOEE RiverSmart Rain Garden Maintenance video] | ||
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**[https://stormwater.pca.state.mn.us/index.php?title=File:Infiltration_trench_basin_operation_maintenance_checklist.xlsx Infiltration trench basin operation maintenance checklist] ([https://stormwater.pca.state.mn.us/index.php?title=Infiltration_trench/basin_%E2%80%93_operation_and_maintenance_checklist link to table]) | **[https://stormwater.pca.state.mn.us/index.php?title=File:Infiltration_trench_basin_operation_maintenance_checklist.xlsx Infiltration trench basin operation maintenance checklist] ([https://stormwater.pca.state.mn.us/index.php?title=Infiltration_trench/basin_%E2%80%93_operation_and_maintenance_checklist link to table]) | ||
*O&M example report | *O&M example report | ||
− | **[https://portal.laserfiche.com/Portal/DocView.aspx?id=3361965&repo=r-a96260ce MSD Example] | + | **[https://portal.laserfiche.com/Portal/DocView.aspx?id=3361965&repo=r-a96260ce MSD Example] (Download the page as it may not be visible on your screen) |
*Maintenance Agreements | *Maintenance Agreements | ||
**[https://stormwater.pca.state.mn.us/index.php?title=Example_Maintenance_Agreement_1 Example Maintenance Agreement 1] | **[https://stormwater.pca.state.mn.us/index.php?title=Example_Maintenance_Agreement_1 Example Maintenance Agreement 1] | ||
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*[[Supplemental guidance - operation and maintenance of rainwater harvesting]] | *[[Supplemental guidance - operation and maintenance of rainwater harvesting]] | ||
− | [[Category: | + | [[Category:Level 3 - Best management practices/Structural practices/Bioretention]] |
+ | [[Category:Level 3 - Best management practices/Specifications and details/Operation and maintenance]] | ||
</noinclude> | </noinclude> |
This page provides guidance for operation and maintenance (O&M) of bioretention and other stormwater infiltration practices, including above- and below-ground infiltration practices. This includes biofiltration, bioinfiltration, infiltration trenches, and infiltration basins.
Supplemental information can be found on the page called Operation and maintenance of bioretention and other stormwater infiltration practices - supplemental information. Supplemental information includes the following.
Bioretention practices and other stormwater infiltration practices (e.g. rain gardens, infiltration trenches) are vegetated landscape practices that capture, filter, and infiltrate stormwater runoff. In addition, these practices can provide ecosystem services such as nutrient cycling and storage, carbon sequestration, reduction in heat island effect, climate adaptation, and habitat for bees, butterflies, and other insects and small animals, including pollinators. Bioretention and other infiltration practices may be subject to high public visibility, greater trash loads, pedestrian traffic, vandalism, and vehicular loads, particularly in urban areas.
These practices require dedicated and regular maintenance to ensure proper and long-lasting operation and ecosystem benefits. Estimated bioretention lifespans range from 10 to 40 years (Drescher, 2012). The most frequently cited O&M concerns for infiltration practices include the following.
The sections below describe best practices to prevent or minimize these common problems.
Designers should design bioretention and infiltration practices in ways that prevent or minimize O&M issues. Examples include the following.
Designers should consult and include any local requirements regarding green infrastructure. O&M considerations often depend on whether the practice is located on public land, private land, or in the public right of way. For example, plantings in the public right of way that conflict with any traffic safety considerations could require increased O&M, such as pruning or complete removal.
Designers should also recognize the need to perform frequent landscaping maintenance to remove trash, check for clogging, and maintain vigorous and healthy vegetation. Designers can incorporate design solutions to facilitate maintenance activities. Examples include
The designer should also provide a site-specific O&M plan that includes
Example O&M plans are provided below.
For more design information and criteria for individual infiltration practices, see the Design criteria for bioretention or Design criteria for infiltration practices pages.
Proper construction methods and sequencing play a significant role in reducing O&M problems. Some key items during the construction phase include the following.
For information on construction specifications, see the links below.
Effective short and long-term operation of bioretention and infiltration practices requires dedicated and routine maintenance. Proper maintenance will not only increase the expected lifespan of the facility but will improve ecological function, aesthetics, and property value. Important post-construction considerations are provided below.
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:
|
Common problems and how to troubleshoot them for bioretention and infiltration practices
Link to this table
Symptom | Possible causes | Solution |
---|---|---|
Standing water within the infiltration area for more than 48 hours | The surface of the ponding area may become clogged with fine sediment over time. This might be because the pretreatment is no longer working, or there are excessive sediment loads due to erosion or high sediment loads from the contributing area. |
|
Rainwater does not appear to flow to the infiltration area | Leaves, sediment, trash, or plant debris may be blocking the flow path. | Remove these materials on a regular basis |
Vegetation is not able to establish | Plant selection is inappropriate for the site | Consult with a landscaper or horticulturist. Check that plants are suited to the local conditions. Make sure BMP is protected from snow storage or salt application. |
Erosion or scouring around the inlet | Flow is obstructed by debris or improper grading | Correct for drainage and flow path issues to make sure flows are evenly distributed. Make sure the flow paths are unobstructed. |
Maintenance costs will vary with a number of factors, including but not limited to
Preventative maintenance is key to minimizing major costs associated with repairs. A general rule of thumb to estimate maintenance costs is 3%-6% of the installation costs, but can run higher. Maintenance may be higher the first few years, while plants are being established. Maintenance costs should account for the number of hours of labor, the cost for different types of labor expertise required, and any equipment needed to successfully complete the maintenance activities.
A study published in 2017 by the American Society of Civil Engineers (ASCE) shows the median annual maintenance cost of bioretention devices was estimated at $0.687/sq ft with lower and higher costs of $0.13/sq ft and $2.30/sq ft, respectively. The survey also provides average annual reported maintenance costs, which range from $250 to $3880 with a median of $850 (Clary, 2017).
Supplemental information can be found on the page called Operation and maintenance of bioretention and other stormwater infiltration practices - supplemental information. Supplemental information includes the following.
MPCA has compiled publicly available O&M resources related to green infrastructure. This non-exhaustive catalog is intended as a resource to practitioners.
Supplemental guidance
This page was last edited on 31 January 2023, at 22:25.