Operation and Maintenance Considerations for Green Infrastructure
On this page:
- Design with Maintenance in Mind
- Plan for Maintenance
- Dedicated Funding
- Operation and Maintenance Education and Training
- Green Infrastructure Equipment Needs
- Maintenance Resources
All stormwater management systems, whether gray or green, require maintenance. Appropriate operation and maintenance activities ensure that green infrastructure will continue to function properly and yield expected water quality and environmental benefits, protect public safety, meet legal standards, and protect communities’ financial investment.
To maximize the environmental benefits and reduce the cost of green infrastructure projects over the long-term, green infrastructure projects should be designed with maintenance in mind. For green infrastructure projects to properly capture and infiltrate stormwater and perform as expected, there are several factors to consider before project implementation.
- Type of maintenance to be performed
- Frequency of maintenance and available personnel to perform maintenance
- Cost of component replacement (e.g., plants, shrubs, permeable pavement)
- Sufficient and dedicated funds to cover operation and maintenance activities, including cost of replacement components
Maintenance plans and strategies will vary depending on the green infrastructure project. Proper maintenance is essential to maximizing the environmental, social, and economic benefits of green infrastructure, as well as ensuring that projects perform as expected. Establishing written plans and procedures ensure proper long-term maintenance and are critical components to the success of any green infrastructure project. Below are ways to ensure that green infrastructure is maintained over the long-term.
- Identify Staff Resources for Inspection and Maintenance - A municipality needs to determine if green infrastructure inspections and maintenance can be accomplished with existing staff, if additional staff needs to be hired, if specialized training is needed, or if it would be more cost effective to hire an experienced contractor. Consider which municipal departments have the equipment and skill sets to inspect and maintain green infrastructure, such as parks or public works. Training may be needed for both municipal staff and contractors who perform inspections and maintenance.
- Identify Maintenance Triggers - It is important to identify common problems that require non-routine maintenance to aid inspectors in the field. Such maintenance triggers include excess sediment accumulation, trash and debris, overgrown vegetation, dead or diseased vegetation, signs of erosion, structural damage, or standing water present more than 72 hours after a rain storm.
- Update Standard Operating Procedures - If municipalities have standard operating procedures for routine landscape and infrastructure maintenance, they should be updated to incorporate green infrastructure maintenance triggers and remedial actions. Additionally, if contractors are used to maintain practices, include specific language in contracts that require training of maintenance crews. Maintenance schedules should be set for each type of practice, and a tracking system should be in place to ensure that maintenance is performed as prescribed.
- Secure Funding for Maintenance - As with all infrastructure, expenses for green infrastructure maintenance are ongoing. Sources of funding typically pursued for green infrastructure projects, such as state and federal grants and loans, cannot be used for ongoing maintenance. Local funding sources such as tax revenue or utility fees can provide a stable source of funding for maintenance of green infrastructure practices.
- Enlist the Help of Volunteers - Some routine maintenance, such as removing trash and weeds from bioretention areas, can be accomplished by partnering with neighborhood organizations, greenway groups, or garden clubs to leverage their funds/volunteers.
- Procure Equipment - Municipalities should also consider the equipment needed to maintain green infrastructure and determine if additional equipment is needed. Most of the necessary equipment is typical of general landscape maintenance, as shown below. Note that heavy equipment is discouraged for routine maintenance, because it can cause soil compaction, which reduces the effectiveness of the practices.
The establishment of a dedicated source of funding that will allow for a budget capable of covering the costs associated with maintenance, staff, equipment, and the repair and replacement of green infrastructure components helps ensure the continued success of an O&M program. Although there are a number of grant and loan options for planning, designing and implementing green infrastructure, those funding sources generally do not pay for the operations and maintenance of green infrastructure systems.
To cover the costs of operation and maintenance, some communities have established user fees for stormwater infrastructure (e.g., stormwater utility fee), similar to those for traditional wastewater infrastructure (i.e., sanitary sewer fee). In communities that do not have a stormwater utility, options for covering the cost of green infrastructure operation and maintenance include the use of municipal or district funds, the establishment of landowner fee assessments, and partnerships.
Education and training are an essential part of operation and maintenance. Many green infrastructure projects are often implemented by local governments, private landowners, and nonprofit organizations, and may rely on private residents or volunteers to conduct project maintenance. In these cases, many of the individuals may not have experience performing the maintenance activities required for the project to function optimally. To prevent this from causing problems, successful projects not only have an operation and maintenance plan in place, but have also conducted public education efforts, outreach campaigns, and training programs.
Effective operation and maintenance training should be provided in an easy-to-understand format, occur at regular intervals, and target the activities employees, residents, or volunteers are expected to perform. Education and training can also provide information on the water quality and environmental benefits that green infrastructure can yield when properly maintained.
Routine maintenance on vegetated green infrastructure practices is largely similar to general landscape maintenance: removing trash, leaf litter, and debris; keeping plants healthy; and cleaning out accumulated sediment and pollutants. Regular inspections will indicate if the practices are not functioning as intended.
- Leaf litter, trash, debris, and sediment can be removed with rakes, shovels, and trash grabbers.
- Flat-blade shovels are especially useful for scraping accumulated sediment from inlets and along curbs/gutters.
- Vegetation can be kept healthy and attractive using pruning shears and weed pullers, and mowers can be used to maintain turf grass at an appropriate height.
- Watering during the plant establishment period and in extended droughts can be done with a hose, irrigation system, or tree watering bags.
- A ladder is needed for inspecting roof drains that connect to rainwater harvesting systems.
- Permeable pavement is best maintained using a vacuum-powered street sweeper, and replacement pavers are sometimes needed for repairs.
- Heavy equipment, such as backhoes and front-end loaders, may be needed infrequently if the facilities need to be replaced or if large amounts of sediment have accumulated.
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- The University of New Hampshire Stormwater Center created Maintenance Guidelines and Checklists Exit for pervious pavements, subsurface gravel wetlands, and bioretention and tree box systems.
- Field Guide: Maintaining Rain Gardens, Swales, and Stormwater Planters (PDF)(40 pp, 8 MB) Exit hosted by the Oregon State University Extension Service was developed by numerous practitioners to assist contractors and maintenance staff.
- Staying Green: Strategies to Improve Operations and Maintenance of Green Infrastructure in the Chesapeake Bay Watershed (PDF)(62 pp, 3.89 MB) Exit published by American Rivers and Green for All discusses how operation and maintenance occupations are being recognized as important on-ramps to career pathways in the water sustainability field.
- EPA’s The Importance of Operation and Maintenance for the Long-Term Success of Green Infrastructure (PDF)(53 pp, 2.54 MB) provides an overview of O&M practices and highlights both the opportunities and challenges associated with green infrastructure O&M. It documents lessons learned from the green infrastructure projects funded by the CWSRF under the American Recovery and Reinvestment Act.
- The City of Philadelphia Green City, Clean Waters Green Infrastructure Maintenance Manual (PDF)(140 pp, 45 MB) Exit provides an overview of the typical maintenance tasks associated with green infrastructure projects, in addition to standard operating procedures for executing specific maintenance tasks such as vegetation, sediment, and trash removal.
- A Survey of Green Infrastructure Maintenance Programs in the United States (PDF)(21 pp, 698 K) Exit conducted by the Yale School of Forestry and Environmental Studies surveyed eight of the cities in the United States that are leading the trend of GI implementation about the current state of each city’s GI maintenance program.