Most green infrastructure practices require some form of regular maintenance in order to continue to provide their many benefits. Here is a list of resources that can help you explore the maintenance requirements of green infrastructure.

American Rivers. Staying Green: Strategies to Improve Operations and Maintenance of Green Infrastructure in the Chesapeake Bay Watershed.
This report examines some of the major barriers to effective operations and maintenance of green infrastructure practices in the Chesapeake Bay region and identifies strategies and best practices that local governments, practitioners and other groups are using to develop and improve maintenance practices. 

Philadelphia Water Department, 2012. Green City, Clean Waters: Green Infrastructure Maintenance Manual Development Process Plan.
This plan outlines the process of developing a green infrastructure maintenance manual, including evaluating maintenance protocols, developing protocols, checklists and schedules; maintenance contract agreements; program evaluation; and budget development. 

Seattle Public Utilities, 2009. Green Stormwater Operations and Maintenance Manual.
This Seattle Public Utilities manual summarizes routine maintenance activities for the design of natural drainage system (NDS) projects and includes a chart for scheduling and performing maintenance activities and images and descriptions for vegetation, hardscape, infrastructure and infiltration rates. 

U.S. Environmental Protection Agency, 2013. The Importance of Operation and Maintenance for the Long-Term Success of Green Infrastructure.
This report examines the operation and maintenance practices of 22 green infrastructure projects and highlights opportunities and challenges associated with them. 

U.S. Environmental Protection Agency, 2015. Elements of a Green Infrastructure Maintenance Business Plan.
This U.S. EPA report reflects findings from the Milwaukee Metropolitan Sewerage District and local stakeholders regarding the suitability of different business models for conducting maintenance for developing a regional green infrastructure maintenance program.