Identifying Key Factors for Implementation and Maintenance of Green Stormwater Infrastructure

Construction and maintenance can have major implications on the long-term functioning of green stormwater infrastructure (GSI) facilities. The GSI facilities investigated were bioretention, permeable pavement, sand filters, infiltration trenches, and vegetated swales. This study first highlights the most important construction and maintenance items based on relevant studies and state stormwater manuals from the United States. Fairfax County, Virginia, was used as a case study to evaluate the County's current stormwater program and illuminate common maintenance issues found for each GSI type. The data analysis showed that deficiencies found can vary between public and private facilities, depending most likely on site conditions and frequency of routine maintenance. Sediment accumulation was found to be the most common maintenance issue (27.8% of inspections), supporting the importance of adequate pretreatment and good housekeeping when implementing GSI. Current postconstruction inspections performed by the County were found to be failing to detect inadequacies in bioretention facilities due to improper construction. It is recommended that municipal separate storm sewer systems (MS4s) thoroughly record and track construction and postconstruction inspection items to improve the longevity of its facilities and better inform future decision making regarding GSI.