Construction and maintenance can have huge implications on the long-term functioning of GSI facilities. 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. Fairfax County, VA was used as a case study to evaluate the County's current stormwater program and illuminate common maintenance issues found for each GSI type. Data analysis of 3141 inspection records illustrated particular deficiencies for each GSI type and that there are differences between public and private facilities, most likely depending 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. The Northern Virginia Soil and Water Conservation District (NVSWCD) performed a study surveying 63 public bioretention facilities in which they measured ponding depth, filter media depth, ponding area, and infiltration rates. The NVSWCD concluded that deficiencies found in facilities could mostly be attributed to inadequacies during construction. By comparing current post-construction inspections performed by the County to the NVSWCD data, it was found that these County inspections are failing to detect these inadequacies in bioretention facilities from improper construction. It is recommended that MS4s thoroughly record and track construction and post-construction inspection items to improve the longevity of its facilities and better inform future decision making regarding GSI. / Master of Science / Studies have shown that the proper construction and maintenance of green stormwater infrastructure (GSI) is a critical factor concerning its long-term performance; however, little research has been conducted on the necessary protocols and frequency to ensure its longevity. Many MS4s and stormwater managers are implementing these facilities without providing the adequate institutional framework to ensure the proper construction and maintenance. This study concentrates on illuminating the construction and maintenance factors critical for the performance of GSI. Facility types investigated were bioretention, permeable pavement, sand filters, infiltration trenches, and vegetated swales. The effects of local site-conditions and level of routine maintenance on frequency of facility deficiencies was quantified using 3141 records of maintenance and inspection data from Fairfax County, VA. Sediment and debris accumulation were found to be the most common deficiency highlighting the importance of good housekeeping and pretreatment devices. The Northern Virginia Soil and Water Conservation District (NVSWCD) performed a comprehensive review of 63 bioretention facilities in which they inspected elements considered critical to pollutant removal performance including ponding depth, filter media depth, and infiltration rates. By comparing the findings from the NVSWCD to current post-construction inspections performed by the County, it was found that current inspection protocols are missing important design components of bioretention facilities. This study also highlights the importance of thorough and thoughtful databases to track and record inspection and maintenance data surrounding GSI. The proper construction and maintenance of GSI is ultimately dependent on a multitude of factors including site-conditions, facility design specifications, and institutional support.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/83404 |
| Date | 25 May 2018 |
| Creators | Delgrosso, Zack Lee |
| Contributors | Civil and Environmental Engineering, Dymond, Randel L., Young, Kevin D., Hodges, Clayton Christopher |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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