Date on Master's Thesis/Doctoral Dissertation

12-2014

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Civil and Environmental Engineering

Committee Chair

Rockaway, Thomas

Committee Co-Chair (if applicable)

Mohsen, J. P.

Committee Member

McGinley, Mark

Committee Member

Biles, William

Subject

Urban runoff--Management--Kentucky--Louisville; Pavements, Porous; Sustainable engineering--Kentucky--Louisville

Abstract

The Louisville and Jefferson County Metropolitan Sewer District (MSD) has developed a Long-Term Control Plan (LTCP) to address the combined sewer overflow (CSO) issue through a combination of gray and green infrastructure (GI) stormwater management practices in the city of Louisville. In support of this effort, the MSD installed a series of GI stormwater control measures (SCMs) to abate the CSO volumes in an urban sewershed basin. This research is focused on monitoring and evaluating the individual hydrological performance, which included infiltration and exfiltration processes, of two permeable pavement systems over a two year study period. It also assess the combined effectiveness of the suite of GI SCMs in achieving the CSO mitigation. Assessing the hydrological performance of the permeable pavement systems was completed through collected data from embedded electronic sensors and field measurements. Modeling techniques were employed to predict the changes of water level within the storage layer under pavement sections. The developed model was used as an assessment tool to monitor the hydrological performance of the two GI controls. Ultimately the results from the developed model and other data analysis techniques were used to track changes in infiltration and exfiltration performances of both permeable pavement systems. The infiltration performance was observed to be a key component affecting the hydrological performance of a permeable pavement system. The infiltration capacity is limited by clogging formed on the surface of the permeable pavement section but can be restored after applying a suitable maintenance treatment. The modeling effort also provided understanding of the exfiltration processes as the GI controls transferred the captured stormwater runoff to underlying and surrounding soil layers. Seasonal changes in system performance were observed and attributed to changes in dynamic viscosity of water caused by variation of temperature. It was also observed that exfiltration performance is affected by infiltration capacity of the system. To assess the effectiveness of the GI controls in achieving the CSO mitigation, a regression analysis modelling effort was conducted to compare the pre and post-construction conditions. The results showed that almost 2.6 million gallons of overflow volumes were eliminated from the combined sewer system during the second half of 2013 and following the construction of all GI stormwater controls.

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