Quantifying Rainfall-Derived Inflow from Private Foundation Drains in Sanitary Sewers: Case Study in London, Ontario, Canada
Publication: Journal of Hydrologic Engineering
Volume 24, Issue 9
Abstract
Rainfall-derived infiltration and inflow (RDII) is a major issue causing surcharge flows in many municipal sanitary sewer systems. This paper demonstrates a statistical method for characterizing the rainfall-derived inflow (RDI) originating from residential foundation drains (also referred to as weeping tiles), as well as the importance of having site-specific data. The results differentiating the contribution of RDI from residential weeping tiles (WT) to total RDII are demonstrated for a case study site in a residential subdivision in London, Ontario, Canada. This research used statistical linear regression analyses with bootstrapping methods to quantify the RDI and its flow duration. It was found that the RDI from WT contributed up to 85% of the total RDII in the sanitary sewer. By disconnecting WT at this site, the RDI generated as a result of rainfall events was reduced by a minimum of 78% in volume and 32% in flow duration. Thus, this paper presents a novel method to quantify RDI and its duration from statistical perspectives, which provides better supporting evidence and guidance for RDI projects.
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Acknowledgments
This research was funded by Natural Sciences and Engineering Research Council (NSERC) and the Institute for Catastrophic Loss Reduction (ICLR). The authors are grateful for the help and data provided by Mr. Marcy McKillop and the staff in the Engineering Department at the City of London, Ontario, Canada, as well as the many valuable comments from Dan Sandink of the ICLR. In this research, data were processed with R-studio using R-language and Microsoft Excel. Some statistical analyses results were also developed using Minitab18.
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Information & Authors
Information
Published In
Journal of Hydrologic Engineering
Volume 24 • Issue 9 • September 2019
Copyright
©2019 American Society of Civil Engineers.
History
Received: Jul 25, 2018
Accepted: Mar 14, 2019
Published online: Jun 27, 2019
Published in print: Sep 1, 2019
Discussion open until: Nov 27, 2019
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