Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

Timing, Transport, and Impacts of Sewer Subsidies to Pittsburgh’s Nine Mile Run

Forgrave, Rebecca (2022) Timing, Transport, and Impacts of Sewer Subsidies to Pittsburgh’s Nine Mile Run. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

[img]
Preview
PDF
Primary Text

Download (7MB) | Preview

Abstract

This dissertation examines the surface and subsurface connections between sewer pipes and buried streams in a small watershed in Pittsburgh, PA. Rainfall-runoff responses from high-frequency precipitation and discharge records reveal that extensive channel burial led to storm flows that were substantially faster than other urban watersheds of comparable size and imperviousness. Further, several events with anomalously high runoff ratios suggest the contributions of other water subsidies such as sewer overflows, hydrant flushing, and water line breaks to the event flows. These rapid storm responses led to dilution of nitrate and other chemical parameters in the stream water, but an increase in nitrate concentration after the event, suggesting contributions from combined and sanitary sewers filled beyond capacity and subsequent transport to the stream. Triple nitrate isotopes reveal that sewage is the dominant contributor to total nitrate loads in all storms. In low flow conditions between storm events, daily fluctuations in chemical concentrations are affected by the seasonal variation in groundwater elevation, which determines the extent of hydrologic connection between leaking sewer pipes and adjacent buried or surface stream channels. Higher groundwater in spring led to mixing of different end-member chemistries and lack of distinct diurnal patterns, while lower groundwater in fall limited subsurface connectivity. The findings from this dissertation highlight the limitations of end of pipe solutions such as stream restoration to the challenges created by buried streams and sewer infrastructure failures. The rapid event responses from stream burial and solute fluxes from sewer overflows could get worse as climate change predictions suggest an increase in high intensity storms.


Share

Citation/Export:
Social Networking:
Share |

Details

Item Type: University of Pittsburgh ETD
Status: Unpublished
Creators/Authors:
CreatorsEmailPitt UsernameORCID
Forgrave, Rebeccaref61@pitt.eduref61
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairElliott, Emilyeelliott@pit.edu
Committee MemberBain, Danieldbain@pitt.edu
Committee MemberWerne, Josefjwerne@pitt.edu
Committee MemberDuncan, Jonathanjxd523@psu.edu
Date: 3 April 2022
Date Type: Publication
Defense Date: 29 March 2022
Approval Date: 24 October 2024
Submission Date: 7 April 2022
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 152
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Environmental Science
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Urban streams, hydrology, biogoechemistry, sewer leaks, sewer overflows, Nine Mile Run
Related URLs:
Date Deposited: 24 Oct 2024 15:37
Last Modified: 24 Oct 2024 15:41
URI: http://d-scholarship.pitt.edu/id/eprint/42548

Metrics

Monthly Views for the past 3 years

Plum Analytics


Actions (login required)

View Item View Item