2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/24/2021 | 2:00 PM - 3:30 PM | The impact of sewage leak subsidies on baseflow diel nitrate fluctuations in in Pittsburgh’s Nine Mile Run | Virtual Platform
The impact of sewage leak subsidies on baseflow diel nitrate fluctuations in in Pittsburgh’s Nine Mile Run
Sanitary sewer pipe networks, which broadly cover the urban are often cited as an important source of non-point source nutrient pollution to urban streams (Kaushal et al 2011, Divers et al 2014). However, uncertainties remain in terms of how and when these pipes leak, and how this contamination is transported to nearby waterways in low flow conditions. In this study, we pair in-situ sensor measurements with nitrate isotope analyses to understand the transformation and transportation mechanisms controlling sewer leak emergence in a highly impacted urban stream. We collected high-resolution (15-minute) measurements of nitrate, dissolved oxygen concentrations, and discharge. These measurements were coupled with water samples collected hourly for nitrate isotope analysis during low-flow periods in April, July, and November 2020. We observe decreasing concentrations of organic nitrogen throughout the day, midafternoon peaks in dissolved oxygen, nitrate, and nitrite concentrations when the water table is at its lowest, and afternoon enrichment of nitrate isotopes in stream water as concentration increases. Together, these results suggest that pulses of oxygenation due to decreased water table stimulate nitrification in near-pipe soil with subsequent nitrite and nitrate transport to the stream in late afternoon.
- Connectivity
- Biogeochemistry
- Anthropogenic
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Presenters/Authors
Rebecca Forgrave
(), University of Pittsburgh, ref61@pitt.edu;
ASHA DISCLOSURE:
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Emily Elliott
(), University of Pittsburgh, eelliott@pitt.edu;
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