Event Title
Impacts of Combined Sewer Outflow Overflows on Dissolved Oxygen and Turbidity in Possession Sound
Streaming Media
Presentation Abstract
Combined sewer outflow (CSO) overflows are a threat to water quality, particularly in such urbanized areas as the Puget Sound. CSOs contribute to spills of untreated sewage mixed with storm water that wash into water systems during heavy rain events. Possession Sound, fed by the Snohomish River, has 13 CSO outfalls in Everett, Washington, some of which experience CSO events fairly regularly. Contaminants in these CSO overflows can release pathogens, solids, nutrients, toxins, and oxygen-consuming pollutants into the water. These variables can in turn affect DO (dissolved oxygen) and turbidity (measure of water clarity) – two important measures of water quality. This relationship, between turbidity, DO, and CSO overflows catalyzes this study. DO and turbidity data were collected from three CSO outfall areas in the Everett marina of Possession Sound during or shortly after CSO overflows and compared to these same outfall sites under normal conditions. In addition, DO and turbidity data were collected from a control site in Possession Sound away from these CSO-prone areas. Because of the oxygen-consuming pollutants released during CSO overflows, it was expected that DO levels would decrease while turbidity increased. The presence of nutrients may be beneficial to oxygen-producing phytoplankton. However, without much sunlight during fall and winter, there should not be much increase in primary production. These data were compared to non-CSO overflow prone areas which should have higher DO and lower turbidity. Knowing the consequences of CSO overflows on water quality in Possession Sound is key to understanding the human impact on this estuary. If such vital water parameters like DO are affected, there may be other areas of abiotic and biological life impacted in unforeseen ways.
Session Title
Poster Session 4: People Working Together to Protect the Salish Sea
Conference Track
SSE14: Posters
Conference Name
Salish Sea Ecosystem Conference (2022 : Online)
Document Type
Event
SSEC Identifier
SSE-posters-64
Start Date
27-4-2022 4:30 PM
End Date
27-4-2022 5:00 PM
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
Impacts of Combined Sewer Outflow Overflows on Dissolved Oxygen and Turbidity in Possession Sound
Combined sewer outflow (CSO) overflows are a threat to water quality, particularly in such urbanized areas as the Puget Sound. CSOs contribute to spills of untreated sewage mixed with storm water that wash into water systems during heavy rain events. Possession Sound, fed by the Snohomish River, has 13 CSO outfalls in Everett, Washington, some of which experience CSO events fairly regularly. Contaminants in these CSO overflows can release pathogens, solids, nutrients, toxins, and oxygen-consuming pollutants into the water. These variables can in turn affect DO (dissolved oxygen) and turbidity (measure of water clarity) – two important measures of water quality. This relationship, between turbidity, DO, and CSO overflows catalyzes this study. DO and turbidity data were collected from three CSO outfall areas in the Everett marina of Possession Sound during or shortly after CSO overflows and compared to these same outfall sites under normal conditions. In addition, DO and turbidity data were collected from a control site in Possession Sound away from these CSO-prone areas. Because of the oxygen-consuming pollutants released during CSO overflows, it was expected that DO levels would decrease while turbidity increased. The presence of nutrients may be beneficial to oxygen-producing phytoplankton. However, without much sunlight during fall and winter, there should not be much increase in primary production. These data were compared to non-CSO overflow prone areas which should have higher DO and lower turbidity. Knowing the consequences of CSO overflows on water quality in Possession Sound is key to understanding the human impact on this estuary. If such vital water parameters like DO are affected, there may be other areas of abiotic and biological life impacted in unforeseen ways.
