Anthropogenic Dissolved Oxygen Depletions in Budd Inlet
Presentation Abstract
Portions of Budd Inlet do not meet the water quality standards and are on the Clean Water Act Section 303(d) list for dissolved oxygen (DO). The project involved data collection to characterize the sources and processes relevant to the impairments as well as development of a calibrated computer model to predict observed circulation, and water quality characteristics. Major processes included in the model were dissolved oxygen depletions due to eventual decay of algal blooms (previously mediated by anthropogenic nutrient loading), and steady state oxygen depletion in the sediment. Dissolved oxygen concentrations under natural conditions were predicted using the calibrated computer model. Finally, predicted dissolved oxygen concentrations under existing and future conditions were compared with State’s numeric dissolved oxygen standard and natural conditions to assess temporal and spatial violations of the standard. The combined effects of nonpoint and point sources currently exceed the pollutant loading capacity of Budd Inlet and Capitol Lake for nutrients. Pollutant load reductions are required to meet water quality standards for DO. Several scenarios of anthropogenic source reductions were evaluated including removal of Capitol Lake dam, advanced nitrogen removal at the smaller municipal wastewater treatment plants, relocation of LOTT outfall, and reductions in external anthropogenic nutrient loads north of Budd Inlet. There is a critical area in East Bay of Budd inlet where the magnitude of the dissolved oxygen violation is the largest. At this location the Capitol Lake dam cause a dissolved oxygen depletion of about 2 mg/l, where as the rest of the depletion (approximately 1 mg/L) is caused by the combined effect of anthropogenic nutrient loads from the open boundary (external sources) and local point and nonpoint sources.
Session Title
Session S-01A: Current Salish Sea Water Quality
Conference Track
Marine Water Quality
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
1-5-2014 5:00 PM
End Date
1-5-2014 6:30 PM
Location
Room 6C
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Water--Dissolved oxygen--Washington (State)--Puget Sound--Computer simulation; Water--Dissolved oxygen--Washington (State)--Budd Inlet--Computer simulation; Water--Dissolved oxygen--Washington (State)--Capitol Lake; Nutrient pollution of water--Washington (State)--Puget Sound--Computer simulation; Nutrient pollution of water--Washington (State)--Budd Inlet--Computer simulation; Nutrient pollution of water--Washington (State)--Capitol Lake--Computer simulation
Geographic Coverage
Salish Sea (B.C. and Wash.); Budd Inlet (Wash.); Capitol Lake (Wash.); Puget Sound (Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Anthropogenic Dissolved Oxygen Depletions in Budd Inlet
Room 6C
Portions of Budd Inlet do not meet the water quality standards and are on the Clean Water Act Section 303(d) list for dissolved oxygen (DO). The project involved data collection to characterize the sources and processes relevant to the impairments as well as development of a calibrated computer model to predict observed circulation, and water quality characteristics. Major processes included in the model were dissolved oxygen depletions due to eventual decay of algal blooms (previously mediated by anthropogenic nutrient loading), and steady state oxygen depletion in the sediment. Dissolved oxygen concentrations under natural conditions were predicted using the calibrated computer model. Finally, predicted dissolved oxygen concentrations under existing and future conditions were compared with State’s numeric dissolved oxygen standard and natural conditions to assess temporal and spatial violations of the standard. The combined effects of nonpoint and point sources currently exceed the pollutant loading capacity of Budd Inlet and Capitol Lake for nutrients. Pollutant load reductions are required to meet water quality standards for DO. Several scenarios of anthropogenic source reductions were evaluated including removal of Capitol Lake dam, advanced nitrogen removal at the smaller municipal wastewater treatment plants, relocation of LOTT outfall, and reductions in external anthropogenic nutrient loads north of Budd Inlet. There is a critical area in East Bay of Budd inlet where the magnitude of the dissolved oxygen violation is the largest. At this location the Capitol Lake dam cause a dissolved oxygen depletion of about 2 mg/l, where as the rest of the depletion (approximately 1 mg/L) is caused by the combined effect of anthropogenic nutrient loads from the open boundary (external sources) and local point and nonpoint sources.
