Instream Attenuation of Nitrogen and Phosphorus in the Puget Sound Basin
Presentation Abstract
Delivery of nutrients from major rivers in the Puget Sound basin to the marine environment can be large. Therefore, it is important to understand how nutrients are retained, or attenuated, within streams and rivers in the Puget Sound basin. Using a review of the scientific literature and multiple empirical modeling approaches for estimating nutrient attenuation in streams and rivers we estimated potential instream nutrient attenuation for the major river basins in Puget Sound. Instream nutrient attenuation was explained in terms of four primary factors: sinuosity, channel slope, specific discharge, and uptake velocity (vf) of the reach. A scoring procedure based on these factors showed that reaches where attenuation scores were high, we saw higher relative attenuation of nutrients. From a management perspective, preservation and improvement of instream nutrient attenuation should focus on two goals, (1) increasing the travel time through a reach and contact time of water sediment (reactive) surfaces and (2) lowering nutrient concentrations (and loads) to avoid saturation of instream attenuation. These goals can be reached by (1) maintaining and restoring channel-floodplain connectivity, (2) maintaining and restoring healthy riparian zones along streams, (3) managing point and nonpoint nutrient loads to streams and rivers, and (4) restoration of channel features such as woody debris and maintaining pool-riffle morphologies. Fortunately, many of these management approaches are already being undertaken during projects aimed to restore quality salmon habitat. Therefore we believe there is a dual benefit to these projects that may also lead to enhanced potential for nitrogen and phosphorus attenuation.
Session Title
General Pollution Topics
Conference Track
Fate and Effects of Pollutants
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Start Date
2016 12:00 AM
End Date
2016 12:00 AM
Location
2016SSEC
Type of Presentation
Poster
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)
Nutrient pollution of water--Washington (State)--Puget Sound; Aquatic habitats--Washington (State)--Puget Sound--Management; Stream ecology
Geographic Coverage
Salish Sea (B.C. and 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
Instream Attenuation of Nitrogen and Phosphorus in the Puget Sound Basin
2016SSEC
Delivery of nutrients from major rivers in the Puget Sound basin to the marine environment can be large. Therefore, it is important to understand how nutrients are retained, or attenuated, within streams and rivers in the Puget Sound basin. Using a review of the scientific literature and multiple empirical modeling approaches for estimating nutrient attenuation in streams and rivers we estimated potential instream nutrient attenuation for the major river basins in Puget Sound. Instream nutrient attenuation was explained in terms of four primary factors: sinuosity, channel slope, specific discharge, and uptake velocity (vf) of the reach. A scoring procedure based on these factors showed that reaches where attenuation scores were high, we saw higher relative attenuation of nutrients. From a management perspective, preservation and improvement of instream nutrient attenuation should focus on two goals, (1) increasing the travel time through a reach and contact time of water sediment (reactive) surfaces and (2) lowering nutrient concentrations (and loads) to avoid saturation of instream attenuation. These goals can be reached by (1) maintaining and restoring channel-floodplain connectivity, (2) maintaining and restoring healthy riparian zones along streams, (3) managing point and nonpoint nutrient loads to streams and rivers, and (4) restoration of channel features such as woody debris and maintaining pool-riffle morphologies. Fortunately, many of these management approaches are already being undertaken during projects aimed to restore quality salmon habitat. Therefore we believe there is a dual benefit to these projects that may also lead to enhanced potential for nitrogen and phosphorus attenuation.
