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| Title | Lower Duwamish Waterway: Tracing Short-Term Movements of Suspended Sediment, Summary Report | |||
| Month-Year Published | September 2009 | |||
| Online Availability |
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| Short Description |
This field study involved the release and recovery of sediment tracer particles in the Lower Duwamish Waterway, a sediment cleanup site in Seattle. The tracers were labeled with both fluorescent and magnetic properties. In February 2009, the sand-sized and silt-sized tracers were released upstream of the cleanup site. During the two months following release, tracer particles were recovered from the water column and surface sediments. Samples were analyzed to determine mass of tracer particles present. Results generally supported two modeled predictions: (1) sand-sized particles accumulate in the site, and (2) approximately one-half of the silt-sized particles pass through the site. (Also see abstract below) | |||
| Publication Number | 09-03-048 | |||
| Author(s) | Sloan, J. and T. Gries | |||
| Print Availability | ||||
| Number of pages | 24 + attachments (194 total) | |||
| Keywords | Ecology, Green River , Lower Duwamish Waterway, model, river, suspended sediment, water, waterway | |||
| Subject Waterbodies |
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| Related Publications | Title | Relationship | ||
| Quality Assurance Project Plan: Loading of Contaminants to the Lower Duwamish Waterway from Suspended Sediments in the Green River | supporting publication | |||
| POSTER: Use of Fluorescent Tracer Particles in the Lower Duwamish Waterway | poster | |||
| Quality Assurance Project Plan: Tracking Short-Term Movements of Suspended Sediments in the Lower Duwamish Waterway. | supporting publication | |||
| POSTER: Sediment transport and contaminant loading to the Lower Duwamish Superfund Site from the Green River: Application of innovative sampling technologies to verify model predictions | related publication | |||
| Abstract | Long Description |
During 2009, the Washington State Department of Ecology (Ecology) conducted a field study at the Lower Duwamish Waterway (LDW) sediment cleanup site in Seattle. The study involved the release and recovery of sediment tracer particles having both fluorescent and magnetic properties. The main goal of this short-term study was to assess the movement and fate of incoming suspended sediments from the Green River. Ecology contracted with Partrac Ltd. to manufacture and analyze these tracer particles. This summary report describes the study methods, major findings, and recommendations presented in two attached Partrac Ltd. reports produced as a result of the field study: 1. Assessment of the Hydraulic Characteristics of Native Sediments (Lower Duwamish Waterway) and Tracer Design and Testing. 2. Tracking Short-Term Movements of Suspended Sediment in the Lower Duwamish Waterway. In February 2009, Ecology released sand-sized and silt-sized tracers upstream of the cleanup site. During the two months following release, tracer particles were recovered from the water column and surface sediments. Samples were analyzed to determine mass of tracer particles present. Overall, the manufactured tracers successfully mimicked native suspended sediments. Tracers were released with little difficulty and did not alter concentrations of total suspended solids in the Green River. Tracers were recovered in a variety of samples collected from the LDW over a two- month period. The distribution of the tracer types and their masses generally confirmed sediment transport model (STM) predictions: |
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