Utilizing Sediment Tracer Studies to Evaluate Transport Pathways at the Mouth of the Columbia River, Usa

Abstract

During 2006 to 2009, two sediment tracer studies were implemented at the mouth of the Columbia River (MCR) to improve our understanding of littoral sediment transport pathways along the ocean margins of the inlet. Science-based data from these tracer studies is being integrated with other analysis methods to evaluate if dredged material can be preferentially placed within the coastal near shore to augment the sediment budget of the inlet and adjacent coastal margin. This paper summarizes the MCR tracer study methodology and results, with specific emphasis of how the general limitations for tracer studies were addressed and overcome. Results from these studies conclusively show that tracer particles released along the coastal margin of the MCR (at water depth of 13-14 meters) were transported into the active littoral zone of Oregon and Washington, with tracer deposition occurring on beaches. The results indicate that the sand-sized sediment at MCR is dispersed differently along the northern side of the inlet as compared to the southern side. Report Documentation Page Form Approved OMB No. 0704-0188Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES in ABSTRACT During 2006 to 2009, two sediment tracer studies were implemented at the mouth of the Columbia River (MCR) to improve our understanding of littoral sediment transport pathways along the ocean margins of the inlet. Science-based data from these tracer studies is being integrated with other analysis methods to evaluate if dredged material can be preferentially placed within the coastal near shore to augment the sediment budget of the inlet and adjacent coastal margin. This paper summarizes the MCR tracer study methodology and results, with specific emphasis of how the general limitations for tracer studies were addressed and overcome. Results from these studies conclusively show that tracer particles released along the coastal margin of the MCR (at water depth of 13-14 meters) were transported into the active littoral zone of Oregon and Washington, with tracer deposition occurring on beaches. The results indicate that the sand-sized sediment at MCR is dispersed differently along the northern side of the inlet as compared to the southern side. 15. SUBJECT TERMS 16. SECURITY CLASSIFICA...

Metrics of Success for Nearshore Nourishment Projects Constructed with Dredged Sediment

“…Sediment tracers or geo-tracers are another way to determine if the sediment is moving and where it is going. Sediment tracer studies have been done at nearshore nourishment projects in Brunswick, GA (Smith et al 2007), MCR (Moritz et al 2011), Coos Bay, OR (Li et al 2018), and South Padre Island, TX (Figlus et al 2021). Sediment tracer studies are expensive but are good at defining qualitative transport pathways and rates.…”

Is Rhodamine a good tracer to predict coal transport in water?

“…Liquid tracers have been used to identify sediment transport mechanisms at river mouths (Moritz et al, 2011), estuaries (Royal Haskoning, 2016a and open coasts (Royal Haskoning, 2016b), or to understand the fate of dredging material deposition (Smith et al, 2007;Vroom et al, 2017). Although rhodamine has been used under the Winckler, P., Molteni, F., Reyes, M., Gubler, A., Sandoval, J. and Aleixo, R. (2021).…”

Strategic placement for beneficial use of dredged material

“…The Mouth of the Columbia River (MCR) (Oregon-Washington border) is one of the most energetic coastal inlets in the world. Longshore transport rates near the MCR are millions of cubic yards per year (Moritz et al 2011). Shoreline recession and increased nearshore water depths (morphology recession) are occurring at several locations both north and south of the inlet (Byrnes and Li 1998;Gelfenbaum et al 1999).…”