USDA Forest Service

Pacific Southwest Research Station


Pacific Southwest Research Station
800 Buchanan Street
Albany, CA 94710-0011

(510) 559-6300

United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Analysis of Particle Size Data

LTIMP SitesVery fine particles are a major cause of reduced clarity of Lake Tahoe. Consequently, measurements of particle size distributions (PSD) are exceptionally important in evaluating samples collected from the lake, streams, urban runoff, and the atmosphere. Researchers will develop recommendations for particle size analysis and reporting protocols, and they will create a database of available data.

Full title: Tahoe basin particle size analysis and protocol development

Lead Researchers: Alan Heyvaert, Desert Research Institute; S. Geoffrey Schladow, University of California, Davis; Todd Caldwell, Desert Research Institute


  1. Provide guidance for the standardized collection and reporting of all new PSD data by various groups.
  2. Create a uniform, consistent and inter-comparable database that includes all available data on particle size distribution and composition for Lake Tahoe, streams, urban runoff, and the atmosphere.

Sites: Lake Tahoe and streams monitored as part of Lake Tahoe Interagency Monitoring Program (LTIMP) (see Figure at right), stormwater sites monitored as part of the Tahoe total maximum daily load (TMDL).

Timeframe: October 2007 through December 2009 (2.2 years)

Expected date of final products: January 2011. Progress Report available for download


  1. Initial guidance on particle size data analysis and reporting.
  2. Data compilation of available particle size distribution analytic results.
  3. Summary report presenting preliminary assessment of particle size and composition data relevant to the Tahoe TMDL Water Clarity Model and to help achieve management objectives in best management practices evaluations and monitoring.
  4. Workshop and guidance on analytic methods and reporting protocols for particle size and composition data.
  5. Report on the results from interlaboratory comparison of methods and samples.
  6. Final report on recommended methods for particle size and composition analysis of different sample types and reporting protocols, along with a summary report of the available data analyzed by those methods.
Last Modified: Mar 28, 2013 02:52:07 PM