Sediment Laboratories

GMA operates two in-house Sediment Laboratories, specializing in detection and analysis of fine and coarse sediment concentrations and particle size distributions. Each lab is fully equipped for high-volume, rapid analysis. Both GMA Laboratories are inspected and approved by the USGS. The fine sediment lab has participated in the USGS Sediment Laboratory Quality Assurance Program (USGS SLQA) since 2001. Laboratory results from GMA Water Quality Lab's are acceptable for publication by the USGS. GMA has analyzed sediment samples for a wide variety of clients including Federal, State, Tribal, County, and Private entities.

GMA Laboratory sample results are entered into the WISKI Water Quality Module (WQM). WQM is a fully integrated WISKI Module, which allows seamless transfer to data into the WISKI hydrologic workbench to timeseries and hydrographic analyses.

Fine Sediment Laboratory

  • Suspended sediment concentration, sand/fine split, and particle size distribution analysis (>0.063mm, wet sieve), using ASTM Method D3977-97;
  • Turbidity, consistent with EPA Method 180.1;
  • Two USGS Quality Assurance Reviews.

Coarse Sediment Laboratory

  • Bedload and Bulk sample analysis over a full range of sediment particle sizes (0.063mm-256mm);
  • Rigorous QA/QC procedures and sample tracking;
  • One USGS Quality Assurance Review