Salmon Forever has demonstrated that turbidity/suspended sediment monitoring in the sediment-impaired watersheds of Humboldt Bay and Eel River provides a reasonable, accurate, and reliable method for determining whether the Basin Plan Objectives for water quality are being attained. Salmon Forever began water quality monitoring in 1997 with assistance from members of the Trees Foundation (see www.salmon-forever.org).

Turbidity/suspended sediment monitoring has become an indispensable tool to characterize attainment of Water Quality standards for domestic uses and fish habitat in both pristine and impaired watersheds. Figure 1 is a comparison (courtesy of Randy Klein, hydrologist) depicting the durations of chronic turbidity impairment in a variety of streams in Redwood National Park (Prairie Creek and Little Lost Man Creek) and Pacific Lumber timberlands (Freshwater Creek and North Fork Elk River) managed for timber harvest under the HCP/SYP. Chronic turbidity over 25 NTUs has been shown by scientific studies to interfere with the breeding success, survival, feeding, and growth of salmonids, while sub-lethal and lethal effects result from progressively higher turbidities.

Figure 1

This Hydrologic Year (HY 2003), community volunteers and Humboldt State University Work Study students collected over 2000 turbidity/suspended sediment samples from numerous local monitoring sites, which were processed at our Sunny Brae Sediment Lab. Volunteers and students also participated in taking channel measurements, stream discharge measurements, installing automated monitoring equipment, and entering data for analysis.

Automated continuous turbidity monitoring stations similar to the one Salmon Forever has operated in Freshwater Creek since HY1998, have been constructed and have been collecting samples this year in North and South Forks of Elk River during HY 2003. The continuous monitoring stations collect data at ten-minute intervals throughout the year: as many as 40,000 measurements are now collected each year. Salmon Forever hopes to gain funding for dedicated telephone lines to each station such that the data can be made instantaneously available to the National Weather Service, Water Quality Control Board, scientific researchers, and the interested public.

Salmon Forever is participating in Regional Water Quality Control Board's TMDL (Total Maximum Daily Loads) process, which recently began in Elk River and Freshwater Creek. Salmon Forever turbidity monitoring protocols and data will assist in determining causes and remediation for these sediment-impaired watersheds, and have been utilized in the work of Water Quality's Scientific Review Panel which is laying the groundwork for the TMDL efforts.

Clean water is a requirement for proper ecologic function of riparian corridors and healthy native salmon fisheries, and turbidity monitoring indicates that reestablishment of a sustainable "older-growth" timber industry would greatly enhance the quality of life and long-term economic outlook for Northern California riverine resources.


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