On 23-dec-03, at 21:00, Don Johnson wrote:
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Anyone on the list know of a reference relating
nephelometric turbidity units to distance of
visibility in inches?
Mm, the nephelometer is a device quantifying scattering of light from suspended particulate material in water. Relationships exist between the reading of a nephelometer and the total suspended solids (usually measured by filtering and weighing). Although the Secchi disk is advertised as a cheaper and easier, and somewhat less accurate alternative to the nephelometer to assess turbidity, I haven't found any correlation between nephelometer readings and Secchi depth.
The following web sites give useful background info: http://lakeaccess.org/russ/turbidity.htm http://mddnr.chesapeakebay.net/eyesonthebay/whatsitmean.cfm http://www.iisgcp.org/wic/secchi.htm
this site suggests that no direct relationship between the two may exist:
http://everglades.fiu.edu/taskforce/precursor/chapter6.html
although this one offers some relationship; not sure how universal it is:
http://www.nwqmc.org/NWQMC-Proceedings/Papers- Alphabetical%20by%20First%20Name/David%20Smith2.pdf
enjoy
henk
==========================Heisenberg was right!======================== | Dr. Henk J.M. Verhaar | | | Environmental Fate and Ecotoxicology Specialist | | Fly Tier | | | Stichts End 17 | e-mail: [EMAIL PROTECTED] | | NL-1244 PK Ankeveen | phone: +31 35 656 2128 | | the Netherlands | ICQ: 15727113 | ==========================Uncertainty happens!=========================
